基于分子管理石脑油5A分子筛液相模拟移动床吸附分离工艺的优化

Optimization of Liquid-Phase Simulated Moving Bed Technology for Naphtha Separation by 5 A Molecular Sieve Based on Molecular Management

在已有固定床工艺的基础上,提出基于分子管理的液相模拟移动床吸附分离工艺以实现石脑油中的正构烷烃与非正构烷烃的分离。考察了模拟移动床工艺的操作温度、切换时间、进料流速、脱附剂流速以及脱附油抽出流速对分离效果的影响,也考察了后续脱附剂精馏回收过程。结果表明,优化的工艺操作条件为操作温度170℃、切换时间900s、进料流速5mL/min、脱附剂流速20mL/min、脱附油抽出流速10mL/min。经过模拟移动床吸附分离工艺,脱溶剂脱附油中正构烷烃质量分数达到98%,脱溶剂吸余油中非正构烷烃质量分数也达到92%。与原料石脑油相比,脱溶剂脱附油作为乙烯裂解原料时,乙烯收率可以提高约17百分点;脱溶剂吸余油的芳烃潜含量提高了约10百分点,其研究法辛烷值提高了约20个单位。

On the basis of the fixed bed technology, a novel liquid-phase simulated moving bed （SMB） technology for separating normal paraffins from naphtha based on molecular management was proposed. The effects of temperature, switching time, feed flow rate, desorbent flow rate and extract oil flow rate on the separation performance of SMB were investigated. The subsequent desorbent recycle system was simulated. The optimal conditions for SMB were obtained, including temperature of 170℃, switching time of 900 s, feed flow rate of 5 mL/min, desorbent flow rate of 20 mL/min and extract oil flow rate of 10 mL/min, under which the mass fraction of normal paraffins in de-solvent extract oil reached 98% and the mass fraction of non-normal paraffins in de-solvent raffinate oil reached 92%. Compared to naphtha, with the de-solvent extract oil as the feed of ethylene cracking process the ethylene yield increased by 17%, and the potential aromatics content of de-solvent raffinate oil increased by 10% and the octane number increased by 20 units.