CHAPTER 2: Chemical Looping for Hydrogen Production and Purification

Chemical Looping is an interesting technology that allows (partial) oxidation of a fuel without direct contact between the fuel and air. Instead, a solid material, referred to as oxygen carrier, is used to transport the oxygen from the air to the fuel by solid circulation between two reactors operated under different conditions. As such, the products of the fuel oxidation are nitrogen free. In the case of combustion (full oxidation), this means that the CO₂ is not diluted with nitrogen. In the case of reforming/partial oxidation, the syngas is nitrogen free and thus easier to purify. In the presence of an H₂ permselective membrane, the syngas production (through chemical looping) and pure H₂ separation are combined in the same unit. This chapter introduces the chemical looping principle and describes a new reactor concept that combines the advantages of chemical looping technology and membrane reactors. This concept is referred to as Membrane-Assisted Chemical Looping Reforming (MA-CLR), which allows high hydrogen purity with integrated CO₂ capture and high energy efficiency.