Simulation Research Of Rreaction Distillation In Producing Polysilicon By Decomposition Of Silane

Polycrystalline silicon as the key material of the photovoltaic industry,the research of polycrystalline silicon’s production process has deepened.At present,the most promising process is decomposition of silane,the key step of this method is the production of silane through trichlorosilane disproportionation.As the conversion rate of this process is very low,the whole process needs a large amount of circulation and becomes very complex,which restricts the development of this method.In this paper,the conversion rate of trichlorosilane disproportionation reaction reached nearly 100% through the use of reactive distillation and that solved the problems of traditional process,such as the circulation is large and the process is complex.Because the boiling point of the product is very low,so the top of the column needs expensive low temperature refrigerants,which is not in accordance with the principle of economy.In order to solve this problem,we put forward two solutions from two aspects respectively,incluing to add inter-condenser configuration and coupling a high-pressure separation column configuration,which are extracting heat from column middle and improving the operating pressure.The paper modeled the traditional reaction distillation configuration,adding inter-condenser configuration and coupling a high-pressure separation column configuration in Aspen Plus respectively.The sensitivity analysis of reflux ratio,feed location,stage number,inter-condenser temperature and other parameters are finished to determine the initial value of each parameter for further optimization.Finally,comparisons on the thermodynamic efficiency and the total annual cost of adding inter-condenser configuration and coupling a high-pressure separation column configuration are studied.The results show the two improved configurations have their own advantages,can effectively reduce the amount of low temperature refrigerants and reduce the cost of production from reducing the top condenser load and improving the top condenser temperature respectively.But increasing the number of intermediate condenser have no obviouse effect.