Simulation and Optimization of Defluorination and Desulfurization Processes of Aluminum Electrolysis Flue Gas

Aiming at the harmful gas pollutants of low concentration sulfur dioxide and fluoride in electrolytic aluminum flue gas, the process of fluorine and sulfur removal was simulated by NaOH-CO2 gas–liquid absorption system, and the influence of operation and structure parameters such as gas flow rate, liquid flow rate, size, and type of filler on gas-liquid mass transfer process was explored. The results show that the gas flow rate is 1.5–2.0 m3/h, the liquid flow rate is 10–12 m3/h, and the filler is a Bauer ring with the nominal diameter (DN) of 16 mm, the gas–liquid mass transfer effect is the best and the maximum CO2 utilization rate is about 46%. According to the simulation results, when ammonia system is used to absorb sulfur dioxide and hydrogen fluoride, the concentration of sulfur dioxide and hydrogen fluoride can be reduced to 42 mg/m3 and 0.8 mg/ m3, respectively.