Documents disponibles écrits par cet auteur

Catalytic hydrolysis of urea with fly ash for generation of ammonia in a batch reactor for flue gas conditioning and nox reduction / J.N. Sahu in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Titre : Catalytic hydrolysis of urea with fly ash for generation of ammonia in a batch reactor for flue gas conditioning and nox reduction Type de document : texte imprimé Auteurs : J.N. Sahu, Auteur ; P. Gangadharan, Auteur ; Anada V. Patwardhan, Auteur Année de publication : 2009 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Catalytic  Hydrolysis Résumé : Ammonia is a highly volatile noxious material with adverse physiological effects, which become intolerable even at very low concentrations and present substantial environmental and operating hazards and risk. Yet ammonia has long been known to be used for feedstock of flue gas conditioning and NOx reduction. Urea as the source of ammonia for the production of ammonia has the obvious advantages that no ammonia shipping, handling, and storage is required. The process of this invention minimizes the risks and hazards associated with the transport, storage, and use of anhydrous and aqueous ammonia. Yet no such rapid urea conversion process is available as per requirement of high conversion in shorter time, so here we study the catalytic hydrolysis of urea for fast conversion in a batch reactor. The catalyst used in this study is fly ash, a waste material originating in great amounts in combustion processes. A number of experiments were carried out in a batch reactor at different catalytic doses, temperatures, times, and at a constant concentration of urea solution 10% by weight, and equilibrium and kinetic studies have been made. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801491j [article] Catalytic hydrolysis of urea with fly ash for generation of ammonia in a batch reactor for flue gas conditioning and nox reduction [texte imprimé] / J.N. Sahu, Auteur ; P. Gangadharan, Auteur ; Anada V. Patwardhan, Auteur . - 2009. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Mots-clés : Catalytic  Hydrolysis Résumé : Ammonia is a highly volatile noxious material with adverse physiological effects, which become intolerable even at very low concentrations and present substantial environmental and operating hazards and risk. Yet ammonia has long been known to be used for feedstock of flue gas conditioning and NOx reduction. Urea as the source of ammonia for the production of ammonia has the obvious advantages that no ammonia shipping, handling, and storage is required. The process of this invention minimizes the risks and hazards associated with the transport, storage, and use of anhydrous and aqueous ammonia. Yet no such rapid urea conversion process is available as per requirement of high conversion in shorter time, so here we study the catalytic hydrolysis of urea for fast conversion in a batch reactor. The catalyst used in this study is fly ash, a waste material originating in great amounts in combustion processes. A number of experiments were carried out in a batch reactor at different catalytic doses, temperatures, times, and at a constant concentration of urea solution 10% by weight, and equilibrium and kinetic studies have been made. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801491j

Equilibrium and kinetic studies on the hydrolysis of urea for ammonia generation in a semibatch reactor / J.N. Sahu in Industrial & engineering chemistry research, Vol. 47 n°14 (Juillet 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4689–4696 Titre : Equilibrium and kinetic studies on the hydrolysis of urea for ammonia generation in a semibatch reactor Type de document : texte imprimé Auteurs : J.N. Sahu, Auteur ; K. Mahalik, Auteur ; A. V. Patwardhan, Auteur ; B. C. Meikap, Auteur Année de publication : 2008 Article en page(s) : p. 4689–4696 Note générale : Bibliogr. p. 4695-4696 Langues : Anglais (eng) Mots-clés : Ammonia;  Urea  hydrolysis;  Kinetic  study Résumé : The present study is concerned with the methods and means to safely produce relatively small amounts (i.e., up to 50 kg/h) of ammonia. The equilibrium and kinetic study of urea hydrolysis was conducted in a semibatch reactor at atmospheric pressure to investigate the effects of reaction temperature, initial feed concentration, and time on ammonia production. This study reveals that conversion increases exponentially with increasing temperature but decreases slightly with increasing initial feed concentration of urea. Furthermore, the effect of time on conversion was also studied; it was found that conversion increases with increasing time. Using collision theory, the temperature dependency of the forward rate constant was determined, from which the activation energy of the reaction and the frequency factor were calculated. The activation energy and frequency factor of the urea hydrolysis reaction at atmospheric pressure were found to be 60.93 kJ/mol and 4.259 × 105 min−1, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800481z [article] Equilibrium and kinetic studies on the hydrolysis of urea for ammonia generation in a semibatch reactor [texte imprimé] / J.N. Sahu, Auteur ; K. Mahalik, Auteur ; A. V. Patwardhan, Auteur ; B. C. Meikap, Auteur . - 2008 . - p. 4689–4696. Bibliogr. p. 4695-4696 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4689–4696 Mots-clés : Ammonia;  Urea  hydrolysis;  Kinetic  study Résumé : The present study is concerned with the methods and means to safely produce relatively small amounts (i.e., up to 50 kg/h) of ammonia. The equilibrium and kinetic study of urea hydrolysis was conducted in a semibatch reactor at atmospheric pressure to investigate the effects of reaction temperature, initial feed concentration, and time on ammonia production. This study reveals that conversion increases exponentially with increasing temperature but decreases slightly with increasing initial feed concentration of urea. Furthermore, the effect of time on conversion was also studied; it was found that conversion increases with increasing time. Using collision theory, the temperature dependency of the forward rate constant was determined, from which the activation energy of the reaction and the frequency factor were calculated. The activation energy and frequency factor of the urea hydrolysis reaction at atmospheric pressure were found to be 60.93 kJ/mol and 4.259 × 105 min−1, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800481z

