초록
Ethanol is one alternative to the use of petroleum-based fuels. It is produced on a large scale in Brazil from sugarcane to the magnitude of billions of liters per year. During the ethanol production step, a considerable amount of byproducts is obtained and treated as waste. Carbon dioxide is one of these byproducts and a substance of interest especially for food industries. Because the production of 1000kg of ethanol generates approximately 950kg of CO<SUB>2</SUB>, this work intends to analyze a cryogenic distillation process for the production of CO<SUB>2</SUB> by means of computational simulations. The results obtained were in agreement with real operational conditions, achieving CO<SUB>2</SUB> concentrations up to 100% (v/v). With an initial CO<SUB>2</SUB> concentration of 95% (v/v), 7 separation stages were obtained, achieving the limit of 5 stages for higher CO<SUB>2</SUB> concentrations in the raw gas. The effect of initial CO<SUB>2</SUB> concentrations on the final product and the concentration profiles along the column are also presented. In order to optimize the process, it was observed that, for a maximum feed flow of 3333kg/h (CO<SUB>2</SUB> concentration of 99%), the plant was able to obtain 10.48kgCO<SUB>2</SUB>/kW, recovering about 2828kgCO<SUB>2</SUB>/h at a final product concentration of 99.90% (v/v) at -25<SUP>o</SUP>C.