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Impacts of air-assist flare blower configurations on flaring emissions / Fahad M. Al Fadhli in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12606-12610 Titre : Impacts of air-assist flare blower configurations on flaring emissions Type de document : texte imprimé Auteurs : Fahad M. Al Fadhli, Auteur ; Vincent M. Torres, Auteur ; David T. Allen, Auteur Année de publication : 2012 Article en page(s) : pp. 12606-12610 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Air  assist  flare Résumé : Air-assisted flares, operating under low flow conditions (<1% of maximum flow) with low BTU gases, have relatively narrow bands of air-to-vent gas ratios that can achieve destruction and removal efficiencies (DREs, fraction of waste gases destroyed by complete and incomplete combustion) greater than 98%. If blower configurations are not able to operate within these narrow bands, emissions may be greater than those predicted based on 98% DRE, but if air-assist rates can be finely tuned, emissions much lower than those predicted assuming 98% DRE are achievable. This work examines the potential impact on emissions of using four different blower configurations (single fixed speed, dual fixed speed, single variable speed, and dual variable speed) on an air-assisted flare. Typical patterns of flare vent gas flow rates were obtained from hourly data on flared gas flow rates from Houston, Texas. The analyses indicate that flare emissions can be much greater (up to a factor of 40) than a base case assuming 98% DRE if single, fixed speed blower configurations are used. Conversely, flare emissions can be much lower than a base case assuming 98% DRE if air-assist rates can be closely matched to stoichiometric requirements. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3012209 [article] Impacts of air-assist flare blower configurations on flaring emissions [texte imprimé] / Fahad M. Al Fadhli, Auteur ; Vincent M. Torres, Auteur ; David T. Allen, Auteur . - 2012 . - pp. 12606-12610. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12606-12610 Mots-clés : Air  assist  flare Résumé : Air-assisted flares, operating under low flow conditions (<1% of maximum flow) with low BTU gases, have relatively narrow bands of air-to-vent gas ratios that can achieve destruction and removal efficiencies (DREs, fraction of waste gases destroyed by complete and incomplete combustion) greater than 98%. If blower configurations are not able to operate within these narrow bands, emissions may be greater than those predicted based on 98% DRE, but if air-assist rates can be finely tuned, emissions much lower than those predicted assuming 98% DRE are achievable. This work examines the potential impact on emissions of using four different blower configurations (single fixed speed, dual fixed speed, single variable speed, and dual variable speed) on an air-assisted flare. Typical patterns of flare vent gas flow rates were obtained from hourly data on flared gas flow rates from Houston, Texas. The analyses indicate that flare emissions can be much greater (up to a factor of 40) than a base case assuming 98% DRE if single, fixed speed blower configurations are used. Conversely, flare emissions can be much lower than a base case assuming 98% DRE if air-assist rates can be closely matched to stoichiometric requirements. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3012209

Industrial flare performance at low flow conditions. 2. / Vincent M. Torres in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12569–12576 Titre : Industrial flare performance at low flow conditions. 2. : Steam- and air-assisted flares Type de document : texte imprimé Auteurs : Vincent M. Torres, Auteur ; Scott Herndon, Auteur ; David T. Allen, Auteur Année de publication : 2012 Article en page(s) : pp. 12569–12576 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Industrial  flare  Steam Résumé : Full-scale tests of steam- and air-assisted industrial flares were conducted using low BTU content (lower heating value) vent gases at low flow rates. A 36″ diameter steam-assisted flare with a flow capacity of 937,000 lb/h and a 24″ diameter air-assisted flare with a flow capacity of 144,000 pounds per hour were operated with mixtures of natural gas, propylene, and nitrogen or natural gas, propane, and nitrogen at flow rates less than 1% of maximum flow. Combustion efficiency (percentage of the flared gases converted to carbon dioxide and water) ranged from less than 50% to more than 99%. For the steam-assisted flare, combustion efficiency (CE) at low steam-to-vent gas flow ratios (0.5–1.0) was typically in excess of 95%. CE would gradually decrease as steam-to-vent gas ratio increased, to a point, after which CE would decrease dramatically. The steam-to-vent gas ratio at which CE would decrease dramatically depended on the heating value of the vent gas and the position of the steam injection. Higher heating values of the vent gas (600 vs 350 BTU/scf) and the minimization of steam coinjected with the vent gas, rather than injected at the flare tip, promoted higher CE. For the air-assisted flare, CE at low air assist rates (<30–50 times the vent gas flow rate) was typically above 90%. The CE decreased linearly with increasing air assist to vent gas ratio and did not exhibit the rapid decrease exhibited by the steam-assisted flare. Combustion efficiencies for vent gases with higher heating values (600 BTU/scf versus 350 BTU/scf) decreased more slowly in the air assisted flare. For both the steam- and air-assisted flares, the composition of the vent gas (propane vs propylene) had a much smaller effect on combustion characteristics than steam or air injection and vent gas heating value. Products of incomplete combustion were dominated by CO; other significant species included acetylene, ethylene, formaldehyde, acetaldehyde, and acrolein. The effect of wind speed on CE was estimated to be less than 2.5% of the CE, over the range of wind speeds 0–16 mph. