Research on Carbon Emission of Solar Grade Polysilicon Produced by Metallurgical Route Using Digital Simulation Technology

Abstract

Under the enormous pressure of carbon reduction, we need to have a clear understanding of the environmental impact of the energy-intensive and high-emission polysilicon industry. With the rapid development of technology, we now have the ability to monitor the inflow and outflow of materials in enterprises, so as to obtain the life cycle inventory required for environmental impact assessment. And solve the problems of large data collection workload and long working cycle encountered in conventional life cycle assessment. By combining digital simulation technology and life cycle assessment, we analyze carbon dioxide (CO2) emission in each production process of 1 kg solar grade polysilicon (SoG-Si) by metallurgical route (MR) in detail. We not only analyze four typical production processes of MR, namely slag refining, hydrometallurgy, directional solidification and electron beam refining. The production process of metallurgical grade silicon is also analyzed. It is obtained that the production of 1 kg SoG-Si by MR will produce 69.77 kg CO2. The contribution analysis shows that the CO2 produced by electron beam refining, metallurgical silicon smelting, secondary directional solidification and primary directional solidification is more significant, reaching 38.47%, 20.88%, 15.84% and 14.50%, respectively. The sensitivity analysis shows that the sensitivity of electric power in the process of electron beam refining, secondary directional solidification, primary directional solidification and metallurgical silicon smelting is significant, reaching 38.47%, 15.77%, 14.45% and 13.81%, respectively. In addition, according to the analysis results, the improvement suggestions to reduce CO2 emission are given.