Modeling and sensitivity analysis for solar grade silicon production

This paper addresses modeling and control strategy for fluidized bed reactors designed to produce poly-silicon for solar cell applications. This reaction process provides a potential alternative to the Siemens process which is widely used in the current poly-silicon solar market. Thermal decomposition of silane takes place in the fluidized bed reactor and seed particles are growing due to the chemical vapor deposition and the scavenging powders generated in homogeneous decomposition. A discretized population balance is developed to describe the dynamics of particles. The model employs ordinary differential and algebraic equations to track particle movement through discrete size intervals to capture the size distributions. A novel sensitivity analysis for the steady state operation is presented to demonstrate the impact of control parameters to the process and is validated via experimental data obtained from pilot plants in Renewable Energy Corporation.