纤维素模板改性钙基CO_(2)吸附剂的蒸汽水合活化

STEAM HYDRATION ACTIVATION OF CELLULOSE TEMPLATE MODIFIED Ca-BASED CO_(2) SORBENT

采用挤出-滚圆法制备了改性钙基吸附剂颗粒,基于双固定床反应系统测试了吸附剂CO_(2)循环捕集性能。添加质量分数5%的水泥和10%纤维素模板的吸附剂20个循环后,CO_(2)吸附量最高为0.19 g/g。为再生其CO_(2)捕获性能,采用不同蒸汽体积分数和温度对改性钙基吸附剂进行煅烧后单独水合活化。结果表明:体积分数30%蒸汽、300℃为最佳活化再生工况,20个循环后改性吸附剂的CO_(2)吸附量为0.59 g/g。为探究水合处理对吸附剂碳酸化阶段的反应动力学影响,基于热天平进行了水合活化后吸附剂的第1、10、20次碳酸化,发现蒸汽水合活化可提升吸附剂碳酸化过程产物扩散控制阶段的反应速率。水合活化前后吸附剂颗粒的微观形貌、孔隙结构和机械性能测试结果表明,活化后吸附剂表面出现裂隙,破碎力和抗磨性能显著下降。

The modified Ca-based sorbent particles were prepared by the extrusion-spheronization method.The cyclic CO_(2) capture capacity was tested using the dual fixed bed reaction system.After 20 cycles,the CO_(2) uptake of the sorbents with 5%cement and 10%cellulose added was 0.19 g/g.The modified Ca-based absorbents were treated with separate hydration after the calcination under different steam volume fraction and temperature,to regenerate the CO_(2) capture performance.The CO_(2) sorption of the modified sorbent was 0.59 g/g after 20 cycles,which was realized by the hydration with 30%steam of 300℃.The 1st,10th,20th carbonation of the sorbent treated with steam hydration was examined by using the thermal gravimetric analyzer,in order to investigate the effect of hydration treatment on the reaction kinetics of the carbonation stage of the sorbent.It was found that steam hydration reactivation improves the reaction rate of the product layer diffusion control stage of carbonation.Furthermore,the test results of the micro-morphology,pore structure,and mechanical properties of the sorbent particles before and after hydration reactivation showed significant cracks on the surface of the adsorbents after activation,and the crushing force and anti-abrasion properties also decreased remarkably.