甲醇制丙烯分离流程的研究与优化

Research and optimization of separation technology of methanol to propylene

以170万吨/年甲醇制丙烯(MTP)实际装置为背景,对MTP分离流程进行了研究和优化,借鉴石脑油乙烯装置分离的经验,并针对MTP产品气的组成特点,优化形成了适合MTP产品气分离的顺序、前脱丙烷和前脱乙烷分别组合装置自身物料做吸收剂的中冷油吸收技术的三种分离流程,省去了乙烯制冷系统。通过对全流程模拟计算数据的对比分析,优选出了前脱乙烷组合装置自身物料做吸收剂的中冷油吸收技术分离流程。对优化组合采用脱乙烷预分离技术、脱甲烷塔尾气回收分凝分馏塔技术、吸收剂物流的选择、碳二分离高度热耦合技术进行了研究,并通过对全流程模拟计算数据的比较分析,优选出了最优化的分离流程,即前脱乙烷中冷油吸收流程组合预分离技术、用自身物流混合碳四做吸收剂、分凝分馏塔回收脱甲烷塔尾气技术和高度热耦合的脱碳二分离技术。在没有乙烯、碳四和碳五循环回MTP反应器及尾气中乙烯损失满足设计要求的前提下,采用此优选分离流程,产品气压缩机和丙烯压缩机双机功率为19.8 MW。

Based on the actual equipment of 1.7 million tons/year methanol to propylene(MTP),this paper studies and optimizes the MTP separation process,draws on the experience of separation of naphtha ethylene unit,and optimizes the formation characteristics of MTP product gas.The process combination,process simulation and optimization of the separation technology are carried out together with de-methanizer tower and its exhaust gas recovery system,highly thermal coupling decarburization system(de-ethanizer and ethylene rectifying column),sorbent selection,and screen out a more suitable separation technology consisting of the following process unit:pre-cutting front-end deethanizer,recovery of de-methanizer tail gas by combination of intercooling oil absorption and throttle expansion,highly thermally coupled deethanizer system,take carbon four mixture as absorbing agent,etc.Assuming that there are no ethylene,carbon four and carbon five cycles back to the MTP reactor,the ethylene loss in the exhaust meets the design requirements,using the optimized separation technique,the dual power of the compressor and propylene compressor is 19.8 MW.The simulation results show that the optimized flow has a good application prospect.