The Study Of Modeling And Optimal Operation Of Rectification Process

The rectification process is a typical unit producing process, which is common in the industrial and medical fields. The rectify column is the key equipment of rectification process, used to separate the raw material into different fractions. Optimizing the operation of rectify column brings high benefits. This paper is concerned with the rectify column model and optimization model of multicomponent rectification based on the features of rectification process, and optimizes the optimization model.MESH equations, the equilibrium stage model, are developed after multicomponent rectification process is analyzed. Some variables such as production flow, rate ratio, theoretic tray counts and theoretic input place are gained, and the mathematical model MESH equations are brought out. The bubble-point method (BP) and tridiagonal matrix method are proposed as solution of MESH equations(Material equation, phase Equilibrium equation, Summation equation, Heat equation), through which equations could be solved quickly and steadily, and the composing mole fraction at the top of tower and Key composition profiles and temperature of every stage are given. Simulation results show that the model has good accuracy.The optimal object and constraints are determined considering the enterprise requirement and process restriction. The optimal object is the product throughput, and the constraints are product quality, tower process ability, and proper operation condition. The influence of reflux rate and input flow on product composition is analyzed based on the rectification process, and some operation points are given based on equilibrium stage model. The empirical formula is gained by using nonlinear regression of those operation points. The optimization method is genetic algorithm based on exterior point penalty function method. The result of optimization shows that this method can provide optimal operation guide, and enhance throughput and benefit all along.