Simulation and optimization of high-purity trichlorosilane distillation process with analysis of material properties

The new two-tower process of thrichlorosilane distillation consisting of removal of light components after removing heavy components is analyzed by assistant of a chemical process simulation software. In order to achieve lower energy consumption, the parameters for each tower in the new process are optimized, such as the number of theoretical plates, the position of feed plate, reflux ratio and distillate (bottoms) to feed ratio. The results show that the optimum parameters for the first tower are the number of theoretical plates of 32, the position of feed plate of 24, reflux ratio of 2.5 and the distillate to feed ratio of 0.8516. For the second tower, the number of theoretical plates, the position of feed plate, the reflux ratio and the bottoms to feed ratio are 80, 16, 143 and 0.9652 respectively. Applying the optimized results in practical production, mass fraction of PCl3 in overhead of the first tower is reduced by two orders of magnitude, condenser duty and reboiler duty of the second tower are dropped by more than eight percent while obtaining higher purity trichlorosilane products.