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Vol. 51 N° 15 - Avril 2012 [texte imprimé] . - 2012 . - p. 5375-5634 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierGreen high - gravitational synthesis of silver nanoparticles using a rotating packed bed reactor (RPBR) / Chee Meng Ng in Industrial & engineering chemistry research, Vol. 51 N° 15 (Avril 2012)
Titre : Green high - gravitational synthesis of silver nanoparticles using a rotating packed bed reactor (RPBR) Type de document : texte imprimé Auteurs : Chee Meng Ng, Auteur ; Pao Chi Chen, Auteur ; Sivakumar Manickam, Auteur Année de publication : 2012 Article en page(s) : pp. 5375-5381 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Fixed bed reactor Nanoparticle Résumé : Although the synthesis of silver nanopartides via chemical precipitation is the easiest to scale up for industrial production, the use of conventional stirring methods suffers from large and widely distributed particle sizes due to poor macro-and micromixing efficiency which is vital in providing the necessary supersaturated conditions. These problems can be mitigated using the high-gravitational mixing method which significantly improves mixing efficiency and greatly reduces reaction times. In this work, we describe the preparation of silver nanoparticles from green materials using a high-gravitational rotating packed bed reactor and present our findings on the significance and effects of concentration and feed flow rate of reactants and packed bed rotation speed on the sample particle size and recovery yield. Taguchi statistical analysis was used to optimize each parameter for small particle size and high product yield. To determine the particle size and silver concentration of the synthesized samples, dynamic light scattering (DLS) and inductively coupled plasma mass spectrometry (ICP) were used respectively. X-ray diffraction (XRD), UV-vis spectroscopy, and transmission electron microscopy (TEM) imaging were used for further characterization of the produced nanoparticles. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815813
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5375-5381[article] Green high - gravitational synthesis of silver nanoparticles using a rotating packed bed reactor (RPBR) [texte imprimé] / Chee Meng Ng, Auteur ; Pao Chi Chen, Auteur ; Sivakumar Manickam, Auteur . - 2012 . - pp. 5375-5381.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5375-5381
Mots-clés : Fixed bed reactor Nanoparticle Résumé : Although the synthesis of silver nanopartides via chemical precipitation is the easiest to scale up for industrial production, the use of conventional stirring methods suffers from large and widely distributed particle sizes due to poor macro-and micromixing efficiency which is vital in providing the necessary supersaturated conditions. These problems can be mitigated using the high-gravitational mixing method which significantly improves mixing efficiency and greatly reduces reaction times. In this work, we describe the preparation of silver nanoparticles from green materials using a high-gravitational rotating packed bed reactor and present our findings on the significance and effects of concentration and feed flow rate of reactants and packed bed rotation speed on the sample particle size and recovery yield. Taguchi statistical analysis was used to optimize each parameter for small particle size and high product yield. To determine the particle size and silver concentration of the synthesized samples, dynamic light scattering (DLS) and inductively coupled plasma mass spectrometry (ICP) were used respectively. X-ray diffraction (XRD), UV-vis spectroscopy, and transmission electron microscopy (TEM) imaging were used for further characterization of the produced nanoparticles. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815813 Exemplaires
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Titre : Effects of catalyst bed failure on thermochemical phenomena for a hydrazine monopropellant thruster using Ir / A l2O3 catalysts Type de document : texte imprimé Auteurs : Chang Hwan Hwang, Auteur ; Sung Nam Lee, Auteur ; Seung Wook Baek, Auteur Année de publication : 2012 Article en page(s) : pp. 5382–5393 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Propellants Catalysts Résumé : Hydrazine monopropellant has been used in thrusters for maneuvering satellites and landing spacecraft. Testing and handling procedures for hydrazine monopropellant thrusters are complicated, because of the toxicity of the hydrazine and its decomposition product gases. Therefore, simulated numerical analysis can help elucidate the effects of various thruster design parameters and can reduce both development time and expenses. In this study, a simulated numerical analysis was performed in which the catalyst bed was modeled as a one-dimensional porous medium. The resulting physical phenomena were examined by considering variations in catalyst bed characteristics incurred by catalyst pellet failure. From observations of various hot-firing experiments, it was determined that the upper region of the decomposition chamber was preferentially damaged in failure situations, which led to the conclusion that catalyst failure occurs in the upper region only. We simulated various cases based on the crushing and mass loss of catalyst pellets. The distributions of temperature, species mass fraction, heterogeneous reaction rate, and pressure were calculated after catalyst bed failure. The pressures at the decomposition chamber exit and the thrust at the nozzle exit were monitored with time. Through these analyses, the thermochemical phenomena inside a hydrazine monopropellant thruster system were interpreted in detail. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202347f
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5382–5393[article] Effects of catalyst bed failure on thermochemical phenomena for a hydrazine monopropellant thruster using Ir / A l2O3 catalysts [texte imprimé] / Chang Hwan Hwang, Auteur ; Sung Nam Lee, Auteur ; Seung Wook Baek, Auteur . - 2012 . - pp. 5382–5393.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5382–5393
Mots-clés : Propellants Catalysts Résumé : Hydrazine monopropellant has been used in thrusters for maneuvering satellites and landing spacecraft. Testing and handling procedures for hydrazine monopropellant thrusters are complicated, because of the toxicity of the hydrazine and its decomposition product gases. Therefore, simulated numerical analysis can help elucidate the effects of various thruster design parameters and can reduce both development time and expenses. In this study, a simulated numerical analysis was performed in which the catalyst bed was modeled as a one-dimensional porous medium. The resulting physical phenomena were examined by considering variations in catalyst bed characteristics incurred by catalyst pellet failure. From observations of various hot-firing experiments, it was determined that the upper region of the decomposition chamber was preferentially damaged in failure situations, which led to the conclusion that catalyst failure occurs in the upper region only. We simulated various cases based on the crushing and mass loss of catalyst pellets. The distributions of temperature, species mass fraction, heterogeneous reaction rate, and pressure were calculated after catalyst bed failure. The pressures at the decomposition chamber exit and the thrust at the nozzle exit were monitored with time. Through these analyses, the thermochemical phenomena inside a hydrazine monopropellant thruster system were interpreted in detail. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202347f Exemplaires
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Titre : Functionalization of cotton with UV - cured flame retardant coatings Type de document : texte imprimé Auteurs : Haixia Yuan, Auteur ; Weiyi Xing, Auteur ; Ping Zhang, Auteur Année de publication : 2012 Article en page(s) : pp. 5394–5401 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Textiles Fibers Résumé : A novel phosphorus monomer (PDHA) was synthesized and incorporated onto the surface of cotton fabric via UV-induced graft polymerization to improve flame retardancy and thermal stability. The structure of PDHA was characterized by 1H nuclear magnetic resonance (1H NMR), 31P NMR, and Fourier transform infrared spectra (FTIR) and the grafting processes were followed by IR (ATR) spectroscopy and scanning electron microscopy (SEM). The thermal stability and flame retardancy of the treated fabrics were studied by thermogravimetric analysis (TGA), thermogravimetric analysis/infrared spectrometry (TGA-IR), and microscale combustion colorimeter (MCC). Test performed on real time FTIR analysis for treated cotton showed that the coatings containing phosphorus could catalyze the dehydration and char formation of cotton textiles at a lower temperature. The enhanced flame retardant action may be caused by the thermal decomposition of phosphate acrylate producing acidic intermediates, which could react with fabrics to alter its thermal decomposition. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202468u
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5394–5401[article] Functionalization of cotton with UV - cured flame retardant coatings [texte imprimé] / Haixia Yuan, Auteur ; Weiyi Xing, Auteur ; Ping Zhang, Auteur . - 2012 . - pp. 5394–5401.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5394–5401
Mots-clés : Textiles Fibers Résumé : A novel phosphorus monomer (PDHA) was synthesized and incorporated onto the surface of cotton fabric via UV-induced graft polymerization to improve flame retardancy and thermal stability. The structure of PDHA was characterized by 1H nuclear magnetic resonance (1H NMR), 31P NMR, and Fourier transform infrared spectra (FTIR) and the grafting processes were followed by IR (ATR) spectroscopy and scanning electron microscopy (SEM). The thermal stability and flame retardancy of the treated fabrics were studied by thermogravimetric analysis (TGA), thermogravimetric analysis/infrared spectrometry (TGA-IR), and microscale combustion colorimeter (MCC). Test performed on real time FTIR analysis for treated cotton showed that the coatings containing phosphorus could catalyze the dehydration and char formation of cotton textiles at a lower temperature. The enhanced flame retardant action may be caused by the thermal decomposition of phosphate acrylate producing acidic intermediates, which could react with fabrics to alter its thermal decomposition. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202468u Exemplaires
