Safety, Economic, and Environmental Optimization Applied to Three Processes for the Production of Solar-Grade Silicon

In this work, we present the multiobjective optimization of the Siemens Process, the Intensified FBR Union Carbide Process, and the Hybrid Process (the three processes to obtain solar-grade silicon), including considerations of safety, economic, and environmental impact at the design stage of the process. Safety is considered through the individual risk index, the economy through the return on investment, and the environmental impact using the eco-indicator 99. The design of the Siemens Process turned out to be the one that showed the best safety, profitability, and environmental indexes, despite having the lowest solar-grade silicon production capacity, a fourth of that of the Hybrid Process. The results showed similar profitability values for the Hybrid and Siemens processes. In general, because of the high demand of the product of interest and under the premise of a safe process, the Hybrid Process can be chosen as a promising option for its industrial implementation.