Cryogenic CO₂ condensation and membrane separation of syngas for large-scale LH2 production.

Liquid hydrogen (LH2) has the potential to become a global energy commodity analogous to liquefied natural gas (LNG) in the future. This will require LH2 production capacities of similar scale as for large-scale LNG plants. Natural gas is an attractive energy source for production of carbon-neutral LH2. This production will require efficient CO₂ capture and storage (CCS) combined with hydrogen purification. This work presents an advanced technology combination for large-scale hydrogen production with CCS intended for subsequent liquefaction and ship transport. Pure hydrogen for liquefaction is produced by exposing shifted syngas to a palladium membrane unit. The CO₂-rich retentate is dehydrated and separated in a cryogenic condensation unit. The decarbonised, hydrogen-rich top gas from the cryogenic unit can be partly recycled to the membrane unit to increase the hydrogen recovery ratio and CO₂ capture ratio. This paper investigates the influence of central process design parameters on important process performance indicators such as hydrogen recovery ratio and CO₂ capture ratio.