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Titre : Production of biodiesel by esterification of stearic acid over aminophosphonic acid resin D418 Type de document : texte imprimé Auteurs : Chen, Wen, Auteur ; Ping Yin, Auteur ; Hou Chen, Auteur Année de publication : 2012 Article en page(s) : pp. 5402–5407 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Biodiesel Esterification Résumé : Biodiesel production has become a very intense research field because of its environmental benefits and the growing interest in finding new resources and alternatives for conventional fuels. In the present work, biodiesel production from the esterification of the free fatty acid stearic acid with ethanol over aminophosphonic acid resin D418 was studied. The effects of experimental factors such as the amount of D418, reaction temperature, and molar ratio of ethanol to stearic acid on the conversion ratio were evaluated. Process optimization using response surface methodology (RSM) was performed, and the interactions between the operating variables were elucidated. The optimum values for maximum esterification percentage were obtained by using a Box–Behnken center-united design with a minimum of experimental work. Moreover, the kinetics of the esterification catalyzed by D418 was studied, and the pseudohomogeneous (PH) model was used to simulate the experimental data. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202786w
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5402–5407[article] Production of biodiesel by esterification of stearic acid over aminophosphonic acid resin D418 [texte imprimé] / Chen, Wen, Auteur ; Ping Yin, Auteur ; Hou Chen, Auteur . - 2012 . - pp. 5402–5407.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5402–5407
Mots-clés : Biodiesel Esterification Résumé : Biodiesel production has become a very intense research field because of its environmental benefits and the growing interest in finding new resources and alternatives for conventional fuels. In the present work, biodiesel production from the esterification of the free fatty acid stearic acid with ethanol over aminophosphonic acid resin D418 was studied. The effects of experimental factors such as the amount of D418, reaction temperature, and molar ratio of ethanol to stearic acid on the conversion ratio were evaluated. Process optimization using response surface methodology (RSM) was performed, and the interactions between the operating variables were elucidated. The optimum values for maximum esterification percentage were obtained by using a Box–Behnken center-united design with a minimum of experimental work. Moreover, the kinetics of the esterification catalyzed by D418 was studied, and the pseudohomogeneous (PH) model was used to simulate the experimental data. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202786w Exemplaires
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Titre : Anticorrosion potential of 4 - Amino - 3 - methyl - 1,2,4 - triazole - 5 - thione derivatives (SAMTT and DBAMTT) on mild steel in hydrochloric acid solution Type de document : texte imprimé Auteurs : Moorthy Saravana Kumar, Auteur ; Saravana Loganathan Ashok Kumar, Auteur ; Anandaram Sreekanth, Auteur Année de publication : 2012 Article en page(s) : pp. 5408–5418 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Corrosion Hydrochloric acid Electrochemical Résumé : The corrosion inhibition efficiency of two Schiff bases 4-salicylideneamino-3-methyl-1,2,4-triazole-5-thione (SAMTT) and 4-(2,4-dihydroxybenzylideneamino)-3-methyl-1H-1,2,4-triazole-5(4H)-thione (DBAMTT) on mild steel in hydrochloric acid was tested by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. The results revealed that both SAMTT and DBAMTT act as excellent inhibitors, and the inhibition efficiencies obtained from the weight loss and electrochemical experiments were in good agreement. Scanning electron microscopic and atomic force microscopic images showed the efficiency of the compounds as inhibitors on mild steel in acid media, and both surface analysis techniques revealed that the inhibition occurs due to adsorption of the inhibitor molecules at the metal/solution interface. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie203022g
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5408–5418[article] Anticorrosion potential of 4 - Amino - 3 - methyl - 1,2,4 - triazole - 5 - thione derivatives (SAMTT and DBAMTT) on mild steel in hydrochloric acid solution [texte imprimé] / Moorthy Saravana Kumar, Auteur ; Saravana Loganathan Ashok Kumar, Auteur ; Anandaram Sreekanth, Auteur . - 2012 . - pp. 5408–5418.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5408–5418
Mots-clés : Corrosion Hydrochloric acid Electrochemical Résumé : The corrosion inhibition efficiency of two Schiff bases 4-salicylideneamino-3-methyl-1,2,4-triazole-5-thione (SAMTT) and 4-(2,4-dihydroxybenzylideneamino)-3-methyl-1H-1,2,4-triazole-5(4H)-thione (DBAMTT) on mild steel in hydrochloric acid was tested by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. The results revealed that both SAMTT and DBAMTT act as excellent inhibitors, and the inhibition efficiencies obtained from the weight loss and electrochemical experiments were in good agreement. Scanning electron microscopic and atomic force microscopic images showed the efficiency of the compounds as inhibitors on mild steel in acid media, and both surface analysis techniques revealed that the inhibition occurs due to adsorption of the inhibitor molecules at the metal/solution interface. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie203022g Exemplaires
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Titre : Experimental studies on decomposing properties of desulfurization gypsum in a thermogravimetric Analyzer and Multiatmosphere Fluidized Beds Type de document : texte imprimé Auteurs : Zhu, Miao, Auteur ; Hairui Yang, Auteur ; Yuxin Wu, Auteur Année de publication : 2012 Article en page(s) : pp. 5419–5423 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gas Desulfurization Thermogravimetric analyzer Résumé : This paper proposes a new technical process to utilize flue gas desulfurization (FGD) gypsum in fluidized beds. Gypsum is stable in the inert atmosphere and instable in the reducing atmosphere. Decomposing properties of gypsum in multiatmospheres were investigated in both a thermogravimetric analyzer (TGA) and a fluidized bed reactor. Results from the TGA showed that the initial decomposing temperatures of gypsum in all reducing atmospheres are about 800 °C; however, the ratio between CaS and CaO in the product is influenced by CO concentration ([CO]). Higher [CO] is beneficial to speeding the decomposition. The analysis of mass spectrometer showed that part of CaS was oxidized to CaO when the atmosphere was changed from the reducing one with [CO] = 2% to the oxidizing one with O2 concentration of 0.6%, which was proved by the XRD analysis of the final product with content of CaO of 91.6%. Fluidized bed experiments were done in a hot, lab scale, bubbling reactor. Results showed that CO2 can increase the CaO content in the product by restraining the side production of CaS significantly. After gypsum decomposition in the reducing atmosphere, a certain amount of air was injected to change the atmosphere to oxidizing, and more SO2 was released. The present research proves that a multistage fluidized bed system with multiatmospheres is feasible for gypsum decomposition. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300092s
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5419–5423[article] Experimental studies on decomposing properties of desulfurization gypsum in a thermogravimetric Analyzer and Multiatmosphere Fluidized Beds [texte imprimé] / Zhu, Miao, Auteur ; Hairui Yang, Auteur ; Yuxin Wu, Auteur . - 2012 . - pp. 5419–5423.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5419–5423
Mots-clés : Gas Desulfurization Thermogravimetric analyzer Résumé : This paper proposes a new technical process to utilize flue gas desulfurization (FGD) gypsum in fluidized beds. Gypsum is stable in the inert atmosphere and instable in the reducing atmosphere. Decomposing properties of gypsum in multiatmospheres were investigated in both a thermogravimetric analyzer (TGA) and a fluidized bed reactor. Results from the TGA showed that the initial decomposing temperatures of gypsum in all reducing atmospheres are about 800 °C; however, the ratio between CaS and CaO in the product is influenced by CO concentration ([CO]). Higher [CO] is beneficial to speeding the decomposition. The analysis of mass spectrometer showed that part of CaS was oxidized to CaO when the atmosphere was changed from the reducing one with [CO] = 2% to the oxidizing one with O2 concentration of 0.6%, which was proved by the XRD analysis of the final product with content of CaO of 91.6%. Fluidized bed experiments were done in a hot, lab scale, bubbling reactor. Results showed that CO2 can increase the CaO content in the product by restraining the side production of CaS significantly. After gypsum decomposition in the reducing atmosphere, a certain amount of air was injected to change the atmosphere to oxidizing, and more SO2 was released. The present research proves that a multistage fluidized bed system with multiatmospheres is feasible for gypsum decomposition. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300092s Exemplaires
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Titre : Oxidation of some macromolecules. kinetics and mechanism of oxidation of methyl cellulose polysaccharide by permanganate ion in acid perchlorate solutions Type de document : texte imprimé Auteurs : Refat Hassan, Auteur ; Abdel Rahman Dahy, Auteur ; Samia Ibrahim, Auteur Année de publication : 2012 Article en page(s) : pp. 5424–5432 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics Oxidation Résumé : The kinetics of oxidation of methyl cellulose polysaccharide by acidic permanganate at a constant ionic strength of 2.0 mol dm–3 has been investigated, spectrophotometrically. Pseudo-first-order plots showed two distinct stages. The first stage was found to be relatively slow which corresponded to the formation of the substrate radical and Mn3+ or Mn4+ species as initial oxidation products, followed by an increase in the reaction rate at longer time periods. The reaction kinetics showed first-order dependence in permanganate and fractional second-order kinetics with respect to methyl cellulose concentration. The hydrogen ion dependence of the reaction rates indicated that the oxidation process is acid catalyzed. The induced polymerization of acrylonitrile indicated the intervention of free-radical mechanism. A kinetic evidence for the formation of 1:2 intermediate complex between the oxidant and the reductant, respectively, was revealed. The activation parameters have been evaluated, and a tentative reaction mechanism consistent with the kinetic results obtained is discussed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200646p
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5424–5432[article] Oxidation of some macromolecules. kinetics and mechanism of oxidation of methyl cellulose polysaccharide by permanganate ion in acid perchlorate solutions [texte imprimé] / Refat Hassan, Auteur ; Abdel Rahman Dahy, Auteur ; Samia Ibrahim, Auteur . - 2012 . - pp. 5424–5432.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5424–5432