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202675f [article] Industrial flare performance at low flow conditions. 2. : Steam- and air-assisted flares [texte imprimé] / Vincent M. Torres, Auteur ; Scott Herndon, Auteur ; David T. Allen, Auteur . - 2012 . - pp. 12569–12576. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12569–12576 Mots-clés : Industrial  flare  Steam Résumé : Full-scale tests of steam- and air-assisted industrial flares were conducted using low BTU content (lower heating value) vent gases at low flow rates. A 36″ diameter steam-assisted flare with a flow capacity of 937,000 lb/h and a 24″ diameter air-assisted flare with a flow capacity of 144,000 pounds per hour were operated with mixtures of natural gas, propylene, and nitrogen or natural gas, propane, and nitrogen at flow rates less than 1% of maximum flow. Combustion efficiency (percentage of the flared gases converted to carbon dioxide and water) ranged from less than 50% to more than 99%. For the steam-assisted flare, combustion efficiency (CE) at low steam-to-vent gas flow ratios (0.5–1.0) was typically in excess of 95%. CE would gradually decrease as steam-to-vent gas ratio increased, to a point, after which CE would decrease dramatically. The steam-to-vent gas ratio at which CE would decrease dramatically depended on the heating value of the vent gas and the position of the steam injection. Higher heating values of the vent gas (600 vs 350 BTU/scf) and the minimization of steam coinjected with the vent gas, rather than injected at the flare tip, promoted higher CE. For the air-assisted flare, CE at low air assist rates (<30–50 times the vent gas flow rate) was typically above 90%. The CE decreased linearly with increasing air assist to vent gas ratio and did not exhibit the rapid decrease exhibited by the steam-assisted flare. Combustion efficiencies for vent gases with higher heating values (600 BTU/scf versus 350 BTU/scf) decreased more slowly in the air assisted flare. For both the steam- and air-assisted flares, the composition of the vent gas (propane vs propylene) had a much smaller effect on combustion characteristics than steam or air injection and vent gas heating value. Products of incomplete combustion were dominated by CO; other significant species included acetylene, ethylene, formaldehyde, acetaldehyde, and acrolein. The effect of wind speed on CE was estimated to be less than 2.5% of the CE, over the range of wind speeds 0–16 mph. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202675f

Temporal variability in flaring emissions in the houston–galveston area / Radovan T. Pavlovic in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12653–12662 Titre : Temporal variability in flaring emissions in the houston–galveston area Type de document : texte imprimé Auteurs : Radovan T. Pavlovic, Auteur ; David T. Allen, Auteur ; Elena C. McDonald-Buller, Auteur Année de publication : 2012 Article en page(s) : pp. 12653–12662 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Industrial  air  pollutant  emission Résumé : Recent studies performed in the Houston–Galveston–Brazoria (HGB) area indicate that some industrial air pollutant emission sources exhibit high temporal variability that can lead to very rapid ozone formation, especially when emissions include highly reactive volatile organic compounds. This motivated the collection of a unique data set of air pollutant emissions, from industrial facilities, reported with an hourly time resolution. The industrial flares portion of this data set was utilized in this work to characterize and model the highly variable temporal patterns of flare emissions at petrochemical facilities. Petrochemical and chemical manufacturing flares were grouped into categories based on industrial process they service, chemical composition of the flared gas, and the temporal patterns of their emissions. Stochastic models were developed for each categorization of flare emissions and provide representative temporal profiles for flares in specific types of operations in the petrochemical and chemical manufacturing sectors. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2013357 [article] Temporal variability in flaring emissions in the houston–galveston area [texte imprimé] / Radovan T. Pavlovic, Auteur ; David T. Allen, Auteur ; Elena C. McDonald-Buller, Auteur . - 2012 . - pp. 12653–12662. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12653–12662 Mots-clés : Industrial  air  pollutant  emission Résumé : Recent studies performed in the Houston–Galveston–Brazoria (HGB) area indicate that some industrial air pollutant emission sources exhibit high temporal variability that can lead to very rapid ozone formation, especially when emissions include highly reactive volatile organic compounds. This motivated the collection of a unique data set of air pollutant emissions, from industrial facilities, reported with an hourly time resolution. The industrial flares portion of this data set was utilized in this work to characterize and model the highly variable temporal patterns of flare emissions at petrochemical facilities. Petrochemical and chemical manufacturing flares were grouped into categories based on industrial process they service, chemical composition of the flared gas, and the temporal patterns of their emissions. Stochastic models were developed for each categorization of flare emissions and provide representative temporal profiles for flares in specific types of operations in the petrochemical and chemical manufacturing sectors. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2013357