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

摘要： 醇胺溶液吸收CO₂是沼气提纯领域重要的研究课题。在实验填料吸收塔中,以乙醇胺(MEA)、二乙醇胺(DEA)为吸收剂,研究了吸收剂浓度、进气流量、CO₂浓度、进液温度对吸收过程转化率η、吸收速率N以及气相总体积传质系数K_Ga_e的影响。结果表明,吸收剂浓度增加可有效提高η、N及K_Ga_e;进气流率增加,η逐渐降低,N先增加后降低,K_Ga_e先增加后降低最终趋于稳定;随着CO₂浓度增加,η和K_Ga_e不断降低,N逐渐增加;随着进液温度升高,η和K_Ga_e均先升高后降低;MEA、DEA的最佳进液温度在40～60℃之间,并随CO₂负载量增大而逐渐降低。研究结果对于醇胺溶液吸收法沼气提纯技术的研究开发和实际应用有参考作用。

关键词: 沼气提纯, 填料塔, 醇胺, 传质, 总体积传质系数