Mots-clés : Kinetics Oxidation Résumé : The kinetics of oxidation of methyl cellulose polysaccharide by acidic permanganate at a constant ionic strength of 2.0 mol dm–3 has been investigated, spectrophotometrically. Pseudo-first-order plots showed two distinct stages. The first stage was found to be relatively slow which corresponded to the formation of the substrate radical and Mn3+ or Mn4+ species as initial oxidation products, followed by an increase in the reaction rate at longer time periods. The reaction kinetics showed first-order dependence in permanganate and fractional second-order kinetics with respect to methyl cellulose concentration. The hydrogen ion dependence of the reaction rates indicated that the oxidation process is acid catalyzed. The induced polymerization of acrylonitrile indicated the intervention of free-radical mechanism. A kinetic evidence for the formation of 1:2 intermediate complex between the oxidant and the reductant, respectively, was revealed. The activation parameters have been evaluated, and a tentative reaction mechanism consistent with the kinetic results obtained is discussed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200646p Exemplaires
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Titre : Synthesis of dipentyl carbonate by transesterification using basic ionic liquid [bmIm] OH catalyst Type de document : texte imprimé Auteurs : Sheng Han, Auteur ; Ming Luo, Auteur ; Xiaoli Zhou, Auteur Année de publication : 2012 Article en page(s) : pp. 5433–5437 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : catalytic Ionic liquid Résumé : The catalytic synthesis from transesterification of dimethyl carbonate (DMC) and 1-pentanol (1-PeOH) over alkaline ionic liquid 1-butyl-3-methylimidazolium hydroxide ([bmIm]OH), as well as the optimal reaction conditions, was studied. Results showed that [bmIm]OH exhibited high activity and when the reaction time was 4 h, catalyst dosage was 2.0%, n(DMC):n(1-PeOH) was 1:4, and the dipentyl carbonate (DPC) yield was up to 75.81%. After the alkaline ionic liquid [bmIm]OH was used 5 times repeatedly, the catalytic activity still remained at 94%. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202628m
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5433–5437[article] Synthesis of dipentyl carbonate by transesterification using basic ionic liquid [bmIm] OH catalyst [texte imprimé] / Sheng Han, Auteur ; Ming Luo, Auteur ; Xiaoli Zhou, Auteur . - 2012 . - pp. 5433–5437.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5433–5437
Mots-clés : catalytic Ionic liquid Résumé : The catalytic synthesis from transesterification of dimethyl carbonate (DMC) and 1-pentanol (1-PeOH) over alkaline ionic liquid 1-butyl-3-methylimidazolium hydroxide ([bmIm]OH), as well as the optimal reaction conditions, was studied. Results showed that [bmIm]OH exhibited high activity and when the reaction time was 4 h, catalyst dosage was 2.0%, n(DMC):n(1-PeOH) was 1:4, and the dipentyl carbonate (DPC) yield was up to 75.81%. After the alkaline ionic liquid [bmIm]OH was used 5 times repeatedly, the catalytic activity still remained at 94%. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202628m Exemplaires
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Titre : Activity of calcium methoxide catalyst for synthesis of high oleic palm oil based trimethylolpropane triesters as lubricant base stock Type de document : texte imprimé Auteurs : Teck-Sin Chang, Auteur ; Hassan Masood, Auteur ; Robiah Yunus, Auteur Année de publication : 2012 Article en page(s) : pp. 5438-5442 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Lubricant Catalyst Résumé : High oleic palm oil based trimethylolpropane triesters (TMPTE) are potential biodegradable base stocks for lubricant production. Calcium methoxide was used as a catalyst for the synthesis of TMPTE through chemical transesterification of high oleic palm oil methyl esters (POME) with trimethylolpropane (TMP). The effects of the main operating variables, i.e., temperature, pressure, molar ratio of TMP to POME, and the catalyst amount, on the yield of TMPTE were appraised. The amount of soap produced under these conditions was examined. The optimum conditions for the reaction were the reaction temperature set at 170 °C, molar ratio of TMP:POME set at 1:6, pressure of the system maintained at 50 mbar, and mass ratio of calcium methoxide set at 0.3% per weight of reaction mixture. Trimethylolpropane esters containing 98% w/w triesters were successfully synthesized under these conditions within 8 h reaction time. Saponification occurred under these conditions; however, the soap formation was less than that produced when homogeneous catalyst was used. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815821
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5438-5442[article] Activity of calcium methoxide catalyst for synthesis of high oleic palm oil based trimethylolpropane triesters as lubricant base stock [texte imprimé] / Teck-Sin Chang, Auteur ; Hassan Masood, Auteur ; Robiah Yunus, Auteur . - 2012 . - pp. 5438-5442.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5438-5442
Mots-clés : Lubricant Catalyst Résumé : High oleic palm oil based trimethylolpropane triesters (TMPTE) are potential biodegradable base stocks for lubricant production. Calcium methoxide was used as a catalyst for the synthesis of TMPTE through chemical transesterification of high oleic palm oil methyl esters (POME) with trimethylolpropane (TMP). The effects of the main operating variables, i.e., temperature, pressure, molar ratio of TMP to POME, and the catalyst amount, on the yield of TMPTE were appraised. The amount of soap produced under these conditions was examined. The optimum conditions for the reaction were the reaction temperature set at 170 °C, molar ratio of TMP:POME set at 1:6, pressure of the system maintained at 50 mbar, and mass ratio of calcium methoxide set at 0.3% per weight of reaction mixture. Trimethylolpropane esters containing 98% w/w triesters were successfully synthesized under these conditions within 8 h reaction time. Saponification occurred under these conditions; however, the soap formation was less than that produced when homogeneous catalyst was used. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815821 Exemplaires
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Titre : Lipase - catalyzed consecutive batch reaction for production of steryl esters from vegetable oil deodorizer distillates Type de document : texte imprimé Auteurs : A. R. S. Teixeira, Auteur ; J. L. C. Santos, Auteur ; J. G. Crespo, Auteur Année de publication : 2012 Article en page(s) : pp. 5443–5455 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Esterification Vegetable oil deodorizer distillates Résumé : A significant decrease of the yield of steryl esters production via the esterification of sterols and free fatty acids (FFA) present in vegetable oil deodorizer distillates was observed when consecutive batch reactions (24 hr each) were carried out using the same enzyme and under optimal operating conditions. The objective of this work is to identify the causes of such phenomena, in order to avoid or minimize it, allowing for reuse of the Candida rugosa lipase catalyst in consecutive batch reactions. The effect of water activity and glycerol produced by hydrolysis of acylglycerides, on the stability of the enzyme was studied. Results show that these effects were not the main reason for the decrease of yield in consecutive batch reactions. The presence of oxidation products proved to play an important role in the enzyme inactivation. Because of the high concentration of antioxidants (phenolic compounds, squalene, and tocopherols) naturally present in deodorizer distillates, the inactivation of the enzyme was minimized; nevertheless, it could not be avoided. A partial reuse of the enzyme is technically a possible solution, by adding fresh enzyme in the beginning of each batch reaction. Four consecutive batch reactions (24 hr each) were successfully carried out under optimal conditions, keeping a constant yield of steryl esters (SE) production (>85%). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202853f
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5443–5455[article] Lipase - catalyzed consecutive batch reaction for production of steryl esters from vegetable oil deodorizer distillates [texte imprimé] / A. R. S. Teixeira, Auteur ; J. L. C. Santos, Auteur ; J. G. Crespo, Auteur . - 2012 . - pp. 5443–5455.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5443–5455
Mots-clés : Esterification Vegetable oil deodorizer distillates Résumé : A significant decrease of the yield of steryl esters production via the esterification of sterols and free fatty acids (FFA) present in vegetable oil deodorizer distillates was observed when consecutive batch reactions (24 hr each) were carried out using the same enzyme and under optimal operating conditions. The objective of this work is to identify the causes of such phenomena, in order to avoid or minimize it, allowing for reuse of the Candida rugosa lipase catalyst in consecutive batch reactions. The effect of water activity and glycerol produced by hydrolysis of acylglycerides, on the stability of the enzyme was studied. Results show that these effects were not the main reason for the decrease of yield in consecutive batch reactions. The presence of oxidation products proved to play an important role in the enzyme inactivation. Because of the high concentration of antioxidants (phenolic compounds, squalene, and tocopherols) naturally present in deodorizer distillates, the inactivation of the enzyme was minimized; nevertheless, it could not be avoided. A partial reuse of the enzyme is technically a possible solution, by adding fresh enzyme in the beginning of each batch reaction. Four consecutive batch reactions (24 hr each) were successfully carried out under optimal conditions, keeping a constant yield of steryl esters (SE) production (>85%). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202853f Exemplaires
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Titre : Production of flexible and electrically conductive polyethylene – carbon nanotube shish - kebab structures and their assembly into thin films Type de document : texte imprimé Auteurs : Tao Tao, Auteur ; Ling Zhang, Auteur ; Jan Ma, Auteur Année de publication : 2012 Article en page(s) : pp. 5456-5460 Note générale : Industry chemistry Langues : Anglais (eng) Mots-clés : Thin film Production Résumé : Polyethylene-multiwalled carbon nanotube shish-kebab (PE/MWCNT SK) structures with a large aspect ratio were synthesized by solvothermal growth followed by recrystallization. The effects of different crystallization temperatures (95, 105, and 115 °C) on the polymer were investigated, and the diameter of the PE crystal lamellae on the nanotubes was found to decrease with increasing crystallization temperature. Moreover, isothermal recrystallization of the SK structure at 115 °C produced crystal lamellae that were uniform in diameter, with dimensions that could be controlled by the recrystallization time. We studied also the stretchable electrical properties of uniform PE/MWCNT SK structures films on elastomer substrates under different strains. The electrical resistance of an SK/elastomer film was found to increase more slowly, compared to that of a film without the SK configuration, where an abrupt transition at a critical point was observed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815823
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5456-5460[article] Production of flexible and electrically conductive polyethylene – carbon nanotube shish - kebab structures and their assembly into thin films [texte imprimé] / Tao Tao, Auteur ; Ling Zhang, Auteur ; Jan Ma, Auteur . - 2012 . - pp. 5456-5460.
