CH4-N2在自支撑颗粒型Silicalite-1上的吸附分离及PSA模拟  

PSA simulation and adsorption separation of CH4-N2 by self-supporting pellets Silicalite-1

作　　者：尚华[1] 白洪灏 刘佳奇 杨江峰[1,2] 李晋平 SHANG Hua;BAI Honghao;LIU Jiaqi;YANG Jiangfeng;LI Jinping(Research Institute of Special Chemicals,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China;Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization,Taiyuan 030024,Shanxi,China)

机构地区：[1]太原理工大学化学化工学院精细化工研究所,山西太原030024 [2]气体能源高效清洁利用山西省重点实验室,山西太原030024

出　　处：《化工学报》2020年第5期2088-2098,共11页CIESC Journal

基　　金：国家自然科学基金项目(21676175, 51672186);山西省煤层气联合基金项目(2016012005)。

摘　　要：纯硅分子筛Silicalite-1原粉(Si/Al>470)在6 MPa压力下制成自支撑颗粒状吸附剂,经XRD和77 K氮气吸脱附表征表明自支撑颗粒型的Silicalite-1保留了原粉的晶体结构和比表面。静态重量法测试了273/298/313 K下CH4和N2在其上的吸附等温线,利用理想吸附溶液理论(IAST)法计算了吸附剂对CH4/N2的选择性。动态气体穿透实验测试了颗粒型Silicalite-1吸附剂对不同浓度CH4/N2混合气的分离效果,结果表明该吸附剂更适合于低浓度甲烷(20%/80%CH4/N2)的富集脱氮。通过总传质模型利用数值模拟预测了颗粒型Silicalite-1吸附剂的变压吸附分离(PSA)富集低浓度煤层气中甲烷的效果。模拟结果显示20%/80%的CH4/N2混合气经一次提浓,CH4浓度可以提升至37%~41%,回收率达到60%~92%;30%/70%的CH4/N2混合气经一次提浓,CH4浓度可以提升至50%~53%,回收率达到58%~92%。Pure-silica zeolite Silicalite-1 powder was pressed at 6 MPa pressure to form self-supporting pellets. By characterization of powder X-ray diffraction and 77 K nitrogen adsorption-desorption, there was no change in crystalline and specific surface area after pelletization. Single component adsorption equilibrium isotherm of CH4 and N2 on the self-supporting pellets Silicalite-1 at 273/298/313 K were measured by static gravimetric method.Selectivity of CH4/N2 mixtures on the adsorbent were calculated from Ideal Adsorbed Solution Theory(IAST).Separation effects of CH4/N2 mixtures on the adsorbent were investigated by dynamic mixtures breakthrough experiments, which show it is more suitable for enrichment and nitrogen removal from low concentration coal-bed methane. Separation and enrichment of methane from low concentration coal-bed methane by pressure swing adsorption(PSA) on the particle-shaped Silicalite-1 were predicted using total mass-transfer model by numerical simulation based on abovementioned data. The simulation results show that once the 20%/80% CH4/N2 mixture is concentrated, the CH4 concentration can be increased to 37%-41%, and the recovery rate can be 60%-92%;30%/70% CH4/N2 mixture is once concentration, CH4 concentration can be increased to 50%-53%, and the recovery rate is 58%-92%.

关 键 词：甲烷 氮气 变压吸附 纯硅分子筛 

分 类 号：TQ028.1[化学工程]