甲醇制烯烃装置脱甲烷和丙烯回收控制的模拟优化  

Simulation and optimization of demethanization and propylene recovery control in methanol to olefins unit

作　　者：于泳 宋艳红 陶全保 汪泽强 费建国 刘桂莲[2] YU Yong;SONG Yan-hong;TAO Quan-bao;WANG Ze-qiang;FEI Jian-guo;LIU Gui-lian(Zhong′an United Coal Chemical Co Ltd,Huainan 232092,China;School of Chemical Engineering and Technology,Xi′an Jiaotong University,Xi′an 710049,China)

机构地区：[1]中安联合煤化有限责任公司,安徽淮南232092 [2]西安交通大学化学工程与技术学院,陕西西安710049

出　　处：《石化技术与应用》2022年第6期416-422,共7页Petrochemical Technology & Application

基　　金：国家自然科学基金资助项目(项目编号:22078259)。

摘　　要：针对某公司180万t/a(以甲醇进料计)甲醇制烯烃(MTO)装置运行中能耗高的问题,用Aspen Plus软件对该装置的脱甲烷塔(T 202)和丙烯回收单元进行了模拟和灵敏度分析,确定了简单可行的优化改造方案。结果表明:T 202、丙烯回收单元精馏塔(T 205)的灵敏板分别为第9,第85块塔板,其灵敏板的运行参数与相应产品控制组分变化呈现一一对应关系,均可反映并指导相应塔釜及其产品质量的操控;用流经冷却器(E 201)的碳四洗液加热T 202的进料至0℃,不仅可使其乙烯产品满足质量分数不小于99.95%的质量控制要求,而且可降低再沸器和冷凝器的能耗,节省丙烯冷却剂费用402.6万元/a;当T 205和T 206丙烯回收单元两精馏塔的操控压力分别降至1.674,1.600 MPa时,不仅T 206的回流比可降为12.3,并可将T 205塔底丙烷产品中含丙烯质量分数降至0.2%,减少丙烯损失量约为70 kg/h,同时相应减少冷凝器循环水、再沸器急冷水的消耗量分别为62.9,18.9 t/h。Aiming at the problem of high energy consumption in the operation of the methanol-to-olefin(MTO)unit with the processing capacity of 1.8 Mt/a(basing on methanol feed),Aspen Plus software was used to simulate and analyze the sensitivity of the demethanizer(T 202)and the propylene recovery unit,and a simple and feasible optimization scheme was worked out.The results showed that:the sensitive plate of T 202 and the rectification tower(T 205)of propylene recovery unit was the 9th,85thplate,respectively,and the operation parameters of the sensitive plate were in one-to-one correspondence with the changes of the control components of the corresponding target products,which could reflect and guide the operation of T 202,T 205 and the relevant product quality control.It not only made its ethylene product meet the quality control requirements(mass fraction not less than 99.95%)by heating T 202 feed to 0℃with the C4washing liquid flowing through the cooler E 201,but also reduced the energy consumption of reboiler and condenser,saving the cost of propylene coolant of 4.026 million Yuan/a.When the control pressure of both rectifying columns T 205 and T 206 of the propylene recovery unit was reduced to 1.674,1.600 MPa,respectively,not only the reflux ratio of T 206 decreased to 12.3,but also the mass fraction of propylene in the bottom propane product of T 205 could be reduced to 0.2%,and the loss of propylene can be reduced by about 70 kg/h,meanwhile,the consumptions of the circulating water for condenser and the quench water for reboiler could be reduced by 62.9,18.9 t/h,respectively.

关 键 词：甲醇制烯烃 脱甲烷塔 丙烯回收单元 节能降耗 模拟优化 

分 类 号：TQ021.8[化学工程]