Industry chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5456-5460
Mots-clés : Thin film Production Résumé : Polyethylene-multiwalled carbon nanotube shish-kebab (PE/MWCNT SK) structures with a large aspect ratio were synthesized by solvothermal growth followed by recrystallization. The effects of different crystallization temperatures (95, 105, and 115 °C) on the polymer were investigated, and the diameter of the PE crystal lamellae on the nanotubes was found to decrease with increasing crystallization temperature. Moreover, isothermal recrystallization of the SK structure at 115 °C produced crystal lamellae that were uniform in diameter, with dimensions that could be controlled by the recrystallization time. We studied also the stretchable electrical properties of uniform PE/MWCNT SK structures films on elastomer substrates under different strains. The electrical resistance of an SK/elastomer film was found to increase more slowly, compared to that of a film without the SK configuration, where an abrupt transition at a critical point was observed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815823 Exemplaires
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Titre : Crystallization behavior of reactive blends between PBS and PA6IcoT Type de document : texte imprimé Auteurs : Kun Cao, Auteur ; Qiang Wang, Auteur ; Ya-chan Zhou, Auteur Année de publication : 2012 Article en page(s) : pp. 5461-5468 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Crystallization Résumé : A biodegradable crystalline aliphatic polyester, poly(butylene succinate) (PBS), and an amorphous semiaromatic nylon, poly(hexamethylene isophthalamide-co-terephthalamide) (PA6IcoT), were melted and reactively blended with p-toluene sulfonic acid as the catalyst. The isothermal and nonisothermal crystallization processes of PBS and its blends with PA6IcoT were investigated by differential scanning calorimetry (DSC). Three different models (Jeziorny’s, Ozawa’s, and Mo et al.’s methods) were used to simulate the isothermal and nonisothermal crystallization kinetics. Moreover, the crystalline morphologies were observed by polarized optical microscopy. The effects of PA6IcoT and the ester–amide exchange reaction between polyester and polyamide on the crystallization processes and crystalline morphology are described in detail. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815824
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5461-5468[article] Crystallization behavior of reactive blends between PBS and PA6IcoT [texte imprimé] / Kun Cao, Auteur ; Qiang Wang, Auteur ; Ya-chan Zhou, Auteur . - 2012 . - pp. 5461-5468.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5461-5468
Mots-clés : Crystallization Résumé : A biodegradable crystalline aliphatic polyester, poly(butylene succinate) (PBS), and an amorphous semiaromatic nylon, poly(hexamethylene isophthalamide-co-terephthalamide) (PA6IcoT), were melted and reactively blended with p-toluene sulfonic acid as the catalyst. The isothermal and nonisothermal crystallization processes of PBS and its blends with PA6IcoT were investigated by differential scanning calorimetry (DSC). Three different models (Jeziorny’s, Ozawa’s, and Mo et al.’s methods) were used to simulate the isothermal and nonisothermal crystallization kinetics. Moreover, the crystalline morphologies were observed by polarized optical microscopy. The effects of PA6IcoT and the ester–amide exchange reaction between polyester and polyamide on the crystallization processes and crystalline morphology are described in detail. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815824 Exemplaires
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Titre : Dynamic predictive modeling under measured and unmeasured continuous - time stochastic input behavior Type de document : texte imprimé Auteurs : Derrick K. Rollins, Auteur ; Dongmei Zhai, Auteur ; Nidhi Bhandari, Auteur Année de publication : 2012 Article en page(s) : pp. 5469-5479 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Continuous time Modeling Résumé : Many input variables of chemical processes have a continuous-time stochastic (CTS) behavior. The nature of these variables is a persistent, time-correlated variation that manifests as process variation as the variables deviate in time from their nominal levels. This work introduces methodologies in process identification for improving the modeling of process outputs by exploiting CTS input modeling under cases where the input is measured and unmeasured. In the measured input case, the output variable is measured offline, infrequently, and at a varying sampling rate. A method is proposed for estimating CTS parameters from the measured input by exploiting statistical properties of its CTS model. The proposed approach is evaluated based on both output accuracy and predictive ability several steps ahead of the current input measurement. Two parameter estimation techniques are proposed when the input is unmeasured. The first is a derivative-free approach that uses sample moments and analytical expressions for population moments to estimate the CTS model parameters. The second exploits the CTS input model and uses the analytical solution of the dynamic model to estimate these parameters. The predictive ability of the latter approach is evaluated in the same way as the measured input case. All of the data in this work were artificially generated under the probabilistic CTS model. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815825
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5469-5479[article] Dynamic predictive modeling under measured and unmeasured continuous - time stochastic input behavior [texte imprimé] / Derrick K. Rollins, Auteur ; Dongmei Zhai, Auteur ; Nidhi Bhandari, Auteur . - 2012 . - pp. 5469-5479.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5469-5479
Mots-clés : Continuous time Modeling Résumé : Many input variables of chemical processes have a continuous-time stochastic (CTS) behavior. The nature of these variables is a persistent, time-correlated variation that manifests as process variation as the variables deviate in time from their nominal levels. This work introduces methodologies in process identification for improving the modeling of process outputs by exploiting CTS input modeling under cases where the input is measured and unmeasured. In the measured input case, the output variable is measured offline, infrequently, and at a varying sampling rate. A method is proposed for estimating CTS parameters from the measured input by exploiting statistical properties of its CTS model. The proposed approach is evaluated based on both output accuracy and predictive ability several steps ahead of the current input measurement. Two parameter estimation techniques are proposed when the input is unmeasured. The first is a derivative-free approach that uses sample moments and analytical expressions for population moments to estimate the CTS model parameters. The second exploits the CTS input model and uses the analytical solution of the dynamic model to estimate these parameters. The predictive ability of the latter approach is evaluated in the same way as the measured input case. All of the data in this work were artificially generated under the probabilistic CTS model. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815825 Exemplaires
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Titre : Modeling and optimization of membrane reactors for carbon capture in integrated gasification combined cycle units Type de document : texte imprimé Auteurs : Fernando V. Lima, Auteur ; Prodromos Daoutidis, Auteur ; Michael Tsapatsis, Auteur Année de publication : 2012 Article en page(s) : pp. 5480-5489 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gasification Membrane reactor Optimization Modeling Résumé : This paper investigates the alternative of precombustion capture of carbon dioxide from integrated gasification combined cycle (IGCC) plants using membrane reactors equipped with H2-selective zeolite membranes for the water gas shift reaction. Specifically, a one-dimensional and isothermal membrane reactor model is developed. This model is used for simulation and optimization studies considering cocurrent and countercurrent modes of reactor operation. The simulation results indicate successful countercurrent cases that satisfy all of the specified targets and constraints. With use of this developed model, a novel optimization problem is formulated and solved to guide the selection of the optimal reactor design among typical scenarios of operation. The optimization results suggest as optimal solution a reactor design with a preshift followed by a membrane reactor. The obtained optimal design enables a more efficient membrane use by placing it in the optimal location. This design also results in savings of as high as 25% (in the range of 10-25%) in terms of membrane material when compared to the original membrane reactor design. For the price range of zeolite membranes considered on the order of $1000-10 000/m2 and for large-scale applications, in which the membrane surface areas are on the order of 2000 m2, 25% of savings implies cost reductions on the order of millions of dollars (as high as $5 000 000 in this case). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815826
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5480-5489[article] Modeling and optimization of membrane reactors for carbon capture in integrated gasification combined cycle units [texte imprimé] / Fernando V. Lima, Auteur ; Prodromos Daoutidis, Auteur ; Michael Tsapatsis, Auteur . - 2012 . - pp. 5480-5489.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5480-5489
Mots-clés : Gasification Membrane reactor Optimization Modeling Résumé : This paper investigates the alternative of precombustion capture of carbon dioxide from integrated gasification combined cycle (IGCC) plants using membrane reactors equipped with H2-selective zeolite membranes for the water gas shift reaction. Specifically, a one-dimensional and isothermal membrane reactor model is developed. This model is used for simulation and optimization studies considering cocurrent and countercurrent modes of reactor operation. The simulation results indicate successful countercurrent cases that satisfy all of the specified targets and constraints. With use of this developed model, a novel optimization problem is formulated and solved to guide the selection of the optimal reactor design among typical scenarios of operation. The optimization results suggest as optimal solution a reactor design with a preshift followed by a membrane reactor. The obtained optimal design enables a more efficient membrane use by placing it in the optimal location. This design also results in savings of as high as 25% (in the range of 10-25%) in terms of membrane material when compared to the original membrane reactor design. For the price range of zeolite membranes considered on the order of $1000-10 000/m2 and for large-scale applications, in which the membrane surface areas are on the order of 2000 m2, 25% of savings implies cost reductions on the order of millions of dollars (as high as $5 000 000 in this case). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815826 Exemplaires
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Titre : The zootechnical anaerobic supernatants : Nutrient removal by a biological advanced process Type de document : texte imprimé Auteurs : M. Santinelli, Auteur ; A. L. Eusebi, Auteur ; M. Santini, Auteur Année de publication : 2012 Article en page(s) : pp. 5490-5496 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Anaerobe Résumé : This paper deals with the evaluation of total nitrogen (TN) removal from zootechnical wastes in a pilot scale reactor, treating digested supernatants by biological way. The high performances in terms of total nitrogen removal by nitrites, greater than 95%, enabled to design a medium scale treatment platform, by combining the anaerobic digestion (AD) and dewatering (DW) units with the alternate cycles (AC) biological process for pig and cattle supernatants. Theoretical mass balances carried out on maximum loading conditions allowed to define an optimal process chain and its sizing. Influent and effluent main parameters were determined for each operation unit, defining a final TN value for pig slurry equal to 14.1 g d-1 head-1 in the dewatered amount and 12.3 g d-1 head-1 from the AC reactor, besides an inner TN load of 49.6 g d-1 head-1. Concerning the cattle slurry treatment, the DW process gained a TN removal of 74%, allowing the AC process to remove the remaining amount of TN of about 30.1 g d-1 head-1. An evaluation of the reliability of a fermentation process to support the anoxic phase of the biological process was further investigated. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815827
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5490-5496[article] The zootechnical anaerobic supernatants : Nutrient removal by a biological advanced process [texte imprimé] / M. Santinelli, Auteur ; A. L. Eusebi, Auteur ; M. Santini, Auteur . - 2012 . - pp. 5490-5496.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5490-5496
