Simulation And Design Of Ethyl Acetate And Water Azeotropic Distillation Process In Acetic Anhydride Refine System

Acetic anhydride is a basic organic chemical raw material to promoted by the country,which is mainly used for the production of cellulose acetate. Acetic aicd,being a raw material and a by-product in acetic anhydride production, is an important chemical raw material,which exists widely in all kinds of industrial process. It is widely used in organic synthesis,medicine, dyes, spices, pesticides and other industries, and the demand is also great.Acetic acid aqueous solution is produced in the vinyl acetate production with acetic as raw materials,as well as in the cellulose acetate synthesis process if the aqueous solution is directly discharge, not only the environment will be polluted, but also waste the resources.For a long time, people study on the separation of acetic acid water system in-depth, this is not only because of the wide application of acetic acid, but also because of the separation of acetic acid water plays an important role in the development of chemical separation, chemical and environmental protection and other disciplines.It has important significance for the utilization of resources and environmental protection.Distillation is the most commonly used method for purification of acetic anhydride.Acetic acid and water do not form a azeotropic point, but the relative volatility of the two is relatively low, and acetic acid in the liquid phase has a strong association.It is a highly non ideal system. At present, common distillation and azeotropic distillation process is adopted in the industry. Common distillation needs a large number of theoretical plates and the reflux is large,resulting in a high energy consumption.The economy is low.Azeotropic distillation for low boiling entrainer added,increases the relative volatility of acetic acid and water.The plate number and reflux are reduced accordingly.So the energy consumption is relatively low.This paper mainly simulated and calculated acetic acid recovery unit of acetic anhydride refining process,and wo focused on the azeotropic distillation tower,focused on chemical thermodynamics research of non ideal liquid mixtures.With the activity coefficient method Newton iteration method,and Wilson model,C program for vapor liquid phase equilibrium under the low pressure condition of non ideal system was designed.The vapor liquid phase equilibrium data for acetic acid-water,acetic acid-ethyl acetate,ethyl acetate-water systems were calculated,and y-x,T-xy diagrams were drawn,providing the separation of acetic acid and water with basic data.Then through the Aspen Plus software,normal pressure vapor liquid equilibriums of the three components of acetic acid-water-ethyl acetate were simulated.The optimum azeotropic point of ethyl acetate and water was obtained.In addition,under theoperating conditions,the calculation of distillation column,the auxiliary condenser,the built-in condenser and external condenser of the two conditions were calculated and compared to obtain the best conditions.