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Vol. 51 N° 39 - Octobre 2012 [texte imprimé] . - 2012 . - p. 12557-12992 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierIndustrial flare performance at low flow conditions. 1. / Vincent M. Torres in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012)
Titre : Industrial flare performance at low flow conditions. 1. : Study overview Type de document : texte imprimé Auteurs : Vincent M. Torres, Auteur ; Scott Herndon, Auteur ; Zach Kodesh, Auteur Année de publication : 2012 Article en page(s) : pp. 12559–12568 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Industrial flare Flow conditions Résumé : A series of full-scale industrial flare tests were conducted at low flow and low BTU content of flared gases at an industrial test facility. Both a 24” diameter air-assisted flare with a flow capacity of 144,000 lb/h and a 36” steam-assisted flare with a flow capacity of 937,000 lb/h were employed in the testing. Flared gases were mixtures of natural gas, propylene, and nitrogen or natural gas, propane, and nitrogen. Natural gas to propane or propylene ratio was 1:4 by volume for all experiments. Nitrogen was used as a diluent to achieve the desired lower heating values (LHV) for the vent gas. The range of flared gas flow rates was 0.1% to 0.65% of the flare’s design capacity. Flare operation was characterized by measurements of flow rates to the flare, extractive measurements made of the vent gases fed to the flare, extractive measurements made at the end of the flare plume, and remote sensing measurements of the flare plume made by a variety of spectroscopic instruments. Destruction/removal efficiencies (DRE, fraction of vent gas reacted) of flared species were calculated based on the observed composition of the species in the plume. The tests demonstrated that destruction efficiencies for steam-assisted flares drop dramatically when combustion zone heating values fall below 250 BTU/scf. Air-assisted flares showed a linear drop in DRE as a function of air flow. While the primary focus of the measurements was on DRE, products of incomplete combustion were also measured. Dominant products of incomplete combustion were CO, ethylene, formaldehyde, acetylene, and acetaldehyde. CO represented approximately 24% to 80% (carbon basis) of the total products of incomplete combustion for DRE > 90%. While DREs of 98–99% were observed in some experiments, many operating conditions produced DREs of substantially less than 99%. Since prescribed methods for estimating emissions would have predicted 98–99% DRE for all the tests, some test conditions resulted in the production of flare emissions multiple times the value that would be calculated using the prescribed estimation methods. In practice, total emissions from flares will depend on both operating conditions and the duration of operation at the various operating conditions. ISSN : 1385-8947 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202674t
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12559–12568[article] Industrial flare performance at low flow conditions. 1. : Study overview [texte imprimé] / Vincent M. Torres, Auteur ; Scott Herndon, Auteur ; Zach Kodesh, Auteur . - 2012 . - pp. 12559–12568.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12559–12568
Mots-clés : Industrial flare Flow conditions Résumé : A series of full-scale industrial flare tests were conducted at low flow and low BTU content of flared gases at an industrial test facility. Both a 24” diameter air-assisted flare with a flow capacity of 144,000 lb/h and a 36” steam-assisted flare with a flow capacity of 937,000 lb/h were employed in the testing. Flared gases were mixtures of natural gas, propylene, and nitrogen or natural gas, propane, and nitrogen. Natural gas to propane or propylene ratio was 1:4 by volume for all experiments. Nitrogen was used as a diluent to achieve the desired lower heating values (LHV) for the vent gas. The range of flared gas flow rates was 0.1% to 0.65% of the flare’s design capacity. Flare operation was characterized by measurements of flow rates to the flare, extractive measurements made of the vent gases fed to the flare, extractive measurements made at the end of the flare plume, and remote sensing measurements of the flare plume made by a variety of spectroscopic instruments. Destruction/removal efficiencies (DRE, fraction of vent gas reacted) of flared species were calculated based on the observed composition of the species in the plume. The tests demonstrated that destruction efficiencies for steam-assisted flares drop dramatically when combustion zone heating values fall below 250 BTU/scf. Air-assisted flares showed a linear drop in DRE as a function of air flow. While the primary focus of the measurements was on DRE, products of incomplete combustion were also measured. Dominant products of incomplete combustion were CO, ethylene, formaldehyde, acetylene, and acetaldehyde. CO represented approximately 24% to 80% (carbon basis) of the total products of incomplete combustion for DRE > 90%. While DREs of 98–99% were observed in some experiments, many operating conditions produced DREs of substantially less than 99%. Since prescribed methods for estimating emissions would have predicted 98–99% DRE for all the tests, some test conditions resulted in the production of flare emissions multiple times the value that would be calculated using the prescribed estimation methods. In practice, total emissions from flares will depend on both operating conditions and the duration of operation at the various operating conditions. ISSN : 1385-8947 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202674t Exemplaires
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Titre : Industrial flare performance at low flow conditions. 2. : Steam- and air-assisted flares Type de document : texte imprimé Auteurs : Vincent M. Torres, Auteur ; Scott Herndon, Auteur ; David T. Allen, Auteur Année de publication : 2012 Article en page(s) : pp. 12569–12576 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Industrial flare Steam Résumé : Full-scale tests of steam- and air-assisted industrial flares were conducted using low BTU content (lower heating value) vent gases at low flow rates. A 36″ diameter steam-assisted flare with a flow capacity of 937,000 lb/h and a 24″ diameter air-assisted flare with a flow capacity of 144,000 pounds per hour were operated with mixtures of natural gas, propylene, and nitrogen or natural gas, propane, and nitrogen at flow rates less than 1% of maximum flow. Combustion efficiency (percentage of the flared gases converted to carbon dioxide and water) ranged from less than 50% to more than 99%. For the steam-assisted flare, combustion efficiency (CE) at low steam-to-vent gas flow ratios (0.5–1.0) was typically in excess of 95%. CE would gradually decrease as steam-to-vent gas ratio increased, to a point, after which CE would decrease dramatically. The steam-to-vent gas ratio at which CE would decrease dramatically depended on the heating value of the vent gas and the position of the steam injection. Higher heating values of the vent gas (600 vs 350 BTU/scf) and the minimization of steam coinjected with the vent gas, rather than injected at the flare tip, promoted higher CE. For the air-assisted flare, CE at low air assist rates ( ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202675f
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12569–12576[article] Industrial flare performance at low flow conditions. 2. : Steam- and air-assisted flares [texte imprimé] / Vincent M. Torres, Auteur ; Scott Herndon, Auteur ; David T. Allen, Auteur . - 2012 . - pp. 12569–12576.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12569–12576
Mots-clés : Industrial flare Steam Résumé : Full-scale tests of steam- and air-assisted industrial flares were conducted using low BTU content (lower heating value) vent gases at low flow rates. A 36″ diameter steam-assisted flare with a flow capacity of 937,000 lb/h and a 24″ diameter air-assisted flare with a flow capacity of 144,000 pounds per hour were operated with mixtures of natural gas, propylene, and nitrogen or natural gas, propane, and nitrogen at flow rates less than 1% of maximum flow. Combustion efficiency (percentage of the flared gases converted to carbon dioxide and water) ranged from less than 50% to more than 99%. For the steam-assisted flare, combustion efficiency (CE) at low steam-to-vent gas flow ratios (0.5–1.0) was typically in excess of 95%. CE would gradually decrease as steam-to-vent gas ratio increased, to a point, after which CE would decrease dramatically. The steam-to-vent gas ratio at which CE would decrease dramatically depended on the heating value of the vent gas and the position of the steam injection. Higher heating values of the vent gas (600 vs 350 BTU/scf) and the minimization of steam coinjected with the vent gas, rather than injected at the flare tip, promoted higher CE. For the air-assisted flare, CE at low air assist rates ( ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202675f Exemplaires
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Titre : Application of the carbon balance method to flare emissions characteristics Type de document : texte imprimé Auteurs : Scott C. Herndon, Auteur ; David D. Nelson, Auteur ; Ezra C. Wood, Auteur Année de publication : 2012 Article en page(s) : pp. 12577-12585 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon balance Résumé : The destruction and removal efficiency (DRE) computation of target hydrocarbon species in the flaring process is derived using carbon balance methodologies. This analysis approach is applied to data acquired during the Texas Commission on Environmental Quality 2010 Flare Study. Example DRE calculations are described and discussed. Carbon balance is achieved to within 2% for the analysis of flare vent gases. Overall method uncertainty is evaluated and examined together with apparent variability in flare combustion performance. Using fast response direct sampling measurements to characterize flare combustion parameters is sufficiently accurate to produce performance curves on a large-scale industrial flare operating at low vent gas flow rates. En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419211
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12577-12585[article] Application of the carbon balance method to flare emissions characteristics [texte imprimé] / Scott C. Herndon, Auteur ; David D. Nelson, Auteur ; Ezra C. Wood, Auteur . - 2012 . - pp. 12577-12585.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12577-12585
Mots-clés : Carbon balance Résumé : The destruction and removal efficiency (DRE) computation of target hydrocarbon species in the flaring process is derived using carbon balance methodologies. This analysis approach is applied to data acquired during the Texas Commission on Environmental Quality 2010 Flare Study. Example DRE calculations are described and discussed. Carbon balance is achieved to within 2% for the analysis of flare vent gases. Overall method uncertainty is evaluated and examined together with apparent variability in flare combustion performance. Using fast response direct sampling measurements to characterize flare combustion parameters is sufficiently accurate to produce performance curves on a large-scale industrial flare operating at low vent gas flow rates. En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419211 Exemplaires
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Titre : Particulate emissions measured during the TCEQ comprehensive flare emission study Type de document : texte imprimé Auteurs : E. C. Fortner, Auteur ; W. A. Brooks, Auteur ; T. B. Onasch, Auteur Année de publication : 2012 Article en page(s) : pp. 12586-12592 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Particle properties Steam Résumé : During the 2010 TCEQ Comprehensive Flare Emission Study, a suite of instruments deployed on the Aerodyne Mobile Laboratory performed online measurements of fine particle properties. Steam and air-assisted flare emissions from propane and propene vent gases were measured. Black carbon (BC) mass was measured with a soot particle–aerosol mass spectrometer (SP-AMS) and a multi angle absorption photometer (MAAP). The SP-AMS obtained the mass of inorganic and organic species. A scanning mobility particle sizer (SMPS) measured particle number size distributions. Particulate matter (PM) flare emissions changed dramatically with variations in destruction removal efficiencies (DREs). BC was found to be removed at a higher DRE with steam assist (93%) relative to air assist where it remained above background levels through the lowest DRE tested (63%). Unique fullerene BC signatures and black carbon/organic carbon (BC/OC) ratios may be useful as tracers of propene flare ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202692y
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12586-12592[article] Particulate emissions measured during the TCEQ comprehensive flare emission study [texte imprimé] / E. C. Fortner, Auteur ; W. A. Brooks, Auteur ; T. B. Onasch, Auteur . - 2012 . - pp. 12586-12592.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12586-12592
Mots-clés : Particle properties Steam Résumé : During the 2010 TCEQ Comprehensive Flare Emission Study, a suite of instruments deployed on the Aerodyne Mobile Laboratory performed online measurements of fine particle properties. Steam and air-assisted flare emissions from propane and propene vent gases were measured. Black carbon (BC) mass was measured with a soot particle–aerosol mass spectrometer (SP-AMS) and a multi angle absorption photometer (MAAP). The SP-AMS obtained the mass of inorganic and organic species. A scanning mobility particle sizer (SMPS) measured particle number size distributions. Particulate matter (PM) flare emissions changed dramatically with variations in destruction removal efficiencies (DREs). BC was found to be removed at a higher DRE with steam assist (93%) relative to air assist where it remained above background levels through the lowest DRE tested (63%). Unique fullerene BC signatures and black carbon/organic carbon (BC/OC) ratios may be useful as tracers of propene flare ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202692y Exemplaires
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Titre : Impacts of emission variability and flare combustion efficiency on ozone formation in the houston–galveston–brazoria area Type de document : texte imprimé Auteurs : Radovan T. Pavlovic, Auteur ; Fahad M. Al Fadhli, Auteur ; Yosuke Kimura, Auteur Année de publication : 2012 Article en page(s) : pp. 12593-12599 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Pollutant formation Combustion Résumé : Recent studies in the Houston―Galveston―Brazoria (HGB) area of Texas have suggested that industrial flares exhibit high temporal emissions variability and that flare combustion efficiencies could vary with air and steam assist rates, particularly at lower flow rates, and when low heating value gases are combusted. This work examined the difference in ozone formation potential associated with accounting for temporal variability in flaring emissions, as opposed to assuming the same amount of mass was emitted at a constant, average flow rate. The temporal variability in flare emissions was found to lead to differences in ozone concentrations of as much as 27 ppb in the HGB area. This work also examined the potential ozone formation impacts of flare combustion efficiencies of less than 98―99%, applied to 25 flares throughout the HGB region. Deterioration in combustion efficiency (CE) was found to affect ozone concentrations by a few to more than 50 ppb, depending on the level of the assumed CE. While the ozone impacts associated with temporal variability in emissions typically lasted a few hours, consistent with the length of large flaring events, lowering of the CE significantly increased emissions and ozone concentrations over periods ranging from several hours to several days for some flare types. Thus, changes in CE may affect ozone concentrations for longer durations and over larger spatial extents than episodic emissions events. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419213
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12593-12599[article] Impacts of emission variability and flare combustion efficiency on ozone formation in the houston–galveston–brazoria area [texte imprimé] / Radovan T. Pavlovic, Auteur ; Fahad M. Al Fadhli, Auteur ; Yosuke Kimura, Auteur . - 2012 . - pp. 12593-12599.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12593-12599
Mots-clés : Pollutant formation Combustion Résumé : Recent studies in the Houston―Galveston―Brazoria (HGB) area of Texas have suggested that industrial flares exhibit high temporal emissions variability and that flare combustion efficiencies could vary with air and steam assist rates, particularly at lower flow rates, and when low heating value gases are combusted. This work examined the difference in ozone formation potential associated with accounting for temporal variability in flaring emissions, as opposed to assuming the same amount of mass was emitted at a constant, average flow rate. The temporal variability in flare emissions was found to lead to differences in ozone concentrations of as much as 27 ppb in the HGB area. This work also examined the potential ozone formation impacts of flare combustion efficiencies of less than 98―99%, applied to 25 flares throughout the HGB region. Deterioration in combustion efficiency (CE) was found to affect ozone concentrations by a few to more than 50 ppb, depending on the level of the assumed CE. While the ozone impacts associated with temporal variability in emissions typically lasted a few hours, consistent with the length of large flaring events, lowering of the CE significantly increased emissions and ozone concentrations over periods ranging from several hours to several days for some flare types. Thus, changes in CE may affect ozone concentrations for longer durations and over larger spatial extents than episodic emissions events. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419213 Exemplaires
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Titre : Emissions of nitrogen oxides from flares operating at low flow conditions Type de document : texte imprimé Auteurs : Vincent M. Torres, Auteur ; Scott Herndon, Auteur ; Ezra Wood, Auteur Année de publication : 2012 Article en page(s) : pp. 12600-12605 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nitrogen Oxides Résumé : Full scale flare tests have been conducted to test the impacts of flare operating conditions on the fraction of flared gases that are converted to carbon dioxide and water (combustion efficiency, CE) for flares combusting low heating value gases (350–600 BTU/scf) at low flow rates (0.1–0.25% of maximum flow). Flares produce lower flame temperatures when operating with low heating value gases at low combustion efficiencies than when operating with high heating value gases at high combustion efficiencies. This leads to reduced formation of nitrogen oxides (NOx) in the flame. For a series of tests conducted under low flow conditions, with low heating value gases, NOx emission factors ranged between 10 and 120% of the NOx emission factor reported in AP-42. Emissions of NOx were highest for air assisted flares operating at high CE and lowest for steam assisted flares operating at low CE. In general, emissions were lower in steam assisted flare tests than in air assisted flare tests conducted under similar conditions. Photochemical modeling simulations indicated that these reductions in NOx emissions had relatively small impacts on the ozone formation potential of flares operating at low CE. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300179x
