Process and apparatus for producing hydrogen and carbon monoxide

A process for producing a H2-containing product stream and CO-containing product stream from a process gas, the process comprising:

• generating the process gas in a production unit, the process gas comprising H2, CO, CO2, and H2O;
• removing H2O from the process gas;
• removing CO2 from the process gas without cryogenically fractionating the process gas;
• separating H2 from the process gas by pressure swing adsorption in a pressure swing adsorber thereby forming the H2-containing product stream and a pressure swing adsorber residual gas stream, the residual gas stream withdrawn from the pressure swing adsorber at a pressure between 260 kPa and 420 kPa, the residual gas stream withdrawn having a time-varying molar concentration of one or more components with an amplitude greater than 2.5 mole % during a pressure swing adsorber cycle;
• attenuating the amplitude of the molar concentration of the one or more components in the residual gas stream to less than 1 mole % in a mixing device;
• compressing the residual gas stream in a compressor;
• passing the residual gas stream from the compressor to a drier to remove H2O and CO2 prior to passing the residual gas to the cryogenic separation unit;
• passing at least a portion of the residual gas stream from the drier to a second mixing device thereby dampening pressure variation and further attenuating the amplitude of the molar concentration of the one or more components in the residual gas prior to passing the residual gas stream to a cryogenic separation unit;
• passing the residual gas stream to the cryogenic separation unit subsequent to the steps of attenuating and compressing;
• separating the residual gas stream into the CO-containing product stream, a H2-enriched stream, a methane-enriched stream, and a CO-containing intermediate stream by cryogenic fractionation in the cryogenic separation unit;
• and
• introducing at least a portion of the H2-enriched stream into the pressure swing adsorber.