Model Predictive Control (MPC)-Based Supervisory Control and Design of Off-Gas Recovery Plant with Periodic Disturbances from Parallel Batch Reactors

This paper proposes a plantwide control structure and a model predictive control (MPC) scheme for the effective separation of off-gas from a polysilicon plant with periodic disturbances in the feed. The target process studied in this work produces 10 000 MT of polysilicon per year with 28 chemical vapor deposition (CVD) reactors. CVD reaction kinetic models were constructed, and their parameters were identified using a genetic algorithm. Aspen Dynamics was used to model the off-gas recovery process and implement proportional–integral (PI) controllers for regulating the inventory levels. A centralized supervisory layer based on MPC, to minimize the fluctuation of the recovered concentration, was linked with regulatory controllers through a MATLAB/SIMULINK environment. Using a rigorous plantwide dynamic model, four cases were studied with different control schemes with and without buffer t…