LNG Oxy-Fuel Power and Green Methanol Poly Generation Systems Associated with CO2 Condensation Capture: Techno-Economic Environmental Assessment

To achieve energy-environment synergy and sustainability, this study proposes a poly generation system that integrates the energy release process of liquefied natural gas (LNG) oxy-fuel power generation with the energy storage process of green methanol synthesis from renewable energy. In this system, oxygen, the byproduct of water hydrolysis to hydrogen, can support LNG oxy-fuel power generation; while the cold energy released during LNG regasification can serve as a cold source for carbon capture, the captured CO2 can be utilized as the carbon source for methanol synthesis, thus realizing cleaner methanol production and an efficient power generation process with near-zero carbon emission. Following the process design, the parameters were optimized with minimum levelized production cost of methanol and electricity as the objective function through Matlab using the "MADS" algorithm, resulting in 683.79 $/tonne and 68.05 $/MW h, respectively, with overall exergy efficiency of 50.28%. Notably, as green methanol synthesis requires additional CO2, a reduction of 2272.59 kg/h can be achieved. The study concludes that the novel poly generation process is superior in exergy efficiency and CO2 capture and utilization but inferior in high production costs.