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12600-12605[article] Emissions of nitrogen oxides from flares operating at low flow conditions [texte imprimé] / Vincent M. Torres, Auteur ; Scott Herndon, Auteur ; Ezra Wood, Auteur . - 2012 . - pp. 12600-12605.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12600-12605
Mots-clés : Nitrogen Oxides Résumé : Full scale flare tests have been conducted to test the impacts of flare operating conditions on the fraction of flared gases that are converted to carbon dioxide and water (combustion efficiency, CE) for flares combusting low heating value gases (350–600 BTU/scf) at low flow rates (0.1–0.25% of maximum flow). Flares produce lower flame temperatures when operating with low heating value gases at low combustion efficiencies than when operating with high heating value gases at high combustion efficiencies. This leads to reduced formation of nitrogen oxides (NOx) in the flame. For a series of tests conducted under low flow conditions, with low heating value gases, NOx emission factors ranged between 10 and 120% of the NOx emission factor reported in AP-42. Emissions of NOx were highest for air assisted flares operating at high CE and lowest for steam assisted flares operating at low CE. In general, emissions were lower in steam assisted flare tests than in air assisted flare tests conducted under similar conditions. Photochemical modeling simulations indicated that these reductions in NOx emissions had relatively small impacts on the ozone formation potential of flares operating at low CE. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300179x Exemplaires
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Titre : Impacts of air-assist flare blower configurations on flaring emissions Type de document : texte imprimé Auteurs : Fahad M. Al Fadhli, Auteur ; Vincent M. Torres, Auteur ; David T. Allen, Auteur Année de publication : 2012 Article en page(s) : pp. 12606-12610 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Air assist flare Résumé : Air-assisted flares, operating under low flow conditions ( ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3012209
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12606-12610[article] Impacts of air-assist flare blower configurations on flaring emissions [texte imprimé] / Fahad M. Al Fadhli, Auteur ; Vincent M. Torres, Auteur ; David T. Allen, Auteur . - 2012 . - pp. 12606-12610.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12606-12610
Mots-clés : Air assist flare Résumé : Air-assisted flares, operating under low flow conditions ( ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3012209 Exemplaires
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Titre : Computational fluid dynamics modeling of industrial flares operated in stand-by mode Type de document : texte imprimé Auteurs : Kanwar Devesh Singh, Auteur ; Tanaji Dabade, Auteur ; Hitesh Vaid, Auteur Année de publication : 2012 Article en page(s) : pp. 12611–12620 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Fluid dynamics modeling Résumé : Computational fluid dynamics (CFD) was applied to model industrial flares under low-Btu, low-flow rate conditions (stand-by mode). The modeled tests were conducted at the John Zink R&D facility in Tulsa, OK in September 2010, using propylene/Tulsa Natural Gas/nitrogen as vent gases under open-air conditions. This work focuses on CFD modeling using the EDC (Eddy Dissipation Concept) and PDF (Probability Density Function) models to predict the destruction and removal efficiency (DRE), combustion efficiency (CE), and speciated emissions with a reduced 50-species combustion mechanism. Generally, the EDC model underpredicts DRE/CE while the PDF model overpredicts DRE/CE, when compared with measurements. The sources of discrepancies and the challenges to the flare modeling in the stand-by mode are discussed. In view of the significant differences between the measured and modeled results, further investigations involving a better domain with a refined mesh, a different turbulence model, or a combination of EDC/PDF models are warranted. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300639f
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12611–12620[article] Computational fluid dynamics modeling of industrial flares operated in stand-by mode [texte imprimé] / Kanwar Devesh Singh, Auteur ; Tanaji Dabade, Auteur ; Hitesh Vaid, Auteur . - 2012 . - pp. 12611–12620.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12611–12620
Mots-clés : Fluid dynamics modeling Résumé : Computational fluid dynamics (CFD) was applied to model industrial flares under low-Btu, low-flow rate conditions (stand-by mode). The modeled tests were conducted at the John Zink R&D facility in Tulsa, OK in September 2010, using propylene/Tulsa Natural Gas/nitrogen as vent gases under open-air conditions. This work focuses on CFD modeling using the EDC (Eddy Dissipation Concept) and PDF (Probability Density Function) models to predict the destruction and removal efficiency (DRE), combustion efficiency (CE), and speciated emissions with a reduced 50-species combustion mechanism. Generally, the EDC model underpredicts DRE/CE while the PDF model overpredicts DRE/CE, when compared with measurements. The sources of discrepancies and the challenges to the flare modeling in the stand-by mode are discussed. In view of the significant differences between the measured and modeled results, further investigations involving a better domain with a refined mesh, a different turbulence model, or a combination of EDC/PDF models are warranted. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300639f Exemplaires
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Titre : Comparison of remote sensing and extractive sampling measurements of flare combustion efficiency Type de document : texte imprimé Auteurs : Joda Wormhoudt, Auteur ; Scott C. Herndon, Auteur ; Jon Franklin, Auteur Année de publication : 2012 Article en page(s) : pp. 12621–12629 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Flare combustion Résumé : The 2010 Comprehensive Flare Study provided the opportunity for the first blind validation of a remote sensing technique for flare combustion efficiency (CE) against extractive analysis techniques. The overall test results show that both remote sensing and extractive sampling accurately determined the flare performance curve. Both remote and extractive sampling techniques are challenged by the fluctuating and inhomogeneous nature of the flare exhaust plume. Accurate measurement of CE values near 100% is of interest to flare manufacturers, users, and regulators, while measurement of low CE flares is of interest in the development of other applications of combustion monitoring, and the 2010 tests provided information on both. In practice, accurate values of CE can be determined through the measurement of a small number of gaseous species, including fuel components and products of combustion. Nominal error bars generated from the fluctuations in these component measurements were adequate to account for most of the differences between the remote and extractive sampling CE measurements. The additional analysis reported here focused on individual species measurements and on cases where CE values measured by the two techniques differed by more than the nominal error estimates. In all cases, the key difference was the measurement of the main component of the fuel (in these tests, propene or propane). We discuss the challenges involved in these measurements. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202783m
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12621–12629[article] Comparison of remote sensing and extractive sampling measurements of flare combustion efficiency [texte imprimé] / Joda Wormhoudt, Auteur ; Scott C. Herndon, Auteur ; Jon Franklin, Auteur . - 2012 . - pp. 12621–12629.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12621–12629
Mots-clés : Flare combustion Résumé : The 2010 Comprehensive Flare Study provided the opportunity for the first blind validation of a remote sensing technique for flare combustion efficiency (CE) against extractive analysis techniques. The overall test results show that both remote sensing and extractive sampling accurately determined the flare performance curve. Both remote and extractive sampling techniques are challenged by the fluctuating and inhomogeneous nature of the flare exhaust plume. Accurate measurement of CE values near 100% is of interest to flare manufacturers, users, and regulators, while measurement of low CE flares is of interest in the development of other applications of combustion monitoring, and the 2010 tests provided information on both. In practice, accurate values of CE can be determined through the measurement of a small number of gaseous species, including fuel components and products of combustion. Nominal error bars generated from the fluctuations in these component measurements were adequate to account for most of the differences between the remote and extractive sampling CE measurements. The additional analysis reported here focused on individual species measurements and on cases where CE values measured by the two techniques differed by more than the nominal error estimates. In all cases, the key difference was the measurement of the main component of the fuel (in these tests, propene or propane). We discuss the challenges involved in these measurements. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202783m Exemplaires
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Titre : Minimize flaring through integration with fuel gas networks Type de document : texte imprimé Auteurs : Anoop Jagannath, Auteur ; M. M. Faruque Hasan, Auteur ; Fahad M. Al Fadhli, Auteur Année de publication : 2012 Article en page(s) : pp. 12630-12641 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Fuel gas Résumé : A fuel gas network (FGN) in a petrochemical complex can save energy costs substantially and reduce flaring by utilizing purge/waste fuel streams (Hasan et al. Ind. Eng. Chem. Res. 2011, 50, 7414―7427). A properly designed FGN can involve complex and nonintuitive mixing scenarios and equipment arrangements. Furthermore, the purge/waste gases and their characteristics can vary significantly with changing operation modes in a plant, which makes routing them into an FGN a challenge. This article reports a multiperiod two-stage stochastic programming model to design and operate an FGN that caters to all operating modes, and shows the usefulness of optimized FGN on a refinery case study. Results show that the proposed model produces a resilient FGN and reduces capital costs versus the single-mode model of (Hasan et aL Ind. Eng. Chem. Res. 2011, 50, 7414―7427). In addition, several strategies to minimize flaring and environmental penalties in a refinery operation are examined. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419218
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12630-12641[article] Minimize flaring through integration with fuel gas networks [texte imprimé] / Anoop Jagannath, Auteur ; M. M. Faruque Hasan, Auteur ; Fahad M. Al Fadhli, Auteur . - 2012 . - pp. 12630-12641.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12630-12641
Mots-clés : Fuel gas Résumé : A fuel gas network (FGN) in a petrochemical complex can save energy costs substantially and reduce flaring by utilizing purge/waste fuel streams (Hasan et al. Ind. Eng. Chem. Res. 2011, 50, 7414―7427). A properly designed FGN can involve complex and nonintuitive mixing scenarios and equipment arrangements. Furthermore, the purge/waste gases and their characteristics can vary significantly with changing operation modes in a plant, which makes routing them into an FGN a challenge. This article reports a multiperiod two-stage stochastic programming model to design and operate an FGN that caters to all operating modes, and shows the usefulness of optimized FGN on a refinery case study. Results show that the proposed model produces a resilient FGN and reduces capital costs versus the single-mode model of (Hasan et aL Ind. Eng. Chem. Res. 2011, 50, 7414―7427). In addition, several strategies to minimize flaring and environmental penalties in a refinery operation are examined. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419218 Exemplaires
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Titre : Multivariate image analysis (MIA) for industrial flare combustion control Type de document : texte imprimé Auteurs : David Castiñeira, Auteur ; Blake C. Rawlings, Auteur ; Thomas F. Edgar, Auteur Année de publication : 2012 Article en page(s) : pp. 12642-12652 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Combustion Image analysis Résumé : A new approach for flare monitoring is proposed so that flare combustion efficiency can be predicted online in industrial plants. Multivariate image analysis (MIA), which is based on principal component analysis (PCA) and projection to latent structures (PLS), has been applied to flare combustion systems in order to predict their resulting combustion efficiencies as a function of the crosswind velocity, using simulated results, and as a function of steam or air flow rates, using experimental tests of a full-size flare. The results show that a multivariate regression model based on flare color images can be used to predict the flare performance over a range of operating conditions for steam-assisted flares. Therefore, simple two-dimensional color images of industrial flares may be a fast, accurate, and inexpensive approach for online monitoring of these industrial combustion systems. This would allow for developing effective flare control and mitigation strategies. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419219
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12642-12652[article] Multivariate image analysis (MIA) for industrial flare combustion control [texte imprimé] / David Castiñeira, Auteur ; Blake C. Rawlings, Auteur ; Thomas F. Edgar, Auteur . - 2012 . - pp. 12642-12652.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12642-12652
Mots-clés : Combustion Image analysis Résumé : A new approach for flare monitoring is proposed so that flare combustion efficiency can be predicted online in industrial plants. Multivariate image analysis (MIA), which is based on principal component analysis (PCA) and projection to latent structures (PLS), has been applied to flare combustion systems in order to predict their resulting combustion efficiencies as a function of the crosswind velocity, using simulated results, and as a function of steam or air flow rates, using experimental tests of a full-size flare. The results show that a multivariate regression model based on flare color images can be used to predict the flare performance over a range of operating conditions for steam-assisted flares. Therefore, simple two-dimensional color images of industrial flares may be a fast, accurate, and inexpensive approach for online monitoring of these industrial combustion systems. This would allow for developing effective flare control and mitigation strategies. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419219 Exemplaires
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Titre : Temporal variability in flaring emissions in the houston–galveston area Type de document : texte imprimé Auteurs : Radovan T. Pavlovic, Auteur ; David T. Allen, Auteur ; Elena C. McDonald-Buller, Auteur Année de publication : 2012 Article en page(s) : pp. 12653–12662 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Industrial air pollutant emission Résumé : Recent studies performed in the Houston–Galveston–Brazoria (HGB) area indicate that some industrial air pollutant emission sources exhibit high temporal variability that can lead to very rapid ozone formation, especially when emissions include highly reactive volatile organic compounds. This motivated the collection of a unique data set of air pollutant emissions, from industrial facilities, reported with an hourly time resolution. The industrial flares portion of this data set was utilized in this work to characterize and model the highly variable temporal patterns of flare emissions at petrochemical facilities. Petrochemical and chemical manufacturing flares were grouped into categories based on industrial process they service, chemical composition of the flared gas, and the temporal patterns of their emissions. Stochastic models were developed for each categorization of flare emissions and provide representative temporal profiles for flares in specific types of operations in the petrochemical and chemical manufacturing sectors. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2013357
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12653–12662[article] Temporal variability in flaring emissions in the houston–galveston area [texte imprimé] / Radovan T. Pavlovic, Auteur ; David T. Allen, Auteur ; Elena C. McDonald-Buller, Auteur . - 2012 . - pp. 12653–12662.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12653–12662
Mots-clés : Industrial air pollutant emission Résumé : Recent studies performed in the Houston–Galveston–Brazoria (HGB) area indicate that some industrial air pollutant emission sources exhibit high temporal variability that can lead to very rapid ozone formation, especially when emissions include highly reactive volatile organic compounds. This motivated the collection of a unique data set of air pollutant emissions, from industrial facilities, reported with an hourly time resolution. The industrial flares portion of this data set was utilized in this work to characterize and model the highly variable temporal patterns of flare emissions at petrochemical facilities. Petrochemical and chemical manufacturing flares were grouped into categories based on industrial process they service, chemical composition of the flared gas, and the temporal patterns of their emissions. Stochastic models were developed for each categorization of flare emissions and provide representative temporal profiles for flares in specific types of operations in the petrochemical and chemical manufacturing sectors. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2013357 Exemplaires
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Titre : Impact of flare destruction efficiency and products of incomplete combustion on ozone formation in houston, texas Type de document : texte imprimé Auteurs : Fahad M. Al Fadhli, Auteur ; Yosuke Kimura, Auteur ; Elena C. McDonald-Buller, Auteur Année de publication : 2012 Article en page(s) : pp. 12663-12673 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Pollutant formation Combustion Résumé : The impact of flare destruction removal efficiency (DRE) and Products of Incomplete Combustion (PICs) on ozone formation was examined using a regional photochemical model. Emission scenarios for five industrial flares were considered. For each flare, four DRE values (95, 90, 75, and 50%) were assumed, along with a base case that assumed 98 or 99% DRE. For each DRE level, a scenario assuming that no PICs and a scenario assuming a level of PICs consistent with full scale flare tests was evaluated. Simulation results indicated that low DREs can increase ambient ozone concentrations by more than 15 ppb under some conditions, but under other conditions, may raise ozone concentrations by 1 ppb or less. Emission rates of unburned flare gases and the chemical reactivity of the unburned hydrocarbons explain much of the variability in ozone formation. The air quality simulations also showed that unburned flare gases can have a larger impact on ozone formation than PICs. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419221
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12663-12673[article] Impact of flare destruction efficiency and products of incomplete combustion on ozone formation in houston, texas [texte imprimé] / Fahad M. Al Fadhli, Auteur ; Yosuke Kimura, Auteur ; Elena C. McDonald-Buller, Auteur . - 2012 . - pp. 12663-12673.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12663-12673
