A hydrogen production system for producing a hydrogen gas product includes a geologic hydrogen source configured to provide a feedstock comprising hydrogen, nitrogen, and helium and purification equipment comprising two or more of: a pressure swing adsorption (PSA) device; a guard bed; a separation membrane; a reactive membrane; or a cryogenic separation device. The purification equipment is configured to receive the feedstock from the geologic hydrogen source and produce a hydrogen gas product, and production of the hydrogen gas product exhibits a carbon intensity score less than 3.0 kg CO.sub.2 eq/kg H.sub.2.

The invention relates to a method for separating gases which comprises: a first step in which a gas fuel stream comprising combustible substances that produce gas products when oxidised, and an oxygen-rich inlet stream are passed through at least two modules of oxygen-separating ceramic membranes, such that the two streams come into contact through the membranes and exchange heat; a second step of selective diffusion of oxygen from the oxygen-rich stream to the fuel stream, such that the outlet streams from the membrane modules are an oxygen-depleted or completely oxygen-free stream and a partially or completely oxidised stream; and a third step of recovery of at least two separate outlet streams of at least two gases selected from oxygen, nitrogen, carbon dioxide and hydrogen.

A system and method of ultra-high purity (UHP) oxygen production from an argon and oxygen producing cryogenic air separation unit incorporating a dedicated methane rejection column or column section having a liquid to vapor (L/V) ratio lower than the L/V ratio in the associated argon rectifier is provided.

A method for purifying a crude hydrogen feed stream utilizes an adsorbent having a N2/Ar selectivity ranging from 2 to 4 at 30 C. and a Henry's law coefficient for argon ranging from 0.15 to 1.0 mmole/g/atma at 30 C. The composition of crude hydrogen streams from processes in which carbon dioxide is captured necessitates new criteria for adsorbent selection to improve recovery.