case_05苯乙烯精制过程模拟.doc

分离工程工业应用实例：苯乙烯精制过程模拟1 工艺和计算用的流程简述苯乙烯工业生产的主要方法为乙苯催化脱氢法。乙苯脱氢产出的混合液含有乙苯、苯乙烯及少量的苯、甲苯、二甲苯等成分。而乙苯/苯乙烯精馏分离是苯乙烯精制中最关键的一步。由于乙苯和苯乙烯的沸点在常压下很接近（仅相差9），属于较难分离的物系。苯乙烯又是热敏性物质，随温度升高，它会产生自聚，并随着温度升高自聚速度加快。因此，苯乙烯精馏在高真空低釜温条件下进行。本算例是以某石化公司的实际装置为例，详细阐述了其流程及算法。从粗苯乙烯塔塔顶回收乙苯，塔底含有重组分的苯乙烯去精苯乙烯塔，去除重组分后在精苯乙烯塔顶采出苯乙烯产品。粗苯乙烯塔塔顶操作压力为12KPa，釜温为96。工艺流程如图1所示：图1 苯乙烯精制过程模拟例题流程2 需要输入的主要参数原料和工艺参数如 表1和表2所示。 表1 原料组成序号组分Kg/hr1AIR85.70002H2O46.50013BNZN192.60044TOLU 730.20175223450.10016EBZN 14928.33407STYR26022.36138PXYL0.60009MXYL0.700010OXYL0.200011AMST30.000112DPHM1273.4027流量Kg/hr43275.0温度54.2压力KPa A40.0表2 输入的工艺参数项目单位数值塔顶压力KPa12塔压降KPa9塔顶温度71塔底温度96理论板数块80表3 流程计算模块模块名称流程图上代号入口物流号出口物流粗苯乙烯塔T4011,1A2,2A,3精苯乙烯塔T4033,1C,1B4,4A,B3.软件版本采用PRO/软件5.61版。4.结果分析迭代收敛后，粗苯乙烯塔的塔顶苯乙烯含量、塔底乙苯含量及精苯乙烯塔塔顶苯乙烯含量均满足要求。表4 输出主要关键点参数表项目单位数值T401塔顶苯乙烯含量1.0T401塔底乙苯含量ppm800T401全塔压降KPa9T403塔顶苯乙烯含量99.95. 输入文件 TITLE DBASE DATA=PC1 PRINT INPUT=ALL, STREAM=ALL, RATE=WT, PERCENT=WT DIMENSION METRIC, TEMP=C, PRES=KPA, WT=KG, TIME=HR, LIQVOL=M3, & VAPVOL=M3, XDENSITY=SPGR, ENERGY=KCAL, WORK=KW, CONDUCT=KCH, & VISCOSITY=CP, SURFACE=DYNE SEQUENCE SIMSCI CALCULATION TRIALS=100COMPONENT DATA LIBID 1,AIR/2,H2O/3,BNZN/4,TOLU/5,2234/6,EBZN/7,STYR/8,PXYL/9,MXYL/ & 10,OXYL/11,AMST/12,DPHMTHERMODYNAMIC DATA METHOD KVAL(VLE)=REGU, VISCOSITY(L)=PURE, VISCOSITY(V)=PURE, & CONDUCTIVITY(L)=PURE, CONDUCTIVITY(V)=PURE, SURFTENSION=PURE, & ENTHALPY(L)=IDEAL, ENTHALPY(V)=IDEAL, DENSITY(L)=IDEAL, & DENSITY(V)=IDEAL, SET=SET01, DEFAULTSTREAM DATA PROPERTY STREAM=1, TEMPERATURE=54.2, PRESSURE=40, PHASE=M, & RATE(WT)=43274.9, COMPOSITION(WT)=2,46.5/3,192.6/4,730.2/ & 5,50.1/6,14928.3/7,26022.3/8,0.6/9,0.7/10,0.2/11,30/12,1273.4, & NORMALIZE PROPERTY STREAM=1A, TEMPERATURE=54.2, PRESSURE=100, PHASE=M, & RATE(WT)=85.7002, COMPOSITION(WT)=1,100, NORMALIZE PROPERTY STREAM=1B, TEMPERATURE=80, PRESSURE=21, PHASE=M, & RATE(WT)=50, COMPOSITION(WT)=1,100, NORMALIZE PROPERTY STREAM=1C, TEMPERATURE=146.07, PRESSURE=20, PHASE=M, & RATE(WT)=5440.97, COMPOSITION(WT)=5,0.1401/6,0.0551/7,3723.57/ & 8,0.004/9,0.0025/10,0.0177/11,501.809/12,1215.34, NORMALIZE NAME 1,FEED/1A,KONG QI/1B,KONG QI/1C,YUANLIAOUNIT OPERATIONS COLUMN UID=T401, NAME=t401 PARAMETER TRAY=80,IO=100 FEED 1,34/1A,78,SEPARATE PRODUCT OVHD(M)=2,10, LDRAW(M)=2A,1,10, BTMS(M)=3, & SUPERSEDE=ON CONDENSER TYPE=MIX, PRESSURE=9, TEST=45 DUTY 1,1/2,80 PSPEC PTOP=12, DPCOLUMN=9 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, CTEMP=45, TTEMP=70, BTEMP=95, & RTEMP=97 SPEC STREAM=2A, RATE(WT,KG/H),TOTAL,WET, VALUE=15654.7 SPEC STREAM=2A,FRACTION(WT), COMP=7,WET, VALUE=0.00975 SPEC STREAM=3,FRACTION(WT), COMP=6,WET, VALUE=0.000845 VARY DUTY=1,2 VARY DRAW=2A METHOD SET=SET01,80 COLUMN UID=T403, NAME=T403 PARAMETER TRAY=20,IO=100 FEED 3,10/1B,19/1C,19,SEPARATE PRODUCT OVHD(M)=4,10, LDRAW(M)=4A,1,10, BTMS(M)=5, & SUPERSEDE=ON CONDENSER TYPE=MIX, PRESSURE=9, TEST=43.5 DUTY 1,1/2,20 PSPEC PTOP=12, DPCOLUMN=4 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, CTEMP=43.5, TTEMP=80, BTEMP=95, & RTEMP=97 SPEC STREAM=4A,FRACTION(WT), COMP=11,W