Novel approach for low CO₂ intensity hydrogen production from natural gas

Hydrogen from natural gas with CO₂ capture can be a key transition technology to a low carbon energy system due to the abundance of natural gas and the possibility to increase the hydrogen production capacity quickly. However, it is necessary to achieve both a high energy efficiency and a high CO₂ capture ratio for it to be a viable option. The liquefaction of CO₂ is one promising separation technology as it provides the captured CO₂ in a transportable format. This paper proposes a hydrogen production process with integrated CO₂ liquefaction. Efficiencies of up to 84.7% (based on the higher heating value) and CO₂ capture ratios of up to 97.2% can be achieved. One advantage of the utilization of CO₂ liquefaction as separation technology is furthermore the possibility to incorporate a partial recycle of the flue gas from the separation to the water–gas shift reaction without additional equipment, increasing both energy efficiency and carbon capture ratio.