Simulation And Optimization Of Organic Silicon Monomer Distillation Process

Preparation of silicone materials requires high-purity organic silicon monomer,but organic silicon monomer synthesized by direct method contains many components with close boiling points.As a result,the separation of different organic silicon monomers is very difficult.To solve the problem of low purity and high energy consumption existing in the domestic organic silicon market,the separation processes were simulated and optimized in this paper.The study would play a guiding role for actual production.The main work of this paper is as follows:1.Aspen Plus software was adopted to simulate the five existing separation processes of organic silicon monomer,and the main operating parameters were optimized.The results showed that,by optimizing the operating parameters,the purity of dimethyldichlorosilane in trans-cutting separation process,cis-cutting separation process,side-draw process and middle-cutting separation process could reach 99.99%.Other main monomers could also achieve the required purity.With the same purity,the products yield in above process was close.The heat duty of middle-cutting separation process was the lowest in the above four kinds of separation processes,and trans-cutting separation process has the highest heat duty.The purity and yield of main monomer in seven columns separation process was lower and could not reach the requirement in this paper.2.Easy separation coefficient and Relative cost function were adopted to synthesize the separation system of organic silicon monomer.Two separation processes were established and Aspen Plus was adopted to simulate the two processes.TAC was set up to compare different processes.The results showed that middle-cutting process has the minimum TAC and trans-cutting separation process has the maximum TAC.The operation cost was the most important factor in TAC.3.Taking middle-cutting process as the primary separation sequence,four similar sequences were found through the method of optimization.Aspen Plus software was adopted to simulation the processes.Computing and comparing TAC of four processes,the results showed that sequence 3 has the minimum TAC,and saved 1.82% cost to middle-cutting process,while TAC of other three sequences were more than middle-cutting separation process.So sequence 3 was chosen as the optimal sequence.4.Pinch technology was adopted to analyze energy consumption of the optimal process.The pinch analysis discovered that it could not heat-integration in the optimal process.By changing the press of distillation columns and adopting double-effect distillation,hot and cold streams could match the heat exchange.Heat-integration process saved 48.1% energy consumption and 32% TAC than primary process.In this paper,operating parameters and separating sequence of organic silicon monomer separation process,and the purity of organic silicon monomer was improved.The energy consumption of organic silicon monomer separation was reduced significantly by heat-integration.The research results have some guidance on energy saving in organic silicon monomer separation.