以膨润土为载体的碳酸盐吸收剂对二氧化碳的吸收

采用膨润土为载体,KHCO3为前驱物通过喷雾-干燥法制成固体碳酸钾吸收剂,制成的固体吸收剂粒径大小为0.5—2.0 mm,密度为1.73 g.mL-1.通过K2CO3负载量、吸收温度、吸收时间、床层纵横比等因素考察固体吸收剂对CO2气体的吸收效率及循环反应特性.分析碳酸钾吸收剂对CO2的吸收机理,并与以碳酸氢钠为前驱物制备的吸收剂进行对比,比较两种吸收剂对CO2吸收效果的差异性.通过XRD测试吸收剂吸收反应前后组成的变化,BET多点法测试吸收剂比表面积,扫描电镜观察吸收剂表面形态特征.结果表明,碳酸钾吸收剂和碳酸钠吸收剂对CO2气体均具有较高的吸收量,相比而言碳酸钾吸收剂的碳酸化反应速率较快,而且经过多次循环反应后吸收效果未发生衰减,在60℃—80℃范围内,碳酸钾吸收剂对CO2的吸收能力最佳.

CO_2 absorption of carbonate sorbent using bentonite as the supporter

Using bentonite as the supporter and KHCO3 as precursor,potassium-based solid sorbent was prepared by the spray-drying method.The sorbent had a size distribution of 0.5—2.0 mm,and a bulk density of 1.73 g · mL-1.During several continuous operations,parameters such as loading amount,carbonation temperature,sorption reaction time and aspect ratio of the bed were used to evaluate CO2 absorption efficiencies of potassium-based solid sorbent.The mechanism of carbon dioxide absorption by potassium-based solid sorbent was analyzed.In addition,NaHCO3 was employed as precursor to manufacture sodium-based sorbent,and its carbonation characteristics were compared with potassium-based sorbent.The structure and carbonation characteristics of the solid potassium-based sorbent for CO2 capture were investigated with X-ray diffraction,gas adsorption method BET and scanning electron microscopy.The experimental results show that both potassium-based and sodium-based sorbent has a high CO2 absorption efficiency,and potassium-based sorbent has a higher rate of carbonation reaction.The CO2 absorption efficiency of potassium-based sorbent did not diminish during multiple continuous operations,and it has an excellent CO2 absorption efficiency in the temperature range of 60 ℃—80 ℃.