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Analysis of the autoignition process under the industrial partial oxidation conditions using detailed kinetic modeling / Yefei Liu in Industrial & engineering chemistry research, Vol. 50 N° 10 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6009–6016 Titre : Analysis of the autoignition process under the industrial partial oxidation conditions using detailed kinetic modeling Type de document : texte imprimé Auteurs : Yefei Liu, Auteur ; Tiefeng Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 6009–6016 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Autoignition  process Résumé : In the noncatalytic partial oxidation process, autoignition of the heated premixed combustible gases is a major source of reactor damage, unstable operation, and even explosion accidents. The knowledge of the autoignition behavior is of great importance to risk assessment and loss prevention in the partial oxidation reactors. The large experimental effort could be reduced if a reliable modeling procedure is available to identify the safe operating conditions. In this work the reliability of the detailed kinetic modeling method was investigated by comparing the simulated results with the experimental data reported in the literatures. It was found that the USC II mechanism gave the best predictions on the ignition delay times for the methane/air mixtures with equivalence ratios of 3.33 and 6.67. This mechanism was used to extrapolate the ignition delay times in the industrial partial oxidation process. The effects of initial temperature and equivalence ratio on ignition delay times were also investigated. The species concentration profiles were analyzed to understand the underlying ignition chemistry. The sensitivity analysis was carried out for the identification of the main reactions affecting the autoignition process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102485v [article] Analysis of the autoignition process under the industrial partial oxidation conditions using detailed kinetic modeling [texte imprimé] / Yefei Liu, Auteur ; Tiefeng Wang, Auteur . - 2011 . - pp. 6009–6016. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6009–6016 Mots-clés : Autoignition  process Résumé : In the noncatalytic partial oxidation process, autoignition of the heated premixed combustible gases is a major source of reactor damage, unstable operation, and even explosion accidents. The knowledge of the autoignition behavior is of great importance to risk assessment and loss prevention in the partial oxidation reactors. The large experimental effort could be reduced if a reliable modeling procedure is available to identify the safe operating conditions. In this work the reliability of the detailed kinetic modeling method was investigated by comparing the simulated results with the experimental data reported in the literatures. It was found that the USC II mechanism gave the best predictions on the ignition delay times for the methane/air mixtures with equivalence ratios of 3.33 and 6.67. This mechanism was used to extrapolate the ignition delay times in the industrial partial oxidation process. The effects of initial temperature and equivalence ratio on ignition delay times were also investigated. The species concentration profiles were analyzed to understand the underlying ignition chemistry. The sensitivity analysis was carried out for the identification of the main reactions affecting the autoignition process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102485v

Investigation of operation regimes in a multistage internal - loop airlift reactor / Wei Yu in Industrial & engineering chemistry research, Vol. 49 N° 22 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11752–11759 Titre : Investigation of operation regimes in a multistage internal - loop airlift reactor Type de document : texte imprimé Auteurs : Wei Yu, Auteur ; Tiefeng Wang, Auteur ; Malin Liu, Auteur Année de publication : 2011 Article en page(s) : pp. 11752–11759 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Multiphase  Airlift  reactor Résumé : Multiphase internal-loop airlift reactor is effective in reducing liquid back-mixing. To further improve the distribution of solid particles in different stages, a novel interstage internal, i.e., a perforated plate with several long tubes, was used to provide a separate flowing path for gas and slurry phases. With this novel internal, a gas layer was formed between the two adjacent stages and had a significant effect on the operation regimes. In this work, the effects of the opening ratio of the internal and superficial gas and liquid velocities on the operation regimes were experimentally studied for both cocurrent and countercurrent flows. The experimental results show that the superficial gas and liquid velocities have significant effects on the operation regimes. The effect of the opening ratio for gas channels on the operation regimes was more significant than that of the opening ratio for liquid channels. Compared with the traditional perforated plate internal, the novel internal showed better performance for operation flexibility. The regime map was obtained from the calculated gas layer height with the mathematical model proposed in our previous work and was in good agreement with the experiential results. The results in this work can provide guidance for design and scaleup of the multistage reactors. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100746z [article] Investigation of operation regimes in a multistage internal - loop airlift reactor [texte imprimé] / Wei Yu, Auteur ; Tiefeng Wang, Auteur ; Malin Liu, Auteur . - 2011 . - pp. 11752–11759. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11752–11759 Mots-clés : Multiphase  Airlift  reactor Résumé : Multiphase internal-loop airlift reactor is effective in reducing liquid back-mixing. To further improve the distribution of solid particles in different stages, a novel interstage internal, i.e., a perforated plate with several long tubes, was used to provide a separate flowing path for gas and slurry phases. With this novel internal, a gas layer was formed between the two adjacent stages and had a significant effect on the operation regimes. In this work, the effects of the opening ratio of the internal and superficial gas and liquid velocities on the operation regimes were experimentally studied for both cocurrent and countercurrent flows. The experimental results show that the superficial gas and liquid velocities have significant effects on the operation regimes. The effect of the opening ratio for gas channels on the operation regimes was more significant than that of the opening ratio for liquid channels. Compared with the traditional perforated plate internal, the novel internal showed better performance for operation flexibility. The regime map was obtained from the calculated gas layer height with the mathematical model proposed in our previous work and was in good agreement with the experiential results. The results in this work can provide guidance for design and scaleup of the multistage reactors. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100746z

Investigation of the gas layer height in a multistage internal-loop airlift reactor / Wei Yu in Industrial & engineering chemistry research, Vol. 48 N° 20 (Octobre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9278–9285 Titre : Investigation of the gas layer height in a multistage internal-loop airlift reactor Type de document : texte imprimé Auteurs : Wei Yu, Auteur ; Tiefeng Wang, Auteur ; Feifei Song, Auteur Année de publication : 2010 Article en page(s) : pp. 9278–9285 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Multistage  internal-loop  airlift  reactor  Interstage  internal  Gas  layer Résumé : A novel multistage internal-loop airlift reactor was realized by using a novel interstage internal. In this reactor, a gas layer is formed below the internal and has important effects on the hydrodynamic behavior. The effects of the opening ratio of the internal for the gas and liquid channels and superficial gas and liquid velocities were experimentally studied in both cocurrent and countercurrent operations. The results show that the gas layer height increases with an increase in the superficial gas velocity for both cocurrent and countercurrent flows. With an increase in the superficial liquid velocity, the gas layer height decreases for cocurrent flow, but increases for countercurrent flow. The opening ratio of the internal for gas channels has a much more significant influence on the gas layer height than that for the liquid channel. A mathematical model for predictions of the gas layer height was proposed based on the balance between the pressure drops of the gas and liquid through the internal. A good agreement was obtained between the calculated and experimental data. This model can be used for the optimum design of the novel multistage internal-loop airlift reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002156 [article] Investigation of the gas layer height in a multistage internal-loop airlift reactor [texte imprimé] / Wei Yu, Auteur ; Tiefeng Wang, Auteur ; Feifei Song, Auteur . - 2010 . - pp. 9278–9285. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9278–9285 Mots-clés : Multistage  internal-loop  airlift  reactor  Interstage  internal  Gas  layer Résumé : A novel multistage internal-loop airlift reactor was realized by using a novel interstage internal. In this reactor, a gas layer is formed below the internal and has important effects on the hydrodynamic behavior. The effects of the opening ratio of the internal for the gas and liquid channels and superficial gas and liquid velocities were experimentally studied in both cocurrent and countercurrent operations. The results show that the gas layer height increases with an increase in the superficial gas velocity for both cocurrent and countercurrent flows. With an increase in the superficial liquid velocity, the gas layer height decreases for cocurrent flow, but increases for countercurrent flow. The opening ratio of the internal for gas channels has a much more significant influence on the gas layer height than that for the liquid channel. A mathematical model for predictions of the gas layer height was proposed based on the balance between the pressure drops of the gas and liquid through the internal. A good agreement was obtained between the calculated and experimental data. This model can be used for the optimum design of the novel multistage internal-loop airlift reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002156

Liquid backmixing and particle distribution in a novel multistage internal-loop airlift slurry reactor / Wei Yu in Industrial & engineering chemistry research, Vol. 47 n°11 (Juin 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°11 (Juin 2008) . - p. 3974–3982 Titre : Liquid backmixing and particle distribution in a novel multistage internal-loop airlift slurry reactor Type de document : texte imprimé Auteurs : Wei Yu, Auteur ; Tiefeng Wang, Auteur ; Malin Liu, Auteur ; Zhanwen Wang, Auteur Année de publication : 2008 Article en page(s) : p. 3974–3982 Note générale : Bibliogr. p. 3982 Langues : Anglais (eng) Mots-clés : Liquid  backmixing;  Interstage  internals;  Axial  distribution Résumé : The control of liquid backmixing is an important issue in reactor design for processes with high conversions. In this work, interstage internals were used in a novel multistage internal-loop airlift slurry reactor to decrease backmixing in the liquid phase. Two types of interstage internals, namely, Internal I (perforated plate) and Internal II (perforated plate with tubes) were investigated. The axial distributions of the solid particles inside each stage and between different stages were measured with a sampling method. Interstage liquid backmixing was measured with two electrical conductivity probes using the tracing method. The effects of the structure of the interstage internal, superficial gas and liquid velocities, and particle size on interstage liquid backmixing and the distribution of solid particles were investigated. The superficial liquid velocity had more effect on interstage liquid backmixing than the superficial gas velocity. Backmixing in the liquid phase became negligible when the superficial liquid velocity exceeded a small critical value. Internal II, which was specially designed for this work, was better than the perforated plate for the uniform distribution of solid particles in the different stages. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071100h [article] Liquid backmixing and particle distribution in a novel multistage internal-loop airlift slurry reactor [texte imprimé] / Wei Yu, Auteur ; Tiefeng Wang, Auteur ; Malin Liu, Auteur ; Zhanwen Wang, Auteur . - 2008 . - p. 3974–3982. Bibliogr. p. 3982 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°11 (Juin 2008) . - p. 3974–3982 Mots-clés : Liquid  backmixing;  Interstage  internals;  Axial  distribution Résumé : The control of liquid backmixing is an important issue in reactor design for processes with high conversions. In this work, interstage internals were used in a novel multistage internal-loop airlift slurry reactor to decrease backmixing in the liquid phase. Two types of interstage internals, namely, Internal I (perforated plate) and Internal II (perforated plate with tubes) were investigated. The axial distributions of the solid particles inside each stage and between different stages were measured with a sampling method. Interstage liquid backmixing was measured with two electrical conductivity probes using the tracing method. The effects of the structure of the interstage internal, superficial gas and liquid velocities, and particle size on interstage liquid backmixing and the distribution of solid particles were investigated. The superficial liquid velocity had more effect on interstage liquid backmixing than the superficial gas velocity. Backmixing in the liquid phase became negligible when the superficial liquid velocity exceeded a small critical value. Internal II, which was specially designed for this work, was better than the perforated plate for the uniform distribution of solid particles in the different stages. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071100h

Mass - transfer behaviors in alcohol solutions in an internal - loop airlift reactor of 5 - m height / Zhonghuo Deng in Industrial & engineering chemistry research, Vol. 50 N° 20 (Octobre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 20 (Octobre 2011) . - pp. 11537–11543 Titre : Mass - transfer behaviors in alcohol solutions in an internal - loop airlift reactor of 5 - m height Type de document : texte imprimé Auteurs : Zhonghuo Deng, Auteur ; Tiefeng Wang, Auteur ; Nian Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 11537–11543 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mass  transfer Résumé : Gas–liquid mass-transfer behaviors in aqueous alcohol solutions were studied in an internal-loop airlift reactor of 5-m height and 0.28-m i.d. in the superficial gas velocity (Ug) range from 2.0 to 10.0 cm/s. Air and aqueous n-butanol solutions were used as the gas and liquid phases, respectively. It was found that the volumetric mass-transfer coefficient decreased with increasing n-butanol concentration (CA) below a critical CA value of 0.5 wt % and increased with increasing CA above this concentration. To confirm this result, further experiments were also carried out in a bubble column of 0.12-m i.d. at Ug = 6 cm/s, and similar results were obtained. Further analysis showed that the value of kla/αg was independent of the superficial gas velocity and equal to 0.21 1/s in the air–water system; however, it decreased with increasing CA up to 0.25 wt % in n-butanol solutions, and further addition of n-butanol had no effect on kla/αg. A critical CA value of 0.5 wt % was also found for the liquid-side mass-transfer coefficient (kl). Below this concentration, kl decreased with increasing CA, whereas above this concentration, further addition of n-butanol had no effect on kl. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2001988 [article] Mass - transfer behaviors in alcohol solutions in an internal - loop airlift reactor of 5 - m height [texte imprimé] / Zhonghuo Deng, Auteur ; Tiefeng Wang, Auteur ; Nian Zhang, Auteur . - 2011 . - pp. 11537–11543. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 20 (Octobre 2011) . - pp. 11537–11543 Mots-clés : Mass  transfer Résumé : Gas–liquid mass-transfer behaviors in aqueous alcohol solutions were studied in an internal-loop airlift reactor of 5-m height and 0.28-m i.d. in the superficial gas velocity (Ug) range from 2.0 to 10.0 cm/s. Air and aqueous n-butanol solutions were used as the gas and liquid phases, respectively. It was found that the volumetric mass-transfer coefficient decreased with increasing n-butanol concentration (CA) below a critical CA value of 0.5 wt % and increased with increasing CA above this concentration. To confirm this result, further experiments were also carried out in a bubble column of 0.12-m i.d. at Ug = 6 cm/s, and similar results were obtained. Further analysis showed that the value of kla/αg was independent of the superficial gas velocity and equal to 0.21 1/s in the air–water system; however, it decreased with increasing CA up to 0.25 wt % in n-butanol solutions, and further addition of n-butanol had no effect on kla/αg. A critical CA value of 0.5 wt % was also found for the liquid-side mass-transfer coefficient (kl). Below this concentration, kl decreased with increasing CA, whereas above this concentration, further addition of n-butanol had no effect on kl. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2001988