Mots-clés : Pollutant formation Combustion Résumé : The impact of flare destruction removal efficiency (DRE) and Products of Incomplete Combustion (PICs) on ozone formation was examined using a regional photochemical model. Emission scenarios for five industrial flares were considered. For each flare, four DRE values (95, 90, 75, and 50%) were assumed, along with a base case that assumed 98 or 99% DRE. For each DRE level, a scenario assuming that no PICs and a scenario assuming a level of PICs consistent with full scale flare tests was evaluated. Simulation results indicated that low DREs can increase ambient ozone concentrations by more than 15 ppb under some conditions, but under other conditions, may raise ozone concentrations by 1 ppb or less. Emission rates of unburned flare gases and the chemical reactivity of the unburned hydrocarbons explain much of the variability in ozone formation. The air quality simulations also showed that unburned flare gases can have a larger impact on ozone formation than PICs. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419221 Exemplaires
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Titre : Direct measurement of volatile organic compound emissions from industrial flares using real-time online techniques : Proton transfer reaction mass spectrometry and tunable infrared laser differential absorption spectroscopy Type de document : texte imprimé Auteurs : W. Berk Knighton, Auteur ; Scott C. Herndon, Auteur ; Jon F. Franklin, Auteur Année de publication : 2012 Article en page(s) : pp. 12674-12684 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Laser Mass spectrometry Real time system Volatile organic compound Résumé : During the 2010 Comprehensive Flare Study a suite of analytical instrumentation was employed to monitor and quantify in real-time the volatile organic compound (VOC) emissions emanating from an industrial chemical process flare burning either propene/natural gas or propane/natural gas. To our knowledge this represents the first time the VOC composition has been directly measured as a function of flare efficiency on an operational full-scale flare. This compositional information was obtained using a suite of proton-transfer-reaction mass spectrometers (PTR-MS) and quantum cascade laser tunable infrared differential absorption spectrometers (QCL-TILDAS) to measure the unburned fuel and associated combustion byproducts. Methane, ethyne, ethene, and formaldehyde were measured using the QC-TLLDAS. Propene, acetaldehyde, methanol, benzene, acrolein, and the sum of the C3H6O isomers were measured with the PTR-MS. A second PTR-MS equipped with a gas chromatograph (GC) was operated in parallel and was used to verify the identity of the neutral components that were responsible for producing the ions monitored with the first PTR-MS. Additional components including 1,3-butadiene and C3H4 (propyne or allene) were identified using the GC/PTR-MS. The propene concentrations derived from the PTR-MS were found to agree with measurements made using a conventional GC with a flame ionization detector (FID). The VOC product (excludes fuel components) speciation profile is more dependent on fuel composition, propene versus propane, than on flare type, air-assisted versus steam-assisted, and is essentially constant with respect to combustion efficiency for combustion efficiencies >0.8. Propane flares produce more alkenes with ethene and propene accounting for approximately 80% (per carbon basis) of the VOC combustion product. The propene partial combustion product profile was observed to contain relatively more oxygenated material where formaldehyde and acetaldehyde are major contributors and account for ∼20 - 25% of VOC product carbon. Steam-assisted flares produce less ethyne and benzene than air-assisted flares. This observation is consistent with the understanding that steam assisted flares are more efficient at reducing soot, which is formed via the same reaction mechanisms that form benzene and ethyne. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419222
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12674-12684[article] Direct measurement of volatile organic compound emissions from industrial flares using real-time online techniques : Proton transfer reaction mass spectrometry and tunable infrared laser differential absorption spectroscopy [texte imprimé] / W. Berk Knighton, Auteur ; Scott C. Herndon, Auteur ; Jon F. Franklin, Auteur . - 2012 . - pp. 12674-12684.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12674-12684
Mots-clés : Laser Mass spectrometry Real time system Volatile organic compound Résumé : During the 2010 Comprehensive Flare Study a suite of analytical instrumentation was employed to monitor and quantify in real-time the volatile organic compound (VOC) emissions emanating from an industrial chemical process flare burning either propene/natural gas or propane/natural gas. To our knowledge this represents the first time the VOC composition has been directly measured as a function of flare efficiency on an operational full-scale flare. This compositional information was obtained using a suite of proton-transfer-reaction mass spectrometers (PTR-MS) and quantum cascade laser tunable infrared differential absorption spectrometers (QCL-TILDAS) to measure the unburned fuel and associated combustion byproducts. Methane, ethyne, ethene, and formaldehyde were measured using the QC-TLLDAS. Propene, acetaldehyde, methanol, benzene, acrolein, and the sum of the C3H6O isomers were measured with the PTR-MS. A second PTR-MS equipped with a gas chromatograph (GC) was operated in parallel and was used to verify the identity of the neutral components that were responsible for producing the ions monitored with the first PTR-MS. Additional components including 1,3-butadiene and C3H4 (propyne or allene) were identified using the GC/PTR-MS. The propene concentrations derived from the PTR-MS were found to agree with measurements made using a conventional GC with a flame ionization detector (FID). The VOC product (excludes fuel components) speciation profile is more dependent on fuel composition, propene versus propane, than on flare type, air-assisted versus steam-assisted, and is essentially constant with respect to combustion efficiency for combustion efficiencies >0.8. Propane flares produce more alkenes with ethene and propene accounting for approximately 80% (per carbon basis) of the VOC combustion product. The propene partial combustion product profile was observed to contain relatively more oxygenated material where formaldehyde and acetaldehyde are major contributors and account for ∼20 - 25% of VOC product carbon. Steam-assisted flares produce less ethyne and benzene than air-assisted flares. This observation is consistent with the understanding that steam assisted flares are more efficient at reducing soot, which is formed via the same reaction mechanisms that form benzene and ethyne. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419222 Exemplaires
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Titre : Combustion and destruction/removal efficiencies of In-use chemical flares in the greater houston area Type de document : texte imprimé Auteurs : Ezra C. Wood, Auteur ; Scott C. Herndon, Auteur ; Ed C. Fortner, Auteur Année de publication : 2012 Article en page(s) : pp. 12685-12696 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Combustion Résumé : Alkene emissions from the petrochemical industry contribute significantly to ozone production in the greater Houston area but are underestimated in emission inventories. It is not well-known which processes (e.g., fugitive emissions, chemical flare emissions, etc.) are responsible for these underreported emissions. We use fast time response and ground-based mobile measurements of numerous trace gas species to characterize alkene plumes from three identified chemical flares in the greater Houston area. We calculate the combustion efficiency and destruction and removal efficiency (DRE) values of these flares using the carbon balance method. All three flares were operating at DRE values lower than required by regulation. An examination of photochemistry in flare exhaust plumes indicates that the impact of direct formaldehyde emissions from flares on ozone formation is small as compared to the impact of alkene emissions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419223
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12685-12696[article] Combustion and destruction/removal efficiencies of In-use chemical flares in the greater houston area [texte imprimé] / Ezra C. Wood, Auteur ; Scott C. Herndon, Auteur ; Ed C. Fortner, Auteur . - 2012 . - pp. 12685-12696.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12685-12696
Mots-clés : Combustion Résumé : Alkene emissions from the petrochemical industry contribute significantly to ozone production in the greater Houston area but are underestimated in emission inventories. It is not well-known which processes (e.g., fugitive emissions, chemical flare emissions, etc.) are responsible for these underreported emissions. We use fast time response and ground-based mobile measurements of numerous trace gas species to characterize alkene plumes from three identified chemical flares in the greater Houston area. We calculate the combustion efficiency and destruction and removal efficiency (DRE) values of these flares using the carbon balance method. All three flares were operating at DRE values lower than required by regulation. An examination of photochemistry in flare exhaust plumes indicates that the impact of direct formaldehyde emissions from flares on ozone formation is small as compared to the impact of alkene emissions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419223 Exemplaires
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Titre : Optimal reduction of the C1–C3 combustion mechanism for the simulation of flaring Type de document : texte imprimé Auteurs : Helen H. Lou, Auteur ; Daniel Chen, Auteur ; Christopher B. Martin, Auteur Année de publication : 2012 Article en page(s) : pp. 12697–12705 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Combustion Résumé : Flaring is a combustion process designed to relieve pressures and safely dispose of vent gases from chemical and petrochemical plants. An industrial flaring activity typically involves various combustible waste gases and a large number of reactions and species. Because most of the detailed kinetic mechanisms for the speciation study of flaring events are too complicated to use in the computational fluid dynamics simulation of industrial-scale flares, several techniques for reduction of the detailed combustion mechanisms have been developed. In this paper, a new rigorous skeleton mechanism (RSM) based reduction technique, namely, the LU 2.0 algorithm, is proposed. It falls under the category of identification of redundancy. Other techniques in this category try to remove redundant species and reactions based on criteria such as sensitivity and quasi-steady-state analyses. These are highly dependent on the preanalysis of the mechanism and require species concentration sets for the conditions of interest. This algorithm tries to find out the skeleton mechanism with the lowest possible error. It works by rigorously testing all of the possible combinations of species sets. This RSM-based optimized mechanism was validated successfully against experimental data for various key performance indicators (laminar flame speeds, burner-stabilized flame, adiabatic flame temperature, and ignition delay) for methane, ethylene, and propylene flames. The efficacy of this algorithm was demonstrated by its improved predictability. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2027684
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12697–12705[article] Optimal reduction of the C1–C3 combustion mechanism for the simulation of flaring [texte imprimé] / Helen H. Lou, Auteur ; Daniel Chen, Auteur ; Christopher B. Martin, Auteur . - 2012 . - pp. 12697–12705.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12697–12705
Mots-clés : Combustion Résumé : Flaring is a combustion process designed to relieve pressures and safely dispose of vent gases from chemical and petrochemical plants. An industrial flaring activity typically involves various combustible waste gases and a large number of reactions and species. Because most of the detailed kinetic mechanisms for the speciation study of flaring events are too complicated to use in the computational fluid dynamics simulation of industrial-scale flares, several techniques for reduction of the detailed combustion mechanisms have been developed. In this paper, a new rigorous skeleton mechanism (RSM) based reduction technique, namely, the LU 2.0 algorithm, is proposed. It falls under the category of identification of redundancy. Other techniques in this category try to remove redundant species and reactions based on criteria such as sensitivity and quasi-steady-state analyses. These are highly dependent on the preanalysis of the mechanism and require species concentration sets for the conditions of interest. This algorithm tries to find out the skeleton mechanism with the lowest possible error. It works by rigorously testing all of the possible combinations of species sets. This RSM-based optimized mechanism was validated successfully against experimental data for various key performance indicators (laminar flame speeds, burner-stabilized flame, adiabatic flame temperature, and ignition delay) for methane, ethylene, and propylene flames. The efficacy of this algorithm was demonstrated by its improved predictability. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2027684 Exemplaires
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Titre : Detecting fugitive emissions of 1,3-butadiene and styrene from a petrochemical facility : An application of a mobile laboratory and a modified proton transfer reaction mass spectrometer Type de document : texte imprimé Auteurs : W. Berk Knighton, Auteur ; Scott C. Herndon, Auteur ; Ezra C. Wood, Auteur Année de publication : 2012 Article en page(s) : pp. 12706-12711 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Petrochemical industry Fugacity Résumé : The petrochemical industry is a major source of 1,3-butadiene and styrene emissions within the Houston-Galveston area. Both compounds are listed as hazardous air pollutants by the Environmental Protection Agency (EPA), and the Texas Commission on Environmental Quality (TCEQ) lists 1,3-butadiene as a highly reactive volatile organic compound. The Aerodyne Mobile Laboratory (AML) was deployed in 2009 as part of the Study of Houston Atmospheric Radical Precursor (SHARP) project to survey the petrochemical complexes in the Houston ship channel area for air toxics releases. This paper describes how the AML, equipped with a modified proton transfer reaction mass spectrometer configured to operate with NO+ as the reagent ion, was used to characterize and quantify fugitive emissions. On April 26, 2009, the AML surveyed the Goodyear Tire and Rubber and Texas Petrochemical (GY-TPC) complex by circumnavigating the facility on public roads while making continuous measurements. The extensive suite of trace gas instrumentation onboard the AML was used to identify fugitive emissions of 1,3-butadiene and styrene from the industrial complex and to distinguish them from any interfering mobile sources. The mobile lab detected significantly enhanced concentrations of 1,3-butadiene (30 ppbv max) and styrene (15 ppbv max). These results are examined with respect to the prevailing winds and routine ambient air monitoring data from TCEQ's Milby Park AutoGC, which is located adjacent to the GY-TPC complex. Simple Gaussian point source plume model calculations predict source emission rates that are consistent with reported emission inventories. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419225
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12706-12711[article] Detecting fugitive emissions of 1,3-butadiene and styrene from a petrochemical facility : An application of a mobile laboratory and a modified proton transfer reaction mass spectrometer [texte imprimé] / W. Berk Knighton, Auteur ; Scott C. Herndon, Auteur ; Ezra C. Wood, Auteur . - 2012 . - pp. 12706-12711.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12706-12711
Mots-clés : Petrochemical industry Fugacity Résumé : The petrochemical industry is a major source of 1,3-butadiene and styrene emissions within the Houston-Galveston area. Both compounds are listed as hazardous air pollutants by the Environmental Protection Agency (EPA), and the Texas Commission on Environmental Quality (TCEQ) lists 1,3-butadiene as a highly reactive volatile organic compound. The Aerodyne Mobile Laboratory (AML) was deployed in 2009 as part of the Study of Houston Atmospheric Radical Precursor (SHARP) project to survey the petrochemical complexes in the Houston ship channel area for air toxics releases. This paper describes how the AML, equipped with a modified proton transfer reaction mass spectrometer configured to operate with NO+ as the reagent ion, was used to characterize and quantify fugitive emissions. On April 26, 2009, the AML surveyed the Goodyear Tire and Rubber and Texas Petrochemical (GY-TPC) complex by circumnavigating the facility on public roads while making continuous measurements. The extensive suite of trace gas instrumentation onboard the AML was used to identify fugitive emissions of 1,3-butadiene and styrene from the industrial complex and to distinguish them from any interfering mobile sources. The mobile lab detected significantly enhanced concentrations of 1,3-butadiene (30 ppbv max) and styrene (15 ppbv max). These results are examined with respect to the prevailing winds and routine ambient air monitoring data from TCEQ's Milby Park AutoGC, which is located adjacent to the GY-TPC complex. Simple Gaussian point source plume model calculations predict source emission rates that are consistent with reported emission inventories. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419225 Exemplaires
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Titre : Treatment of spent pot-lining with aluminum anodizing wastewaters : Selective precipitation of aluminum and fluoride as an aluminum hydroxyfluoride hydrate product Type de document : texte imprimé Auteurs : Diego F. Lisbona, Auteur ; Christopher Somerfield, Auteur ; Karen M. Steel, Auteur Année de publication : 2012 Article en page(s) : pp 12712–12722 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Wastewaters Hydroxyfluoride Résumé : Wastewaters generated by the aluminum anodizing industry have been identified as a source of acid, Al3+, and caustic values that could be used for the treatment of spent pot-lining (SPL) generated in primary aluminum smelting. In this paper, recovery of aluminum and fluoride values as an aluminum fluoride product that could be converted into smelter grade (SG) AlF3 for recycling in aluminum smelting is reported. Experimental observations were contrasted with a thermodynamic model of the solution equilibria and new values for the solubility product of AlF2OH·1.4H2O, 10–15 at 30 °C and 10–23.8 at 50 °C, are reported. Neutralization of leachates obtained from SPL treatment with aluminum anodizing acid wastewaters was performed using 2 M NaOH and, alternatively, waste caustic solutions from the aluminum anodizing industry. pH-static precipitation with 2 M NaOH successfully recovered 92 wt % of the solubilized fluoride as AlF2OH·1.4H2O at pH 4.0 and 70 °C, although a hydrolyzed Na5Al3F14-like product (3–5 wt % Na) coprecipitated. Seeded heterogeneous nucleation of AlF2OH·1.4H2O on SG Al(OH)3 yielded a product that could be acceptable to AlF3 manufacturers, meeting specifications for particle size and phosphorus and silicon content. Caustic wastewaters from the aluminum anodizing industry were identified as suitable to provide the caustic values required for precipitation, providing that Al concentration is decreased by aging the solutions under seeded conditions. The use of caustic waste from the aluminum anodizing industry to treat the SPL leachates obtained with acidic anodizing waste totally removes the need of chemical reagents for SPL treatment and fluoride recovery. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3013506
