Exergy and Exergoeconomic Analysis of the Gas Subcooled Process for the Brazilian Market: An Approach to Enhance Natural Gas Liquids Recovery

The gas subcooled process (GSP) is the most widely adopted natural gas liquid (NGL) recovery method due to its adaptability to varying gas compositions and its alignment with the market emphasis in Brazil on lighter hydrocarbons. However, the process remains limited by high energy consumption and significant thermodynamic inefficiencies, particularly in the expansion and separation stages. To address these drawbacks, this research employs a detailed exergy and exergoeconomic assessment of four GSP configurations, termed Turbo-Expander (TE), Joule-Thomson (JT), Turbo-Expander with Mechanical Refrigeration (TEMR), and Joule-Thomson with Mechanical Refrigeration (JTMR), to identify and quantify the sources of energy degradation and their associated economic impacts. The results reveal that the TE configuration achieves the highest exergy efficiency (71%) and demonstrates superior cost performance by maximizing the shaft work recovery. Conversely, the TEMR setup incurs the highest exergy destruction cost (US $ 5687/h), primarily due to its energy-intensive refrigeration cycle. By integrating thermodynamic and economic diagnostics at the equipment level, these research findings provide actionable insights into improving GSP system design, support infrastructure modernization, and guide investment decisions, thereby contributing directly to the advancement of a more sustainable and competitive natural gas sector in Brazil.