脱除CO_2的膜吸收过程研究

Study on membrane gas absorption for CO_2 removal

研究了用中空纤维膜组件脱除CO2的吸收过程,制备了一系列不同装填率的中空纤维膜组件.用这些膜组件进行实验,以不同浓度的单乙醇胺(MEA)溶液为吸收剂,研究了气液两相的流量和浓度、组件的装填率、吸收剂的循环使用等因素对CO2膜吸收过程的影响.实验结果表明:气、液相流量的增大和液相MEA浓度的增加都可使CO2的传质通量增大;气相CO2浓度的增加会使总传质系数减小;在组件进口气液流量和浓度相同的条件下,组件装填率(0.5%～21%)的变大有利于CO2的脱除;随着吸收液循环次数的增加,CO2的传质通量和其脱除率都会降低.

The process of CO2 absorbed in hollow fiber membrane absorbers was studied using MEA aqueous solution as absorbent. A series of hollow fiber membrane modules with different packing fraction were made for the absorption experiments. The parameters that have effects on the CO2 removal in the process were investigated, including gas and liquid flow, rates, MEA concentration in the absorbent, CO2 concentration in the feed gas, and the packing fraction of membrane modules. In addition, the effect of recycling the absorbent was also studied. The experiments show that the CO2 absorption flux increases with increasing gas and liquid flow rates and concentration of the absorbent. Increasing CO2 concentration in tire gas phase leads to a reduction in the overall mass transfer coefficient. With the same inlet gas and liquid volumetric flow rate, the fractional removal of CO2 （%） increases when the packing fraction of membrane modules increases from 0.5% to 21%.The results also show that the CO2 absorption flux and fractional temoval of CO2 decrease with increasing the times of recycling the absorbent.