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp 12712–12722[article] Treatment of spent pot-lining with aluminum anodizing wastewaters : Selective precipitation of aluminum and fluoride as an aluminum hydroxyfluoride hydrate product [texte imprimé] / Diego F. Lisbona, Auteur ; Christopher Somerfield, Auteur ; Karen M. Steel, Auteur . - 2012 . - pp 12712–12722.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp 12712–12722
Mots-clés : Wastewaters Hydroxyfluoride Résumé : Wastewaters generated by the aluminum anodizing industry have been identified as a source of acid, Al3+, and caustic values that could be used for the treatment of spent pot-lining (SPL) generated in primary aluminum smelting. In this paper, recovery of aluminum and fluoride values as an aluminum fluoride product that could be converted into smelter grade (SG) AlF3 for recycling in aluminum smelting is reported. Experimental observations were contrasted with a thermodynamic model of the solution equilibria and new values for the solubility product of AlF2OH·1.4H2O, 10–15 at 30 °C and 10–23.8 at 50 °C, are reported. Neutralization of leachates obtained from SPL treatment with aluminum anodizing acid wastewaters was performed using 2 M NaOH and, alternatively, waste caustic solutions from the aluminum anodizing industry. pH-static precipitation with 2 M NaOH successfully recovered 92 wt % of the solubilized fluoride as AlF2OH·1.4H2O at pH 4.0 and 70 °C, although a hydrolyzed Na5Al3F14-like product (3–5 wt % Na) coprecipitated. Seeded heterogeneous nucleation of AlF2OH·1.4H2O on SG Al(OH)3 yielded a product that could be acceptable to AlF3 manufacturers, meeting specifications for particle size and phosphorus and silicon content. Caustic wastewaters from the aluminum anodizing industry were identified as suitable to provide the caustic values required for precipitation, providing that Al concentration is decreased by aging the solutions under seeded conditions. The use of caustic waste from the aluminum anodizing industry to treat the SPL leachates obtained with acidic anodizing waste totally removes the need of chemical reagents for SPL treatment and fluoride recovery. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3013506 Exemplaires
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Titre : Experimental and theoretical study of chemical equilibria in the reactive systems of acetals synthesis Type de document : texte imprimé Auteurs : Viviana M. T. M. Silva, Auteur ; Carla S. M. Pereira, Auteur ; Alirio E. Rodrigues, Auteur Année de publication : 2012 Article en page(s) : pp. 12723-12729 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Chemical equilibrium Résumé : The chemical equilibria of acetals of acetaldehyde reactive systems (with methanol, ethanol, and n-butanol to form 1,1-dimethoxyethane, 1,1-diethoxyethane, and 1,1-dibuthoxyethane, respectively) were studied in the temperature range (293-333 K) in the liquid phase. The three reactive systems exhibit a strong nonideal behavior in the liquid phase. The knowledge of the activity coefficients is required to obtain the thermodynamic equilibrium constants Ka. The activity coefficients were estimated by the modified UNIFAC method, which already includes the parameters for the acetal group. The reaction enthalpies for the three acetalizations in the liquid phase were obtained from the temperature dependences of the corresponding thermodynamic equilibrium constants. These values were compared to those obtained by high-level ab initio calculations of the reaction participants using the Gaussian 03 program package. Absolute electronic energy values of the molecules have been obtained using G3(MP2) level. Using these results, calculated equilibrium constants and enthalpies of reaction of the acetals synthesis in the liquid phase based on the principles of statistical thermodynamics are found to be in acceptable agreement with the data obtained from the thermochemical measurements. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419227
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12723-12729[article] Experimental and theoretical study of chemical equilibria in the reactive systems of acetals synthesis [texte imprimé] / Viviana M. T. M. Silva, Auteur ; Carla S. M. Pereira, Auteur ; Alirio E. Rodrigues, Auteur . - 2012 . - pp. 12723-12729.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12723-12729
Mots-clés : Chemical equilibrium Résumé : The chemical equilibria of acetals of acetaldehyde reactive systems (with methanol, ethanol, and n-butanol to form 1,1-dimethoxyethane, 1,1-diethoxyethane, and 1,1-dibuthoxyethane, respectively) were studied in the temperature range (293-333 K) in the liquid phase. The three reactive systems exhibit a strong nonideal behavior in the liquid phase. The knowledge of the activity coefficients is required to obtain the thermodynamic equilibrium constants Ka. The activity coefficients were estimated by the modified UNIFAC method, which already includes the parameters for the acetal group. The reaction enthalpies for the three acetalizations in the liquid phase were obtained from the temperature dependences of the corresponding thermodynamic equilibrium constants. These values were compared to those obtained by high-level ab initio calculations of the reaction participants using the Gaussian 03 program package. Absolute electronic energy values of the molecules have been obtained using G3(MP2) level. Using these results, calculated equilibrium constants and enthalpies of reaction of the acetals synthesis in the liquid phase based on the principles of statistical thermodynamics are found to be in acceptable agreement with the data obtained from the thermochemical measurements. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419227 Exemplaires
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Titre : Synthesis of TS-1 from an inorganic reactant system and its catalytic properties for allyl chloride epoxidation Type de document : texte imprimé Auteurs : Meng Wang, Auteur ; Jicheng Zhou, Auteur ; Guiyue Mao, Auteur Année de publication : 2012 Article en page(s) : pp. 12730–12738 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Inorganic reactant Résumé : TS-1 has been synthesized from an inorganic reactant system using Ti(SO4)2 as the titanium source, TPABr as the templating agent, and ammonia as the base to provide the alkalinity needed for crystallization. The effects of preparation parameters, such as titanium sources, crystallization temperature and time, SiO2/TiO2, TPABr/SiO2, ammonia/SiO2 and seed crystals on the physicochemical and catalytic properties of TS-1 were investigated in detail. The TS-1 samples were characterized by XRD, FT-IR, UV–vis, SEM, and ICP-AES, and the catalytic performance of TS-1 was evaluated in the epoxidation of allyl chloride. The results show that the catalytic performance of TS-1 synthesized using Ti(SO4)2 was excellent, and the crystal size of the catalyst was small. The synthesis conditions had a great influence on the properties of TS-1. The optimum synthesis conditions for the present system should employ a gel composition of SiO2/TiO2/NH3/TPABr/H2O = 1:0.022:2.5:0.15:35 and carry out the crystallization at 443 K for 3 days; the addition of seed in the synthesis gel played an important role in the crystallization of TS-1. Moreover, the stability and reusability of TS-1 prepared from this system was fine. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202524t
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12730–12738[article] Synthesis of TS-1 from an inorganic reactant system and its catalytic properties for allyl chloride epoxidation [texte imprimé] / Meng Wang, Auteur ; Jicheng Zhou, Auteur ; Guiyue Mao, Auteur . - 2012 . - pp. 12730–12738.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12730–12738
Mots-clés : Inorganic reactant Résumé : TS-1 has been synthesized from an inorganic reactant system using Ti(SO4)2 as the titanium source, TPABr as the templating agent, and ammonia as the base to provide the alkalinity needed for crystallization. The effects of preparation parameters, such as titanium sources, crystallization temperature and time, SiO2/TiO2, TPABr/SiO2, ammonia/SiO2 and seed crystals on the physicochemical and catalytic properties of TS-1 were investigated in detail. The TS-1 samples were characterized by XRD, FT-IR, UV–vis, SEM, and ICP-AES, and the catalytic performance of TS-1 was evaluated in the epoxidation of allyl chloride. The results show that the catalytic performance of TS-1 synthesized using Ti(SO4)2 was excellent, and the crystal size of the catalyst was small. The synthesis conditions had a great influence on the properties of TS-1. The optimum synthesis conditions for the present system should employ a gel composition of SiO2/TiO2/NH3/TPABr/H2O = 1:0.022:2.5:0.15:35 and carry out the crystallization at 443 K for 3 days; the addition of seed in the synthesis gel played an important role in the crystallization of TS-1. Moreover, the stability and reusability of TS-1 prepared from this system was fine. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202524t Exemplaires
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Titre : Effect of reaction and adsorption at the surface of porous pellets on the concentration of slurries Type de document : texte imprimé Auteurs : Mauricio Sales-Cruz, Auteur ; Francisco J. Valdés-Parada, Auteur ; Benoît Goyeau, Auteur Année de publication : 2012 Article en page(s) : pp. 12739-12750 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Porous material Pellet Adsorption Résumé : In this work, we analyze the influence of interfacial reaction and adsorption processes over the predictions of the unsteady average macroscopic concentrations in slurries. The isothermal mass transport model consists of the equations for the well-mixed fluid and the one corresponding to the pellets. The latter consist of porous media where first-order reaction kinetics and linear adsorption take place. The interfacial flux boundary condition considers the mass transfer resistance in the fluid, as well as superficial reaction and accumulation terms. The model solution is carried out by means of Fourier series expansions. It is shown that, unless the adsorption and reaction at the surface of the porous pellets are much more intense than in the bulk, the error introduced by not considering these interfacial phenomena is negligible. The results from this work are relevant for improving design and control applications of slurries involving fast reactions or strong adsorption. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419229
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12739-12750[article] Effect of reaction and adsorption at the surface of porous pellets on the concentration of slurries [texte imprimé] / Mauricio Sales-Cruz, Auteur ; Francisco J. Valdés-Parada, Auteur ; Benoît Goyeau, Auteur . - 2012 . - pp. 12739-12750.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12739-12750
Mots-clés : Porous material Pellet Adsorption Résumé : In this work, we analyze the influence of interfacial reaction and adsorption processes over the predictions of the unsteady average macroscopic concentrations in slurries. The isothermal mass transport model consists of the equations for the well-mixed fluid and the one corresponding to the pellets. The latter consist of porous media where first-order reaction kinetics and linear adsorption take place. The interfacial flux boundary condition considers the mass transfer resistance in the fluid, as well as superficial reaction and accumulation terms. The model solution is carried out by means of Fourier series expansions. It is shown that, unless the adsorption and reaction at the surface of the porous pellets are much more intense than in the bulk, the error introduced by not considering these interfacial phenomena is negligible. The results from this work are relevant for improving design and control applications of slurries involving fast reactions or strong adsorption. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419229 Exemplaires
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Titre : Chemical equilibrium and reaction kinetics of the heterogeneously catalyzed formation of poly(oxymethylene) dimethyl ethers from methylal and trioxane Type de document : texte imprimé Auteurs : Jakob Burger, Auteur ; Eckhard Ströfer, Auteur ; Hans Hasse, Auteur Année de publication : 2012 Article en page(s) : pp. 12751–12761 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics Heterogeneously catalyzed Résumé : Poly(oxymethylene) dimethyl ethers (OMEs) are attractive components for tailoring diesel fuels. They belong to the group of oxygenates that reduce soot formation in the combustion when added to diesel fuels and can be produced on a large scale based on gas-to-liquid technology. This work deals with a particularly favorable route for their large scale production in which they are formed from methylal and trioxane. Reaction kinetics and chemical equilibrium of the OME formation via this route were studied in a batch reactor using the ion-exchange resin Amberlyst 46 as heterogeneous catalyst at temperatures between 323 and 363 K and for a wide range of feed compositions. An adsorption-based kinetic model is presented that represents both reaction kinetics and equilibrium well. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301490q
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12751–12761[article] Chemical equilibrium and reaction kinetics of the heterogeneously catalyzed formation of poly(oxymethylene) dimethyl ethers from methylal and trioxane [texte imprimé] / Jakob Burger, Auteur ; Eckhard Ströfer, Auteur ; Hans Hasse, Auteur . - 2012 . - pp. 12751–12761.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12751–12761
Mots-clés : Kinetics Heterogeneously catalyzed Résumé : Poly(oxymethylene) dimethyl ethers (OMEs) are attractive components for tailoring diesel fuels. They belong to the group of oxygenates that reduce soot formation in the combustion when added to diesel fuels and can be produced on a large scale based on gas-to-liquid technology. This work deals with a particularly favorable route for their large scale production in which they are formed from methylal and trioxane. Reaction kinetics and chemical equilibrium of the OME formation via this route were studied in a batch reactor using the ion-exchange resin Amberlyst 46 as heterogeneous catalyst at temperatures between 323 and 363 K and for a wide range of feed compositions. An adsorption-based kinetic model is presented that represents both reaction kinetics and equilibrium well. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301490q Exemplaires
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Titre : Hydrothermal stability of Fe–BEA as an NH3-SCR catalyst Type de document : texte imprimé Auteurs : Soran Shwan, Auteur ; Radka Nedyalkova, Auteur ; Jonas Jansson, Auteur Année de publication : 2012 Article en page(s) : pp. 12762–12772 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Résumé : The hydrothermal stability of Fe–BEA as a selective catalytic reduction (SCR) catalyst was experimentally studied. Cordierite supported Fe–BEA samples were hydrothermally treated at 600 and 700 °C for 3–100 h to capture the effect of aging time and temperature. Before and after aging the samples were characterized with BET, XPS, XRD, and NH3-TPD. The catalytic performance of the samples with respect to NO oxidation, NH3 oxidation, and NO reduction (NH3-SCR) was studied by flow reactor experiments to correlate changes of the catalytic performance with structural changes of the zeolite and the iron phases. The NH3-SCR experiments did not show any significant decrease in activity after a short time of aging (3 h at 700 °C) even though the ammonia storage capacity decreased by 40% and the oxidation state of iron slightly increased. A longer time of aging resulted in decreased activity for NO reduction during low temperatures (150–300 °C), while at higher temperatures (400–500 °C) the activity remained high. The results indicate that the NO reduction is more sensitive at low temperatures to changes in the oxidation state of iron caused by hydrothermal aging than at higher temperatures. Furthermore, a maximum in activity for NO oxidation and increased oxidation state of iron (Fe3+) indicate Fe2O3 particle growth. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301516z
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12762–12772[article] Hydrothermal stability of Fe–BEA as an NH3-SCR catalyst [texte imprimé] / Soran Shwan, Auteur ; Radka Nedyalkova, Auteur ; Jonas Jansson, Auteur . - 2012 . - pp. 12762–12772.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12762–12772
Mots-clés : Catalyst Résumé : The hydrothermal stability of Fe–BEA as a selective catalytic reduction (SCR) catalyst was experimentally studied. Cordierite supported Fe–BEA samples were hydrothermally treated at 600 and 700 °C for 3–100 h to capture the effect of aging time and temperature. Before and after aging the samples were characterized with BET, XPS, XRD, and NH3-TPD. The catalytic performance of the samples with respect to NO oxidation, NH3 oxidation, and NO reduction (NH3-SCR) was studied by flow reactor experiments to correlate changes of the catalytic performance with structural changes of the zeolite and the iron phases. The NH3-SCR experiments did not show any significant decrease in activity after a short time of aging (3 h at 700 °C) even though the ammonia storage capacity decreased by 40% and the oxidation state of iron slightly increased. A longer time of aging resulted in decreased activity for NO reduction during low temperatures (150–300 °C), while at higher temperatures (400–500 °C) the activity remained high. The results indicate that the NO reduction is more sensitive at low temperatures to changes in the oxidation state of iron caused by hydrothermal aging than at higher temperatures. Furthermore, a maximum in activity for NO oxidation and increased oxidation state of iron (Fe3+) indicate Fe2O3 particle growth. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301516z Exemplaires
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Titre : Preparation and characterization of Fe2O3/Al2O3 using the solution combustion approach for chemical looping combustion Type de document : texte imprimé Auteurs : Jianshe Zhang, Auteur ; Qingjie Guo, Auteur ; Yongzhuo Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 12773-12781 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Combustion Preparation Résumé : Chemical looping combustion (CLC) is an attractive technology for CO2 capture with high energy efficiency. In this article, an Fe2O3/Al2O3 (Fe:Al = 3:1) oxygen carrier was first prepared by the solution combustion approach for the CLC process. The prepared oxygen carrier was characterized by different means. XRD identification has substantiated the necessity of calcinations to synthesize Fe2O3/Al2O3 oxygen carrier. SEM and TEM images showed the regular spherical and cubical shape and abundant porous structure in Fe2O3/Al2O3 oxygen carrier, respectively. Structural characteristics displayed that the pore shape of Fe2O3/Al2O3 particles was heterogeneous. The average pore size and surface area were 64.76 nm and 4.01 m2/g, respectively. Further, H2 temperature programmed reduction (TPR) of Fe2O3/Al2O3 oxygen carrier indicated that the reduction reaction had only one distinct DTG peak with the weight loss rate reaching 4.75 wt %/min. Finally, five cycles of red-ox reaction by alternating with CH4 and air demonstrated that Fe2O3/Al2O3 oxygen carrier had excellent reactivity and sintering resistance and consequently was capable of the CLC process. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419232
