Simulation And Optimization Of Process For The Continuous Preparation Of Benzyl Alcohol

Benzyl alcohol is an important synthetic fragrances and pharmaceutical intermediates,and is widely used in photographic,dyeing,cosmetics,paints and inks and other fields.Benzyl alcohol can be produced in many ways,the process for the preparation of benzyl alcohol by continuous hydrolysis of benzyl chloride with water has the advantages of high yield and pollution free,and the research about it in China just reaches a basic stage.Therefore,the research on the process has an important practical significance.In this paper,the process for the preparation of benzyl alcohol by continuous hydrolysis of benzyl chloride with water was redesigned based on the related literatures,the new process can be divided into three sections:Reaction Section、Recovery Section、Separation Section, and a steady-state simulation model was set up for the process for the preparation of8000T/a benzyl alcohol by using Aspen Plus.Then it was simulated and optimized.Compared to the results of simulation and the data from literatures,the accuracy of the NRTL and ELECNRTL property method was confirmed.The simulation of distillation columns were carried out respectively with DSTWU model and RADFRAC model,and the process parameters were obtained.The simulation results were in almost total agreement with the design value, which indicated that the models were suitable.After that,the operation parameters of the Separation Section’s distillation columns,such as pressure、reflux ratio、feed stage、number of stages and mole ratio of distillate to feed were optimized on the basis of sensitivity analysis.After optimization,on the precondition of guaranteeing the yield and purity of products,the number of stages of the product distillation column was reduced by16.67%,the heat duty of the condenser was reduced by1.81%, the heat duty of the reboiler was reduced by2.56%.The operation expense of the product distillation column and the cost of benzyl alcohol products was also decreased.The simulation and optimization of process for the continuous preparation of benzyl alcohol can provide theory evidence for the development and application of the process.