粘结剂对颗粒活性炭PSA分离CH_4/N_2性能的影响

Effect of Binders on CH_4/N_2 Performances of Granular Activated Carbons by Pressure Swing Adsorption

以褐煤为原料,分别采用煤焦油、可溶淀粉和聚丙烯酰胺(PAM)作粘结剂,制备了用于变压吸附(PSA)分离CH_4和N_2混合气体(CH_4/N_2)的三种颗粒活性炭GAC C、GAC-T和GAC-P,对样品的表面官能团和孔结构进行表征,研究了粘结剂对活性炭PSA分离CH_4/N_2性能的影响。结果表明:粘结剂的种类和用量对样品分离效果影响较大,GAC-T的PSA分离CH_4/N_2的性能最好。粘结剂用量(粘结剂与煤粉的质量比)为0.15-0.20时,GAC-T可将CH_4浓缩28%左右;GAC-C、GAC-T和GAC-P表面含氧官能团含量的关系排序为GAC-T>GAC-C>GAC-P,而三者的孔结构范围则为10-30 nm、2-10 nm和0.4-2 nm,相差较大;样品碱性表面含氧官能团的含量越高越有利于CH_4/N_2的PSA分离;CH_4/N_2分离效果受微孔的影响较大,0.4-0.7 nm的微孔是造成GAC-C、GAC-T和GAC-P分离效果差异的主要因素。

Three kinds of granular activated carbons（GACs）,GAC-C,GAC-T and GAC-P were prepared with lignite by using coal tar,tragantine and PAM as binders,respectively.The pore structures and surface functional groups of GAC-C,GAC-T and GAC-P were characterized,and the effects of binders on the CH_4/N_2 separation performances of GACs by PSA were investigated.The results show that the influences of binders on the performance of GAC for enrichment methane from CH_4/N_2 are very notable. Among the three kinds of GACs,GAC-T has the best PSA separation performance.When the mass ratio of tragantine to lignite is 0.15-0.20,GAC-T can improve the concentration of CH_4 about 28%.The relationship of surface oxygen-containing functional groups contents for GAC-C,GAC-T and GAC-P is GAC-TGAC-CGAC-P,and there are some differences in the ranges of pore distribution 10-30 nm, 2-10 nm and 0.4-2 nm for the three GACs.The CH_4/N_2 separation performances of GAC-C,GAC-T and GAC-P are mainly influenced by basic surface oxygen-containing functional groups and micropore. The higher basic surface oxygen- containing functional groups concentrations are suitable for CH_4/N_2 separation by PSA,and the micropores from 0.4nm to 0.7nm are the important factors resulting in the separation performance differences of GAC-C,GAC-T and GAC-P.