隔壁精馏塔分离芳烃混合物的模拟研究

采用隔壁精馏塔分离苯-甲苯-对二甲苯物系,用Aspen Plus软件模拟了隔壁精馏塔内温度分布及液相组成分布,考察了汽相和液相分配比对产品纯度的影响。对隔壁精馏塔模拟得到的优化操作条件为:隔壁精馏塔的理论板数为30块,侧线采出在第14块理论板,进料段为15块理论板,在进料段的第7块理论板进料,进料组成n(苯)∶n(甲苯)∶n(对二甲苯)为1∶3∶1,回流比为8.8,液相分配比为2.96,汽相分配比为0.83。在此条件下,各组分的摩尔分数大于98.5%,与实验结果基本吻合。当进料组成n(苯)∶n(甲苯)∶n(对二甲苯)为1∶3∶1时,采用隔壁精馏塔可比常规两塔流程节能27.18%。

Simulation of Separation of Aromatic Hydrocarbon Mixture in Distillation Column with Dividing Wall

A distillation column with dividing wall was used to separate aromatic hydrocarbon mixture of benzene,toluene and o-xylene.Distribution of temperature,composition in column,and effects of liquid distribution ratio and vapor distribution ratio on purities of three products were systematically studied.Under optimal operation conditions:30 theoretical plates in the column,middle outlet at 14th plate,15 theoretical plates in feed segment,feed at 7th plate of feed segment,n(benzene)∶n(toluene)∶n(o-xylene)1 ∶3 ∶1,reflux ratio 8.8,flow ratio of liquid into outlet segment to liquid into feed segment 2.96,flow ratio of vapor into outlet segment to vapor into feed segment 0.83,mole fraction of all products can reach more than 98.5%.Simulation data conform basically with experimental data.The distillation column with dividing wall can reduce energy consumption and capital investment in comparing with conventional distillation systems.When n(benzene)∶n(toluene)∶n(o-xylene)in the feed is 1 ∶3 ∶1,dividing wall distillation column can save energy 27.18% in comparing with conventional distillation systems.