Efficient hydrogen production with CO2 capture using gas switching reforming

Highlights: • Process design of the pure-H₂ production plant with CO₂ capture (GSR-H2) is presented. • Optimum design pressure for the gas switching reforming (GSR) reactor is identified. • GSR-H2 with 96% CO₂ capture shows only 3.8%-point efficiency penalty relative to conventional H₂ production process. • The efficiency penalty in GSR-H2 is eliminated by including additional thermal mass in the GSR reactor. -- Abstract: Hydrogen is a promising carbon-neutral energy carrier for a future decarbonized energy sector. This work presents process simulation studies of the gas switching reforming (GSR) process for hydrogen production with integrated CO₂ capture (GSR-H2 process) at a minimal energy penalty. Like the conventional steam methane reforming (SMR) process, GSR combusts the off-gas fuel from the pressure swing adsorption unit to supply heat to the endothermic reforming reactions. However, GSR completes this combustion using the chemical looping combustion mechanism to achieve fuel combustion with CO₂ separation. For this reason, the GSR-H2 plant incurred an energy penalty of only 3.8 %-points relative to the conventional SMR process with 96% CO₂ capture. Further studies showed that the efficiency penalty is reduced to 0.3 %-points by including additional thermal mass in the reactor to maintain a higher reforming temperature, thereby facilitating a lower steam to carbon ratio. GSR reactors are standalone bubbling fluidized beds that will be relatively easy to scale up and operate under pressurized conditions, and the rest of the process layout uses commercially available technologies. The ability to produce clean hydrogen with no energy penalty combined with this inherent scalability makes the GSR-H2 plant a promising candidate for further research.