Synthesis Gas Production by Chemical-Looping Reforming of Methane Using Lattice Oxygen

Chemical looping reforming (CLR) of methane to obtain synthesis gas using lattice oxygen of oxygen carriers instead of molecular oxygen is a novel technology for producing synthesis gas from methane, which has higher economic benefits and environmental benign. CLR has several advantages, such as, saving oxygen generation equipment, capable of self-heating, suitable hydrogen/carbon ratio, useful by-products and realizing industrialization easily, so, it has been growing interest for researchers at home and aboard. Firstly, the basic concept and characteristics of CLR are introduced, which is partial oxidation of methane through controlling the value of lattice oxygen/fuel, thus, the synthesis gas is produced through the gas-solid reaction between methane and oxygen carriers, and the reduced oxygen carriers are re-oxidized by air or H2O to restore its lattice oxygen. Direct contact between fuel and combustion air is avoided in the CLR. Instead, an oxygen carrier performs the task of bringing O-2 from the air to the fuel. In particular, it is summarized for the research progress of monometallic and composite metal oxygen carriers. And the same time, several kinds of typical representative reactor in CLR are discussed, among which interconnected fluidized bed reactor will be most effective for CLR to realize industrialization in the future. Finally, the expand application of CLR and the trends coupled with other technology are prospected.