钙基CO_2吸收剂的循环特性

Repetitive calcination-carbonation capability of Ca-based CO_2 absorbent

对钙基CO2吸收剂的循环特性进行了实验研究,考察了煅烧温度和碳酸化(吸收)温度对吸收剂最大转化率的影响,比较了常压煅烧-碳酸化(CC)过程和煅烧-水合-碳酸化(CHC)过程中吸收剂的最大吸收能力,并就添加剂对吸收剂循环性能的影响进行了实验研究.结果表明,随着循环次数的增加,吸收剂的吸收能力明显下降,未经处理的吸收剂,循环10次后,其吸收能力基本都下降到20%左右;温和的煅烧温度和较高的吸收温度下,吸收剂的最大转化率比较高;CC过程中吸收剂的最大转化率明显低于CHC过程;添加了氯化钠和碳酸钠的吸收剂的吸收能力急剧下降,但循环性能稳定;多次循环后对吸收剂进行再活化,可使其活性恢复到初始的95%.

The repetitive calcination-carbonation capability of Ca-based absorbent was investigated by using a laboratory-scale vertical-tube reactor. The effect of temperatures of calcination and carbonation on the decline of absorbency was studied, and the maximal capture capability of the calcination-carbonation （CC） process and the calcination-hydration-carbonation （CHC） process was compared. The experiment on the absorbents saturated with additive was also carried out. The CO2 capture capacity of the absorbents decreased obviously with the number of cycles, and the CO2 capture capacity for the absorbents without any treatment declined to about 20 % after 10 cycles. For example, the capture capacity declined to 20.0% from 73.4% after 10 cycles at 900℃ for calcination and 650℃ for carbonation. A mild calcination temperature and a higher carbonation temperature favored the process and the maximal capture capability could be higher. The maximal conversion ratio of absorbents for the CC process was obviously lower than that of the CHC process. The capture capacity of absorbents added with NaCl and Na2CO3 severely decreased, but the repetitive capability was steady. Regeneration treatment after multiple cycles could make the reactivity of absorbents reach 95% of first carbonation.