Experiments and simulation of varying parameters in cryogenic flue gas desulfurization process based on Aspen plus

The study of flue gas desulfurization is of great significance to environmental protection. With the principle that sulfur dioxide (SO2) can be liquefied with the cooling of flue gas and further be removed with gas-liquid separation, a cryogenic desulfurization process was designed based on Aspen plus. The steady state process was simulated by using appropriate property methods included in Aspen plus, and the two-stage cryogenic desulfurization test bench was set up, to carry out the cryogenic process experiments. To explore the rule of cryogenic desulfurization and determine the appropriate process parameters, the influence of temperature, pressure, concentration of SO2 and the water vapor volume fraction were analyzed. It was found that the desulfurization efficiency can be improved from 33% to 73.2% with the temperature of fuel gas decreased from −12 °C to −45 °C, and can be further improved to the maximum of 90.2% with the cryogenic pressure increased from 0.5 MPa to 2.5 MPa. The desulfurization efficiency also can increase with the increase of SO2 concentration, but decrease with the increase of the inlet temperature. Based on the simulations and the practical application in engineering project comprehensively, the more suitable operating conditions were obtained.