Research On Enzymatic Reaction In A Reaction-distillation Integrated Process

Enzyme catalyzed reactive distillation process is a new type of green chemical process enhancement technology,which couples enzyme catalyzed reaction with distillation process,which can effectively break the limitation of reversible reaction chemical balance.At the same time,it makes use of the advantages of green environmental protection and high selectivity of enzyme catalyst.However,enzyme catalytic distillation technology has some limitations,such as low liquid holding capacity,short material residence time,consistent reaction conditions and separation conditions.In order to expand the application field of enzyme catalytic distillation technology,a side-reactor enzyme catalytic reactive distillation with distillation column coupled with multiple side reactors is proposed.The external reactor helps to overcome the problems of enzyme catalyst deactivation,difficult catalyst replacement and insufficient material residence time.The research focused on the following aspects:(1)The kinetics of transesterification reaction between ethyl butyrate and n-butanol was studied using the immobilized lipase Novozym435 as catalyst.The effect of catalyst dosage,alcohol-ester ratio,reaction temperature and stirring speed on the conversion of n-butanol were investigated.The optimal operating conditions of 1.0 % w/w catalyst dosage,1:3alcohol-ester ratio,reaction temperature 333.15 K,and stirring speed 400 rpm were obtained.At the same time,the experimental data was fitted to determine the kinetic parameters.Experimental data were correlated with the reduced Ping-Pong bi-bi model,and the correlation between temperature and model parameters was also obtain.(2)The side-reactor reaction distillation integrated process models were built in Aspen Plus.The conversion of n-butanol and the purity of ethanol at the top of the tower were simulated and optimized.Under the condition of fixed section,the effects of the number of side-reactors,reflux ratio on the reaction conversion of n-butanol and purity of ethanol at the top were investigated.Under the optimal conditions,the reaction conversion rate of n-butanol reaches 99.85%,and the purity of ethanol at the top of the tower is 94.71%.(3)Based on the above research,a set of side-reactor reactive distillation experimental device is established.Through the determination of n-butanol conversion and ethanol purity at the top of the tower under different feed molar ratio,reflux ratio and side line recovery in the experimental process.Compared with the simulated values,the experimental date are consistent with the simulated calculation rules,and the relative errors are within 8%,which verifies the correctness of the simulation research.