Zero-emissions ‘chemical looping’ converts fossil fuels into electricity

The researchers, engineers from Ohio State University in Columbus, have published their findings in two papers in the journal Energy and Environmental Science. Developing a technology called coal-direct chemical looping combustion (CDCL), which project leader Prof Liang-Shih Fan and his team first invented five years ago, the engineers describe their technique as a stop gap for providing clean energy while the cost of renewable generation continues to fall.

In its first paper, the team describes how the process converts shale gas, and also states that it can be fuelled by coal and biomass. CDCL works by changing the source of oxygen for combustion from the air to iron oxide particles in a high-pressure moving-bed reactor. ‘Burning’ the carbon chemically releases the chemical potential energy of the carbon fuel as heat that can be used to power electricity-generating turbines, while producing a highly concentrated stream of pure carbon dioxide that can be used as a partial substitute for methane in a steam-reforming process to produce syngas, a mixture of carbon monoxide and steam that can be converted into methane and thence to useful chemical products via well-understood chemical engineering processes.