Influence of carbothermic reduction on submerged arc furnace energy efficiency during silicon production

In this study, we investigated the exergetic efficiency and thermal energy source of the off-gas system of a submerged arc furnace, which varied from 27% to 35% and 47% to 55%, respectively, of the total energy supply. We used a case study to evaluate the thermal exergy in the off-gas of a real furnace, which exhibited an additional power capacity up to 2.7 MW amounting to 10% of the total energy supplied to the process (or 23% of the electrical power fed to the furnace.) We also determined the perfect negative correlation coefficients (r as the standard) between the exergetic efficiency and raw material consumption via linear regression and observed moderately positive relevance between power consumption and raw material consumption in the furnace. We attributed this correlation to increased graphitization and reduced resistivity of carbonaceous materials as the charging began sink slowly into the reaction zone and the charging temperature increased. Compared to coal, petroleum coke showed a significant impact on total power consumption according to the linear regression results; especially in regards to the fact that petroleum coke underwent graphitization more easily than coal as charging temperature increased.