Process Research Of N-Butyl Acetate Produced By Transesterification In A Catalytic Distillation Column

The reactive distillation with a solid catalyst fixed in the column is called catalytict distillation. It is a new chemical technology with the benefits of simple, energy-saving, lower investment and operating cost etc. Process research on experiment and simulation of n-butyl acetate produced by transesterification in a catalytic distillation column was conducted in this paper. The research contents are as follows:The transesterification kinetics of methyl acetate with n-butanol catalyzed by an ion exchange resin,NKC-9,was measured in a continuous stired-tank reactor (CSTR). The main influence factors on reaction rate were researched and the pseudo-homogeneous kinetic model was obtained.The reactive section and catalytic distillation equipment was self-designed. The transesterification carried out in the catalytic distillation column was researched. The operation factors influencing the methyl acetate conversion were investigated.A non-equilibrium stable state model of catalytic distillation process was proposed and calculated with Newton-homotopy continuation method. This model is verified by the comparison of simulation results with experimental results. The steady-state performance of catalytic distillation process, such as the influence of reflux ratio, molar ratio of feeds, feeding quantity per hour, catalyst amount in each reactive section and reactive stages, etc., was investigated systematically using the model. The simulation results were compared with that of Katpak-s and Katapak-sp catalyst loading style. The results showed that the reactive zection developed in this paper was more favorable for chemical reaction, so the conversion of methyl acetate was higher than the values reported in literature. The simulation results obtained from ASPEN Plus and PRO II were compared with that from non-equilibrium model. It could be concluded that the simulation model established in this paper was more reasonable for avoiding the HETP estimation and its simulation results were closer to the experimental results.A two-dimensional two-phase flow CFD model using the VOF method was presented. The catalyst loading zone was simulated with Porous Media Model. The phase distributation at different liquid inlet velocity and gas inlet velocity was investigated. The calculation results showed that the catalyst was completely dipped in the liquid when the liquid-inlet velocity was 0.06m/s, which was propitious to promote the reaction. The three-dimentional flow CFD model was presented and the velocity and pressure distributation in reactive section was obtained. The results showed that the liquid flowed slowly in catalyst zone which can provide enough contacting time for reaction liquid and catalyst.