水蒸气流态化下Na/K基复合吸收剂再生特性

Regeneration Characteristic of Na/K-Based Composite Sorbent under Water Vapor Fluidization

制备了一种Na/K基复合吸收剂,通过对吸附剂进行氮吸附试验来探究其内部孔结构。在小型流化床反应器中,以水蒸气为流态化气体,考察水蒸气温度(100、150、200和250℃)和反应气氛(一定比例的水蒸气和N 2)升温速率(5、10、15、20℃/min)对吸收剂再生特性的影响规律,并通过热分析动力学确定再生反应特性参数。结果表明:该复合吸收剂具有较好的孔隙结构;提高水蒸气温度和反应气氛升温速率可减少再生反应所需时间、增大再生反应转化率;当水蒸气温度为250℃时,有最大峰值体积分数(26.5%),有最短再生反应时间(16 min);当升温速率20℃/min时,有最大峰值反应速率(221.4 mL/min),有最大平均反应速率(62.6 mL/min);在水蒸气氛围下,4种升温速率的吸收剂再生反应活化能较为接近,为88.0~97.4 kJ/mol,表明升温速率并非影响再生反应活化能的主要因素。

A kind of Na/K-based composite sorbent was prepared,and its internal pore structure was studied by nitrogen adsorption experiment.In a small fluidized bed reactor,the effects of water vapor temperature(100,150,200 and 250℃)and heating rate(5,10,15 and 20℃/min)of reaction atmosphere(a certain amount of water vapor and N 2)on regeneration characteristics were investigated with water vapor as fluidizing gas.The regeneration characteristic parameters were analyzed by thermal analysis kinetics.The results show that the composite sorbent has good pore structure.The time of regeneration reaction can be reduced while the conversion rate of regeneration reaction can be increased by increasing the temperature of water vapor and heating rate of reaction atmosphere.When the water vapor temperature is 250℃,the peak volume fraction is 26.5%,and the shortest regeneration reaction time is 16 min.When the heating rate is 20℃/min,the peak reaction rate is 221.4 mL/min,and the maximum average reaction rate is 62.6 mL/min.Under the water vapor atmosphere,the activation energy of regeneration reaction of the four sorbents with different temperature rise rates is close to each other,ranging from 88.0 kJ/mol to 97.4 kJ/mol,which indicates that the heating rate is not the main factor in affecting the activation energy of regeneration reaction.