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

Abstract

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.