燃煤飞灰负载钾基CO_2吸收剂再生反应特性的动力学分析

Regeneration kinetics analysis of potassium-based sorbents loaded with coal ash for CO_2 capture

采用热重分析的方法对吸收剂的再生反应进行研究,说明了燃煤飞灰负载钾基CO_2吸收剂的制备方法,探讨了在不同升温速率下燃煤飞灰负载钾基CO_2吸收剂和纯KHCO_3的再生反应特性。结果表明:燃煤飞灰负载吸收剂的峰值失重速率为0.13~0.73 mg·min^(-1),在升温速率为20℃·min^(-1)时,反应温度区间最小,为94.34℃;采用多种分析方法对吸收剂的受热分解反应进行动力学分析,纯KHCO_3的反应活化能为85.7~92.0 kJ·mol^(-1);燃煤飞灰负载钾基CO_2吸收剂的反应活化能为66.2~69.4 kJ·mol^(-1),随着转化率上升,2种样品的活化能均先减小后增大。燃煤飞灰负载钾基吸收剂再生反应的活化能小于纯KHCO_3的活化能,说明将KHCO_3负载于燃煤飞灰上有利于再生反应的进行。

The regeneration reaction of sorbent was studied by thermogravimetric analysis. The preparation method of potassium-based sorbent loaded with coal ash was briefly described. The regeneration reaction characteristics of the sorbent and pure KHCO3 at different heating rates were discussed. Results showed that the peak weight loss rate of the sorbent was from 0.13 to 0.73 mg·min^-1, and the minimum reaction temperature range was 94.34 ℃ at the heating rate of 20 ℃·min^-1. The thermal decomposition of the sorbent was analyzed. The kinetic analysis results showed that the activation energy of pure KHCO3 was from 85.7 to 92.0 kJ·mol^-1, the sorbent was from 66.2 to 69.4 kJ·mol^-1, the activation energies of both pure KHCO3 and the sorbent were decreasing first and then increasing with the conversion rate increasing. The activation energy of potassium-based sorbent was less than that of pure KHCO3,indicating that KHCO3 loading on coal ash was beneficial for regeneration reaction.