固定床双塔并联吸附分离石脑油中正构烷烃

在固定床单柱吸附分离研究的基础上，通过程序控制的5A分子筛固定床双塔并联吸附分离试验装置，对中国石化上海高桥分公司石脑油中正构烷烃吸附/脱附分离过程进行连续操作，考察了多周期运转的吸附分离效果，并对工艺条件进行考察。研究结果表明，吸余油中正构烷烃含量经过5个吸附/脱附周期后趋于稳定，优化的吸附分离操作条件为：石脑油原料体积空速153.4 h-1，吸附/脱附温度270 ℃，吸附/脱附切换时间30 min，脱附气体体积空速127.5 h-1，中间油切割时间2 min。在该工艺条件下，稳定操作的吸余油中正构烷烃质量分数小于3%，芳烃潜含量比石脑油提高12.31百分点；脱附油中正构烷烃质量分数大于95%，作蒸汽裂解制乙烯原料时，与石脑油相比，乙烯收率提高约14百分点。

ADSORPTION OF NORMAL PARAFFINS FROM NAPHTHA USING 5A MOLECULAR SIEVES IN A DOUBLE-COLUMN FIXED-BED

In order to make a better use of different components in naphtha to produce ethylene and aromatics based on the strategy of molecular scale management, this article carried out the studies on the adsorption separation of normal paraffins from naphtha using 5A molecular sieves in a double-column fixed-bed. After 5 adsorption/desorption circles，the adsorption separation process reached dynamic balance. The optimal conditions for the adsorption/desorption process were an operation temperature of 270℃, a naphtha feed space velocity of 153.4h-1, a switch time of 30 minutes, using N2 as desorption gas and a space velocity of 127.5h-1, an intermediate oil cutting time of 2 minutes. The normal paraffin content in the raffinate oil was less than 3% and the potential aromatic content of the raffinate oil was 10% higher than that of the SGPC naphtha. The normal paraffin content of the desorption oil was over 95% and the ethylene yield was improved by 13%-14% using the desorption oil as stream cracking feed compared to the naphtha feed.