Mots-clés : Anaerobe Résumé : This paper deals with the evaluation of total nitrogen (TN) removal from zootechnical wastes in a pilot scale reactor, treating digested supernatants by biological way. The high performances in terms of total nitrogen removal by nitrites, greater than 95%, enabled to design a medium scale treatment platform, by combining the anaerobic digestion (AD) and dewatering (DW) units with the alternate cycles (AC) biological process for pig and cattle supernatants. Theoretical mass balances carried out on maximum loading conditions allowed to define an optimal process chain and its sizing. Influent and effluent main parameters were determined for each operation unit, defining a final TN value for pig slurry equal to 14.1 g d-1 head-1 in the dewatered amount and 12.3 g d-1 head-1 from the AC reactor, besides an inner TN load of 49.6 g d-1 head-1. Concerning the cattle slurry treatment, the DW process gained a TN removal of 74%, allowing the AC process to remove the remaining amount of TN of about 30.1 g d-1 head-1. An evaluation of the reliability of a fermentation process to support the anoxic phase of the biological process was further investigated. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815827 Exemplaires
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Titre : Dynamic multimode process modeling and monitoring using adaptive gaussian mixture models Type de document : texte imprimé Auteurs : Xiang Xie, Auteur ; Hongbo Shi, Auteur Année de publication : 2012 Article en page(s) : pp. 5497-5505 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Surveillance Modeling Résumé : For multimode processes, it is inevitable to encounter disturbances, such as equipment aging, catalyst deactivation, sensor drifting, reaction kinetics drifting, or adding new operating modes. The existing monitoring algorithms are established either for coping with multimode feature under time-invariant circumstance or for handling the time-varying problem of processes with single operating mode. The purpose of this article is to develop an effective modeling and monitoring approach for complex processes with both multimode and time-varying properties. We propose a novel adaptive monitoring scheme based on Gaussian Mixture Model (GMM). The new method is able to model different operating modes as well as trace process variations. The effectiveness and efficiency of the new method are validated by a numerical example and the Tennessee Eastman (TE) simulation platform in different scenarios. REFERENCE : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815828
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5497-5505[article] Dynamic multimode process modeling and monitoring using adaptive gaussian mixture models [texte imprimé] / Xiang Xie, Auteur ; Hongbo Shi, Auteur . - 2012 . - pp. 5497-5505.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5497-5505
Mots-clés : Surveillance Modeling Résumé : For multimode processes, it is inevitable to encounter disturbances, such as equipment aging, catalyst deactivation, sensor drifting, reaction kinetics drifting, or adding new operating modes. The existing monitoring algorithms are established either for coping with multimode feature under time-invariant circumstance or for handling the time-varying problem of processes with single operating mode. The purpose of this article is to develop an effective modeling and monitoring approach for complex processes with both multimode and time-varying properties. We propose a novel adaptive monitoring scheme based on Gaussian Mixture Model (GMM). The new method is able to model different operating modes as well as trace process variations. The effectiveness and efficiency of the new method are validated by a numerical example and the Tennessee Eastman (TE) simulation platform in different scenarios. REFERENCE : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815828 Exemplaires
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Titre : Hidden Markov Model Based Adaptive Independent Component Analysis Approach for Complex Chemical Process Monitoring and Fault Detection Type de document : texte imprimé Auteurs : Mudassir M. Rashid, Auteur ; Jie Yu, Auteur Année de publication : 2012 Article en page(s) : pp. 5506-5514 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Failure detection Surveillance Independent component analysis Modeling Résumé : For complex chemical processes with multiple operating conditions and inherent system uncertainty, conventional multivariate process monitoring techniques such as principal component analysis (PCA) and independent component analysis (ICA) are ill-suited because they are unable to characterize shifting modes and process uncertainty. In this article, a novel hidden Markov model (HMM) based ICA approach is proposed for process monitoring and fault detection. First the hidden Markov model is built from measurement data to estimate dynamic mode sequence. Further the localized ICA models are developed to characterize various operating modes adaptively. HMM based state estimation is then used to classify the monitored samples into the corresponding modes, and the HMM based I2 and SPE statistics are established for fault detection. The effectiveness of the proposed monitoring approach is demonstrated through the Tennessee Eastman Chemical process. The comparison of monitoring results shows that the proposed HMM-ICA approach is superior to the conventional ICA method and can achieve accurate detection of various types of process faults with minimized false alarms. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815829
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5506-5514[article] Hidden Markov Model Based Adaptive Independent Component Analysis Approach for Complex Chemical Process Monitoring and Fault Detection [texte imprimé] / Mudassir M. Rashid, Auteur ; Jie Yu, Auteur . - 2012 . - pp. 5506-5514.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5506-5514
Mots-clés : Failure detection Surveillance Independent component analysis Modeling Résumé : For complex chemical processes with multiple operating conditions and inherent system uncertainty, conventional multivariate process monitoring techniques such as principal component analysis (PCA) and independent component analysis (ICA) are ill-suited because they are unable to characterize shifting modes and process uncertainty. In this article, a novel hidden Markov model (HMM) based ICA approach is proposed for process monitoring and fault detection. First the hidden Markov model is built from measurement data to estimate dynamic mode sequence. Further the localized ICA models are developed to characterize various operating modes adaptively. HMM based state estimation is then used to classify the monitored samples into the corresponding modes, and the HMM based I2 and SPE statistics are established for fault detection. The effectiveness of the proposed monitoring approach is demonstrated through the Tennessee Eastman Chemical process. The comparison of monitoring results shows that the proposed HMM-ICA approach is superior to the conventional ICA method and can achieve accurate detection of various types of process faults with minimized false alarms. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815829 Exemplaires
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Titre : New experimental data and modeling of the solubility of compounds in supercritical carbon dioxide Type de document : texte imprimé Auteurs : Zhao Tang, Auteur ; Jun-su Jin, Auteur ; Ze-ting Zhang, Auteur Année de publication : 2012 Article en page(s) : pp. 5515–5526 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Solid solubility Carbon dioxide Résumé : The solid solubility of o-nitrobenzoic acid in supercritical carbon dioxide (SCCO2) was measured using a dynamic-flow technique at 308, 318, and 328 K and in the pressure range of 10.0–21.0 MPa. The experimental solubility data of the solute in SCCO2 were correlated by six different theoretical semiempirical models [the Chrastil, Kumar and Johnston, Sung and Shim (SS), Méndez-Santiago and Teja, Bartle–Clifford–Jafar–Shilstone, and Jouyban–Chan–Foster models] with the average absolute relative deviation from 4.30% to 6.61%. The correlated results indicate that the SS model provides the best fit. Solubility data from 54 different compounds of different functional groups (including carboxyl, amino, chain alkyl, heterocycle, azo, diglycolic, and anthraquinone) were collected from the literature to compare and evaluate these models. The division criteria of temperature, pressure, mole fraction solubility of the solutes, and number of experimental data points were established. The predictive capability and applicability of these models for different types of solutes and at different conditions are demonstrated in this paper. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2016224
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5515–5526[article] New experimental data and modeling of the solubility of compounds in supercritical carbon dioxide [texte imprimé] / Zhao Tang, Auteur ; Jun-su Jin, Auteur ; Ze-ting Zhang, Auteur . - 2012 . - pp. 5515–5526.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5515–5526
Mots-clés : Solid solubility Carbon dioxide Résumé : The solid solubility of o-nitrobenzoic acid in supercritical carbon dioxide (SCCO2) was measured using a dynamic-flow technique at 308, 318, and 328 K and in the pressure range of 10.0–21.0 MPa. The experimental solubility data of the solute in SCCO2 were correlated by six different theoretical semiempirical models [the Chrastil, Kumar and Johnston, Sung and Shim (SS), Méndez-Santiago and Teja, Bartle–Clifford–Jafar–Shilstone, and Jouyban–Chan–Foster models] with the average absolute relative deviation from 4.30% to 6.61%. The correlated results indicate that the SS model provides the best fit. Solubility data from 54 different compounds of different functional groups (including carboxyl, amino, chain alkyl, heterocycle, azo, diglycolic, and anthraquinone) were collected from the literature to compare and evaluate these models. The division criteria of temperature, pressure, mole fraction solubility of the solutes, and number of experimental data points were established. The predictive capability and applicability of these models for different types of solutes and at different conditions are demonstrated in this paper. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2016224 Exemplaires
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Titre : A first report on the selective precipitation of sodium chloride from the evaporated residue of reverse osmosis reject salt generated from the leather industry Type de document : texte imprimé Auteurs : R. Boopathy, Auteur ; A. Gnanamani, Auteur ; A. B. Mandal, Auteur Année de publication : 2012 Article en page(s) : pp. 5527–5534 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Osmosis Sodium chloride Résumé : The reverse osmosis process has been actively implemented in the leather sector for the recovery of water from secondary biologically treated wastewater. The membrane reject stream is evaporated in solar evaporation pan/multiple effect evaporator. The evaporated residue (ER) of the reject stream from reverse osmosis lacks reusable characteristics, owing to a high contamination of inorganic and organic salts. In this investigation, an attempt was made to separate sodium chloride from the saturated solution of ER by the common ion effect in the presence of other inorganic and organic contaminants, using hydrogen chloride gas. The optimized process parameters for the selective precipitation of sodium chloride were as follows: time, 3 min; pH, 8.0; temperature, 40 °C; and concentration of ER, 60% (w/v). The ER and the recovered salts were characterized, using SEM-EDX and XRD. This is probably the first report on the precipitation of sodium chloride from the ER. The cost toward the disposal of this ER was also analyzed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201735s
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5527–5534[article] A first report on the selective precipitation of sodium chloride from the evaporated residue of reverse osmosis reject salt generated from the leather industry [texte imprimé] / R. Boopathy, Auteur ; A. Gnanamani, Auteur ; A. B. Mandal, Auteur . - 2012 . - pp. 5527–5534.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5527–5534
Mots-clés : Osmosis Sodium chloride Résumé : The reverse osmosis process has been actively implemented in the leather sector for the recovery of water from secondary biologically treated wastewater. The membrane reject stream is evaporated in solar evaporation pan/multiple effect evaporator. The evaporated residue (ER) of the reject stream from reverse osmosis lacks reusable characteristics, owing to a high contamination of inorganic and organic salts. In this investigation, an attempt was made to separate sodium chloride from the saturated solution of ER by the common ion effect in the presence of other inorganic and organic contaminants, using hydrogen chloride gas. The optimized process parameters for the selective precipitation of sodium chloride were as follows: time, 3 min; pH, 8.0; temperature, 40 °C; and concentration of ER, 60% (w/v). The ER and the recovered salts were characterized, using SEM-EDX and XRD. This is probably the first report on the precipitation of sodium chloride from the ER. The cost toward the disposal of this ER was also analyzed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201735s Exemplaires
