荆门石化气体分馏装置流程模拟技术应用

The Application of Process Simulation Technology in Sinopec Jingmen Co.′s Gas Fractionation Unit

荆门石化总厂气体分馏装置处理能力为55×104t/a,采用脱丙烷塔、脱乙烷塔、丙烯塔(两塔)三塔流程。以该气体分馏装置为研究对象,采用Aspen Plus流程模拟软件,建立与装置实际工况相符合的稳态流程模拟模型。利用此模型,对脱丙烷塔、脱乙烷塔、丙烯塔等进行灵敏度分析,研究各塔压力、热负荷、回流比等参数间的相互关系,并以模型为指导,对装置进行如下优化调整:脱丙烷塔顶控制压力由1.85MPa下调到1.40MPa,既能满足产品质量要求,又能大幅降低装置蒸汽消耗,塔顶温度和塔底温度均大幅下降,塔底温度由109℃降到95℃左右,蒸汽流量平均值下降约5t/h,使蒸汽单耗下降到约0.1kg标油/t,该装置综合能耗下降7.6kg标油/t。装置年开工时数按8400h计算,全年减少蒸汽消耗4.2×104t,蒸汽价格按150元/t计算,则全年共创节能效益630万元,装置能耗大幅降低。

The gas fractionation unit in Sinopec Jingmen Company′s general petrochemical plant has a processing capacity of 55×104t/a and uses a three-column process-a depropanizer,a dethanizer and a propylene column（dual columns）.Using the Aspen Plus process simulation software,technicians established a steady-state process simulation model reflecting the actual operating conditions of the unit.Based on the model,these technicians conducted a sensitivity analysis for the depropanizer,the dethanizer and the propylene column and examined the relationships between a series of parameters of these columns such as pressure,heat load and reflux ratio.They optimized the unit′s parameters as follows with the help of the model：reducing the control pressure at the top of the depropanizer to 1.40MPa from 1.85MPa to dramatically reduce the steam consumption of the unit while ensuring product quality,dramatically reducing the temperatures at both the top and bottom of the column（the temperature at the bottom of the column dropped to some 95℃ from 109℃） and reducing the flow rate of steam by about 5t/h on average（thus reducing the unit consumption of steam to about 0.1kg of oil equivalent per ton）.As a result,the overall energy consumption of the unit dropped by 7.6kg of oil equivalent per ton.Assuming the unit operates 8,400 hours per year,4.2×104t of steam would be saved annually.If steam price sands at 150 yuan per ton,annual economic benefits from the energy saving would reach 6.3 million yuan.