Design and Control of Pressure-Swing Heat Integration Distillation for the Trichlorosilane Purification Process

Trichlorosilane (TCS) is a crucial intermediate product in the polysilicon manufacturing process, and its purification consumes a significant amount of energy. The design and control of the TCS heat integration pressure-swing distillation (HIPSD) process was investigated using Aspen Plus V8.4 and Aspen dynamics in this study. Three partial processes and one full HIPSD process were investigated by adjusting the operating conditions and rationally configuring the material flow. Compared with the conventional distillation process, the partial and full HIPSD can reduce total annual cost by 15.75 and 27.39%, respectively. The aforementioned process was controlled robustly by adding the ratio of reboiler heat duty to feed (Q(R)/F) feedforward control structure and the ratio of recycle to feed (F-REC/F) control structure. In addition, the performance of the control structure was evaluated by introducing +/- 10% disturbances of the feed flowrate and composition. To compare the performance of the control structure, the integral squared error value is combined with the dynamic response curve. The full HIPSD scheme can resist +/- 10% disturbances of flow and composition with the best economic performance. This study has certain reference significance for the distillation process and control strategy design of TCS in the polysilicon manufacturing process.