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Titre : Novel procedure for coproduction of ethyl acetate and n - butyl acetate by reactive distillation Type de document : texte imprimé Auteurs : Hui Tian, Auteur ; Huidong Zheng, Auteur ; Zhixian Huang, Auteur Année de publication : 2012 Article en page(s) : pp. 5535–5541 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Reactive distillation Ethyl Acetate Résumé : A novel energy saving procedure for the coproduction of ethyl acetate and n-butyl acetate by reactive distillation is simulated by Aspen Plus in this paper. Its feasibility is theoretically analyzed on the basis of the physical properties of ethyl acetate/n-butyl acetate system. The new procedure not only significantly reduces energy consumption, but also eliminates the acetic acid purification column, as compared with the individual processes. The outputs of ethyl acetate and n-butyl acetate can be adjusted flexibly by changing the feed molar ratio of ethanol to n-butanol in a certain range. When the feed molar ratio is less than 1.0, the purity of the products is the same as that for those obtained from the individual procedures. Also, energy-saving increases as the feed molar ratio of ethanol to n-butanol decreases. When the feed molar ratio of ethanol to n-butanol is 0.5, 20.40% energy-saving is achieved, as compared with the individual procedures. At last, the total annual cost (TAC) of the individual and coproduction procedure is calculated, and the TAC of the coproduction is 3 795 912 USD/Y (U.S. dollars per year) less than the individual’s 5 190 921 USD/Y, when 10 000 t EtAc and 26 363 t n-BuAc are produced. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202154x
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5535–5541[article] Novel procedure for coproduction of ethyl acetate and n - butyl acetate by reactive distillation [texte imprimé] / Hui Tian, Auteur ; Huidong Zheng, Auteur ; Zhixian Huang, Auteur . - 2012 . - pp. 5535–5541.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5535–5541
Mots-clés : Reactive distillation Ethyl Acetate Résumé : A novel energy saving procedure for the coproduction of ethyl acetate and n-butyl acetate by reactive distillation is simulated by Aspen Plus in this paper. Its feasibility is theoretically analyzed on the basis of the physical properties of ethyl acetate/n-butyl acetate system. The new procedure not only significantly reduces energy consumption, but also eliminates the acetic acid purification column, as compared with the individual processes. The outputs of ethyl acetate and n-butyl acetate can be adjusted flexibly by changing the feed molar ratio of ethanol to n-butanol in a certain range. When the feed molar ratio is less than 1.0, the purity of the products is the same as that for those obtained from the individual procedures. Also, energy-saving increases as the feed molar ratio of ethanol to n-butanol decreases. When the feed molar ratio of ethanol to n-butanol is 0.5, 20.40% energy-saving is achieved, as compared with the individual procedures. At last, the total annual cost (TAC) of the individual and coproduction procedure is calculated, and the TAC of the coproduction is 3 795 912 USD/Y (U.S. dollars per year) less than the individual’s 5 190 921 USD/Y, when 10 000 t EtAc and 26 363 t n-BuAc are produced. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202154x Exemplaires
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Titre : Modeling and optimization of a fermentation process integrated with cell recycling and pervaporation for multiple objectives Type de document : texte imprimé Auteurs : Shivom Sharma, Auteur ; G.P. Rangaiah, Auteur Année de publication : 2012 Article en page(s) : pp. 5542-5551 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Membrane separation Pervaporation Recycling Fermentation Optimization Modeling Résumé : Biofuels have potential to replace fossil fuels as a clean energy source. Bioethanol and biodiesel are the most commonly produced biofuels. Bioethanol is produced by fermenting sugar components of biomass (e.g., sugarcane, com, cellulosic materials). Although ethanol production using sugar and starch as feedstocks is well established, it can still be improved. Ethanol concentration in the fermentor inhibits conversion of fermentable sugars to ethanol, which results in low yield and productivity; these can be improved by better fermentation kinetics and/or process design. Ethanol can be removed from the fermentor by using extraction or a membrane process. Recently, bioethanol production process with interstage extraction has been optimized. The present work models and optimizes a three-stage bioethanol process integrated with cell recycling and pervaporation for multiple objectives using multiobjective differential evolution. The integrated process, with glucose and xylose as feedstocks, has been optimized for both ethanol productivity and xylose conversion simultaneously. The performance of the three-stage fermentation process integrated with pervaporation is compared with the three-stage fermentation process integrated with extraction, and the former is found to be better. The net flow method is used to rank the obtained nondominated solutions for the three-stage fermentation process integrated with cell recycling and pervaporation. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815833
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5542-5551[article] Modeling and optimization of a fermentation process integrated with cell recycling and pervaporation for multiple objectives [texte imprimé] / Shivom Sharma, Auteur ; G.P. Rangaiah, Auteur . - 2012 . - pp. 5542-5551.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5542-5551
Mots-clés : Membrane separation Pervaporation Recycling Fermentation Optimization Modeling Résumé : Biofuels have potential to replace fossil fuels as a clean energy source. Bioethanol and biodiesel are the most commonly produced biofuels. Bioethanol is produced by fermenting sugar components of biomass (e.g., sugarcane, com, cellulosic materials). Although ethanol production using sugar and starch as feedstocks is well established, it can still be improved. Ethanol concentration in the fermentor inhibits conversion of fermentable sugars to ethanol, which results in low yield and productivity; these can be improved by better fermentation kinetics and/or process design. Ethanol can be removed from the fermentor by using extraction or a membrane process. Recently, bioethanol production process with interstage extraction has been optimized. The present work models and optimizes a three-stage bioethanol process integrated with cell recycling and pervaporation for multiple objectives using multiobjective differential evolution. The integrated process, with glucose and xylose as feedstocks, has been optimized for both ethanol productivity and xylose conversion simultaneously. The performance of the three-stage fermentation process integrated with pervaporation is compared with the three-stage fermentation process integrated with extraction, and the former is found to be better. The net flow method is used to rank the obtained nondominated solutions for the three-stage fermentation process integrated with cell recycling and pervaporation. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815833 Exemplaires
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Titre : Biogas purification using cryogenic packed - bed technology Type de document : texte imprimé Auteurs : Martin J. Tuinier, Auteur ; Martin Van Sint Annaland, Auteur Année de publication : 2012 Article en page(s) : pp. 5552–5558 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Biogas treatment Résumé : A novel process concept for biogas treatment based on dynamically operated cryogenic packed beds (CPB) has been proposed and studied with numerical simulations. This work describes the CPB concept and investigates the different process steps involved with simulation results. To demonstrate the potential to treat biogas using the proposed process, the performance is compared to vacuum pressure swing adsorption (VPSA) on the basis of several criteria: purity and recovery of the obtained product, bed dimensions, and energy requirements. Simulation results reveal that the purity and recovery of CH4 are higher for the CPB concept, while also the bed capacity is much higher: the productivity (defined as kgCH4 h–1 mpacking–3) is a factor of 8 higher. The recovery is carried out with air and when operated in reversed flow mode, the novel CPB technology requires a 22% lower energy duty (2.9 MJ/kgCH4 vs 3.7 MJ/kgCH4 for the VPSA process). Furthermore, simultaneous deep H2S removal is possible using the proposed concept, although initial bed temperatures as low as −150 °C are required. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202606g
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5552–5558[article] Biogas purification using cryogenic packed - bed technology [texte imprimé] / Martin J. Tuinier, Auteur ; Martin Van Sint Annaland, Auteur . - 2012 . - pp. 5552–5558.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5552–5558
Mots-clés : Biogas treatment Résumé : A novel process concept for biogas treatment based on dynamically operated cryogenic packed beds (CPB) has been proposed and studied with numerical simulations. This work describes the CPB concept and investigates the different process steps involved with simulation results. To demonstrate the potential to treat biogas using the proposed process, the performance is compared to vacuum pressure swing adsorption (VPSA) on the basis of several criteria: purity and recovery of the obtained product, bed dimensions, and energy requirements. Simulation results reveal that the purity and recovery of CH4 are higher for the CPB concept, while also the bed capacity is much higher: the productivity (defined as kgCH4 h–1 mpacking–3) is a factor of 8 higher. The recovery is carried out with air and when operated in reversed flow mode, the novel CPB technology requires a 22% lower energy duty (2.9 MJ/kgCH4 vs 3.7 MJ/kgCH4 for the VPSA process). Furthermore, simultaneous deep H2S removal is possible using the proposed concept, although initial bed temperatures as low as −150 °C are required. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202606g Exemplaires
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Titre : Deep separation of benzene from cyclohexane by liquid extraction using ionic liquids as the solvent Type de document : texte imprimé Auteurs : Teng Zhou, Auteur ; Ziyun Wang, Auteur ; Yinmei Ye, Auteur Année de publication : 2012 Article en page(s) : pp. 5559-5564 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ionic liquid Résumé : Separation of benzene and cyclohexane is one of the most important and difficult processes in the petrochemical industry, especially for low benzene concentration. In this work, three ionic liquids (ILs), [Bmim][BF4], [Bpy][BF4], and [Bmim][SCN], were investigated as the solvent in the extraction of benzene from cyclohexane. The corresponding ternary liquid-liquid equilibria (LLE) were experimentally determined at T = 298.15 K and atmospheric pressure. The LLE data were correlated with the nonrandom two-liquid model, and the parameters were fitted. The separation capabilities of the ILs were evaluated in terms of the benzene distribution coefficient and solvent selectivity. The effect of the IL structure on the separation was explained based on a well-founded physical model, COSMO-RS. Finally, the extraction processes were defined, and the operation parameters were analyzed. It shows that the ILs studied are suitable solvents for the extractive separation of benzene and cyclohexane, and their separation efficiency can be generally ranked as [Bmim][BF4] > [Bpy][BF4] > [Bmim][SCN]. The extraction process for a feed with 15 mol % benzene was optimized. High product purity (cyclohexane 0.997) and high recovery efficiency (cyclohexane 96.9% and benzene 98.1%) can be reached. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815835
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5559-5564[article] Deep separation of benzene from cyclohexane by liquid extraction using ionic liquids as the solvent [texte imprimé] / Teng Zhou, Auteur ; Ziyun Wang, Auteur ; Yinmei Ye, Auteur . - 2012 . - pp. 5559-5564.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5559-5564
