Abstract
Liquefied natural gas (LNG) plays a key role in the energy transition, but its production is often limited by the high CO2 content of some reservoirs, which increases operating costs and solidification risks. This study evaluates the dual-pressure low-temperature cryogenic distillation process applied to a recently discovered gas field with a high CO2 content (25%) for LNG production. The critical properties of the gas streams and the process operating conditions were analyzed using Aspen Plus v14. The results indicate that reducing the CO2 concentration throughout the column is essential to prevent solid formation by maintaining a fluid composition with a freezing temperature below the operating temperature of the stages. It was also observed that the reflux affects LNG purity and freezing temperature in all stages. Furthermore, the adoption of a low-pressure separator upstream of the distillation proved crucial to producing condensates within commercial specifications. The work extends the understanding of the dual-pressure low-temperature cryogenic distillation to the 25% CO2 range and highlights the potential of cryogenic distillation to enable LNG production in fields with high CO2 content.