Design and control of the off-gas recovery plant with periodic disturbances (ICCAS 2015)

This paper proposes a rigorous process design and plant-wide control scheme that allow for the effective separation of the off-gas from polysilicon plant with periodic disturbances in the feed. The target process studied in this work produces 10,000 MT polysilicon per year and the number of chemical vapor deposition (CVD) reactors is 28. In order to construct rigorous dynamic process models in Aspen Plus and Aspen Dynamics, CVD reaction kinetic models were constructed and their parameters were identified using the genetic algorithm. Proportional-integral (PI) controllers were implemented for regulation of the inventory levels, and a centralized supervisory layer based on model predictive control (MPC) minimizes the recovered flow fluctuation, were designed using MATLAB/SIMULINK. Using the rigorous plant-wide dynamic model, the performance of the developed control strategy was compared with fully decentralized classical PID schemes.