Hydrogen production with integrated CO2 capture in a novel gas switching reforming reactor: Proof-of-concept

- Gas Switching Reforming (GSR) reactor is experimentally demonstrated.
- GSR can be an easily scalable alternative for elevated pressure operation.
- GSR distinctly separates reduction and reforming steps.
- This makes GSR more applicable to pure hydrogen production.

This paper reports an experimental investigation on a novel reactor concept for steam-methane reforming with integrated CO2 capture: the gas switching reforming (GSR). This concept uses a cluster of fluidized bed reactors which are dynamically operated between an oxidation stage (feeding air) and a reduction/reforming stage (feeding a fuel). Both oxygen carrier reduction and methane reforming take place during the reduction stage. This novel reactor configuration offers a simpler design compared with interconnected reactors and facilitates operation under pressurized conditions for improved process efficiency.The performance of the bubbling fluidized bed reforming reactor (GSR) is evaluated and compared with thermodynamic equilibrium. Results showed that thermodynamic equilibrium is achieved under steam-methane reforming conditions. First, a two-stage GSR configuration was tested, where CH4 and steam were fed during the entire reduction stage after the oxygen carrier was fully oxidized during the oxidation stage. In this configuration a large amount of CH4 slippage was observed during the reduction stage. Therefore, a three-stage GSR configuration was proposed to maximize fuel conversion, where the reduction stage is completed with another fuel gas with better reactivity with the oxygen carrier, e.g. PSA-off gases, after a separate reforming stage with CH4 and steam feeds. A high GSR performance was achieved when H2 was used in the reduction stage. A sensitivity analysis of the GSR process performance on the oxygen carrier utilization and target working temperature was carried out and discussed.