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12773-12781[article] Preparation and characterization of Fe2O3/Al2O3 using the solution combustion approach for chemical looping combustion [texte imprimé] / Jianshe Zhang, Auteur ; Qingjie Guo, Auteur ; Yongzhuo Liu, Auteur . - 2012 . - pp. 12773-12781.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12773-12781
Mots-clés : Combustion Preparation Résumé : Chemical looping combustion (CLC) is an attractive technology for CO2 capture with high energy efficiency. In this article, an Fe2O3/Al2O3 (Fe:Al = 3:1) oxygen carrier was first prepared by the solution combustion approach for the CLC process. The prepared oxygen carrier was characterized by different means. XRD identification has substantiated the necessity of calcinations to synthesize Fe2O3/Al2O3 oxygen carrier. SEM and TEM images showed the regular spherical and cubical shape and abundant porous structure in Fe2O3/Al2O3 oxygen carrier, respectively. Structural characteristics displayed that the pore shape of Fe2O3/Al2O3 particles was heterogeneous. The average pore size and surface area were 64.76 nm and 4.01 m2/g, respectively. Further, H2 temperature programmed reduction (TPR) of Fe2O3/Al2O3 oxygen carrier indicated that the reduction reaction had only one distinct DTG peak with the weight loss rate reaching 4.75 wt %/min. Finally, five cycles of red-ox reaction by alternating with CH4 and air demonstrated that Fe2O3/Al2O3 oxygen carrier had excellent reactivity and sintering resistance and consequently was capable of the CLC process. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419232 Exemplaires
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Titre : Visible–light–induced photodegradation of rhodamine B over hierarchical TiO2 : Effects of storage period and water-mediated adsorption switch Type de document : texte imprimé Auteurs : Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xin-Yu Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 12782-12786 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adsorption Storage Titanium oxide Photochemical degradation Visible radiation Résumé : Hierarchical TiO2 was prepared via hydrolysis method and characterized by XRD, N2 adsorption―desorption, UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of prepared materials decrease rapidly. The photoactivity was evaluated using the self-sensitized photodegradation of rhodamine B under visible light The fresh samples show higher activity than P-25 due to higher surface area and more effective light utilization. After stored in air for ca. half a year, the materials show significantly increased photoactivity, due to the prebonding of water on surface bridging hydroxyls, which induces water-mediated adsorption switch from covalent mode to electrostatic one. Water treatment further promotes the photoactivity of stored samples, because more water are bonded on TiO2 surface. It is found that the water-mediated effect closely depends on the surface area and amount of surface bridging hydroxyls. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419233
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12782-12786[article] Visible–light–induced photodegradation of rhodamine B over hierarchical TiO2 : Effects of storage period and water-mediated adsorption switch [texte imprimé] / Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xin-Yu Liu, Auteur . - 2012 . - pp. 12782-12786.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12782-12786
Mots-clés : Adsorption Storage Titanium oxide Photochemical degradation Visible radiation Résumé : Hierarchical TiO2 was prepared via hydrolysis method and characterized by XRD, N2 adsorption―desorption, UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of prepared materials decrease rapidly. The photoactivity was evaluated using the self-sensitized photodegradation of rhodamine B under visible light The fresh samples show higher activity than P-25 due to higher surface area and more effective light utilization. After stored in air for ca. half a year, the materials show significantly increased photoactivity, due to the prebonding of water on surface bridging hydroxyls, which induces water-mediated adsorption switch from covalent mode to electrostatic one. Water treatment further promotes the photoactivity of stored samples, because more water are bonded on TiO2 surface. It is found that the water-mediated effect closely depends on the surface area and amount of surface bridging hydroxyls. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419233 Exemplaires
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Titre : Fe3O4 Nanoparticles and carboxymethyl cellulose : A green option for the removal of atmospheric benzene, toluene, ethylbenzene, and o-xylene (BTEX) Type de document : texte imprimé Auteurs : Nermin A. Eltouny, Auteur ; Parisa A. Ariya, Auteur Année de publication : 2012 Article en page(s) : pp. 12787-12795 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticle Résumé : In this work, we investigate the interaction of gaseous benzene, toluene, ethylbenzene, and o-xylene (BTEX) with Fe3O4 nanoparticles and demonstrate the potential application of Fe3O4 nanoparticles as adsorbents for BTEX. On the basis of X-ray diffraction, transmission electron microscopy, gas chromatography-mass spectrometry, and gas chromatography―flame ionization detection results, using toluene as a model compound, we find that adsorption is of a heterogeneous nature. At relatively high concentrations of toluene (300-2790 ppmv), X-ray photoelectron spectroscopy results indicate an increase in the divalent cations relative to the trivalent cations of Fe3O4 nanoparticles, which is possibly triggered by nanoscale effects. Removal efficiency experiments show that Fe3O4 nanoparticles (4 g) reduce 100 ppmv of BETX in air by 83 ± 8%, 95 ± 5%, 97 ± 1%, and 98 ± 2%, respectively. Comparable removal efficiencies were observed for recycled Fe3O4 nanoparticles. Toluene was also removed from a flow by Fe3O4 nanoparticles bound together with carboxymethyl cellulose, without releasing undesired aerosols. Fe3O4 nanoparticles (bare and as a composite) show potential as practical and environmental friendly materials for the remediation of BTEX from air. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419234
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12787-12795[article] Fe3O4 Nanoparticles and carboxymethyl cellulose : A green option for the removal of atmospheric benzene, toluene, ethylbenzene, and o-xylene (BTEX) [texte imprimé] / Nermin A. Eltouny, Auteur ; Parisa A. Ariya, Auteur . - 2012 . - pp. 12787-12795.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12787-12795
Mots-clés : Nanoparticle Résumé : In this work, we investigate the interaction of gaseous benzene, toluene, ethylbenzene, and o-xylene (BTEX) with Fe3O4 nanoparticles and demonstrate the potential application of Fe3O4 nanoparticles as adsorbents for BTEX. On the basis of X-ray diffraction, transmission electron microscopy, gas chromatography-mass spectrometry, and gas chromatography―flame ionization detection results, using toluene as a model compound, we find that adsorption is of a heterogeneous nature. At relatively high concentrations of toluene (300-2790 ppmv), X-ray photoelectron spectroscopy results indicate an increase in the divalent cations relative to the trivalent cations of Fe3O4 nanoparticles, which is possibly triggered by nanoscale effects. Removal efficiency experiments show that Fe3O4 nanoparticles (4 g) reduce 100 ppmv of BETX in air by 83 ± 8%, 95 ± 5%, 97 ± 1%, and 98 ± 2%, respectively. Comparable removal efficiencies were observed for recycled Fe3O4 nanoparticles. Toluene was also removed from a flow by Fe3O4 nanoparticles bound together with carboxymethyl cellulose, without releasing undesired aerosols. Fe3O4 nanoparticles (bare and as a composite) show potential as practical and environmental friendly materials for the remediation of BTEX from air. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419234 Exemplaires
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Titre : Evaluation of novel ceria-supported metal oxides as oxygen carriers for chemical-looping combustion Type de document : texte imprimé Auteurs : Ali Hedayati, Auteur ; Abdul-Majeed Azad, Auteur ; Magnus Rydén, Auteur Année de publication : 2012 Article en page(s) : pp. 12796–12806 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Metal oxides Combustion Résumé : Oxygen carrier particles consisting of 60 wt % copper, iron, or manganese oxide supported on 40 wt % ceria (CeO2) or gadolinia doped-ceria (Ce0.9Gd0.1O1.9) have been manufactured and examined as oxygen carrier materials for chemical-looping combustion (CLC). Unlike conventional support materials, such as alumina (Al2O3), these ceria-based support materials are active under prevailing conditions in the fuel reactor and have the ability to participate in redox reactions. The oxygen carrier materials were synthesized via extrusion and were examined by successive oxidation and reduction cycles in a bench-scale fluidized bed reactor made of quartz. The experiments were conducted at 900 and 925 °C for copper-based materials, and at 950 °C for iron- and manganese-based materials. Methane or syngas (50% CO and 50% H2) using a flow rate of 900 mL/min for Cu-based materials and 450 mL/min for Mn- and Fe-based materials was used as the fuel. For all experiments, 15 g of oxygen carrier was used. The oxidation was performed with a gas mixture of 5% O2 and 95% N2. The results show that CeO2 and Ce0.9Gd0.1O1.9 are viable support materials for the oxides of copper and iron. Moreover, the active particles supported on Ce0.9Gd0.1O1.9 were more reactive compared to those supported on CeO2. CH4 was completely converted to CO2 and H2O by CuO supported on Ce0.9Gd0.1O1.9, while the conversion of CH4 for Fe2O3 supported on Ce0.9Gd0.1O1.9 was as high as 90%. Ceria-supported Mn3O4 particles showed poor performance when CH4 was used as fuel. Syngas was fully converted to CO2 and H2O by all the oxygen carriers synthesized and examined in this work. The ability of CuO and Mn2O3 to release O2 in gas phase when fluidized in inert background was also investigated; in the case of copper oxide, substantial oxygen release was observed. Analysis of fresh and used particles by X-ray diffractometry did not reveal the formation of any unexpected phases. All particles showed good fluidization properties with low attrition and little tendency toward agglomeration. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300168j
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12796–12806[article] Evaluation of novel ceria-supported metal oxides as oxygen carriers for chemical-looping combustion [texte imprimé] / Ali Hedayati, Auteur ; Abdul-Majeed Azad, Auteur ; Magnus Rydén, Auteur . - 2012 . - pp. 12796–12806.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12796–12806
Mots-clés : Metal oxides Combustion Résumé : Oxygen carrier particles consisting of 60 wt % copper, iron, or manganese oxide supported on 40 wt % ceria (CeO2) or gadolinia doped-ceria (Ce0.9Gd0.1O1.9) have been manufactured and examined as oxygen carrier materials for chemical-looping combustion (CLC). Unlike conventional support materials, such as alumina (Al2O3), these ceria-based support materials are active under prevailing conditions in the fuel reactor and have the ability to participate in redox reactions. The oxygen carrier materials were synthesized via extrusion and were examined by successive oxidation and reduction cycles in a bench-scale fluidized bed reactor made of quartz. The experiments were conducted at 900 and 925 °C for copper-based materials, and at 950 °C for iron- and manganese-based materials. Methane or syngas (50% CO and 50% H2) using a flow rate of 900 mL/min for Cu-based materials and 450 mL/min for Mn- and Fe-based materials was used as the fuel. For all experiments, 15 g of oxygen carrier was used. The oxidation was performed with a gas mixture of 5% O2 and 95% N2. The results show that CeO2 and Ce0.9Gd0.1O1.9 are viable support materials for the oxides of copper and iron. Moreover, the active particles supported on Ce0.9Gd0.1O1.9 were more reactive compared to those supported on CeO2. CH4 was completely converted to CO2 and H2O by CuO supported on Ce0.9Gd0.1O1.9, while the conversion of CH4 for Fe2O3 supported on Ce0.9Gd0.1O1.9 was as high as 90%. Ceria-supported Mn3O4 particles showed poor performance when CH4 was used as fuel. Syngas was fully converted to CO2 and H2O by all the oxygen carriers synthesized and examined in this work. The ability of CuO and Mn2O3 to release O2 in gas phase when fluidized in inert background was also investigated; in the case of copper oxide, substantial oxygen release was observed. Analysis of fresh and used particles by X-ray diffractometry did not reveal the formation of any unexpected phases. All particles showed good fluidization properties with low attrition and little tendency toward agglomeration. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300168j Exemplaires
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Titre : Coloration of cotton fibers with anisotropic silver nanoparticles Type de document : texte imprimé Auteurs : Bin Tang, Auteur ; Mingwen Zhang, Auteur ; Xueliang Hou, Auteur Année de publication : 2012 Article en page(s) : pp. 12807-12813 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticle Coloration Résumé : Anisotropic silver nanoparticles were assembled on cotton fibers to realize the coloration of cotton. The assembly of silver nanoparticles on fibers was achieved by linking of poly(diallyldimethylammonium chloride) (PDDA) at room temperature. The silver nanoparticle treated cotton showed different colors because of localized surface plasmon resonance (LSPR) property of silver nanoparticles. The coloration was completed through electrostatic interaction between the PDDA treated cotton surface and the anisotropic silver nanoparticles in the reaction system. Scanning electron microscopy (SEM) characterization demonstrated that the morphologies of silver nanoparticles remained unchanged during the coloration process, so the treated cotton inherited the LSPR optical features of silver nanoparticles. Moreover, the cotton colorated with silver nanoparticles showed reasonably good color fastness to washing, which will facilitate the practical application of this coloration process. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419236
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12807-12813[article] Coloration of cotton fibers with anisotropic silver nanoparticles [texte imprimé] / Bin Tang, Auteur ; Mingwen Zhang, Auteur ; Xueliang Hou, Auteur . - 2012 . - pp. 12807-12813.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12807-12813
Mots-clés : Nanoparticle Coloration Résumé : Anisotropic silver nanoparticles were assembled on cotton fibers to realize the coloration of cotton. The assembly of silver nanoparticles on fibers was achieved by linking of poly(diallyldimethylammonium chloride) (PDDA) at room temperature. The silver nanoparticle treated cotton showed different colors because of localized surface plasmon resonance (LSPR) property of silver nanoparticles. The coloration was completed through electrostatic interaction between the PDDA treated cotton surface and the anisotropic silver nanoparticles in the reaction system. Scanning electron microscopy (SEM) characterization demonstrated that the morphologies of silver nanoparticles remained unchanged during the coloration process, so the treated cotton inherited the LSPR optical features of silver nanoparticles. Moreover, the cotton colorated with silver nanoparticles showed reasonably good color fastness to washing, which will facilitate the practical application of this coloration process. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419236 Exemplaires
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Titre : Mechanism of solvent effect in polymorphic crystallization of BPT Type de document : texte imprimé Auteurs : Mitsutaka Kitamura, Auteur ; Emi Umeda, Auteur ; Kenichi Miki, Auteur Année de publication : 2012 Article en page(s) : pp. 12814-12820 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Crystallization Solvent effect Résumé : The effect of solvent on the crystallization behavior of the polymorphs of 2-(3-cyano-4-isobutyloxvphenyl)-4-methyl-5-thiazolecarboxylic acid (BPT) was investigated under rapid cooling. From methanol (MeOH) and ethanol (EtOH) solutions, only the solvated crystals of the D forms of methanol (D(MeOH)) and ethanol (D(EtOH)) crystallized. Both D forms are stable and have similar crystal structures. However, the solubility of the D(EtOH) form is 1.5 times higher than that of the D(MeOH) form. With the release of alcohol molecules, both D forms transformed to the C form with an increase in temperature for the DSC measurement. After that, the C form transformed to the A form via a melt-mediated mechanism. The release temperature of alcohol was higher for D(EtOH) than for D(MeOH). When the crystallization was performed in 1-propanol (1-PrOH) and 2-propanol (2-PrOH), the metastable A form preferentially crystallized. On the other hand, in acetonitrile (MeCN) solutions the stable C form was selectively obtained. These crystallization behaviors in each solvent did not depend on supersaturation in solutions. The FTIR spectra of BPT in EtOH and 1-PrOH suggested that BPT molecules in solution take a conformation similar to that in each crystal. These results suggest that the solvent effect is controlled by the thermodynamic equilibrium properties such as the conformation of the solute and the solute-solvent interactions rather than the crystallization kinetics of the polymorphs. Furthermore, the solution-mediated transformation rate from the A form to the C form is higher in MeCN than those in 1-PrOH and 2-PrOH. In the mixed solvents of I-PrOH and MeCN with water, the same polymorphs crystallized as those obtained in pure solvents in the water volume fraction up to the range of 0.1. However, the hydrated crystals (BH form) predominantly crystallized with further addition of water. Solubility measurements suggested that such behavior is related to the solvated structure surrounding the BPT molecule. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419237
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12814-12820[article] Mechanism of solvent effect in polymorphic crystallization of BPT [texte imprimé] / Mitsutaka Kitamura, Auteur ; Emi Umeda, Auteur ; Kenichi Miki, Auteur . - 2012 . - pp. 12814-12820.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12814-12820
