Documents disponibles écrits par cet auteur

Calcium looping process for clean coal conversion / Nihar Phalak in Industrial & engineering chemistry research, Vol. 51 N° 30 (Août 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 30 (Août 2012) . - pp. 9938-9944 Titre : Calcium looping process for clean coal conversion : Design and operation of the subpilot - scale carbonator Type de document : texte imprimé Auteurs : Nihar Phalak, Auteur ; Shwetha Ramkumar, Auteur ; Niranjani Deshpande, Auteur Année de publication : 2012 Article en page(s) : pp. 9938-9944 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Design  Coal Résumé : The calcium looping process (CLP), which is being developed at The Ohio State University (OSU), is a clean coal technology for the production of hydrogen (H2) and electricity from coal-derived syngas. It integrates the water―gas shift (WGS) reaction with in situ removal of carbon dioxide (CO2) and other contaminants like sulfides and halides, thus resulting in the production of high-purity H2, The in situ removal of CO2 drives the equilibrium-limited WGS reaction forward. The CLP has the potential to reduce the overall footprint of a coal-to-H2 process because of the integration of several unit operations in a single-stage reactor. The high-temperature operation and the different exothermic reactions involved provide various sources of heat, which, when integrated appropriately, result in a process with low energy penalty. Prior work conducted in a fixed-bed reactor has shown that high carbon monoxide (CO) conversions and high H2 purities can be obtained, depending on the operating pressures. On the basis of the encouraging results obtained from the fixed-bed reactor, a subpilot-scale fluidized-bed reactor (carbonator) has been designed and constructed at OSU. In this work, the design of this reactor has been detailed and some operational results have been provided. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26201405 [article] Calcium looping process for clean coal conversion : Design and operation of the subpilot - scale carbonator [texte imprimé] / Nihar Phalak, Auteur ; Shwetha Ramkumar, Auteur ; Niranjani Deshpande, Auteur . - 2012 . - pp. 9938-9944. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 30 (Août 2012) . - pp. 9938-9944 Mots-clés : Design  Coal Résumé : The calcium looping process (CLP), which is being developed at The Ohio State University (OSU), is a clean coal technology for the production of hydrogen (H2) and electricity from coal-derived syngas. It integrates the water―gas shift (WGS) reaction with in situ removal of carbon dioxide (CO2) and other contaminants like sulfides and halides, thus resulting in the production of high-purity H2, The in situ removal of CO2 drives the equilibrium-limited WGS reaction forward. The CLP has the potential to reduce the overall footprint of a coal-to-H2 process because of the integration of several unit operations in a single-stage reactor. The high-temperature operation and the different exothermic reactions involved provide various sources of heat, which, when integrated appropriately, result in a process with low energy penalty. Prior work conducted in a fixed-bed reactor has shown that high carbon monoxide (CO) conversions and high H2 purities can be obtained, depending on the operating pressures. On the basis of the encouraging results obtained from the fixed-bed reactor, a subpilot-scale fluidized-bed reactor (carbonator) has been designed and constructed at OSU. In this work, the design of this reactor has been detailed and some operational results have been provided. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26201405

Subpilot demonstration of the carbonation − calcination reaction (CCR) process / William Wang in Industrial & engineering chemistry research, Vol. 49 N° 11 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 11 (Juin 2010) . - pp. 5094–5101 Titre : Subpilot demonstration of the carbonation − calcination reaction (CCR) process : high - temperature CO2 and sulfur capture from coal - fired power plants Type de document : texte imprimé Auteurs : William Wang, Auteur ; Shwetha Ramkumar, Auteur ; Songgeng Li, Auteur Année de publication : 2010 Article en page(s) : pp. 5094–5101 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbonation  calcination  reaction  High  temperature. Résumé : Increasing concerns over growing CO2 levels in the atmosphere have led to a worldwide demand for efficient, cost-effective, and clean carbon capture technologies. One of these technologies is the Carbonation−Calcination Reaction (CCR) process, which utilizes a calcium-based sorbent in a high-temperature reaction (carbonation) to capture the CO2 from the flue gas stream and releases a pure stream of CO2 in the subsequent calcination reaction that can be sequestered. A 120 KWth subpilot-scale combustion plant utilizing coal at 20 pph along with natural gas has been established at The Ohio State University to test the CCR process. Experimental studies on CO2 capture using calcium-based sorbents have been performed at this facility. Greater than 99% CO2 and SO2 capture has been achieved at the subpilot-scale facility on a once-through basis at a Ca:C mole ratio of 1.6. In addition, the sorbent reactivity is maintained over multiple cycles by the incorporation of a sorbent reactivation hydration step in the carbonation−calcination cycle. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901509k [article] Subpilot demonstration of the carbonation − calcination reaction (CCR) process : high - temperature CO2 and sulfur capture from coal - fired power plants [texte imprimé] / William Wang, Auteur ; Shwetha Ramkumar, Auteur ; Songgeng Li, Auteur . - 2010 . - pp. 5094–5101. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 11 (Juin 2010) . - pp. 5094–5101 Mots-clés : Carbonation  calcination  reaction  High  temperature. Résumé : Increasing concerns over growing CO2 levels in the atmosphere have led to a worldwide demand for efficient, cost-effective, and clean carbon capture technologies. One of these technologies is the Carbonation−Calcination Reaction (CCR) process, which utilizes a calcium-based sorbent in a high-temperature reaction (carbonation) to capture the CO2 from the flue gas stream and releases a pure stream of CO2 in the subsequent calcination reaction that can be sequestered. A 120 KWth subpilot-scale combustion plant utilizing coal at 20 pph along with natural gas has been established at The Ohio State University to test the CCR process. Experimental studies on CO2 capture using calcium-based sorbents have been performed at this facility. Greater than 99% CO2 and SO2 capture has been achieved at the subpilot-scale facility on a once-through basis at a Ca:C mole ratio of 1.6. In addition, the sorbent reactivity is maintained over multiple cycles by the incorporation of a sorbent reactivation hydration step in the carbonation−calcination cycle. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901509k

