Energy saving technology research on the trichlorosilane distillation in polysilicon production

Polysilicon industrial profile were introduced together with the technology of distillation thermally coupled with different pressures.Different pressure thermally coupled distillation for high-purity trichlorosilane was developed to achieve heat integration and process optimization.Top stream from high-pressure column was used as a heat source for the reboiler of the low-pressure column.In order to explain the specific operating parameters of two-column different pressure thermally coupled distillation and corresponding columns,modern chemical simulation software PRO/Ⅱ8.1 was used for optimization design.The results showed that,with this technology,the energy consumption was reduced 50.1% in two-column coupled distillation,and 66.7% in three-column one.The recovery rate of trichlorosilane was 92%.The technology has been successfully industrialized,the existing industrial data showed that the average energy saving was about 40%—60%,at the same time,a large-scale reduction was obtained in equipment investment.