Mots-clés : Crystallization Solvent effect Résumé : The effect of solvent on the crystallization behavior of the polymorphs of 2-(3-cyano-4-isobutyloxvphenyl)-4-methyl-5-thiazolecarboxylic acid (BPT) was investigated under rapid cooling. From methanol (MeOH) and ethanol (EtOH) solutions, only the solvated crystals of the D forms of methanol (D(MeOH)) and ethanol (D(EtOH)) crystallized. Both D forms are stable and have similar crystal structures. However, the solubility of the D(EtOH) form is 1.5 times higher than that of the D(MeOH) form. With the release of alcohol molecules, both D forms transformed to the C form with an increase in temperature for the DSC measurement. After that, the C form transformed to the A form via a melt-mediated mechanism. The release temperature of alcohol was higher for D(EtOH) than for D(MeOH). When the crystallization was performed in 1-propanol (1-PrOH) and 2-propanol (2-PrOH), the metastable A form preferentially crystallized. On the other hand, in acetonitrile (MeCN) solutions the stable C form was selectively obtained. These crystallization behaviors in each solvent did not depend on supersaturation in solutions. The FTIR spectra of BPT in EtOH and 1-PrOH suggested that BPT molecules in solution take a conformation similar to that in each crystal. These results suggest that the solvent effect is controlled by the thermodynamic equilibrium properties such as the conformation of the solute and the solute-solvent interactions rather than the crystallization kinetics of the polymorphs. Furthermore, the solution-mediated transformation rate from the A form to the C form is higher in MeCN than those in 1-PrOH and 2-PrOH. In the mixed solvents of I-PrOH and MeCN with water, the same polymorphs crystallized as those obtained in pure solvents in the water volume fraction up to the range of 0.1. However, the hydrated crystals (BH form) predominantly crystallized with further addition of water. Solubility measurements suggested that such behavior is related to the solvated structure surrounding the BPT molecule. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419237 Exemplaires
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Titre : Preparation and performance of polyimide-reinforced clay aerogel composites Type de document : texte imprimé Auteurs : Wei Wu, Auteur ; Kai Wang, Auteur ; Mao-Sheng Zhan, Auteur Année de publication : 2012 Article en page(s) : pp. 12821-12826 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Composite material Preparation Résumé : Low-density polyimide (PI)/clay aerogel composites were produced by freeze-drying of a poly(amic acid) ammonium salt/clay precursor suspension, followed by a multistep temperature-programmed imidization. The densities of the resulting aerogel composites were in the range of 0.04―0.09 g·cm―3. With the increase of PI content, a more perfect "layer―strut" bracing structure was exhibited in the composites, which resulted in vastly improved mechanical properties. Polyimide did not intercalate the interlayer of clay, and the onset decomposition temperatures (Td) of the aerogels were more than 410 °C. The obtained PI/clay aerogel composites show considerable promise in structural and high-temperature insulation applications. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419238
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12821-12826[article] Preparation and performance of polyimide-reinforced clay aerogel composites [texte imprimé] / Wei Wu, Auteur ; Kai Wang, Auteur ; Mao-Sheng Zhan, Auteur . - 2012 . - pp. 12821-12826.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12821-12826
Mots-clés : Composite material Preparation Résumé : Low-density polyimide (PI)/clay aerogel composites were produced by freeze-drying of a poly(amic acid) ammonium salt/clay precursor suspension, followed by a multistep temperature-programmed imidization. The densities of the resulting aerogel composites were in the range of 0.04―0.09 g·cm―3. With the increase of PI content, a more perfect "layer―strut" bracing structure was exhibited in the composites, which resulted in vastly improved mechanical properties. Polyimide did not intercalate the interlayer of clay, and the onset decomposition temperatures (Td) of the aerogels were more than 410 °C. The obtained PI/clay aerogel composites show considerable promise in structural and high-temperature insulation applications. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419238 Exemplaires
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Titre : Fabrication of lightweight microcellular polyimide foams with three-dimensional shape by CO2 foaming and compression molding Type de document : texte imprimé Auteurs : Wentao Zhai, Auteur ; Weiwei Feng, Auteur ; Jianqiang Ling, Auteur Année de publication : 2012 Article en page(s) : pp. 12827-12834 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Molding Compression Foaming Carbon dioxide Morphology Foam Résumé : Microcellular structure endows polymeric foams with the improved mechanical properties, but the preparation of lightweight microcellular polyimide (PI) foams with a large size is challenging and inefficient, because of low gas solubility, high stiffness, and an extremely long saturation time. In this study, PI foam was prepared by solid-state microcellular foaming technology with the compressed CO2 as a physical blowing agent and tetrahydrofuran as coblowing agent The presence of coblowing agent was verified to increase the gas sorption of PI, causing a dramatic increase in the expansion ratio of miaocellular PI beads from 2.9 to 15.7. Using a novel compression molding process, the prepared PI foams were molded into the 3-D shaped products. Before the molding, the foamed PI beads were coated by poly(ether imide) (PEI)/chloroform solution. The contact angle tests indicated that PEI/chloroform could infiltrate well PI foams' surface, which facilitated the formation of strong interbead bonding between bead foams. The thickness of the coated PEI layer and the interbead bonding regions were the important parameters to adjust the bending and compression properties of the molded PI foam (MPI) product. The experimental results indicated that the bending strength and compression strength (at 10% strain) of MPI sample with density of 137.7 kg/m3 were 1.27 and 1.59 MPa, respectively. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419239
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12827-12834[article] Fabrication of lightweight microcellular polyimide foams with three-dimensional shape by CO2 foaming and compression molding [texte imprimé] / Wentao Zhai, Auteur ; Weiwei Feng, Auteur ; Jianqiang Ling, Auteur . - 2012 . - pp. 12827-12834.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12827-12834
Mots-clés : Molding Compression Foaming Carbon dioxide Morphology Foam Résumé : Microcellular structure endows polymeric foams with the improved mechanical properties, but the preparation of lightweight microcellular polyimide (PI) foams with a large size is challenging and inefficient, because of low gas solubility, high stiffness, and an extremely long saturation time. In this study, PI foam was prepared by solid-state microcellular foaming technology with the compressed CO2 as a physical blowing agent and tetrahydrofuran as coblowing agent The presence of coblowing agent was verified to increase the gas sorption of PI, causing a dramatic increase in the expansion ratio of miaocellular PI beads from 2.9 to 15.7. Using a novel compression molding process, the prepared PI foams were molded into the 3-D shaped products. Before the molding, the foamed PI beads were coated by poly(ether imide) (PEI)/chloroform solution. The contact angle tests indicated that PEI/chloroform could infiltrate well PI foams' surface, which facilitated the formation of strong interbead bonding between bead foams. The thickness of the coated PEI layer and the interbead bonding regions were the important parameters to adjust the bending and compression properties of the molded PI foam (MPI) product. The experimental results indicated that the bending strength and compression strength (at 10% strain) of MPI sample with density of 137.7 kg/m3 were 1.27 and 1.59 MPa, respectively. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419239 Exemplaires
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Titre : Anticorrosive properties of date palm (Phoenix dactylifera L.) fruit juice on 7075 type aluminum alloy in 3.5% NaCl solution Type de document : texte imprimé Auteurs : Husnu Gerengi, Auteur Année de publication : 2012 Article en page(s) : pp. 12835–12843 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Anticorrosive properties Date palm Résumé : The influence of date palm (Phoenix dactylifera L.) (PDL) fruit juice on 7075 type aluminum (AA7075) alloy in 3.5% NaCl solution was investigated by Tafel extrapolarization and electrochemical impedance spectroscopy. It was found that PDL fruit juice acted as a slightly cathodic inhibitor, and inhibition efficiencies increased with the increase of PDL fruit juice concentration. The adsorption of the inhibitor on the metal surface was found to obey the Temkin adsorption isotherm and has a physisorption mechanism. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301771u
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12835–12843[article] Anticorrosive properties of date palm (Phoenix dactylifera L.) fruit juice on 7075 type aluminum alloy in 3.5% NaCl solution [texte imprimé] / Husnu Gerengi, Auteur . - 2012 . - pp. 12835–12843.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12835–12843
Mots-clés : Anticorrosive properties Date palm Résumé : The influence of date palm (Phoenix dactylifera L.) (PDL) fruit juice on 7075 type aluminum (AA7075) alloy in 3.5% NaCl solution was investigated by Tafel extrapolarization and electrochemical impedance spectroscopy. It was found that PDL fruit juice acted as a slightly cathodic inhibitor, and inhibition efficiencies increased with the increase of PDL fruit juice concentration. The adsorption of the inhibitor on the metal surface was found to obey the Temkin adsorption isotherm and has a physisorption mechanism. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301771u Exemplaires
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Titre : PBTC as an antiscalant for gypsum precipitation : Interfacial tension and activation energy estimation Type de document : texte imprimé Auteurs : Marina Prisciandaro, Auteur ; Emilia Olivieri, Auteur ; Amedeo Lancia, Auteur Année de publication : 2012 Article en page(s) : pp. 12844-12851 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermodynamic properties Activation energy Interface tension Résumé : The aim of this paper is to measure the induction period for gypsum nucleation when 2-phosphonobutane-1,2,4-tricarboxylic acid (also PBTC, commercial name Bayhibit) is added to a solution as an additive. A well-assessed laser light scattering technique previously devised for the measurement of induction times has been used. The induction period values measured are then used to estimate the values for the interfacial tension between gypsum crystals and the mother solution for three PBTC concentration levels (0.05, 0.10, and 0.50 g/L) at the temperature levels of T = 15, 25, and 35 °C, according to different nucleation mechanisms. Starting from the dependence of induction times on temperature, the activation energy for nucleation is estimated for each tested PBTC concentration, allowing the determination, with an a posteriori analysis, of which is the governing mechanism in gypsum nucleation kinetic, and thus the more reliable interfacial tension values. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419241
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12844-12851[article] PBTC as an antiscalant for gypsum precipitation : Interfacial tension and activation energy estimation [texte imprimé] / Marina Prisciandaro, Auteur ; Emilia Olivieri, Auteur ; Amedeo Lancia, Auteur . - 2012 . - pp. 12844-12851.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12844-12851
Mots-clés : Thermodynamic properties Activation energy Interface tension Résumé : The aim of this paper is to measure the induction period for gypsum nucleation when 2-phosphonobutane-1,2,4-tricarboxylic acid (also PBTC, commercial name Bayhibit) is added to a solution as an additive. A well-assessed laser light scattering technique previously devised for the measurement of induction times has been used. The induction period values measured are then used to estimate the values for the interfacial tension between gypsum crystals and the mother solution for three PBTC concentration levels (0.05, 0.10, and 0.50 g/L) at the temperature levels of T = 15, 25, and 35 °C, according to different nucleation mechanisms. Starting from the dependence of induction times on temperature, the activation energy for nucleation is estimated for each tested PBTC concentration, allowing the determination, with an a posteriori analysis, of which is the governing mechanism in gypsum nucleation kinetic, and thus the more reliable interfacial tension values. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419241 Exemplaires
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Titre : Refinery Production Planning : Multiperiod MINLP with Nonlinear CDU Model Type de document : texte imprimé Auteurs : Abdulrahman M. Alattas, Auteur ; Ignacio E. Grossmann, Auteur ; Ignasi Palou-Rivera, Auteur Année de publication : 2012 Article en page(s) : pp. 12852-12861 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Mathematical programming Modeling Mixed integer Non linear Production planning Refinery Résumé : In a previous paper, Alattas, Grossmann, and Palou-Rivera (2011) developed a single-period, nonlinear programing refinery planning model using the fractionation index (FI) for the crude distillation unit (CDU) equations. In this paper, the single period model is modified to a mixed-integer nonlinear programming (MINLP) model to determine the sequencing, changeovers, and processing times of crude oils over multiple time periods. The MINLP equations include traveling salesman problem constraints to generate the crude oil sequences that maximize profit. Moreover, the disjunction for the fractionation index (FI) is formulated with mixed integer constraints as opposed to the Heaviside function formulation of the previous work. The resulting model is shown to be robust and relatively fast. When subcycles arise, they are eliminated by adding appropriate subtour elimination constraints. Examples with up to 5 crude oils and 6 weeks time horizon are presented to illustrate the application of the proposed model. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419242
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12852-12861[article] Refinery Production Planning : Multiperiod MINLP with Nonlinear CDU Model [texte imprimé] / Abdulrahman M. Alattas, Auteur ; Ignacio E. Grossmann, Auteur ; Ignasi Palou-Rivera, Auteur . - 2012 . - pp. 12852-12861.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12852-12861
Mots-clés : Mathematical programming Modeling Mixed integer Non linear Production planning Refinery Résumé : In a previous paper, Alattas, Grossmann, and Palou-Rivera (2011) developed a single-period, nonlinear programing refinery planning model using the fractionation index (FI) for the crude distillation unit (CDU) equations. In this paper, the single period model is modified to a mixed-integer nonlinear programming (MINLP) model to determine the sequencing, changeovers, and processing times of crude oils over multiple time periods. The MINLP equations include traveling salesman problem constraints to generate the crude oil sequences that maximize profit. Moreover, the disjunction for the fractionation index (FI) is formulated with mixed integer constraints as opposed to the Heaviside function formulation of the previous work. The resulting model is shown to be robust and relatively fast. When subcycles arise, they are eliminated by adding appropriate subtour elimination constraints. Examples with up to 5 crude oils and 6 weeks time horizon are presented to illustrate the application of the proposed model. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419242 Exemplaires
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Titre : Efficient design under uncertainty of renewable power generation systems using partitioning and regression in the course of optimization Type de document : texte imprimé Auteurs : Athanasios I. Papadopoulos, Auteur ; Garyfallos Giannakoudis, Auteur ; Panos Seferlis, Auteur Année de publication : 2012 Article en page(s) : pp. 12862-12876 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Optimization Phase partition Uncertainty Design Résumé : Renewable power generation systems are significantly affected by uncertainty due to intense variability often observed in energy sources. Uncertainty should be considered during design to enable optimum performance within constantly changing conditions. However, the resulting computational complexity and effort is high, especially in view of flowsheets integrating multiple subsystems. To address this challenge, the presented work proposes the partitioning of the space representing uncertain realizations to facilitate the development and continuous update of a surrogate model in the course of optimization. A wide exploration of this strategy reveals and addresses important issues in the implementation of the partitioning and model regression layers. Formal statistical associations are examined regarding the beneficial implications of partitioning to computational efficiency and surrogate model development. The proposed strategy is presented as part of a Simulated Annealing algorithm. This is tested in terms of computational efficiency and solution robustness against an adaptation of Stochastic Annealing, which addresses computational intensity through a different approach while depending entirely on a full system model Results are illustrated through numerical examples and case studies on a stand-alone, hybrid system using renewable energy sources for power generation and storage. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419243
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12862-12876[article] Efficient design under uncertainty of renewable power generation systems using partitioning and regression in the course of optimization [texte imprimé] / Athanasios I. Papadopoulos, Auteur ; Garyfallos Giannakoudis, Auteur ; Panos Seferlis, Auteur . - 2012 . - pp. 12862-12876.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12862-12876
Mots-clés : Optimization Phase partition Uncertainty Design Résumé : Renewable power generation systems are significantly affected by uncertainty due to intense variability often observed in energy sources. Uncertainty should be considered during design to enable optimum performance within constantly changing conditions. However, the resulting computational complexity and effort is high, especially in view of flowsheets integrating multiple subsystems. To address this challenge, the presented work proposes the partitioning of the space representing uncertain realizations to facilitate the development and continuous update of a surrogate model in the course of optimization. A wide exploration of this strategy reveals and addresses important issues in the implementation of the partitioning and model regression layers. Formal statistical associations are examined regarding the beneficial implications of partitioning to computational efficiency and surrogate model development. The proposed strategy is presented as part of a Simulated Annealing algorithm. This is tested in terms of computational efficiency and solution robustness against an adaptation of Stochastic Annealing, which addresses computational intensity through a different approach while depending entirely on a full system model Results are illustrated through numerical examples and case studies on a stand-alone, hybrid system using renewable energy sources for power generation and storage. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419243 Exemplaires
