K改性钙基吸附剂的CO_(2)捕集特性研究

Cyclic CO_(2)Capture Characteristics of the K Modified Ca-based Sorbent

碱金属盐改性是提高钙基吸附剂循环CO_(2)捕集能力的重要手段之一。为获取经济高效的钙基吸附剂,本文提出采用新型水合浸渍法制备了K_(2)CO_(3)改性钙基吸附剂,并利用同步热分析仪研究了不同制备方法以及不同K_(2)CO_(3)掺杂含量对吸附剂CO_(2)捕集能力的影响;通过扫描电镜、X射线衍射仪等研究了吸附剂在循环中微观结构的变化。K_(2)CO_(3)可以提高吸附剂的CO_(2)捕集能力,而通过新型水合浸渍法可以更显著地提高吸附剂的CO_(2)捕集性能,其在30次循环中每1 g吸附剂的CO_(2)捕集量为0.315 g,相比于普通钙基吸附剂提升了113%。在循环中,普通钙基吸附剂的比表面积发生了大幅度衰减,但是改性钙基吸附剂的孔隙结构表现出了更加优良的热稳定性,进而导致了其更加优异的循环CO_(2)捕集特性。

Alkali metal salt modification is one of the most important means to improve the cyclic CO_(2)capture capacity of the CaO-based sorbent.To obtain cost-effective CaO-based sorbents,K_(2)CO_(3)modified CaO-based sorbents were prepared by direct traditional impregnation method(DTI)and simultaneous hydration impregnation method(SHI).The effects of the preparation method and doping content of K_(2)CO_(3)on the CO_(2)capture capacity of sorbents were studied by a synchronous thermal analyzer(TGA/DSC).The changes in the microstructure of the sorbents during cycling were studied by scanning electron microscope(SEM)and X-ray diffraction(XRD).K_(2)CO_(3)direct traditional impregnation can improve the CO_(2)capture capacity of the sorbent,while K_(2)CO_(3)hydration impregnation modification can more significantly improve the CO_(2)capture performance of the sorbent.The CO_(2)capture capacity of“SHI-0.5KCa”during the 30th cycle is 0.315 g of CO_(2)per gram of sorbent,which is 113%higher than that of the initial“CaCO_(3),AR”.Over the cycles,the specific surface area of CaO-based sorbent decreases greatly,but the pore structure of K_(2)CO_(3)modified CaO-based sorbents shows better thermal stability,which lead to their better cyclic CO_(2)capture characteristics.