Influencing factors of CO₂ absorption by diethanolamine solution for biogas purification

The effects of influencing factors such as gas flow rate,liquid flow rate,CO₂ volume fraction,absorption temperature and their interactions on the percent conversion η and the volumetric overall mass transfer coefficient in gas phases K_Ga_eby diethanolamine(DEA) aqueous solution were systematically studied by using orthogonal experimental design and statistical analysis. The impact significance of these influencing factors was estimated. It is found that gas flow rate,liquid flow rate,CO₂ volume fraction,absorption temperature,the interactions between CO₂ volume fraction and gas flow rate,between absorption temperature and liquid flow rate,and between absorption temperature and gas flow rate have remarkable effect on η; however,gas flow rate,liquid flow rate,CO₂ volume fraction,absorption temperature,the interactions between gas flow rate and CO₂ volume fraction and between gas flow rate and absorption temperature have distinguished influence on K_Ga_e. With the increment of gas flow rate,η decreases,while K_Ga_eincreases.η and K_Ga_eincrease as the liquid flow rate increases,but they decrease as the CO₂ volume fraction increases. The impact of absorption temperature on η and K_Ga_eis approximately parabolic.