Simulation of and multi-aspect study of a novel trigeneration process for crude helium, liquefied natural gas, and methanol production; operation improvement and emission reduction

This study suggested a novel integrated trigeneration system for crude helium (He), liquefied natural gas, and methanol production. This proposed system consisted of a cryogenic-based helium recovery unit from natural gas, a syngas synthesis unit by hybrid reforming, a methanol synthesis unit, and a sour water recovery unit. Comprehensive energy, exergy, environmental, and economic analyses were performed to assess the system's performance. Based on the results, the crude helium, liquefied natural gas, and methanol production rates were obtained to be 4105kg/h, 3594000kg/h, and 707800kg/h, respectively. These production rates provided 93.4 % and 94.38 % overall exergy and energy efficiencies. Also, over 60 % of the total exergy destruction occurred in reactors (R1-R4). The application of sour water recovery supplied 85.66 % of the reforming and methanol synthesis process. Regarding environmental analysis, 94 % of the CO2 emission was due to the indirect mode, and the rate of the CO2 emission was estimated to be 0.164 kg(CO2) /kg(prods). Finally, the economic analysis indicated that the total annual production costs were about 440.16 M$ and 0.13 USD/kg. Therefore, the net present value of the designed scheme was estimated to be 364.36 M$.