Simulation And Optimization Of Dynamic Driving Process Of Electronic Grade SiH₄ Distillation System

Silane is used more and more in electronic industry as a special gas.According to the national standard GB/T 15909-2009,the mass fraction of silane needs to reach 99.999 9%(6N)in order to meet the requirements of electronic grade gas.The higher the purity grade,the more difficult the production.Therefore,the technology of producing electronic silane has always been concerned by scholars.At present,a domestic silicon material enterprise uses chlorosilane disproportionation method to produce electronic silane.In order to make the purity of silane reach more than 9N,the enterprise also adds chemical adsorption process after multistage rectification process to further remove phosphate and borane from silane gas.In this paper,the silane rectifying column in the rectification system is taken as the research object.Based on the process simulation calculation method,the steady state and dynamic operation of the silane rectifying column are studied respectively,and the simulation results are compared with the enterprise production data.The research content of this paper is mainly divided into the following three parts:First of all,from a thermodynamic point of view,the system in the silane rectifying column is analyzed.Define the basic properties of each substance,discuss and determine the thermodynamic method according to the property of the substance system.The thermodynamic properties of the system were investigated in Aspen Properties module.The partial pressure diagram,ternary phase diagram and other information are obtained.The results show that the system is easy to separate and does not have an azeotropic point at the selected operating temperature and pressure.Secondly,DSTWU module in Aspen Plus is used to calculate the silane tower simply,and the basic parameters such as reflux ratio RR=4.75 and feed plate = 27 are obtained.Starting from the basic parameters,Rad Frac module is applied to carry out strict checking calculation,and detailed data such as hydraulic parameters of silane rectifying column are obtained to analyze the physical phenomena in the column.Finally,all the data obtained are compared with industrial production equipment and operation parameters,and it is found that all the data are in good agreement.Finally,based on the first and second parts,the dynamic characteristics of silane rectifying column are studied.Based on the simulation of the dynamic operation of silane rectifying column on Aspen Plus Dynamics platform,different system control schemes are formulated,the model and control parameters of each PID controller in the control system are adjusted,and It is found that the scheme with temperature-component cascade control has the best control effect.