Coal has been proven for many decades to be the lowest cost fuel for power generation. However, potential legislative controls on CO₂ emissions are putting coal at a disadvantage in a carbon-constrained world because coal is the most carbon-intensive fuel for power generation. The conventional technologies for carbon reduction from coal-fueled power generation are add-ons requiring significant modification to current PC structures and lay-outs which could be cost intensive. Chemical looping combustion (CLC), introduced by Richter and Knoche, has emerged as an attractive option to separate the greenhouse gas CO₂. This technique replays on the use of an oxygen carrier (usually a transition metal oxide) that transports the oxygen needed for combustion from the air to the fuel, avoiding the direct contact between the fuel and the air. Accordingly, oxygen carriers are the key point for the entire CLC technology.

To date, a lot of research work has focused on developing different types of oxygen carriers mainly from the aspect of performance evaluation under CLC condition. For CLC of solid fuels (e.g. coal), considering the frequent making up of OC due to attrition and fuel impurity contamination, searching for naturally available OC materials has become very popular.

UK-CAER has been investigating the application of chemical looping combustion/gasification to solid fuels since 2006 with total funding level of $7M with focus on pressurized CLC for efficiency improvement, cost-effective material and fabrication technique using bauxite by-product, Red Mud, and oxygen carrier active composition tuning to balance heat management between the fuel and air reactor. Currently, there are four ongoing projects with a CLC or gasification focus, two funded by U.S. DOE NETL, one funded by US-China CERC and one funded by an Industrial-Government-Academic consortium – Carbon Management Research Group, including:

• DE-FE0024000: “Application of Chemical Looping with Spouting Fluidized Bed for Hydrogen-rich Syngas Production from Catalytic Coal Gasification”
• DE-FE0025098: “Application of Spouting Fluidized Bed to Coal-fueled Pressurized Chemical Looping Combustion to Improve Plant Efficiency and Reduce Process Complexity”
• DE-PI000017: “Coal-fueled Chemical Looping Combustion for Future Electricity Generation”
• CMRG: “Understand and Stabilize Cu Enhanced Iron-based OC for Coal-based Chemical Looping Combustion”