A method of obtaining a high-purity helium gas product with simultaneous production of a methanol-water liquid mixture and a methane-rich fuel product from a hydrogen-rich feedstock gas containing helium, a carbon dioxide-rich feedstock gas, and an inert methane-rich gas comprising:
- (a) introducing the hydrogen-rich feedstock gas containing helium, a solvent recovery unit (SRU) high-high pressure recycled carbon dioxide-rich gas, and the inert methane-rich gas to a reverse water gas shift unit (RWGSU), being configured to generate carbon monoxide and water from carbon dioxide and hydrogen within a RWGSU reverse water gas shift reactor at a low pressure and in the presence of the inert methane-rich gas, to produce a RWGSU gaseous carbon monoxide and a RWGSU liquid water, wherein a molar ratio of carbon monoxide to hydrogen in the RWGSU gaseous carbon monoxide is greater than a molar ratio of carbon monoxide to hydrogen in the RWGSU inlet gases mixture;
- (b) introducing the RWGSU gaseous carbon monoxide and a methanol-lean solvent from the solvent recovery unit (SRU) to a methanol production unit (MEP), being configured to generate methanol and water from hydrogen, carbon dioxide, and carbon monoxide, within series-connected methanol reactors and also being configured for selective absorption of the generated methanol and water between the reactors with a high-boiling inert solvent within solvent absorber columns, to produce a MEP gaseous methanol and a methanol-rich solvent, wherein a molar ratio of methanol in the MEP gaseous methanol is greater than a molar ratio of methanol in the RWGSU gaseous carbon monoxide, and wherein a molar ratio of methanol in the methanol-rich solvent is greater than a molar ratio of methanol in the methanol-lean solvent;
- (c) introducing the MEP gaseous methanol, a SRU methanol-rich water liquid, a methane production unit (CH4P) liquid water, a catalytic oxidation unit (COXU) liquid water, and a first portion of a liquid demineralized water to a methanol absorption unit (MEA), being configured for methanol absorption with water liquid within a second water absorber column, to produce a MEA methanol-free gas and a MEA methanol-aqueous solution, wherein a molar fraction of methanol in the MEA methanol-free gas is less than 1.0E-6;
- (d) introducing the MEA methanol-free gas and a SRU high pressure recycled carbon dioxide-rich gas to the methane production unit (CH4P), being configured to generate methane and water from hydrogen, carbon dioxide, and carbon monoxide within series-connected methanation reactors, in the presence of an excess carbon dioxide gas, to produce a CH4P gaseous methane and the CH4P liquid water, wherein a mole percent of carbon dioxide in the mixture of the MEA methanol-free gas and the SRU high pressure recycled carbon dioxide-rich gas exceeds the stoichiometric requirement, reaching up to 40.0%, and wherein a molar ratio of methane in the CH4P gaseous methane is greater than a molar ratio of methane in the CH4P inlet gases mixture;
- (e) introducing the CH4P gaseous methane to a carbon dioxide recovery membrane unit (CRMU), being configured to selectively separate nitrogen, methane, hydrogen, helium, and other gases from carbon dioxide to produce a CRMU gaseous carbon dioxide and a CRMU gaseous methane, wherein a molar ratio of carbon dioxide in the CRMU gaseous carbon dioxide is more than a molar ratio of carbon dioxide in the CH4P gaseous methane;
- (f) introducing the CRMU gaseous methane, the MEA methanol-aqueous solution, and a liquid nitrogen refrigerant to a first portion of a cryogenic nitrogen rejection unit (CNR), being configured for absorption of carbon dioxide and water with a cryogenic temperature liquid methanol within a first carbon dioxide absorber tower, and being configured for absorption of nitrogen and carbon monoxide with a liquid methane within a first methane absorber tower, to produce a CNR gaseous hydrogen, the methane-rich fuel product, the methanol-water liquid mixture, a CNR gaseous nitrogen vent gas, and a CNR degassing drum vent gas, wherein a molar ratio of nitrogen in the CNR gaseous hydrogen is less than a molar ratio of nitrogen in the CRMU gaseous methane;
- (g) introducing the CNR gaseous hydrogen and an oxygen-rich gas to the catalytic oxidation unit (COXU), being configured to remove hydrogen and methane within a hydrogen catalytic combustion reactor, to produce a COXU gaseous helium and the COXU liquid water, wherein a molar fraction of hydrogen in the COXU gaseous helium is less than 1.0E-6;
- (h) introducing the COXU gaseous helium and a high-purity liquid propane to a second portion of the cryogenic nitrogen rejection unit (CNR), being configured for absorption of carbon dioxide and water with a cryogenic temperature liquid methanol within a second carbon dioxide absorber tower, and being configured for absorption of nitrogen and carbon monoxide with a liquid methane within a second methane absorber tower, and being configured for absorption of methane with a cryogenic temperature liquid propane within a propane absorber tower, to produce a CNR gaseous helium, wherein a mole percent of helium in the CNR gaseous helium is greater than 99.99%;
- (i) introducing the CNR gaseous helium to a cryogenic adsorption unit (CAU), being configured to adsorb methane, nitrogen, and other unwanted gases from helium on activated carbon beds at a cryogenic temperature, to produce the helium-rich gas product and a CAU tail gas, wherein a mole percent of helium in the high-purity helium gas product is greater than 99.999%;
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- (j) introducing the RWGSU liquid water, the methanol-rich solvent, the CRMU gaseous carbon dioxide, the carbon dioxide-rich feedstock gas, the CNR degassing drum vent gas, the CAU tail gas, and a second portion of the liquid demineralized water to the solvent recovery unit (SRU), being configured to strip the absorbed methanol and water from the methanol-rich solvent within a methanol stripper tower, and being configured to adsorb the stripped methanol gas with water liquid streams within a first water absorber column, and being configured to increase pressure of nonabsorbable gases of SRU inlet streams, to produce the SRU high pressure recycled carbon dioxide-rich gas, the SRU high-high pressure recycled carbon dioxide-rich gas, the methanol-lean solvent, and the SRU methanol-rich water liquid, wherein the molar ratio of methanol in the methanol-rich solvent is greater than the molar ratio of methanol in the methanol-lean solvent, and wherein a molar fraction of methanol in the SRU gaseous carbon dioxide is less than 1.0E-6.