Optimal process selection for natural gas liquids recovery: Energy, exergy, economic, and environmental perspectives

In contrast with extant studies on industrial natural gas liquids (NGL) recovery processes, this study focuses on the most significant configurations, including the industry-standard single-stage (ISS) process, gas subcooled (GSP) process, cold residue gas-recycle (CRR) process, recycle split-vapor (RSV) process, enhanced NGL recovery process (IPSI-1), and internal refrigeration for enhanced NGL recovery process (IPSI-2). Furthermore, this study in-depth analyses the energy, exergy, economics, and environmental factors to determine the optimal configuration based on specific scenarios and priorities. ASPEN HYSYS® V11 is used to simulate six NGL process configurations, each with a processing capacity of 5000 kmol/h. The study identifies critical design variables concerning energy consumption. The energy analysis reveals that the RSV process exhibits the highest energy consumption, totaling 38.00 MW. Additionally, the RSV configuration demonstrates the highest values for exergy destruction, capital cost, CO₂ emissions, and purity compared to the other configurations. In contrast, the IPSI-1 process exhibits significantly higher energy efficiency than the RSV process, with 46 % lower energy consumption and the lowest specific CO₂ emissions (0.048 kg CO₂/kg feed). However, the analytical values for the lowest or middle rankings differ depending on the perspectives considered. Thus, this study provides valuable methods for selecting a conventional technology based on investment, input resources, and sustainable output requirements.