丙烷预冷混合制冷剂液化流程中原料气与制冷剂匹配研究

Analysis for Selecting Mixed Refrigerant Composition Based on Raw Natural Gas in Propane Pre-Cooled Mixed Refrigerant Liquefaction Process

针对高、中、低3种压力和2种成分组合而成的6种原料天然气,利用Aspen HYSYS流程模拟软件对丙烷预冷混合制冷剂液化流程(PPMR)进行了模拟研究,考虑了混合制冷剂高低压变化、混合制冷剂组分改变,从中获得了制冷剂组分与原料天然气Cp-T热力性质以及混合制冷剂高低压之间的相互关系.混合制冷剂组分的选择依赖于原料天然气Cp-T热力性质,而混合制冷剂高低压会影响制冷剂组分和流量.6种原料天然气在不同混合制冷剂高低压下的PPMR流程比功耗的比较结果表明:原料天然气的Cp-T性质是决定整个PPMR流程的功耗高低的关键因素,而混合制冷剂组分和高低压对系统功耗影响较弱.对于某一固定原料气,混合制冷剂的组分和高低压应当根据原料天然气进行合理选取以避免不必要的能耗增加.

For six raw natural gases, the mixed refrigerant composition in propane pre-cooled mixed refrigerant（PPMR）process for liquefying natural gas is investigated under three kinds of high and low pressures of mixed refrigerant. It is found that the choice of mixed refrigerant composition depends on the specific heat （Cp） property of raw natural gas, while the high and low pressures of mixed refrigerant influence its composition and flowrate. Based on this, the energy consumption of PPMR process is compared for the above eighteen cases,and it is shown that the specific heat property of raw natural gas plays a key role in reducing the whole system energy consumption rather than the high and low pressures of mixed refrigerant or its composition. For a certain feed natural gas, the composition and pressure of mixed refrigerant should be selected appropriately to avoid the unnecessary increase of energy consumption.