纳米陶瓷膜对再生气的水热回收特性研究

Study on heat and water recovery from regeneration gas using nanoporous ceramic membrane

针对在化学吸收法脱碳工艺中再生过程能耗较大,在富液分级流工艺的基础上,采用纳米级陶瓷膜作为分流的富液和再生气间的新型换热器,利用多孔陶瓷膜能够进行热质耦合传递的特性,有效回收再生气中的部分水蒸气及其所携带的热量,达到降低系统再生能耗的目的。以热回收通量和水回收率为指标,研究了再生气温度、流速、水蒸气摩尔分数以及分流的MEA富液温度、流速、MEA浓度等参数对不同孔径和长度的陶瓷膜水热回收效果的影响。结果表明,陶瓷膜的水热回收性能随MEA富液流量的增加而增加,但随富液温度的升高而大幅下降。同时,随着再生气流速和再生气中水蒸气摩尔分数的增大,热回收通量均会增大。10 nm陶瓷膜的热回收性能优于20 nm陶瓷膜。

A large amount of energy is consumed in the regeneration process in chemical absorption decarburization. On the basis of rich solvent split process, nano-scale ceramic membrane was innovatively used as heat exchanger between bypassed rich solvent and regeneration gas in this study. Comparing with traditional heat exchanger, mass transfer happens with heat transfer in ceramic membrane heat exchanger(CMHE). The coupling of heat and mass transfer effectively ensures partially recovery of water and the heat it carries from regeneration gas, thus reduce the regeneration energy consumption. With the index of heat recovery flux and water recovery rate, the effects of regeneration gas temperature, flow rate, water vapor molar fraction and MEA rich solvent temperature, flow rate and MEA concentration were studied. The influence of pore size was also showed. Results shows that the heat recovery performance of CMHE increases with the increase of MEA rich solvent flow rate, but decreases with the increase of rich solvent temperature. Meanwhile, as the gas flow rate and the molar fraction of water vapor increase, the heat recovery flux increases. The heat recovery performance of 10 nm ceramic membrane is better than that of 20 nm ceramic membrane.