C_6异构烷烃对正己烷在成型5A分子筛上高温吸附性能的影响

Effects of C_6 paraffins on high temperature adsorption performance of n-hexane on 5A zeolite pellets

在147～245℃下采用智能重量分析仪,测定C6烷烃(正己烷、3-甲基戊烷(3MP)、2-甲基戊烷(2MP)和甲基环戊烷(MCP))在成型无黏结剂5A分子筛(简称成型5A分子筛)上的吸附等温线;不同C6异构烷烃存在时,在动态吸附实验装置上测定正己烷在成型5A分子筛上的吸附穿透曲线,考察C6异构烷烃对正己烷在成型5A分子筛上动态吸附性能的影响。结果表明:在193～195℃、C6异构烷烃分压为10.80 kPa下,每100 g成型5A分子筛对3MP、MCP和2MP的平衡吸附量分别为1.35、1.31和0.35 g;3MP的存在可导致正己烷在成型5A分子筛上的穿透吸附量下降约6.0%;MCP吸附于成型5A分子筛晶间孔(大孔)中,对正己烷在成型5A分子筛微孔上的动态吸附性能几乎没有影响。用变压吸附(PSA)抽提C6馏分中正己烷的过程,宜在不小于200℃下进行,应主要考虑3MP和MCP对正己烷纯度和回收率的影响。

Adsorption isotherm curves of C6 paraffins（n-hexane,3-methylpentane（3MP）,2-methylpentane（2MP） and methyl-cyclopentane（MCP）） on formed binder-free 5A zeolites were measured by intelligent gravity analysis at 147-245 ℃.Adsorption breakthrough curves of n-hexane with different contents of C6 isoparaffins on the adsorbents were investigated by the dynamic adsorption experimental apparatus.Results showed that adsorption amounts of 3MP,MCP and 2MP at 100 g adsorbents were 1.35,1.31 and 0.35 g at 193-195 ℃ and 10.80 kPa.The breakthrough adsorption amount of n-hexane with the presence of 3MP on the adsorbents decreased about 6.0%.Effects of MCP on the dynamic performance of n-hexane in the micropore could be neglected because MCP was mainly adsorbed in the intergranular pores of 5A zeolites.Extracting n-hexane from C6 fraction by pressure swing adsorption（PSA） process should go on above 200 ℃,and the effects of 3MP and MCP on the purity and the yield of n-hexane needed to be considered.