固定化碳酸酐酶催化吸收模拟烟气中CO_2实验研究

Experimental studies on catalytic absorption of CO_2 in simulated flue gas by immobilized carbonic anhydrase

利用表面羧基化四氧化三铁和戊二醛交联法实现碳酸酐酶的固定,对比考察了游离态碳酸酐酶和固定化碳酸酐酶对CO_2催化吸收效果的影响;还自行设计了填料塔反应装置,在填料塔式反应器中进行了固定化碳酸酐酶催化吸收CO_2实验,考察了操作条件及共存气体SO_2对固定化碳酸酐酶催化吸收CO_2性能的影响。结果表明,游离态碳酸酐酶和固定化碳酸酐酶可缩短CO_2达到饱和浓度所需的时间;同时,得到最优的操作条件为:液气比为28L/m^3,气体流速为25.5cm/min,单位塔体积加酶量为600mg/L(载酶量2mg/L),吸收液温度为35℃;固定化碳酸酐酶经连续5h催化吸收CO_2后,CO_2的去除效率仍可维持在30%以上;此外,SO_2的存在不利于固定化碳酸酐酶对CO_2的催化吸收。

The carbonic anhydrase was immobilized by the carboxylated Fe3O4and glut-aldehyde cross-linking method in this study.The effects of the free carbonic anhydrase and immobilized carbonic anhydrase on the CO2absorption were compared.A packed tower reactor was designed.The effect of the operating conditions and SO2on the performance of CO2catalytic absorption with the immobilized carbonic anhydrase was investigated in the packed tower reactor.The results showed that the free enzyme and immobilized enzyme could shorten the time of CO2reaching saturation concentration.The optimal operating conditions,such as the ratio of liquid to gas,the gas flow rate,enzyme dosage of the unit tower volume,and absorption liquid temperature,were28L/m3,25.5cm/min,600mg/L,and35℃,respectively.The CO2removal efficiency could still reach more than30%,after catalytic absorption with the immobilized enzyme for5h.The existence of SO2had negative effect on the CO2catalytic absorption.