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Titre : Hydrogen source diagram : A procedure for minimization of hydrogen demand in petroleum refineries Type de document : texte imprimé Auteurs : Joana L Borges, Auteur ; Fernando L. P. Pessoa, Auteur ; Eduardo M. Queiroz, Auteur Année de publication : 2012 Article en page(s) : pp. 12877-12885 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Refinery Petroleum Résumé : The consumption of hydrogen in petroleum refineries is increasing due to its growing intensive use in treatment processes and in new refining technologies. This trend and the reduction of hydrogen production in gasoline processing have generated a new panorama. In this new context, target identification for minimum consumption of hydrogen in a distribution network has become fundamental information in the definition of minimum hydrogen requirements in petroleum refineries. This paper presents the hydrogen source diagram (HSD), a new algorithmic method for minimum hydrogen consumption target calculation and, simultaneously, hydrogen network flowsheet synthesis. The proposed HSD procedure is described in details using a case study, showing its wide scope. The results demonstrate the effectiveness of the procedure and show that the generated network can be easily adapted to meet specific plant restrictions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419244
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12877-12885[article] Hydrogen source diagram : A procedure for minimization of hydrogen demand in petroleum refineries [texte imprimé] / Joana L Borges, Auteur ; Fernando L. P. Pessoa, Auteur ; Eduardo M. Queiroz, Auteur . - 2012 . - pp. 12877-12885.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12877-12885
Mots-clés : Refinery Petroleum Résumé : The consumption of hydrogen in petroleum refineries is increasing due to its growing intensive use in treatment processes and in new refining technologies. This trend and the reduction of hydrogen production in gasoline processing have generated a new panorama. In this new context, target identification for minimum consumption of hydrogen in a distribution network has become fundamental information in the definition of minimum hydrogen requirements in petroleum refineries. This paper presents the hydrogen source diagram (HSD), a new algorithmic method for minimum hydrogen consumption target calculation and, simultaneously, hydrogen network flowsheet synthesis. The proposed HSD procedure is described in details using a case study, showing its wide scope. The results demonstrate the effectiveness of the procedure and show that the generated network can be easily adapted to meet specific plant restrictions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419244 Exemplaires
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Titre : General framework for latent variable model inversion for the design and manufacturing of new products Type de document : texte imprimé Auteurs : Emanuele Tomba, Auteur ; Massimiliano Barolo, Auteur ; Salvador García-Muñoz, Auteur Année de publication : 2012 Article en page(s) : pp. 12886-12900 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Manufacturing Design Modeling Résumé : Latent variable regression model (LVRM) inversion is a useful tool to support the development of new products and their manufacturing conditions. The objective of the model inversion exercise is that ot finding the best combination of regressors (e.g., raw material properties, process parameters) that are needed to obtain a desired response (e.g., product quality) from the model. Each of the published applications where model inversion has been applied utilizes a tailored approach to achieve the inversion, given the specific objectives and needs. These approaches range from the direct inversion of the LVRM to the formulation of an objective function that is optimized using nonlinear programming. In this paper we present a framework that aims to give a holistic view of the optimization formulations that can arise from the need to invert an LVRM. The different sets of equations that become relevant (either as a term within the objective function or as a constraint) are discussed, and an example of these scenarios is also provided. Additional to the formulation of the different scenarios and their objective functions, this work proposes a new metric (the P2 statistic) to cross-validate the ability of the model to reconstruct the regressor vector (analogous to the Q2 statistic aimed at the predictability of the response). This new metric comes from the need to not only predict the response from the regressor, but to also reconstruct the regressors from the scores values. In this context, a discussion is provided on the effect of uncertainty in the reconstruction of the regressor (the actual design) as these values are normally given upstream as targets to the supplier of materials, or as set points to the process. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419245
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12886-12900[article] General framework for latent variable model inversion for the design and manufacturing of new products [texte imprimé] / Emanuele Tomba, Auteur ; Massimiliano Barolo, Auteur ; Salvador García-Muñoz, Auteur . - 2012 . - pp. 12886-12900.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12886-12900
Mots-clés : Manufacturing Design Modeling Résumé : Latent variable regression model (LVRM) inversion is a useful tool to support the development of new products and their manufacturing conditions. The objective of the model inversion exercise is that ot finding the best combination of regressors (e.g., raw material properties, process parameters) that are needed to obtain a desired response (e.g., product quality) from the model. Each of the published applications where model inversion has been applied utilizes a tailored approach to achieve the inversion, given the specific objectives and needs. These approaches range from the direct inversion of the LVRM to the formulation of an objective function that is optimized using nonlinear programming. In this paper we present a framework that aims to give a holistic view of the optimization formulations that can arise from the need to invert an LVRM. The different sets of equations that become relevant (either as a term within the objective function or as a constraint) are discussed, and an example of these scenarios is also provided. Additional to the formulation of the different scenarios and their objective functions, this work proposes a new metric (the P2 statistic) to cross-validate the ability of the model to reconstruct the regressor vector (analogous to the Q2 statistic aimed at the predictability of the response). This new metric comes from the need to not only predict the response from the regressor, but to also reconstruct the regressors from the scores values. In this context, a discussion is provided on the effect of uncertainty in the reconstruction of the regressor (the actual design) as these values are normally given upstream as targets to the supplier of materials, or as set points to the process. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419245 Exemplaires
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Titre : Ultrasound assisted cooling crystallization of sodium acetate Type de document : texte imprimé Auteurs : Ujwal N. Hatkar, Auteur ; Parag R. Gogate, Auteur Année de publication : 2012 Article en page(s) : pp. 12901-12909 Note générale : Industrial chemsitry Langues : Anglais (eng) Mots-clés : Crystallization Cooling Ultrasound Résumé : The present work deals with improvement in the cooling crystallization of sodium acetate using ultrasonic irradiations. Initially the effect of different operating parameters in the conventional approach such as seeding temperature, seed amount, and initial amount of dissolved sodium acetate has been investigated. It has been found that seeding is essential for the onset of crystallization, and the amount of the seed had a significant effect on the final crystal size distribution and average particle size. Also the seeding temperature affects the type of crystals generated with formation of trihydrate crystals at a temperature higher than 10 °C, whereas a seeding temperature of 10 °C results in formation of only anhydrous crystals. Experiments under ultrasonic irradiation revealed that the intentional seeding can be avoided using ultrasound provided the irradiation was applied as soon as the cooling is started. The average particle size was found to be dependent on the power dissipation and it decreased with an increase in the irradiation time and power of ultrasound. At low power dissipation levels, unimodal crystal size distribution was obtained. It has been established that the use of ultrasonic irradiation improves the crystallization operation in terms of the avoiding the requirement of intentional seeding and also the final mean crystal size and crystal size distribution can be controlled on the basis of the ultrasound operating parameters. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419246
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12901-12909[article] Ultrasound assisted cooling crystallization of sodium acetate [texte imprimé] / Ujwal N. Hatkar, Auteur ; Parag R. Gogate, Auteur . - 2012 . - pp. 12901-12909.
Industrial chemsitry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12901-12909
Mots-clés : Crystallization Cooling Ultrasound Résumé : The present work deals with improvement in the cooling crystallization of sodium acetate using ultrasonic irradiations. Initially the effect of different operating parameters in the conventional approach such as seeding temperature, seed amount, and initial amount of dissolved sodium acetate has been investigated. It has been found that seeding is essential for the onset of crystallization, and the amount of the seed had a significant effect on the final crystal size distribution and average particle size. Also the seeding temperature affects the type of crystals generated with formation of trihydrate crystals at a temperature higher than 10 °C, whereas a seeding temperature of 10 °C results in formation of only anhydrous crystals. Experiments under ultrasonic irradiation revealed that the intentional seeding can be avoided using ultrasound provided the irradiation was applied as soon as the cooling is started. The average particle size was found to be dependent on the power dissipation and it decreased with an increase in the irradiation time and power of ultrasound. At low power dissipation levels, unimodal crystal size distribution was obtained. It has been established that the use of ultrasonic irradiation improves the crystallization operation in terms of the avoiding the requirement of intentional seeding and also the final mean crystal size and crystal size distribution can be controlled on the basis of the ultrasound operating parameters. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419246 Exemplaires
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Titre : Polymorphic crystallization and transformation of candesartan cilexetil Type de document : texte imprimé Auteurs : Penglei Cui, Auteur ; Qiuxiang Yin, Auteur ; Yuhong Guo, Auteur Année de publication : 2012 Article en page(s) : pp. 12910–12916 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Crystallization Candesartan cilexetil Résumé : In this paper, the acetone solvate of candesartan cilexetil was preferentially crystallized from the acetone solution by cooling crystallization and was characterized by combination methods of X-ray powder diffraction (XRPD), 13C nuclear magnetic resonance (NMR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), Forier transform infrared (FTIR), Raman spectroscopy, and dynamic vapor sorption (DVS). The polymorphic transformation among two polymorphs (form I and form II) and acetone solvates of candesartan cilexetil was investigated, respectively. By regulating the initial solution concentration and composition of solvent mixture (water/acetone), form I or acetone solvate could be obtained. With the aid of in situ Raman spectroscopy, the kinetics of solvent-mediated transformation (form II → acetone solvate) and solid-state transition (acetone solvate → form II) were systematically studied at different temperatures. The results show that the mechanism of solid-state transformation of acetone solvate to form II depends on one-dimensional diffusion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2024855
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12910–12916[article] Polymorphic crystallization and transformation of candesartan cilexetil [texte imprimé] / Penglei Cui, Auteur ; Qiuxiang Yin, Auteur ; Yuhong Guo, Auteur . - 2012 . - pp. 12910–12916.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12910–12916
Mots-clés : Crystallization Candesartan cilexetil Résumé : In this paper, the acetone solvate of candesartan cilexetil was preferentially crystallized from the acetone solution by cooling crystallization and was characterized by combination methods of X-ray powder diffraction (XRPD), 13C nuclear magnetic resonance (NMR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), Forier transform infrared (FTIR), Raman spectroscopy, and dynamic vapor sorption (DVS). The polymorphic transformation among two polymorphs (form I and form II) and acetone solvates of candesartan cilexetil was investigated, respectively. By regulating the initial solution concentration and composition of solvent mixture (water/acetone), form I or acetone solvate could be obtained. With the aid of in situ Raman spectroscopy, the kinetics of solvent-mediated transformation (form II → acetone solvate) and solid-state transition (acetone solvate → form II) were systematically studied at different temperatures. The results show that the mechanism of solid-state transformation of acetone solvate to form II depends on one-dimensional diffusion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2024855 Exemplaires
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Titre : Transient oxygen permeation and surface catalytic properties of lanthanum cobaltite membrane under oxygen–methane gradient Type de document : texte imprimé Auteurs : Tyler T. Norton, Auteur ; Y. S. Lin, Auteur Année de publication : 2012 Article en page(s) : pp. 12917–12925 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oxygen permeation Ceramic membranes Résumé : Oxygen permeation through mixed-conducting ceramic membranes in an air/methane gradient is important for their applications in membrane reactors for air separation and partial oxidation of hydrocarbons. This study examines transient characteristics of oxygen permeation and surface catalytic properties of La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF) membranes in an oxygen/methane gradient for an extended period of time. Upon exposure to an oxygen/methane gradient, the oxygen permeation flux of the membrane increases to a maximum at around 55 h, then decreases and reaches a steady-state value at around 200 h. The maximum and steady-state flux is approximately 60% and 30% higher than the initial flux of the fresh membrane, respectively. The surface catalytic properties of the membrane exposed to methane also change with the exposure time in a similar fashion. However, the apparent activation energy for oxygen permeation for the membranes at various stages of the transient study is nearly constant while the effects of temperature, feed pressure, and sweep flow rate on catalytic properties are also similar for the fresh and aged membranes. The surface of a LSCF membrane reacts with methane resulting in a formation of a thin porous layer which changes the surface catalytic properties. The membrane surface becomes more active for reaction with increased selectivity for carbon monoxide formation upon exposure to methane. This lowers oxygen partial pressure in the permeate side and increases the driving force for oxygen permeation and, therefore, increases oxygen permeation flux. Under the studied experimental conditions the membrane can reach steady-state for continuous operation. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301332d
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12917–12925[article] Transient oxygen permeation and surface catalytic properties of lanthanum cobaltite membrane under oxygen–methane gradient [texte imprimé] / Tyler T. Norton, Auteur ; Y. S. Lin, Auteur . - 2012 . - pp. 12917–12925.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12917–12925
Mots-clés : Oxygen permeation Ceramic membranes Résumé : Oxygen permeation through mixed-conducting ceramic membranes in an air/methane gradient is important for their applications in membrane reactors for air separation and partial oxidation of hydrocarbons. This study examines transient characteristics of oxygen permeation and surface catalytic properties of La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF) membranes in an oxygen/methane gradient for an extended period of time. Upon exposure to an oxygen/methane gradient, the oxygen permeation flux of the membrane increases to a maximum at around 55 h, then decreases and reaches a steady-state value at around 200 h. The maximum and steady-state flux is approximately 60% and 30% higher than the initial flux of the fresh membrane, respectively. The surface catalytic properties of the membrane exposed to methane also change with the exposure time in a similar fashion. However, the apparent activation energy for oxygen permeation for the membranes at various stages of the transient study is nearly constant while the effects of temperature, feed pressure, and sweep flow rate on catalytic properties are also similar for the fresh and aged membranes. The surface of a LSCF membrane reacts with methane resulting in a formation of a thin porous layer which changes the surface catalytic properties. The membrane surface becomes more active for reaction with increased selectivity for carbon monoxide formation upon exposure to methane. This lowers oxygen partial pressure in the permeate side and increases the driving force for oxygen permeation and, therefore, increases oxygen permeation flux. Under the studied experimental conditions the membrane can reach steady-state for continuous operation. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301332d Exemplaires
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Titre : Recovery of lithium using tributyl phosphate in methyl isobutyl ketone and FeCl3 Type de document : texte imprimé Auteurs : Zhiyong Zhou, Auteur ; Wei Qin, Auteur ; Shengke Liang, Auteur Année de publication : 2012 Article en page(s) : pp. 12926-12932 Note générale : Industrial chemsitry Langues : Anglais (eng) Mots-clés : Lithium Phosphate Résumé : Lithium recovery from salt-lake brines was explored using the extraction equilibria of lithium with tributyl phosphate (TBP) in methyl isobutyl ketone (MIBK), with FeCl3 coextractant, for various volume concentrations of TBP, molar ratios of Fe to Li, and volume ratios of the organic to aqueous phases. Washing and stripping equilibria of magnesium and lithium ions with HCl, NH4Cl, and LiCl/HCl and NH4Cl/HCl combinations were investigated. The extraction of lithium ions from salt-lake brines was successful. NH4Cl was a suitable washing agent for magnesium ions but not for stripping lithium ions into the aqueous phase. HCl can wash magnesium ions and strip lithium ions but corrodes equipment. The LiCl/HCl and NH4Cl/HCl combinations reduced equipment corrosion and washed and stripped magnesium and lithium ions, respectively, at appropriate volume ratios. MIBK loss was reduced using high-salinity solutions and large volume ratios during extraction and adjusting the volume ratio and overall chloride-ion concentration during washing/stripping. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3015236
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12926-12932[article] Recovery of lithium using tributyl phosphate in methyl isobutyl ketone and FeCl3 [texte imprimé] / Zhiyong Zhou, Auteur ; Wei Qin, Auteur ; Shengke Liang, Auteur . - 2012 . - pp. 12926-12932.
