Radiation heat savings in polysilicon production: Validation of results through a CVD laboratory prototype

Author-Highlights•Energy savings in polysilicon production CVD reactors are explored.•Energy savings are focused on the radiation heat loss phenomenon.•A theoretical model for radiation heat loss is experimentally validated.•Relevant parameters that affect radiation heat loss and their impact are put forward.•With an adequate reactor design, the radiation heat loss can be reduced by 25%.

This work aims at a deeper understanding of the energy loss phenomenon in polysilicon production reactors by the so-called Siemens process. Contributions to the energy consumption of the polysilicon deposition step are studied in this paper, focusing on the radiation heat loss phenomenon. A theoretical model for radiation heat loss calculations is experimentally validated with the help of a laboratory CVD prototype. Following the results of the model, relevant parameters that directly affect the amount of radiation heat losses are put forward. Numerical results of the model applied to a state-of-the-art industrial reactor show the influence of these parameters on energy consumption due to radiation per kilogram of silicon produced; the radiation heat loss can be reduced by 3.8% when the reactor inner wall radius is reduced from 0.78 to 0.70 m, by 25% when the wall emissivity is reduced from 0.5 to 0.3, and by 12% when the final rod diameter is increased from 12 to 15 cm.