Effect of raw materials on the production process of the silicon furnace

Abstract

The silicon industry is an energy-intensive industry with high energy operating costs and is currently facing new challenges to improve sustainability and become more competitive. Petroleum coke, coal, and charcoal are typically utilized as carbonaceous reductants for silicon production, and the mixture of different carbonaceous materials plays a very important role in the specific power consumption and the exergy efficiency of the process. Of these materials, in particular, charcoal preparation requires large amounts of wood, and continued and extensive deforestation contributes to ecological damage. Thus, it is urgent to study carbonaceous reductants that can be alternatives to charcoal or to find strategies that do not require the application of charcoal in the silicon production process. Exergy efficiency was used as an overall indicator to evaluate the effect of different carbon materials on the process of silicon production in this study. An exergetic efficiency of 0.39 was obtained for silicon produced with a mixture of woodchips and no charcoal. The overall exergy efficiency and the silicon yield exergy indicator results indicated that the addition of woodchips to a mixture of carbonaceous materials improved the performance of the silicon furnace, even if the fixed carbon contribution was lower. There was no change in exergetic efficiency (0.33) for the mixture of petroleum coke and coal as carbonaceous materials with or without charcoal and woodchips. Therefore, a mixture of petroleum coke and coal without charcoal can be used as carbonaceous reductants while maintaining the exergetic efficiency of the process of silicon production.