Mots-clés : Ionic liquid Résumé : Separation of benzene and cyclohexane is one of the most important and difficult processes in the petrochemical industry, especially for low benzene concentration. In this work, three ionic liquids (ILs), [Bmim][BF4], [Bpy][BF4], and [Bmim][SCN], were investigated as the solvent in the extraction of benzene from cyclohexane. The corresponding ternary liquid-liquid equilibria (LLE) were experimentally determined at T = 298.15 K and atmospheric pressure. The LLE data were correlated with the nonrandom two-liquid model, and the parameters were fitted. The separation capabilities of the ILs were evaluated in terms of the benzene distribution coefficient and solvent selectivity. The effect of the IL structure on the separation was explained based on a well-founded physical model, COSMO-RS. Finally, the extraction processes were defined, and the operation parameters were analyzed. It shows that the ILs studied are suitable solvents for the extractive separation of benzene and cyclohexane, and their separation efficiency can be generally ranked as [Bmim][BF4] > [Bpy][BF4] > [Bmim][SCN]. The extraction process for a feed with 15 mol % benzene was optimized. High product purity (cyclohexane 0.997) and high recovery efficiency (cyclohexane 96.9% and benzene 98.1%) can be reached. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815835 Exemplaires
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Titre : Free volume as the basis of gas solubility and selectivity in imidazolium - based ionic liquids Type de document : texte imprimé Auteurs : Matthew S. Shannon, Auteur ; Jason M. Tedstone, Auteur ; Scott P. O. Danielsen, Auteur Année de publication : 2012 Article en page(s) : pp. 5565-5576 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ionic liquid Solubility Free volume Résumé : While molar volume-based models for gas solubility in ionic liquids (ILs) have been proposed, free volume within the IL can be shown to be the underlying property driving gas solubility and selectivity. Previously published observations as to the distinct differences in solubility trends for gases such as CH4 and N2 relative to CO2 in systematically varied ILs can be attributed to positive and negative effects arising from increasing free volume with increasing alkyl chain length. Through the use of COSMOtherm as a powerful and rapid tool to calculate free volumes in 165 existing and theoretical 1-n-alkyl-3- methylimidazolium ([Cnmim][X]) ILs, a previously unreported, yet speculated, critical underlying relationship between gas solubility in ILs is herein described These results build upon previous assertions that Regular Solution Theory is applicable to imidazolium-based ILs, which appeared to indicate that a global maximum had already been observed for CO2 solubility in imidazolium-based ILs. However, the findings of this computational study suggest that the perceived maximum in CO2 solubility might be exceeded through rational design of ILs. We observe that although Henry's constants in ILs are dependent on the inverse of molar volume and free volume, the volume-normalized solubility of CH4 and N2 are proportional to free volume, while CO2 is inversely proportional to the square root of free volume. Our free volume model is compared to experimental data for CO2/CH4 and CO2/N2 selectivity, and a nearly identical plot of selectivity relative to IL molar volume can be generated from the computational method alone. The overall implication is that large, highly delocalized anions paired with imidazolium cations that have minimally sized alkyl chains may hold the key to achieving greater CO2 solubility and selectivity in ILs. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815836
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5565-5576[article] Free volume as the basis of gas solubility and selectivity in imidazolium - based ionic liquids [texte imprimé] / Matthew S. Shannon, Auteur ; Jason M. Tedstone, Auteur ; Scott P. O. Danielsen, Auteur . - 2012 . - pp. 5565-5576.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5565-5576
Mots-clés : Ionic liquid Solubility Free volume Résumé : While molar volume-based models for gas solubility in ionic liquids (ILs) have been proposed, free volume within the IL can be shown to be the underlying property driving gas solubility and selectivity. Previously published observations as to the distinct differences in solubility trends for gases such as CH4 and N2 relative to CO2 in systematically varied ILs can be attributed to positive and negative effects arising from increasing free volume with increasing alkyl chain length. Through the use of COSMOtherm as a powerful and rapid tool to calculate free volumes in 165 existing and theoretical 1-n-alkyl-3- methylimidazolium ([Cnmim][X]) ILs, a previously unreported, yet speculated, critical underlying relationship between gas solubility in ILs is herein described These results build upon previous assertions that Regular Solution Theory is applicable to imidazolium-based ILs, which appeared to indicate that a global maximum had already been observed for CO2 solubility in imidazolium-based ILs. However, the findings of this computational study suggest that the perceived maximum in CO2 solubility might be exceeded through rational design of ILs. We observe that although Henry's constants in ILs are dependent on the inverse of molar volume and free volume, the volume-normalized solubility of CH4 and N2 are proportional to free volume, while CO2 is inversely proportional to the square root of free volume. Our free volume model is compared to experimental data for CO2/CH4 and CO2/N2 selectivity, and a nearly identical plot of selectivity relative to IL molar volume can be generated from the computational method alone. The overall implication is that large, highly delocalized anions paired with imidazolium cations that have minimally sized alkyl chains may hold the key to achieving greater CO2 solubility and selectivity in ILs. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815836 Exemplaires
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Titre : Sorption characteristics and separation of rhenium ions from aqueous solutions using modified nano - Al2O3 Type de document : texte imprimé Auteurs : Lei Zhang, Auteur ; Xiao Q. Jiang, Auteur ; Tian C. Xu, Auteur Année de publication : 2012 Article en page(s) : pp. 5577-5584 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Aqueous solution Sorption Résumé : A novel adsorbent was prepared by NH4HCO3-modifying nanoalumina dioxide and was employed for the separation/preconcentration of ReVII ions from aqueous solution. It was found that ReVII ions could be adsorbed quantitatively (above 94%) on modified nano-Al2O3 in the pH range of 2.0—3.0, while only 8.3% of ReVII ions were adsorbed on unmodified nano-Al2O3. Effects of the pH, concentration of elution solution, and interfering ions on the recovery of ReVII were systematically investigated. Adsorption kinetics for ReVII was found to be very fast, and equilibrium was reached within 5 min following the pseudo-second-order model with observed rate constants (k2) of 14.44 g·mg-1·min-1 at 298 K. The overall rate process appeared to be influenced by both external mass transfer and intraparticle diffusion. The sorption data could be well interpreted by the Langmuir model with a maximum adsorption capacity of 1.94 mg·g-1 of ReVII on modified nano-Al2O3. Moreover, the thermodynamic parameters showed the spontaneous and endothermic nature of the adsorption process. Finally, modified nano-Al2O3 as the sorbent was successfully applied to the separation of ReVII from the ore samples with satisfactory results. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815837
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5577-5584[article] Sorption characteristics and separation of rhenium ions from aqueous solutions using modified nano - Al2O3 [texte imprimé] / Lei Zhang, Auteur ; Xiao Q. Jiang, Auteur ; Tian C. Xu, Auteur . - 2012 . - pp. 5577-5584.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5577-5584
Mots-clés : Aqueous solution Sorption Résumé : A novel adsorbent was prepared by NH4HCO3-modifying nanoalumina dioxide and was employed for the separation/preconcentration of ReVII ions from aqueous solution. It was found that ReVII ions could be adsorbed quantitatively (above 94%) on modified nano-Al2O3 in the pH range of 2.0—3.0, while only 8.3% of ReVII ions were adsorbed on unmodified nano-Al2O3. Effects of the pH, concentration of elution solution, and interfering ions on the recovery of ReVII were systematically investigated. Adsorption kinetics for ReVII was found to be very fast, and equilibrium was reached within 5 min following the pseudo-second-order model with observed rate constants (k2) of 14.44 g·mg-1·min-1 at 298 K. The overall rate process appeared to be influenced by both external mass transfer and intraparticle diffusion. The sorption data could be well interpreted by the Langmuir model with a maximum adsorption capacity of 1.94 mg·g-1 of ReVII on modified nano-Al2O3. Moreover, the thermodynamic parameters showed the spontaneous and endothermic nature of the adsorption process. Finally, modified nano-Al2O3 as the sorbent was successfully applied to the separation of ReVII from the ore samples with satisfactory results. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815837 Exemplaires
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Titre : Carbon Dioxide Mass Transfer in Gas–Liquid–Liquid System Type de document : texte imprimé Auteurs : Alicia García-Abuín, Auteur ; Diego Gomez-Diaz, Auteur ; José M. Navaza, Auteur Année de publication : 2012 Article en page(s) : pp. 5585-5591 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Mass transfer Carbon dioxide Résumé : The present work analyses the mass transfer process of carbon dioxide absorption from a gas phase to a liquid- liquid system, based on an aqueous and organic phase. A careful study has been performed analyzing different variables, mainly the gas flow rate fed to the bubble contactor and the silicone oil concentration in the liquid phase. The organic phase used to perform the emulsions is different silicone oils. The influence of the organic phase viscosity let us analyze the influence of this variable on the mass transfer rate, which usually shows an important negative effect. In the present study, however, this effect is not the most important factor in the mass transfer rate. This work also studies the influence of a surfactant present in the liquid phase, used to stabilize the liquid-liquid system on the gas-liquid mass transfer process, taking into account that the different surfactant concentrations at the interfaces can play a more important role. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815838
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5585-5591[article] Carbon Dioxide Mass Transfer in Gas–Liquid–Liquid System [texte imprimé] / Alicia García-Abuín, Auteur ; Diego Gomez-Diaz, Auteur ; José M. Navaza, Auteur . - 2012 . - pp. 5585-5591.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5585-5591
Mots-clés : Mass transfer Carbon dioxide Résumé : The present work analyses the mass transfer process of carbon dioxide absorption from a gas phase to a liquid- liquid system, based on an aqueous and organic phase. A careful study has been performed analyzing different variables, mainly the gas flow rate fed to the bubble contactor and the silicone oil concentration in the liquid phase. The organic phase used to perform the emulsions is different silicone oils. The influence of the organic phase viscosity let us analyze the influence of this variable on the mass transfer rate, which usually shows an important negative effect. In the present study, however, this effect is not the most important factor in the mass transfer rate. This work also studies the influence of a surfactant present in the liquid phase, used to stabilize the liquid-liquid system on the gas-liquid mass transfer process, taking into account that the different surfactant concentrations at the interfaces can play a more important role. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815838 Exemplaires
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Titre : Thermodynamics of the solubility of KF in N,N - dimethyl ethanolamine, pyridine, diethanolamine, and sulfolane from 308.73 to 367.37 K Type de document : texte imprimé Auteurs : Hua Li, Auteur ; Juan Liu, Auteur ; Xiaoshuang Chen, Auteur Année de publication : 2012 Article en page(s) : pp. 5592-5595 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Solubility Résumé : The solubilities of potassium fluoride (KF) in the different nonproton polar solvents N,N-dimethyl ethanolamine, pyridine, diethanolamine, and sulfolane have been determined using a dynamic method at temperatures ranging from 308.73 to 367.37 K. The experimental data were correlated with the modified Apelblat equation, and the solubilities correlated by the Apelblat model showed good agreement with the experimental data. It provided the basic data for preparation of 2,3,4,5-tetrafluorobenzoic acid. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815839
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5592-5595[article] Thermodynamics of the solubility of KF in N,N - dimethyl ethanolamine, pyridine, diethanolamine, and sulfolane from 308.73 to 367.37 K [texte imprimé] / Hua Li, Auteur ; Juan Liu, Auteur ; Xiaoshuang Chen, Auteur . - 2012 . - pp. 5592-5595.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5592-5595
