Gas Flow and Pressure Drop in Charge Material in Silicon Production

Gassing, outbursts of high-rate gas flows through the taphole, is a phenomenon that sometimes occurs during tapping of silicon furnaces. In addition to being an HSE challenge, this might also affect the tapping, while the warm gas might harm the equipment in the tapping area. The pressure above the metal bath, influencing the gassing, is affected by permeability, and the gas flow through the charge materials in the furnace. Pressure drop and permeability have been measured for different gas velocities through particle beds of different charge mixtures, with the raw materials and particle sizes used in industrial silicon production. The experimental results have been upscaled to conditions in industrial furnaces through modeling flow in a packed bed. The findings are compared with results from measurements of pressure drop in industrial furnaces.