The world-wide consumption of natural gas (NG) and other fossil fuels (e.g., coal and crude oil) is ever increasing. However, most CO 2 resulting from either NG combustion or other processes is released into the atmosphere without capture. Chemical looping combustion (CLC) is a two-step combustion technology for power and heat generation with inherent CO 2 capture, using either gaseous fuels or solid and liquid fuels. A previous review focused on CLC of solid fuels or CLC of all types of fuels but did not give an in-depth and specific discussion of gaseous fuel CLC systems. China is one of the largest consumers of NG, coal, and crude oil in the world, and it is essential to develop an alternative technology to take the place of gaseous fuel (e.g., NG) combustion. This Review summarizes recent research and development work on CLC using gaseous fuels, including a technological and economic assessment, types of oxygen carriers (OCs), reactor types, coke formation and OCs poisoning, efficiency and exergy analyses, and model development based on a literature survey. The plant efficiency of NG-CLC can be up to 52−60% (LHV), including CO 2 compression, based on calculations and simulations, which is about 3−5% more efficient than a NG combined cycle with CO 2 capture. Ni-based materials have been widely developed and applied for NG-CLC because of its fast kinetics for methane conversion. CuO−Cu 2 O/Cu, Mn 3 O 4 −MnO, and Fe 2 O 3 −Fe 3 O 4 are typical OCs with high selectivity toward CO 2 and H 2 O. The operating conditions are closely dependent on reactor configurations, hydrodynamics, mass and heat balances, and characteristics of the OCs in the system. CLC and other CO 2 capture technologies are also compared in the present Review, which has rarely been investigated previously. From simulation and process analysis, a conceptual design of a NG-CLC power plant of thermal input 655 MW th is conducted to clarify its technological advantages and economic benefits compared to other power generation processes. The air reactor, fuel reactor, and OCs do not impose significant economic barriers for scale-up and commercialization of CLC.