Mots-clés : Solubility Résumé : The solubilities of potassium fluoride (KF) in the different nonproton polar solvents N,N-dimethyl ethanolamine, pyridine, diethanolamine, and sulfolane have been determined using a dynamic method at temperatures ranging from 308.73 to 367.37 K. The experimental data were correlated with the modified Apelblat equation, and the solubilities correlated by the Apelblat model showed good agreement with the experimental data. It provided the basic data for preparation of 2,3,4,5-tetrafluorobenzoic acid. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815839 Exemplaires
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Titre : Purification of leachate from simultaneous leaching of galena concentrate and pyrolusite and preparation of PbSO4 and Mn3O4 Type de document : texte imprimé Auteurs : Wenqing Qin, Auteur ; Fen Jiao, Auteur ; Benjun Xu, Auteur Année de publication : 2012 Article en page(s) : pp 5596–5607 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Leachate Pyrolusite Résumé : This paper presents the results of investigation on simultaneous leaching of galena concentrate and pyrolusite in acid medium. It has been confirmed that the leached products as the raw materials—PbCl2, MnCl2 for the PbSO4 and Mn3O4 preparations could be obtained during the leaching processes. Special emphasizes are placed on the purification of the simultaneous leaching solution including removals of Fe2+, Pb2+, Zn2+, Ca2+, and preparations. The factors affecting the purification, such as pH, temperature, agitation rate, and dosages of Cl– and Na2S are investigated in leaching cells. The results show that, at appropriate conditions, iron is removed in the form of FeOOH, Pb2+ and Zn2+ are vulcanized by Na2S, and Ca2+ is removed in the form of CaF2 precipitation. After purification and crystallizing-out of PbCl2 (97.17%), the effects of pH, temperature, reaction time, concentration, stirring rate, and drying methods on preparations are examined. The mechanisms are addressed by theoretical calculations and experiments. The results indicate that the content of PbSO4 is 99.46% characterized by elemental analysis, XRD, and SEM. The purity of Mn3O4 is identified by TG-DSC, chemical analysis, and XRD, and the Mn in the Mn3O4 product accounts for 71.7%. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2024678
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp 5596–5607[article] Purification of leachate from simultaneous leaching of galena concentrate and pyrolusite and preparation of PbSO4 and Mn3O4 [texte imprimé] / Wenqing Qin, Auteur ; Fen Jiao, Auteur ; Benjun Xu, Auteur . - 2012 . - pp 5596–5607.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp 5596–5607
Mots-clés : Leachate Pyrolusite Résumé : This paper presents the results of investigation on simultaneous leaching of galena concentrate and pyrolusite in acid medium. It has been confirmed that the leached products as the raw materials—PbCl2, MnCl2 for the PbSO4 and Mn3O4 preparations could be obtained during the leaching processes. Special emphasizes are placed on the purification of the simultaneous leaching solution including removals of Fe2+, Pb2+, Zn2+, Ca2+, and preparations. The factors affecting the purification, such as pH, temperature, agitation rate, and dosages of Cl– and Na2S are investigated in leaching cells. The results show that, at appropriate conditions, iron is removed in the form of FeOOH, Pb2+ and Zn2+ are vulcanized by Na2S, and Ca2+ is removed in the form of CaF2 precipitation. After purification and crystallizing-out of PbCl2 (97.17%), the effects of pH, temperature, reaction time, concentration, stirring rate, and drying methods on preparations are examined. The mechanisms are addressed by theoretical calculations and experiments. The results indicate that the content of PbSO4 is 99.46% characterized by elemental analysis, XRD, and SEM. The purity of Mn3O4 is identified by TG-DSC, chemical analysis, and XRD, and the Mn in the Mn3O4 product accounts for 71.7%. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2024678 Exemplaires
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Titre : Recoverable platinum nanocatalysts immobilized on magnetic spherical polyelectrolyte brushes Type de document : texte imprimé Auteurs : Shuang Wu, Auteur ; Julian Kaiser, Auteur ; Xuhong Guo, Auteur Année de publication : 2012 Article en page(s) : pp. 5608-5614 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Polyelectrolyte Résumé : Recoverable platinum nanocatalysts immobilized on magnetic spherical polyelectrolyte brushes (MSPB) were synthesized and characterized by high resolution transmission electron microscope (HRTEM), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). High catalytic activity was found by photometrically monitoring the reduction of 4-nitrophenol by NaBH4 in the presence of MSPB-Pt composites. An excellent stability and recyclability of catalyst was observed after consecutive eight runs following by external magnetic-separation and redispersion. This novel approach provides an excited potential application in preparation of recyclable metal nanocatalysts with high activity. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815841
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5608-5614[article] Recoverable platinum nanocatalysts immobilized on magnetic spherical polyelectrolyte brushes [texte imprimé] / Shuang Wu, Auteur ; Julian Kaiser, Auteur ; Xuhong Guo, Auteur . - 2012 . - pp. 5608-5614.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5608-5614
Mots-clés : Polyelectrolyte Résumé : Recoverable platinum nanocatalysts immobilized on magnetic spherical polyelectrolyte brushes (MSPB) were synthesized and characterized by high resolution transmission electron microscope (HRTEM), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). High catalytic activity was found by photometrically monitoring the reduction of 4-nitrophenol by NaBH4 in the presence of MSPB-Pt composites. An excellent stability and recyclability of catalyst was observed after consecutive eight runs following by external magnetic-separation and redispersion. This novel approach provides an excited potential application in preparation of recyclable metal nanocatalysts with high activity. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815841 Exemplaires
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Titre : On the effect of flowing circular entities swarms on strip electrodes conductance Type de document : texte imprimé Auteurs : M. Kostoglou, Auteur Année de publication : 2012 Article en page(s) : pp. 5615-5625 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Electrodes Résumé : The use of finite size conductance electrode strips for the identification of dispersed phase flows may lead to difficulties related to the failure of homogeneous theories for the effective conductivity of dispersions in the particular geometry. In this context, a model problem is presented here: circular nonconducting entities dispersed in a conducting liquid flow at constant velocity over a nonconducting wall with strip electrodes flush mounted on it. The mathematical model is formulated in detail and is decomposed to electrostatic and to swarm generation subproblems. The electrostatic problem is simplified for dilute swarm of small, compared to the electrode width, entities for which an approximate analytical closed form solution is derived. A stochastic algorithm is developed for the generation of entity swarms. It is shown that a swarm generates fluctuations to the effective conductance measured by the electrodes. The strength of the fluctuations is related to the variations of the local electric current magnitude of the electrical field undisturbed by the entities at a distance equal to the average distance between entities. The present work is a first step to understand the interaction between entity swarms flowing over strip electrodes in order to explore the possibility of exploiting the fluctuating conductance signal for the characterization of the swarm further to a simple volume fraction determination. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815842
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5615-5625[article] On the effect of flowing circular entities swarms on strip electrodes conductance [texte imprimé] / M. Kostoglou, Auteur . - 2012 . - pp. 5615-5625.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5615-5625
Mots-clés : Electrodes Résumé : The use of finite size conductance electrode strips for the identification of dispersed phase flows may lead to difficulties related to the failure of homogeneous theories for the effective conductivity of dispersions in the particular geometry. In this context, a model problem is presented here: circular nonconducting entities dispersed in a conducting liquid flow at constant velocity over a nonconducting wall with strip electrodes flush mounted on it. The mathematical model is formulated in detail and is decomposed to electrostatic and to swarm generation subproblems. The electrostatic problem is simplified for dilute swarm of small, compared to the electrode width, entities for which an approximate analytical closed form solution is derived. A stochastic algorithm is developed for the generation of entity swarms. It is shown that a swarm generates fluctuations to the effective conductance measured by the electrodes. The strength of the fluctuations is related to the variations of the local electric current magnitude of the electrical field undisturbed by the entities at a distance equal to the average distance between entities. The present work is a first step to understand the interaction between entity swarms flowing over strip electrodes in order to explore the possibility of exploiting the fluctuating conductance signal for the characterization of the swarm further to a simple volume fraction determination. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815842 Exemplaires
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Titre : Analyzing the minimum entrainment velocity of ternary particle mixtures in horizontal pneumatic transport Type de document : texte imprimé Auteurs : Jason Yong Thian Tay, Auteur ; Jia Wei Chew, Auteur ; Kunn Hadinoto, Auteur Année de publication : 2012 Article en page(s) : pp. 5626-5632 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Transport process Résumé : Thus far, studies on the effects of the polydisperse size distribution on the minimum particle entrainment velocity (UPU) in horizontal pneumatic transport are limited to binary mixtures of sandlike particles. Herein we experimentally investigate UPU of ternary mixtures involving large (i.e., 400 and 170 μm) and fine particles (40 μm), where the roles of the fine particles in the entrainment of the large particles are elucidated. The presence of the 40 μm particles below ≈20% (w/w) enhances the entrainment of the 400 and 170 μm particles attributed to the high interstitial velocity of the conveying air because the fine particles occupy the interstitial spaces of the larger particles. Similar to monodisperse particles, a master curve of the particle Reynolds number versus Archimedes number is obtained for the ternary mixtures. From the master curve, a new empirical correlation for polydisperse UPU is derived using the Sauter mean diameter, where improved UPU predictions are demonstrated. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815843
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5626-5632[article] Analyzing the minimum entrainment velocity of ternary particle mixtures in horizontal pneumatic transport [texte imprimé] / Jason Yong Thian Tay, Auteur ; Jia Wei Chew, Auteur ; Kunn Hadinoto, Auteur . - 2012 . - pp. 5626-5632.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 15 (Avril 2012) . - pp. 5626-5632
Mots-clés : Transport process Résumé : Thus far, studies on the effects of the polydisperse size distribution on the minimum particle entrainment velocity (UPU) in horizontal pneumatic transport are limited to binary mixtures of sandlike particles. Herein we experimentally investigate UPU of ternary mixtures involving large (i.e., 400 and 170 μm) and fine particles (40 μm), where the roles of the fine particles in the entrainment of the large particles are elucidated. The presence of the 40 μm particles below ≈20% (w/w) enhances the entrainment of the 400 and 170 μm particles attributed to the high interstitial velocity of the conveying air because the fine particles occupy the interstitial spaces of the larger particles. Similar to monodisperse particles, a master curve of the particle Reynolds number versus Archimedes number is obtained for the ternary mixtures. From the master curve, a new empirical correlation for polydisperse UPU is derived using the Sauter mean diameter, where improved UPU predictions are demonstrated. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25815843 Exemplaires
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