Optimization of the Helium Extraction Process from Natural Gas with Integrated Cryogenic–Membrane Separation

Helium, recognized as a scarce and vital strategic resource, is predominantly extracted from natural gas through the cryogenic separation method. Nevertheless, conventional cryogenic separation processes are plagued by challenges, such as elevated energy consumption, diminished helium extraction efficiency, and escalated production costs. Through the study of various helium extraction methods and their technological characteristics, this paper proposes a novel natural gas cryogenic–membrane separation helium extraction process coproducing ethane. Simulation of the process was performed with Aspen HYSYS. By calculating the percentage of equipment energy consumption, we analyzed the influence of the operating parameters on the equipment energy consumption, helium concentration, and ethane recovery and then identified the main influencing parameters as optimization variables. Response surface analysis was used for process optimization, and central composite design was selected as the experimental design method; three regression models for equipment energy consumption, ethane recovery, and crude helium concentration were established, and process parameters were optimized and simulated for validation. The maximum error of the three models was 0.772%. The optimized process reduces the total energy consumption of the equipment by 3.301% while meeting the requirements of 89% ethane recovery, 66.7% crude helium concentration, and 99.6% refined helium concentration. This study can provide a theoretical foundation and technical guidance for the operation and management of the cryogenic–membrane separation method for helium extraction from natural gas.