Response Surface Modeling and Optimization of CO Hydrogenation for Higher Liquid Hydrocarbon Using Cu–Co–Cr + ZSM-5 Bifunctional Catalyst / Pravakar Mohanty in Industrial & engineering chemistry research, Vol. 51 N° 13 (Avril 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 13 (Avril 2012) . - pp. 4843–4853 Titre : Response Surface Modeling and Optimization of CO Hydrogenation for Higher Liquid Hydrocarbon Using Cu–Co–Cr + ZSM-5 Bifunctional Catalyst Type de document : texte imprimé Auteurs : Pravakar Mohanty, Auteur ; Sachchit Majhi, Auteur ; J.N. Sahu, Auteur Année de publication : 2012 Article en page(s) : pp. 4843–4853 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization  Hydrogenation  Hydrocarbon Résumé : This paper represents an extensive statistical analysis of the combined effects of operating variables (temperature, pressure, reaction time, and H2/CO flow rate) toward CO-hydrogenation for liquid hydrocarbon which was performed in a fixed bed benchtop reactor system, by means of response surface methodology (RSM). The application of RSM in conjunction with a central composite rotatable design (CCRD) was used for modeling and optimizing the performance of a multivariable FT-synthesis process using bifunctional CuO–CoO–Cr2O3 + ZSM-5 catalyst. The CuO–CoO–Cr2O3 catalyst was synthesized by a coprecipitation method, and its physiochemical characterization was done by using Brunauer–Emmett–Teller, temperature-programmed reduction, thermogravimetric analysis, X-ray diffraction, and transmission electron mocroscopy techniques. Through this work a 50 full factorial (CCRD) experimental design was employed. Maximum CO conversion was predicted and experimentally validated to determine optimum conditions that allow improvement of the performance of the catalyst for a long run time of 120 h. The optimum values of CO conversion, temperature, pressure, and (H2/CO) molar ratio were found to be 64.3%, 310 ± 4 °C, 33–36 bar, and 1.0, respectively. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202866q [article] Response Surface Modeling and Optimization of CO Hydrogenation for Higher Liquid Hydrocarbon Using Cu–Co–Cr + ZSM-5 Bifunctional Catalyst [texte imprimé] / Pravakar Mohanty, Auteur ; Sachchit Majhi, Auteur ; J.N. Sahu, Auteur . - 2012 . - pp. 4843–4853. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 13 (Avril 2012) . - pp. 4843–4853 Mots-clés : Optimization  Hydrogenation  Hydrocarbon Résumé : This paper represents an extensive statistical analysis of the combined effects of operating variables (temperature, pressure, reaction time, and H2/CO flow rate) toward CO-hydrogenation for liquid hydrocarbon which was performed in a fixed bed benchtop reactor system, by means of response surface methodology (RSM). The application of RSM in conjunction with a central composite rotatable design (CCRD) was used for modeling and optimizing the performance of a multivariable FT-synthesis process using bifunctional CuO–CoO–Cr2O3 + ZSM-5 catalyst. The CuO–CoO–Cr2O3 catalyst was synthesized by a coprecipitation method, and its physiochemical characterization was done by using Brunauer–Emmett–Teller, temperature-programmed reduction, thermogravimetric analysis, X-ray diffraction, and transmission electron mocroscopy techniques. Through this work a 50 full factorial (CCRD) experimental design was employed. Maximum CO conversion was predicted and experimentally validated to determine optimum conditions that allow improvement of the performance of the catalyst for a long run time of 120 h. The optimum values of CO conversion, temperature, pressure, and (H2/CO) molar ratio were found to be 64.3%, 310 ± 4 °C, 33–36 bar, and 1.0, respectively. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202866q