轻烃回收装置工艺方案选择

Process scheme selection for light ends recovery unit

对全厂性轻烃回收装置的两种常用工艺流程,即吸收脱丁烷脱乙烷方案（方案一）和吸收脱乙烷脱丁烷方案（方案二）,使用ProⅡ软件进行模拟计算,并将计算结果进行对比分析。与方案二相比,方案一产品的产值高321×10^4RMB$/a,操作费用高2396×10^4RMB$/a,塔器设备投资高77×10^4RMB$。所以选用方案二比较经济。从多组分分离的角度对该结果进行了简单分析,按照Nadgir等人提出的有序直观推断规则,分析得出进料性质对于方案的选择至关重要。对于全厂性的轻烃回收装置,因为吸收塔底油中轻组分H2,C1～C3,H2S较多,应采用方案二。对于常减压装置自带的轻烃回收部分,因为初顶、常顶石脑油中轻组分H2,C1～C3,H2S含量相对较低,应采用方案一。

There are two major process schemes for plant-wide light-ends recovery unit, i.e. absorption- debutanization-deethanization （ option 1 ） and absorption-deethanization-debutanization （ option 2）. ProII software is used to simulate these two process schemes in order to select an economic and appropriate one. The comparison of calculation results show that although the annual economic benefit of option 1 is 3.21 million Yuan RMB higher than option 2, the annual operation cost is 23.96 million Yuan RMB higher than option 2 and an additional columns＇ investment equipment of 0.77 million Yuan RMB is required. Therefore, option 2 is more economics than option 1. The results are analyzed in respect of multi-component separation. According to the analysis by Nadgir＇ s heuristic method for systematic synthesis of initial sequences for multi-component separations, the feed properties of light ends recovery unit are very important for process scheme selection. For the plant-wide light ends recovery unit, option 2 should be selected because the bottom oil of absorption column contains higher amount of H2, C1- C3 and H2S. Whereas, for light lends recovery part of CDU, the option 2 should be considered because the H2, C1- C3 and HaS of in the overhead naphtha of atmospheric tower is lower.