Simulation And Optimization Of Vinyl Acetate Distillation Unit

Vinyl acetate can be used to produce a variety of related derivatives.These derivatives are widely used in many fields.The purity of vinyl acetate affects the quality of these derivatives directly.There are lots of unreacted raw materials and by-products in the crude vinyl acetate from existing synthetic processes so that further refinement is required.Therefore,the indepth study on the process of vinyl acetate distillation is of great significance.Process simulation and optimization of 450 kt vinyl acetate distillation are carried out by using Aspen Plus simulation software in this paper.According to the characteristics of the system and operating conditions,the activity coefficient model of NRTL is selected in the simulation of degassing column,No.1 washing column,No.2 washing column,dethanalization column,extraction column,acetaldehyde rectifying column and vinyl acetate rectifying column.The combing model of NRTL-HOC is selected in the simulation of coarse components column and acetate rectifying column.On the basis of the thermodynamic model,the single column and process simulation of vinyl acetate distillation unit are established.The simulation results agree well with the actual value and the reliability and accuracy of the model are verified.Based on the simulation of vinyl acetate distillation unit process,the effect of process variables such as theoretical plates,reflux ratio,overhead recovery ratio and feed stage is investigated by the Aspen Plus sensitivity analysis tool.Under the optimized process parameters,The mass fraction of acetylene is 98.80%,the mass fraction of acetic acid is 99.78%,the mass fraction of acetaldehyde is 98.07%,the mass fraction of vinyl acetate product is 99.97%,the total heat load of vinyl acetate distillation unit is decreased by 13.50%.The results show that it can improve the purity of vinyl acetate product and achieve the purpose of saving energy by optimizing the process parameters.