Design and optimization of thermally coupled distillation schemes for the trichlorosilane purification process

The trichlorosilane (TCS) purification process has significant energy requirements to achieve a TCS purity of 10 N. In this study, a dividing wall column was used to improve the performance of the TCS process. A response surface methodology was applied to the design of the dividing wall column. The conventional dividing wall column and top dividing wall column have significant benefits, e.g. decreasing the operating cost and minimizing the total annual cost. Incorporating a heat pump in the top diving wall columns was also proposed to enhance the energy efficiency further. Furthermore, a column grand composite curve was used to evaluate the thermodynamic feasibility of implementing the heat pump system into DWC. The operating cost could be reduced by 83% by novel combinations of internal and external heat integration: top dividing wall columns using a top vapor recompression heat pump. A compact integrating TCS purification process was finally proposed.