UTSA-280的氨改性以及C2H4/C2H6分离性能研究  

Ammonia Modification on UTSA-280 for C2H4/C2H6 Separation

作　　者：陈杨[1] 杜亚丹 王勇[1] 刘普旭 李立博[1,2] 李晋平 Chen Yang;Du Yadan;Wang Yong;Liu Puxu;Li Libo;Li Jinping(College of Chemistry and Chemical Engineering,Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization,Taiyuan University of Technology,Taiyuan 030024;Key Laboratory of Coal Science and Technology,Ministry of Education and Shanxi Province,Taiyuan University of Technology,Taiyuan 030024)

机构地区：[1]太原理工大学化学化工学院气体能源高效清洁利用山西省重点实验室,太原030024 [2]太原理工大学煤科学与技术教育部和山西省重点实验室,太原030024

出　　处：《化学学报》2020年第6期534-539,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.21908155,21922810);山西省青年科技研究基金(No.201901D211053);山西省高等学校科技创新项目资助.

摘　　要：炼厂干气中回收乙烯是扩宽C2H4来源的有效途径,但C2H4和C2H6物理性质和分子尺寸非常接近,分离困难.金属有机骨架材料(MOFs)近年来在低碳烃分离领域展现出广阔的前景.本工作采用氨吸附改性调节UTSA-280的结构,通过一维直孔道大小的调节实现C2H4/C2H6的高效分离.改性后的UTSA-280具有独特的超微孔结构能提升C2H4的吸附,而完全不吸附稍大的C2H6,实现理想的C2H4/C2H6吸附选择性(>1000).结果表明,改性后的UTSA-280的C2H4吸附量可提高至2.83 mmol/g,与未改性的材料相比增加29%,并且能阻挡C2H6的吸附,最终达到>1200的C2H4/C2H6选择性.蒙特卡罗分子模拟(GCMC)计算C2H4/C2H6混合气体(1∶1)的吸附得出,改性后UTSA-280孔内的C2H4吸附相比于C2H6具有更多的吸附分布.通过C2H4/C2H6混合气体穿透实验测试,改性后的UTSA-280材料能展现出48 min以上的分离时间,相比于未改性的材料,分离性能提升近1倍.Recovering C2H4 from refinery gas is an effective way to broaden the source of ethylene.However,it’s a challenging task to separate C2H4 and C2H6 due to their very close physical properties and molecular size.Metal-organic frameworks(MOFs)are shown broad prospects in the field of light hydrocarbon separation in recent years.In this work,NH3 is used to modify the structure of UTSA-280,the efficient separation of C2H4/C2H6 can be achieved through the adjustment of one-dimensional channels.UTSA-280 has undergone stepwise adsorption of ammonia gas at 298 K and 100 kPa.After partial ammonia removal,we obtained the modified UTSA-280 that ammonia adsorption modification with a mass loading of 5.6%for UTSA-280-M1 and 2.8% for UTSA-280-M2.The NH3 modified UTSA-280 shows a unique ultramicroporous structure that can enhance the adsorption of C2H4 and does not adsorb the slightly larger C2H6,achieving the ideal C2H4/C2H6 adsorption selectivity(more than 1000).Ammonia molecules play the role of perfectly adjusting the size of one-dimensional channels and realize the ideal screening effect of C2H4/C2H6.The C2H4 adsorption capacity of NH3 modified UTSA-280-M2 can be improved to 2.83 mmol/g at 298 K and 100 kPa(an increase of 29% compared with initial material).And its ultramicroporous structure can fully block the adsorption of C2H6,which finally achieves a C2H4/C2H6 selectivity over 1200.Grand Canonical Monte Carlo(GCMC)simulation of C2H4/C2H6 mixed gases(equal volume)adsorption results showed that the modified UTSA-280 had more C2H4 adsorption distribution in the mixed components than C2H6.Through the C2H4/C2H6 mixed gases breakthrough test at 298 K,NH3 modified UTSA-280-M2 shows a separation time of more than 48 min,which is more than the initial 25 min.Compared with the unmodified material,the separation performance is nearly doubled.Scalable synthesis,stable structure,and the advantages of controllable performance after ammonia modification have prompted this material to have great prospects in the industrialization of C

关 键 词：金属有机骨架材料 氨改性 C2H4/C2H6分离 选择性 

分 类 号：O647.3[理学—物理化学] O623.121[理学—化学]