Thermodynamic and experimental analyses of the three - stage calcium looping process / Shwetha Ramkumar in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7563–7573 Titre : Thermodynamic and experimental analyses of the three - stage calcium looping process Type de document : texte imprimé Auteurs : Shwetha Ramkumar, Auteur ; Liang-Shih Fan, Auteur Année de publication : 2010 Article en page(s) : pp. 7563–7573 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermodynamic  Analyses Résumé : Clean-coal technologies that include carbon dioxide and sulfur capture during the production of electric power, liquid fuels, and hydrogen represent a major thrust area. The calcium looping process (CLP) is one such technology that is being developed to convert syngas obtained from coal gasification to hydrogen using a regenerable calcium oxide sorbent. It integrates the water−gas shift reaction with in situ carbon dioxide, sulfur, and halide removal at high temperatures while eliminating the need for a water−gas shift catalyst and reducing the overall footprint of the hydrogen production process. The CLP comprises three reactors: the carbonation reactor, where the thermodynamic constraint of the water−gas shift reaction is overcome by the constant removal of the carbon dioxide product and high-purity hydrogen is produced with contaminant removal; the calciner, where the calcium sorbent is regenerated and a sequestration-ready carbon dioxide stream is produced; and the hydrator, where the calcined sorbent is reactivated to improve its recyclability. In this article, the reaction chemistry occurring in the three calcium looping reactors and the performance of the reactors at various process conditions are presented through thermodynamic and experimental analyses. High-purity H2 with less than 1 ppm of H2S is obtained in the carbonation stage at a stoichiometric steam-to-carbon ratio at high pressures. Although calcination of the sorbent under realistic conditions causes severe sintering and a loss in reactivity, sorbent reactivation by hydration is effective in restoring sorbent reactivity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100846u [article] Thermodynamic and experimental analyses of the three - stage calcium looping process [texte imprimé] / Shwetha Ramkumar, Auteur ; Liang-Shih Fan, Auteur . - 2010 . - pp. 7563–7573. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7563–7573 Mots-clés : Thermodynamic  Analyses Résumé : Clean-coal technologies that include carbon dioxide and sulfur capture during the production of electric power, liquid fuels, and hydrogen represent a major thrust area. The calcium looping process (CLP) is one such technology that is being developed to convert syngas obtained from coal gasification to hydrogen using a regenerable calcium oxide sorbent. It integrates the water−gas shift reaction with in situ carbon dioxide, sulfur, and halide removal at high temperatures while eliminating the need for a water−gas shift catalyst and reducing the overall footprint of the hydrogen production process. The CLP comprises three reactors: the carbonation reactor, where the thermodynamic constraint of the water−gas shift reaction is overcome by the constant removal of the carbon dioxide product and high-purity hydrogen is produced with contaminant removal; the calciner, where the calcium sorbent is regenerated and a sequestration-ready carbon dioxide stream is produced; and the hydrator, where the calcined sorbent is reactivated to improve its recyclability. In this article, the reaction chemistry occurring in the three calcium looping reactors and the performance of the reactors at various process conditions are presented through thermodynamic and experimental analyses. High-purity H2 with less than 1 ppm of H2S is obtained in the carbonation stage at a stoichiometric steam-to-carbon ratio at high pressures. Although calcination of the sorbent under realistic conditions causes severe sintering and a loss in reactivity, sorbent reactivation by hydration is effective in restoring sorbent reactivity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100846u