Model Simplification And Energy-Saving Control Of Distillation Process

In the chemical, oil, light industrial production, there is often many liquid and gas phase mixture need to be separated and purified. Distillation is an important means of separation and purification. In order to ensure the safety and stable in distillation process operation, it is need to understand its mass and heat transfer process from craft, and establish the mathematical model from mechanism, then simulate the dynamic process, so as to automatic process control the distillation process. The dynamic mechanism model presents distillation and high dimension of nonlinear properties, therefore distillation model simplified became hot, hence people study many methods of established the simplified distillation model.This paper introduces the principle of distillation process, based on the balance at the level of theoretical equations to establish dynamic mathematical mode of production process under the strict mechanism. It is usually a group of differential equation or difference equation, and is needed to be simplified. This article use a binary distillation columns of 18 plate which separate ethanol and water, along with condenser system and columns kettle backflow cans of separation in twenty. Obtained the concentration of light and weight part using the independent calculating method, the simulation result of the mechanism model showed the correctness of the model.The dynamic model of distillation column with high dimension and nonlinear characteristics was simplified using small deviation linearization near the steady-state, 20-order linear model was obtained. Then reduce order with the Marshall method, and finally get a simplified model of three orders, through the simulation of the simplified model, compared with the original model. This model for distillation process control system design and analysis of practical application value and theoretical guidance.As the most widely used in industry production,distillation process is one of the largest consumption of chemical energy problems in operation. Today more and more attention concern energy, it is not avoid economizing on distillation process. First introduced several energy-saving ways of distillation, and then analyzed the problems of current energy-saving distillation control. This article discussed from two aspects of disturbance rejection and "card" operation, and use the third-order model of simplified to design a feed-forward control system and the cascade control system, through the simulation obtain the change of the input variables to flow and see the advanced control system by reducing the distillation process of reflux ratio, thereby lowering the bottom steam, consequently achieve energy saving, and have guiding significance in practical operation.