Aspen Plus在脱丁烷塔降压案例中的应用

APPLICATION OF ASPEN PLUS FOR REDUCING THE OPERATINGPRESSURE OF DE-BUTANE COLUMN

脱丁烷塔聚合物结垢问题是制约乙烯装置长周期运行的主要因素之一。目前新建装置通过降低操作压力在防止脱丁烷塔聚合物结垢方面取得了显著效果。以脱丁烷塔为例,对降压过程的可行性、经济性以及风险点进行分析和总结,利用化工流程模拟软件Aspen Plus对降压后各项工艺参数进行模拟优化,将优化结果应用于实际生产过程。结果表明,脱丁烷塔的降压极限为350 kPa,降压后全塔温度降低约4℃,塔釜粗裂解汽油中的C_(4)摩尔分数降低0.32百分点,节省低压蒸汽1.3 t h,装置能耗和C_(4)产品损失降低,循环水侧压降、循环水在换热器内的流速和对数传热温差均在合理范围之内。

The scaling problem of polymer in the de-butane column is one of the main factors that restrict the long-term operation of ethylene plants.Recently,the newly-built unit has achieved significant results in preventing polymer scaling in the de-butane column by reducing the operating pressure.Taking the de-butane column as an example,the feasibility,economy and risk points of the step-down process were analyzed and summarized,the process parameters after step-down operation were simulated and optimized by using the chemical process simulation software Aspen Plus,and the optimization results were applied to the actual production process.The results showed that the depressurisation limit of the de-butane column was 350 kPa,the temperature of the whole column decreased about 4℃after depressurisation,the C_(4) mole fraction of the crude cracked gasoline in the column kettle decreased by 0.32 percentage point,the low pressure steam was saved by 1.3 t h,and the energy consumption and the loss of the C_(4) product of the plant were reduced.The pressure drop of the circulating water side,the flow rate of the circulating water in the heat exchanger and the temperature difference of the logarithmic heat transfer were all within a reasonable range.