A Multi-Scale Approach for Reverse Engineering Chemical Looping Combustion

Abstract

Chemical looping combustion (CLC) is a promising technology for capturing emissions of carbon dioxide from the combustion of fuels. It has received significant attention in the literature and has been demonstrated in a number of pilot-scale units up to 1 MWth in size. Progress toward industrial implementation is however slow and CLC seems to be caught in the so-called ‘Valley of Death’ between research and widespread implementation at industrial-scale. In this paper, a multi-scale approach is presented that considers CLC holistically for the first time, ranging from the reactions and materials underpinning the technology to its integration into a system, such as an electricity grid. By passing information from the system scale to the smaller scales, it has been possible to reverse engineer aspects of the design and operation of CLC to optimise it for industrial implementation. For the case of an electricity system, reduction in the capital cost was found to be most important for making CLC more attractive. This could be achieved by modifying the design and operation of the CLC reactor system, which contributes significantly to the capital cost of a CLC-based power plant. Oxygen carrier materials are at the heart of the CLC process. A number of influencing characteristics of oxygen carriers have been identified that are worthy of further investigation, since their properties have an impact on the hydrodynamics and the kinetics in a fluidised bed. The multi-scale approach has been applied to CLC in this paper, it is however applicable and would be valuable for the evaluation and optimisation of many technologies in the energy and chemical sectors.

Keywords: High temperature solids looping: chemical looping, carbon capture, oxygen carrier, multi-scale, GHGT-14