A new type of power cycle for large scale generation has been developed based on chemical looping that has theoretically been shown to offer practical thermal efficiencies of between 72% and 82%. Instead of performing hydrocarbon combustion in a single reaction, as in conventional power plant, the hydrocarbon is oxidised using two reactions. An additional species is required, typically a metal, which re-circulates between the two reactions carrying oxygen atoms. The chemical looping technology concerned uses processes comparable to those in the human body for extraction of energy from food but instead of using haemoglobin, metal vapour is used as the carrier for the oxidation and reduction processes. The cycle avoids the large entropy changes associated with Carnot-cycle based engines and high thermal efficiencies are possible with inherent carbon capture for power generation plants.
The technology represents a step change in power generation although a series of technical barriers remain for its implementation including equation of state data, detailed chemical kinetics, development of practicable schemes to duct the highly reactive fluid flows and determination of slag melt thermodynamics. This paper explores the cycle development and technology requirements as well as addressing the need to consider cycle variants in power generation.