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Effect of gas and liquid superficial velocities on the performance of monolithic reactors / Mogalicherla, Aswani Kumar in Industrial & engineering chemistry research, Vol. 49 N° 4 (Fevrier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1631–1641 Titre : Effect of gas and liquid superficial velocities on the performance of monolithic reactors Type de document : texte imprimé Auteurs : Mogalicherla, Aswani Kumar, Auteur ; Deepak Kunzru, Auteur Année de publication : 2010 Article en page(s) : pp 1631–1641 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas  Monolithic  reactors. Résumé : The effect of gas and liquid velocities on the rate of hydrogenation of α-methyl styrene (AMS) in a monolithic reactor has been investigated at different washcoat loadings. The catalyst used was 0.5 wt% Pd/Al2O3. To cover a wide range of velocities, reaction studies were conducted in multichannel as well as single-channel monolith blocks. The liquid channel velocity was varied from 0.5 cm/s to 22 cm/s, and the gas channel velocity was varied from 1.2 cm/s to 22 cm/s. To study the effect of internal diffusional resistance, the washcoat thickness was varied from 11 μm to 62 μm. Under these operating conditions, both external mass-transfer and internal diffusional resistance affected the rate of reaction. At low liquid velocities (<2 cm/s), the measured rate of reaction was not significantly affected by the gas velocity, whereas at high liquid velocities, the measured reaction rate passed through a maximum with increasing gas velocity. The highest reaction rates were obtained for gas and liquid velocities in the range of 5−10 cm/s. At higher liquid velocities (>10 cm/s), the rate of reaction decreased with liquid velocity, most probably because of the increase in liquid slug length and film thickness around the gas bubble. The overall effectiveness factor of the monolith catalyst was determined from the measured rate of reaction and the published intrinsic kinetics. Using the approximation of Gottifredi et al. for nonlinear kinetics [Gottifredi et al. Chem. Eng. Sci. 1981, 36, 313−317], the internal effectiveness factor and overall mass-transfer coefficient were determined. The overall mass-transfer coefficients determined from the reaction-rate data have been compared with the values calculated using the available correlations. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901442d [article] Effect of gas and liquid superficial velocities on the performance of monolithic reactors [texte imprimé] / Mogalicherla, Aswani Kumar, Auteur ; Deepak Kunzru, Auteur . - 2010 . - pp 1631–1641. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1631–1641 Mots-clés : Gas  Monolithic  reactors. Résumé : The effect of gas and liquid velocities on the rate of hydrogenation of α-methyl styrene (AMS) in a monolithic reactor has been investigated at different washcoat loadings. The catalyst used was 0.5 wt% Pd/Al2O3. To cover a wide range of velocities, reaction studies were conducted in multichannel as well as single-channel monolith blocks. The liquid channel velocity was varied from 0.5 cm/s to 22 cm/s, and the gas channel velocity was varied from 1.2 cm/s to 22 cm/s. To study the effect of internal diffusional resistance, the washcoat thickness was varied from 11 μm to 62 μm. Under these operating conditions, both external mass-transfer and internal diffusional resistance affected the rate of reaction. At low liquid velocities (<2 cm/s), the measured rate of reaction was not significantly affected by the gas velocity, whereas at high liquid velocities, the measured reaction rate passed through a maximum with increasing gas velocity. The highest reaction rates were obtained for gas and liquid velocities in the range of 5−10 cm/s. At higher liquid velocities (>10 cm/s), the rate of reaction decreased with liquid velocity, most probably because of the increase in liquid slug length and film thickness around the gas bubble. The overall effectiveness factor of the monolith catalyst was determined from the measured rate of reaction and the published intrinsic kinetics. Using the approximation of Gottifredi et al. for nonlinear kinetics [Gottifredi et al. Chem. Eng. Sci. 1981, 36, 313−317], the internal effectiveness factor and overall mass-transfer coefficient were determined. The overall mass-transfer coefficients determined from the reaction-rate data have been compared with the values calculated using the available correlations. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901442d

Estimation of wetting efficiency in trickle-bed reactors for nonlinear kinetics / Mogalicherla, Aswani Kumar in Industrial & engineering chemistry research, Vol. 48 N°3 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1443–1450 Titre : Estimation of wetting efficiency in trickle-bed reactors for nonlinear kinetics Type de document : texte imprimé Auteurs : Mogalicherla, Aswani Kumar, Auteur ; Gaurav Sharma, Auteur ; Deepak Kunzru, Auteur Année de publication : 2009 Article en page(s) : p. 1443–1450 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Trickle-bed  reactors  Intrinsic  kinetic Résumé : A procedure has been developed for estimating the wetting efficiency in a trickle-bed reactor by using the conversion data obtained for a reaction following nonlinear kinetics. For this purpose, the hydrogenation of α-methylstyrene on 0.5 wt % Pd/Al2O3 catalyst was studied in a batch slurry reactor (1.0−6.0 atm, 313−343 K), as well as in a trickle-bed reactor (313 K, 1.0−2.5 atm). The superficial velocities of gas and liquid in the trickle-bed reactor (TBR) were in the range of 0.25−1.0 cm/s and 0.06−0.24 cm/s, respectively. The intrinsic power-law kinetics, determined from the data obtained in the batch reactor, was used to calculate the effectiveness factors in the TBR. A comparison of these effectiveness factors with those calculated assuming complete external wetting showed that the wetting was not complete. The external wetting efficiencies (f) were determined using the method proposed by Ramachandran and Smith [ AIChE J.1979, 25 (3), 538.]