Industrial chemsitry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12926-12932
Mots-clés : Lithium Phosphate Résumé : Lithium recovery from salt-lake brines was explored using the extraction equilibria of lithium with tributyl phosphate (TBP) in methyl isobutyl ketone (MIBK), with FeCl3 coextractant, for various volume concentrations of TBP, molar ratios of Fe to Li, and volume ratios of the organic to aqueous phases. Washing and stripping equilibria of magnesium and lithium ions with HCl, NH4Cl, and LiCl/HCl and NH4Cl/HCl combinations were investigated. The extraction of lithium ions from salt-lake brines was successful. NH4Cl was a suitable washing agent for magnesium ions but not for stripping lithium ions into the aqueous phase. HCl can wash magnesium ions and strip lithium ions but corrodes equipment. The LiCl/HCl and NH4Cl/HCl combinations reduced equipment corrosion and washed and stripped magnesium and lithium ions, respectively, at appropriate volume ratios. MIBK loss was reduced using high-salinity solutions and large volume ratios during extraction and adjusting the volume ratio and overall chloride-ion concentration during washing/stripping. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3015236 Exemplaires
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Titre : Adsorption study of glycerol in biodiesel on the sulfonated adsorbent Type de document : texte imprimé Auteurs : Bin Chen, Auteur ; Wusheng Wang, Auteur ; Xiao Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 12933-12939 Note générale : Industrial chemsitry Langues : Anglais (eng) Mots-clés : Adsorption Résumé : The adsorption isotherm data of glycerol from biodiesel (FAME, fatty acid alkyl esters) onto the sulfonated adsorbent were obtained via batch equilibrium tests at different temperatures in the range of 303―323 K. Subsequently, these data were fitted by four isotherm models. Freundlich isotherm model was the best fitted (r2 > 0.98), and the model parameter 1/ n implied that the adsorption process was favorable. For the Dubinin-Radushkevich (D-R) isotherm model, the model parameter QD decreased with increasing temperature, and the mean free energy of sorption (E) was less than 8 kJ mol―1. The results of QD and E reflected the exothermic and physical properties of the adsorption process, respectively. The negative values of Gibbs free energy change (ΔG0) and enthalpy change (ΔH0) indicated that the adsorption occurs spontaneously with an exothermic nature, while the positive values of entropy change (ΔS0) suggested the increase in randomness at the solid-liquid interface during adsorption. The isosteric heat of adsorption (ΔHx) suggested that strong hydrogen bonding between glycerol and the ―SO3― groups of the sulfonated adsorbent dominated the adsorption process and that there existed adsorbate-adsorbate mutual attractive interaction. Furthermore, the existence of hydrogen bonding was also confirmed by infrared spectra. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301951p
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12933-12939[article] Adsorption study of glycerol in biodiesel on the sulfonated adsorbent [texte imprimé] / Bin Chen, Auteur ; Wusheng Wang, Auteur ; Xiao Liu, Auteur . - 2012 . - pp. 12933-12939.
Industrial chemsitry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12933-12939
Mots-clés : Adsorption Résumé : The adsorption isotherm data of glycerol from biodiesel (FAME, fatty acid alkyl esters) onto the sulfonated adsorbent were obtained via batch equilibrium tests at different temperatures in the range of 303―323 K. Subsequently, these data were fitted by four isotherm models. Freundlich isotherm model was the best fitted (r2 > 0.98), and the model parameter 1/ n implied that the adsorption process was favorable. For the Dubinin-Radushkevich (D-R) isotherm model, the model parameter QD decreased with increasing temperature, and the mean free energy of sorption (E) was less than 8 kJ mol―1. The results of QD and E reflected the exothermic and physical properties of the adsorption process, respectively. The negative values of Gibbs free energy change (ΔG0) and enthalpy change (ΔH0) indicated that the adsorption occurs spontaneously with an exothermic nature, while the positive values of entropy change (ΔS0) suggested the increase in randomness at the solid-liquid interface during adsorption. The isosteric heat of adsorption (ΔHx) suggested that strong hydrogen bonding between glycerol and the ―SO3― groups of the sulfonated adsorbent dominated the adsorption process and that there existed adsorbate-adsorbate mutual attractive interaction. Furthermore, the existence of hydrogen bonding was also confirmed by infrared spectra. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301951p Exemplaires
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Titre : Electrochemical and quantum chemical investigation of some azine and thiazine dyes as potential corrosion inhibitors for mild steel in hydrochloric acid solution Type de document : texte imprimé Auteurs : Eno E. Ebenso, Auteur ; Mwadham M. Kabanda, Auteur ; Lutendo C. Murulana, Auteur Année de publication : 2012 Article en page(s) : pp 12940–12958 Note générale : Industrial chemsitry Langues : Anglais (eng) Mots-clés : Electrochemical Hydrochloric acid Résumé : The inhibition performances of some selected azine and thiazine dyes, namely, Neutral Red (NR), Azure A Eosinate (AAE), Toluidine Blue (TB), phenosafranin (PS), and Rhodanile Blue (RB), on mild steel corrosion in hydrochloric acid solution was studied the using electrochemical impedance spectroscopy (EIS) and Tafel polarization techniques. Quantum chemical calculations based on the density functional theory (DFT) and semiempirical (PM3) methods were used to investigate the reactivities and selectivities of the studied cationic dyes. The effects of inhibitor concentration on the inhibition efficiency have been studied. Inhibition efficiency increased with increase in concentration of all the studied cationic dyes within the concentration range 100–500 ppm. Potentiodynamic studies revealed that all the inhibitors are of mixed type. The results obtained from the EIS studies showed good agreement with the results from potentiodynamic polarization techniques. The quantitative structure–activity relationship (QSAR) approach was also used to correlate the quantum chemical parameters with the experimentally determined inhibition efficiencies. The results show that thiazine dyes are better corrosion inhibitors than azine dyes; however, when azines contain more electron donor centers than thiazines, they are preferred as corrosion inhibitors to thiazine. Hydrogen bonding could be one of the possible physisorption mechanisms for the adsorption of the selected dyes onto the metal surface because of the many hydrogen bond donor centers in the studied compounds. QSAR results show good correlations between a number of quantum chemical parameters and the determined inhibition efficiency. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300965k
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp 12940–12958[article] Electrochemical and quantum chemical investigation of some azine and thiazine dyes as potential corrosion inhibitors for mild steel in hydrochloric acid solution [texte imprimé] / Eno E. Ebenso, Auteur ; Mwadham M. Kabanda, Auteur ; Lutendo C. Murulana, Auteur . - 2012 . - pp 12940–12958.
Industrial chemsitry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp 12940–12958
Mots-clés : Electrochemical Hydrochloric acid Résumé : The inhibition performances of some selected azine and thiazine dyes, namely, Neutral Red (NR), Azure A Eosinate (AAE), Toluidine Blue (TB), phenosafranin (PS), and Rhodanile Blue (RB), on mild steel corrosion in hydrochloric acid solution was studied the using electrochemical impedance spectroscopy (EIS) and Tafel polarization techniques. Quantum chemical calculations based on the density functional theory (DFT) and semiempirical (PM3) methods were used to investigate the reactivities and selectivities of the studied cationic dyes. The effects of inhibitor concentration on the inhibition efficiency have been studied. Inhibition efficiency increased with increase in concentration of all the studied cationic dyes within the concentration range 100–500 ppm. Potentiodynamic studies revealed that all the inhibitors are of mixed type. The results obtained from the EIS studies showed good agreement with the results from potentiodynamic polarization techniques. The quantitative structure–activity relationship (QSAR) approach was also used to correlate the quantum chemical parameters with the experimentally determined inhibition efficiencies. The results show that thiazine dyes are better corrosion inhibitors than azine dyes; however, when azines contain more electron donor centers than thiazines, they are preferred as corrosion inhibitors to thiazine. Hydrogen bonding could be one of the possible physisorption mechanisms for the adsorption of the selected dyes onto the metal surface because of the many hydrogen bond donor centers in the studied compounds. QSAR results show good correlations between a number of quantum chemical parameters and the determined inhibition efficiency. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300965k Exemplaires
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Titre : The Behavior of chitosan in solvents with different ionic strengths Type de document : texte imprimé Auteurs : Simona Morariu, Auteur ; Cristina-Eliza Brunchi, Auteur ; Maria Bercea, Auteur Année de publication : 2012 Article en page(s) : pp. 12959–12966 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Solvents Ionic strengths Résumé : The thermodynamic behavior of chitosan in acidic aqueous solutions with ionic strengths between 0.04 × 10–2 and 24.30 × 10–2 M was investigated at 25 °C. The intrinsic viscosity and other thermodynamic parameters of chitosan with the molecular weight and the degree of acetylation of 7.14 × 105 g mol–1 and 26%, respectively, were determined and discussed by using both classical equations (Huggins and Fedors) and a new model (Wolf). At low ionic strengths of the solvent, the highest values of the intrinsic viscosity were obtained due to the expansion of the chitosan chains. Two critical concentrations, c* (which separates the dilute-semidilute regimes) and c+ (at which the dimensions of the polymer coils are considered to have shrunk to their unperturbed dimensions), were estimated, and the effect of the solvent ionic strength on their values was discussed. By increasing of the solvent ionic strength from 0.04 × 10–2 to 24.30 × 10–2 M, the persistence length decreased from 17.14 to 4.60 nm, suggesting an increase of the chitosan flexibility due to the decrease of repulsive potential between the polymer chains. The radius of gyration and the persistence length in the unperturbed state were determined as being 52.50 and 3.90 nm, respectively. The viscometric data were corroborated with those obtained by the zeta potential, conductivity, and turbidity measurements for the ionic strength of the solvent between 0.04 × 10–2 and 42.25 × 10–2 M. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301309g
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12959–12966[article] The Behavior of chitosan in solvents with different ionic strengths [texte imprimé] / Simona Morariu, Auteur ; Cristina-Eliza Brunchi, Auteur ; Maria Bercea, Auteur . - 2012 . - pp. 12959–12966.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12959–12966
Mots-clés : Solvents Ionic strengths Résumé : The thermodynamic behavior of chitosan in acidic aqueous solutions with ionic strengths between 0.04 × 10–2 and 24.30 × 10–2 M was investigated at 25 °C. The intrinsic viscosity and other thermodynamic parameters of chitosan with the molecular weight and the degree of acetylation of 7.14 × 105 g mol–1 and 26%, respectively, were determined and discussed by using both classical equations (Huggins and Fedors) and a new model (Wolf). At low ionic strengths of the solvent, the highest values of the intrinsic viscosity were obtained due to the expansion of the chitosan chains. Two critical concentrations, c* (which separates the dilute-semidilute regimes) and c+ (at which the dimensions of the polymer coils are considered to have shrunk to their unperturbed dimensions), were estimated, and the effect of the solvent ionic strength on their values was discussed. By increasing of the solvent ionic strength from 0.04 × 10–2 to 24.30 × 10–2 M, the persistence length decreased from 17.14 to 4.60 nm, suggesting an increase of the chitosan flexibility due to the decrease of repulsive potential between the polymer chains. The radius of gyration and the persistence length in the unperturbed state were determined as being 52.50 and 3.90 nm, respectively. The viscometric data were corroborated with those obtained by the zeta potential, conductivity, and turbidity measurements for the ionic strength of the solvent between 0.04 × 10–2 and 42.25 × 10–2 M. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301309g Exemplaires
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Titre : Heterosegmented perturbed-chain statistical associating fluid theory as a robust and accurate tool for modeling of various alkanes.1. : Pure fluids Type de document : texte imprimé Auteurs : Kamil Paduszynski, Auteur ; Urszula Domanska, Auteur Année de publication : 2012 Article en page(s) : pp. 12967-12983 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Modeling Résumé : Heterosegmented molecular models based on statistical associating fluid theory (SAFT) seem to be very promising and robust tools for modeling thermodynamic properties of fluid mixtures. They differ from conventional SAFT-based methodologies as they take into account varying sizes and interactions of segments constituting chain molecules. Those different types of segments can be assigned to functional groups, and hence, the group contribution (GC) method is incorporated in a straightforward manner into the SAFT approach. In this contribution, we applied a heterosegmented version of perturbed-chain SAFT (hs-PC-SAFT) for modeling thermodynamic behavior of a great variety of pure saturated hydrocarbons, including n-alkanes, branched alkanes, and alkyl-monosubstituted cyclohexanes and cyclopentanes. All the investigated compounds were assumed to be composed of 11 distinct functional groups defined within the GC model. The properties under consideration were saturated liquid and vapor density, vapor pressure, enthalpy of vaporization, surface tension, isobaric heat capacity, speed of sound, the Joule―Thomson coefficient, the Joule―Thomson inversion curve, and the second virial coefficient. The respective model parameters (segments number mv segment diameter σi) for each defined functional group i as well as self- and/or cross-interaction parameters (uij/κB) for each pair of groups i-j were determined by fitting experimental saturated liquid densities and vapor pressures of some selected alkanes over a wide range of temperature. Then, the optimized parameters were used to predict the properties of other compounds, and finally, the resulting predictions were compared to those obtained by using different similar methods described in the literature. It was shown that an overall predictive capacity of the hs-PC-SAFT approach is comparable to other similar methods based on "variable-range" SAFT (SAFT-VR) and superior over the conventional homosegmented SAFT models involving groups contributions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419253
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12967-12983[article] Heterosegmented perturbed-chain statistical associating fluid theory as a robust and accurate tool for modeling of various alkanes.1. : Pure fluids [texte imprimé] / Kamil Paduszynski, Auteur ; Urszula Domanska, Auteur . - 2012 . - pp. 12967-12983.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12967-12983
Mots-clés : Modeling Résumé : Heterosegmented molecular models based on statistical associating fluid theory (SAFT) seem to be very promising and robust tools for modeling thermodynamic properties of fluid mixtures. They differ from conventional SAFT-based methodologies as they take into account varying sizes and interactions of segments constituting chain molecules. Those different types of segments can be assigned to functional groups, and hence, the group contribution (GC) method is incorporated in a straightforward manner into the SAFT approach. In this contribution, we applied a heterosegmented version of perturbed-chain SAFT (hs-PC-SAFT) for modeling thermodynamic behavior of a great variety of pure saturated hydrocarbons, including n-alkanes, branched alkanes, and alkyl-monosubstituted cyclohexanes and cyclopentanes. All the investigated compounds were assumed to be composed of 11 distinct functional groups defined within the GC model. The properties under consideration were saturated liquid and vapor density, vapor pressure, enthalpy of vaporization, surface tension, isobaric heat capacity, speed of sound, the Joule―Thomson coefficient, the Joule―Thomson inversion curve, and the second virial coefficient. The respective model parameters (segments number mv segment diameter σi) for each defined functional group i as well as self- and/or cross-interaction parameters (uij/κB) for each pair of groups i-j were determined by fitting experimental saturated liquid densities and vapor pressures of some selected alkanes over a wide range of temperature. Then, the optimized parameters were used to predict the properties of other compounds, and finally, the resulting predictions were compared to those obtained by using different similar methods described in the literature. It was shown that an overall predictive capacity of the hs-PC-SAFT approach is comparable to other similar methods based on "variable-range" SAFT (SAFT-VR) and superior over the conventional homosegmented SAFT models involving groups contributions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419253 Exemplaires
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Titre : Mechanism research on the development of ash deposits on the heating surface of biomass furnaces Type de document : texte imprimé Auteurs : Xuebin Wang, Auteur ; Yuanyi Liu, Auteur ; Houzhang Tan, Auteur Année de publication : 2012 Article en page(s) : pp 12984–12992 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Biomass Résumé : Sulfate and chlorate are the key species contributing to the formation of ash deposits in a biomass furnace. In this paper, biomass combustion has been tested in a drop-tube furnace, and the ash deposits on a heating surface have been sampled. The physical and chemical characteristics of the deposits were analyzed using transmission electron microscopy in order to investigate the development of the ash deposits. The laboratory results have been compared with the ash deposit samples obtained from a biomass-fired power plant furnace. The results from both the laboratory and the plant samples indicate that most of the alkali chloride has been homogeneously converted into alkali sulfate in flue gas before deposition on the heating surface and that sulfate aerosols play a dominant role in the formation of biomass ash deposits. Finally, major pathways of alkali sulfation and the role of sulfate aerosols formed in the biomass-ash deposition are proposed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302009m
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp 12984–12992[article] Mechanism research on the development of ash deposits on the heating surface of biomass furnaces [texte imprimé] / Xuebin Wang, Auteur ; Yuanyi Liu, Auteur ; Houzhang Tan, Auteur . - 2012 . - pp 12984–12992.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp 12984–12992
Mots-clés : Biomass Résumé : Sulfate and chlorate are the key species contributing to the formation of ash deposits in a biomass furnace. In this paper, biomass combustion has been tested in a drop-tube furnace, and the ash deposits on a heating surface have been sampled. The physical and chemical characteristics of the deposits were analyzed using transmission electron microscopy in order to investigate the development of the ash deposits. The laboratory results have been compared with the ash deposit samples obtained from a biomass-fired power plant furnace. The results from both the laboratory and the plant samples indicate that most of the alkali chloride has been homogeneously converted into alkali sulfate in flue gas before deposition on the heating surface and that sulfate aerosols play a dominant role in the formation of biomass ash deposits. Finally, major pathways of alkali sulfation and the role of sulfate aerosols formed in the biomass-ash deposition are proposed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302009m Exemplaires
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