基于层次分析法优化天然气净化工艺

Optimization of purification process for natural gas using analytic hierarchy process

为了避免杂质腐蚀设备或因低温冻结而堵塞换热器,天然气在进入液化装置前需对其进行净化处理,即脱除天然气中的酸性气体(CO_2、H_2S)和水分。本文选用二乙醇胺(DEA)法脱除天然气中的酸性气体,用三甘醇(TEG)法脱除天然气中的水分,通过耦合DEA法和TEG法得到最终天然气净化工艺,且达到净化指标要求。但由于工程手册只能给出工艺参数的大概范围,尚无法得到最优的工艺方案,因此本文首先应用化工模拟软件HYSYS 8.4对天然气工艺过程进行模拟计算,然后在工艺参数推荐范围内设定9组推荐方案,引入系统评价方法中的层次分析法,并基于Matlab程序计算,对9组推荐方案进行多目标综合评价,最终确定最优的净化组合方案。本文可为天然气净化工艺和其他工艺方案的优选提供指导。

In order to avoid severe corrosion of vessel or freezing in cryogenic exchangers,feed gas from natural gas well heads containing various contaminants and acid gases cannot be sent to the liquefaction unit directly,and must pass through purification units to remove undesirable components such as CO_2,H_2 S and H_2 O. In this paper,DEA and TEG methods are adopted to remove such components,and these two methods are coupled into a natural gas purification process to reach the purification target. As the project handbook only gives the approximate range of process parameters,an optimal process is not available. This paper first applies software HYSYS 8.4 to simulate the natural gas purification process based on relevant data. Then nine combined cases are listed according to the recommended range of process parameters,and a system assessment method,Analytic Hierarchy Process（AHP）,is introduced. Finally,multi-objective comprehensive assessment is made using AHP in Matlab to select the optimal process parameters. This approach can provide reference for optimization of natural gas purification process and other processes.