. To this end, effectiveness factors for the catalyst completely covered with gas or liquid were estimated for this nonlinear kinetics by a previously published procedure. f varied between 40% and 75% with the liquid superficial velocity. The difference between f values calculated from the conversion data and from the correlation developed using residence time distribution (RTD) data was attributed to the presence of stagnant liquid zones between the catalyst particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801305t [article] Estimation of wetting efficiency in trickle-bed reactors for nonlinear kinetics [texte imprimé] / Mogalicherla, Aswani Kumar, Auteur ; Gaurav Sharma, Auteur ; Deepak Kunzru, Auteur . - 2009 . - p. 1443–1450. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1443–1450 Mots-clés : Trickle-bed  reactors  Intrinsic  kinetic Résumé : A procedure has been developed for estimating the wetting efficiency in a trickle-bed reactor by using the conversion data obtained for a reaction following nonlinear kinetics. For this purpose, the hydrogenation of α-methylstyrene on 0.5 wt % Pd/Al2O3 catalyst was studied in a batch slurry reactor (1.0−6.0 atm, 313−343 K), as well as in a trickle-bed reactor (313 K, 1.0−2.5 atm). The superficial velocities of gas and liquid in the trickle-bed reactor (TBR) were in the range of 0.25−1.0 cm/s and 0.06−0.24 cm/s, respectively. The intrinsic power-law kinetics, determined from the data obtained in the batch reactor, was used to calculate the effectiveness factors in the TBR. A comparison of these effectiveness factors with those calculated assuming complete external wetting showed that the wetting was not complete. The external wetting efficiencies (f) were determined using the method proposed by Ramachandran and Smith [ AIChE J.1979, 25 (3), 538.]. To this end, effectiveness factors for the catalyst completely covered with gas or liquid were estimated for this nonlinear kinetics by a previously published procedure. f varied between 40% and 75% with the liquid superficial velocity. The difference between f values calculated from the conversion data and from the correlation developed using residence time distribution (RTD) data was attributed to the presence of stagnant liquid zones between the catalyst particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801305t

Steam reforming of ethanol in a microchannel reactor / Nageswara Rao Peela in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12881-12894 Titre : Steam reforming of ethanol in a microchannel reactor : kinetic study and reactor simulation Type de document : texte imprimé Auteurs : Nageswara Rao Peela, Auteur ; Deepak Kunzru, Auteur Année de publication : 2012 Article en page(s) : pp. 12881-12894 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor  Kinetics  Microreactor  Steam  reforming Résumé : The kinetics of steam reforming of ethanol (SRE) was determined at atmospheric pressure in the temperature range of 450―550 °C over 2% Rh/20% CeO2/Al2O3 in a microchannel reactor. The product distribution could be explained by a reaction scheme consisting of four reactions: reaction of steam with ethanol, decomposition of ethanol, methane steam reforming, and the water-gas shift reaction. The kinetic expression based on Langmuir―Hinshelwood kinetics could explain the experimental data satisfactorily. A two-dimensional simulation was also carried out to predict the performance of a microchannel SRE reactor in which the endothermic heat of reaction was supplied by the co-current flow of a hot gas in the adjacent channel. The performance of the coupled reactor/heat exchange system was evaluated by varying several parameters such as heating side gas velocity and temperature, width of the channel, weight of the catalyst, reactor inlet temperature, and inlet flow rate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267446 [article] Steam reforming of ethanol in a microchannel reactor : kinetic study and reactor simulation [texte imprimé] / Nageswara Rao Peela, Auteur ; Deepak Kunzru, Auteur . - 2012 . - pp. 12881-12894. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12881-12894 Mots-clés : Reactor  Kinetics  Microreactor  Steam  reforming Résumé : The kinetics of steam reforming of ethanol (SRE) was determined at atmospheric pressure in the temperature range of 450―550 °C over 2% Rh/20% CeO2/Al2O3 in a microchannel reactor. The product distribution could be explained by a reaction scheme consisting of four reactions: reaction of steam with ethanol, decomposition of ethanol, methane steam reforming, and the water-gas shift reaction. The kinetic expression based on Langmuir―Hinshelwood kinetics could explain the experimental data satisfactorily. A two-dimensional simulation was also carried out to predict the performance of a microchannel SRE reactor in which the endothermic heat of reaction was supplied by the co-current flow of a hot gas in the adjacent channel. The performance of the coupled reactor/heat exchange system was evaluated by varying several parameters such as heating side gas velocity and temperature, width of the channel, weight of the catalyst, reactor inlet temperature, and inlet flow rate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267446