A Comprehensive Review of Inorganic Refrigerants in LNG Liquefaction Cycles: Thermodynamic Performance and Environmental Impact

Abstract

As the demand for Liquefied Natural Gas (LNG) continues to rise, the need for efficient and environmentally friendly refrigeration technologies has become more critical. This study presents a comprehensive review of inorganic refrigerants used in Liquefied Natural Gas (LNG) liquefaction cycles, concentrating on their thermodynamic performance and environmental effects. Using a thorough literature study, important refrigerants such as nitrogen, argon, krypton, xenon, and ammonia were examined in terms of efficiency, energy consumption, and sustainability. The findings show that inorganic refrigerants can improve energy efficiency by lowering power consumption and increasing exergy performance. Nitrogen was found to require the least amount of energy, whereas ammonia significantly increased the coefficient of performance (COP) in mixed refrigerant applications. Krypton and xenon both demonstrated great exergy efficiency, making them attractive candidates for future LNG operations. While these refrigerants have a lesser environmental effect than standard hydrocarbons, more advances are needed. The study recommends optimizing hybrid refrigerant systems, including renewable energy, and improving safety measures. Advancing these strategies can make LNG production more sustainable, reducing its carbon footprint while maintaining efficiency.