Sweetening of natural gas is a necessary process step to meet transportation and commercial standards. Amine-based solvents have been conventionally used for absorption-based removal of contaminants, like acid gas from natural gas. The process has inherent high energy penalty issues during solvent recovery and large fugitive emissions due to the solvent's low vapor pressure. Contrarily, ionic liquids (ILs) have lower solution enthalpies and vapor pressure compared to conventional alkanolamine solvents. Hence, ILs can offer an energy-saving pathway for the carbon dioxide removal. However, understanding their application at plant-wide scale is limited. This study presents an energy, exergy and economic (3 E) analysis of an ionic liquid-based process for removing carbon dioxide from natural gas in a simulated environment. Pyridinium cation-based IL is analysed as a CO₂ capturing solvent and compared to the monoethanolamine (MEA) and 1,2-dimethoxyethane (DME). Optimal operating conditions for the IL-based carbon capture are evaluated with 99% CH₄ recovery and 99% CH₄ purity as benchmark conditions. The energy analysis shows that 3-methyl-1-ethylpyridinium bis(trifluoromethylsulfonyl)imide (3MEPYNTF₂) ionic liquid provides 90.08% and 80.28% overall energy savings relative to MEA and DME. The exergy analysis further complements the energy analysis as 3MEPYNTF₂ is energy proficient with overall anergy of 13.3 MW, while MEA and DME gives a higher value of 57.45 and 30.98 MW, respectively. Furthermore, economic analysis indicates that at average, 3MEPYNTF₂ offers savings in overall capital (65.86%), operating costs (81.09%), and total annualized costs (78.33%) compared to MEA and DME. The 3 E analysis suggests that pyridinium cation based ILs are a potential replacement for amine-based high pressure natural gas sweetening processes.

天然气脱硫是满足运输和商业标准的必要工艺步骤。传统上，胺基溶剂已用于基于吸收的污染物去除，例如天然气中的酸性气体。该方法在溶剂回收过程中固有的高能量损失问题，并且由于溶剂的蒸汽压低而导致大量的逃逸排放。相反，与常规链烷醇胺溶剂相比，离子液体（IL）的溶液焓和蒸气压更低。因此，离子液体可以为二氧化碳的去除提供一条节能途径。但是，了解它们在整个工厂范围内的应用是有限的。这项研究提出了一种在模拟环境中从天然气中去除二氧化碳的基于离子液体的过程的能源，火用和经济（3 E）分析。₂捕获溶剂，并与单乙醇胺（MEA）和1,2-二甲氧基乙烷（DME）进行比较。以99％CH ₄回收率和99％CH ₄纯度作为基准条件，评估了基于IL的碳捕获的最佳操作条件。能量分析表明，相对于MEA和DME ，3-甲基-1-乙基吡啶双（三氟甲基磺酰基）酰亚胺（3MEPYNTF ₂）离子液体可总体节省90.08％和80.28％的能量。火用分析进一步补充了能量分析，因为3MEPYNTF ₂能效高，总无能为13.3 MW，而MEA和DME分别提供了更高的值57.45和30.98 MW。此外，经济分析表明，平均而言，3MEPYNTF ₂与MEA和DME相比，可节省总资本（65.86％），运营成本（81.09％）和年度总成本（78.33％）。3 E分析表明，基于吡啶鎓阳离子的离子液体可替代基于胺的高压天然气脱硫工艺。