关键词: 沼气提纯, 填料塔, 醇胺, 传质, 总体积传质系数

Abstract: CO₂ absorption by alkanolamine aqueous solution is an important method for biogas purification. A series of experimental tests were conducted in a packed tower using aqueous solution of MEA and DEA,in which the percent conversion η,absorption rate N and volumetric overall mass transfer coefficient in gas phase K_Ga_e were analyzed at various absorbent concentrations,gas flow rates,CO₂ concentrations and absorption temperatures.The results show that the increment of absorbent concentration can improve η,N and K_Ga_e effectively.With the increment of gas flow rate,the percent conversion η decreases obviously,while the absorption rate N increases within a certain range and then decreases,the change of K_Ga_e is similar to that of absorption rate N,but the value of K_Ga_e will maintain a relatively stable value when the gas flow rate is high enough.The percent conversion η and decrease as CO₂ concentration increases,while the absorption rate N increases.The effect of absorption temperature on η and K_Ga_e are approximately parabolic.The optimum absorption temperature of MEA and DEA is about 40-60℃,and it decreases with the increment of CO₂ loading.The experimental results of this study can provide some guidance for the further study and practical application of biogas purification technology by alkanolamine aqueous solution.

Key words: biogas purification, packed tower, alkanolamine, mass transfer, volumetric overall mass transfer coefficient