Study On The Process Design For The Separation Of Organic Silicon Azeotropice Monomers

With excellent feature and unique function, organic silicon compound is one kind of new materials. Not only it can be used as a basic material or structure material in some industrial applications, but also it can be used as functional materials to improve performance. In monomer synthesis, with non-metallic silicon powder and chlorinated hydrocarbons as raw materials, the direct synthesis method is adopted to generate the silane which contains a variety of coarse materials. Coarse silane distillation separation could produce2methyl chlorosilane, etc. A few of the monomers are of commercial value, and then need to be made into organic silicon intermediate, polysiloxane. Residual by-product includes methyl trichlorosilane, methyl hydrogen dichlorosilane, azeotrope, high boiling and low boiling components, etc. Among by-products (except dimethyl monomer), methyl monomers which are flammable and poisonous take account for8%～10%of monomer production. In addition, the high boiling product is flammable and explosive, easy to react with water, and releasing harmful gases. Pulp residue is strongly acidic. Due to the chemical process problems, many enterprises deal with these by-products with a simple processing or putting aside some where, or even burying them directly, which not only brings great problems to safety and environmental protection, but also wastes nature resource seriously. Therefore, how to develop and utilize by-products produced in the production of organic silicon has caused wide public concern. Currently, industries has a deeply research for the use of by products recycling, such as the conversion of high boiling products by catalytic cracking into useful chlorosilane monomer, the utilization of high or low boiling, components and methyl monomer in the production of fumed silica. However, investigations on the utilization of the less contained azeotrope (2～4%) are less.This paper mainly discusses organic silicon monomer azeotrope separation process, and compares the advantages and disadvantages of various processes, and develops esterification separation technology for organic silicon azeotrope monomer by refrencing the twin towers method for silicon tetrachloride esterification invented by Wacker Company, Germany. ASPEN PLUS process simulation software is used to simulate the process of esterification separation and process design conditions and equipment calculation results are given. This paper studies the ester of separation process. The influences of operation parameters on the result of reaction distillation are obtained, operation parameters are optimized through the analysis of the sensitivity to improve product quality and reduce operating costs. DSTWU, RadFrac separation modules in ASPEN PLUS are adopted for process simulation for the in vapor liquid system with organic silicon monomer separation azeotrope esterification. NRTL model is selected for the thermodynamics. The calculation results is satisfactory.