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Yang Z.,Tianjin University | Cui X.,Tianjin University | Yu X.,Peiyang Chemical Equipment Co. | Zhang Y.,Tianjin University | And 3 more authors.
Catalysis Letters | Year: 2015

Several acidic ionic liquids (ILs) with different cations and anions were used as catalysts in the transesterification of methyl acetate with n-butanol. The IL [omim][PF6] can enhance the catalytic activity of the partially soluble IL catalyst. The kinetics for the transesterification using the catalysts [HSO3bmim][p-TS] and [HSO3bmim][OTF] were measured. The ideal homogeneous model and the nonideal homogeneous (NIH) model were used to correlate the kinetic data. The NIH model was more reliable to describe the reaction rate. (Graph Presented). © 2015 Springer Science+Business Media. Source

Qie S.-Y.,Tianjin University | Gao F.,Tianjin University | Yu X.-F.,Tianjin University | Yu X.-F.,Peiyang Chemical Equipment Co. | Liu C.-J.,Tianjin University
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2015

A 2-D airlift loop reactor (2-D ALR) was developed. The hydrodynamics in 2-D ALR with different baffles was investigated with two phases (air and water). PIV experiment was carried out to investigate the hydrodynamics of the 2-D ALR with different draft tubes. Then 2-D and 3-D simulations were carried out by CFD method to study the flow behavior in the experiment. It shows that the area ratio of riser/downcomer influences the hydrodynamics in ALRs. The liquid velocity in downcomer increases with the increasing of draft tube diameter, whereas the liquid circulation flow rate reaches the maximum when the sectional area of the risers is equal to that of the downcomer. The result reveals a satisfactory agreement between the 2-D simulation and the experiment. Furthermore, the results of 3-D simulation indicate that the key factor of deciding liquid circulation flow rate is area ratio of riser/downcomer rather than diameter ratio. ©, 2015, Editorial Office of Chemical Engineering (China). All right reserved. Source

Yang Z.,Tianjin University | Cui X.,Tianjin University | Jie H.,Tianjin University | Yu X.,Peiyang Chemical Equipment Co. | And 4 more authors.
Industrial and Engineering Chemistry Research | Year: 2015

The reaction kinetics and chemical equilibrium of the transesterification of methyl acetate and isoamyl alcohol catalyzed by 1-sulfobutyl-3-methylimidazolium hydrogen sulfate ([HSO3bmim][HSO4]) were investigated. The effects of reaction temperature, initial reactant molar ratio, and catalyst concentration on the kinetics were studied. Two kinetic models, the ideal homogeneous (IH) model and the nonideal homogeneous (NIH) model, were used to correlate the kinetic data. The NIH model was more reliable to describe the reaction rate. The residue curve maps of the reaction system at different mole fractions of IL catalyst were computed, and according to the analysis of residue curve maps, a reactive distillation process was proposed. E ffects of operational and structural parameters of reactive distillation column were investigated. An experiment of the reactive distillation in a lab-scale column was then conducted to validate the simulation results. © 2015 American Chemical Society. Source

Sun B.,Tianjin University | He L.,Peiyang Chemical Equipment Co. | Liu B.T.,Tianjin University | Gu F.,Tianjin Internal Combustion Engine Research Institute | Liu C.J.,Tianjin University
AIChE Journal | Year: 2013

A multi-scale approach with the combination of computational fluid dynamic (CFD) and macroscopic calculation methods has been proposed to predict the hydrodynamics behavior in the corrugated structured packing column. On the basis of the concept of the representative unit, the three-dimensional (3-D) volume of fluid (VOF) model of the structured packing is applied in the small scale simulation, and the stream split fraction coefficients and effective wetted area ratio are calculated. The unit network model, which is a mechanistic model, is applied in large scale calculation basing on the small scale results. The liquid holdup distribution in the entire column can be available by this multi-scale method. A comparison between the simulation results and the experimental data of our previous work is given to validate the present model. The multi-scale model is proved to be prospective to assist the analysis and design of structure packing columns in chemical engineering. © 2013 American Institute of Chemical Engineers. Source

Lin R.,Tianjin University | Cui X.,Tianjin University | Yu X.,Peiyang Chemical Equipment Co. | Zhang Y.,Tianjin University | And 4 more authors.
Fluid Phase Equilibria | Year: 2016

Acetic acid and N,N-dimethylacetamide (DMAC) form a binary maximum boiling azeotrope, and the azeotrope can be separated by extractive distillation. In this work, 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]-imide ([BMIM][Tf2N]) was selected as solvent to separate the azeotrope, and isobaric vapor-liquid equilibrium (VLE) data of the system acetic acid + DMAC + [BMIM][Tf2N] were determined at 7.0 kPa and 12.0 kPa. The non-ideal behavior in vapor phase was caused by the associating effect of acetic acid and calculated by chemical theory and Hayden-O'Connell equation. The experimental VLE data were correlated by the nonrandom two-liquid (NRTL) activity coefficient model and the correlated results agreed well with the experimental data. The results show that ionic liquid [BMIM][Tf2N] produces a notable salting-out effect in the azeotropic mixture, which enhances the relative volatility of acetic acid to N,N-dimethylacetamide. © 2015 Elsevier B.V. Source

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