铝富马酸金属有机骨架成型颗粒CO_(2)动态吸附特性

CO_(2) dynamic adsorption characteristics of Aluminum fumarate metal-organic framework shaping pellets

燃烧后CO_(2)捕集技术能够有效减少CO_(2)排放,可缓解温室效应带来的一系列问题。铝富马酸作为一种金属有机骨架材料,因具有丰富的孔道结构且可大规模生产而备受关注。为了探索铝富马酸颗粒的CO_(2)吸附特性,首先在粉末中添加羧甲基纤维素钠黏结剂制备圆柱形颗粒,通过扫描电子显微镜、比表面积及孔隙分析仪和傅里叶红外变换光谱仪对表面形貌、多孔结构和物质组成进行表征,发现铝富马酸颗粒具有发达的孔隙结构和多个明显的光谱吸收峰,比表面积和微孔容积分别为726.06 m^(2)/g和0.33 cm^(3)/g,成功合成铝富马酸颗粒。然后在固定床吸附系统中研究气体流量、吸附温度、CO_(2)浓度、水蒸气含量对CO_(2)动态吸附性能和循环稳定性的影响,结果表明:气体流量增加可以加快CO_(2)的传输速率,缩短气体在吸附床中的穿透时间。吸附温度升高虽然有利于加快CO_(2)的吸附速率,但会导致吸附量降低。不同CO_(2)浓度下的穿透时间几乎相同,浓度越高吸附能力越好。与干燥条件相比,相对湿度从30%、50%升高至70%时,CO_(2)吸附量下降了13.33%、20.95%、30.95%。吸附剂的循环吸附性能稳定,在干燥和含湿条件下第10次使用后的吸附量分别为初次使用的94.76%和96.99%。在研究范围内,当干燥气体流量为400 mL/min,吸附温度为30℃,CO_(2)体积分数为15%时,铝富马酸颗粒的最大吸附量为0.341 mmol/g。

Post-combustion CO_(2) capture technology can effectively reduce CO_(2) emissions and mitigate a series of problems caused by the greenhouse effect.As a metal-organic framework material,Aluminum fumarate has attracted much attention because of its rich pore structure and massive production.In order to explore the CO_(2) adsorption characteristics of Aluminum fumarate pellets,firstly,cylindrical pellets were prepared by adding sodium carboxymethyl cellulose binder to powder.The surface morphology,porous structure and material composition were characterized and it was found that Aluminum fumarate pellets had developed pore structure and multiple obvious spectral absorption peaks.The specific surface area and micropore volume were 726.06 m^(2)/g and 0.33 cm^(3)/g,respectively.Aluminum fumarate pellets were successful synthesized.Then the effects of gas flow rate,adsorption temperature,CO_(2) concentration,and water vapor amount on CO_(2) dynamic adsorption performance and cycling stability were studied in a fixed bed adsorption system.The results showed that an increase in gas flow rate could improve the CO_(2) transfer rate and shorten the gas breakthrough time in the adsorption bed.Although the increase of adsorption temperature is beneficial to enhance CO_(2) adsorption rate,it will reduce the adsorption capacity.The breakthrough times under different CO_(2) concentrations are almost the same,the adsorption capacity is greater with higher CO_(2) concentration.Compared with dry conditions,the CO_(2) adsorption capacity dropped by 13.33%,20.95%,and 30.95%,respectively when the relative humidity increased to 30%,50%,and 70%.The cyclic adsorption performance of adsorbent is stable,and the adsorption capacity after the 10th use under dry and wet conditions is 94.76%and 96.99%of the initial use,respectively.In the study,when the drying gas flow rate is 400 mL/min,the adsorption temperature is 30℃,and the CO_(2) concentration is 15%,the maximum adsorption capacity of Aluminum fumarate pellets is 0.341 mmol/g.