The main difficulty with carbon capture is high energy penalty and costs for gas separation processes, common for pre-combustion capture, post-combustion capture and oxyfuel combustion. The fundamental novelty of chemical looping combustion (CLC) is that no gas separation step is needed at all. Metal oxides are used to transport oxygen from an air reactor to a fuel reactor. The principle ideally allows elimination of the capture penalty. Circulating fluidized bed (CFB) technology is used, for which there is long commercial experience in power industry with conventional combustion. Moreover, in contrast to pre- and post-combustion capture, CLC reaches capture rates of 100%. In previous EU-projects, CLC for gaseous fuels has developed from paper concept to 120 kW fuel power. Satisfactory fuel conversion performance has been achieved with several nickel-based oxygen carrier materials. However, nickel-based materials are expensive and require special environmental/safety precautions. A focused search for alternative materials with comparable performance is without doubt the most important task to improve this technology. The key challenge is to make CLC less dependent on expensive nickel-based oxygen carrier materials. This project addresses this by investigating two groups of particles: (i) nickel-free materials with and without taking advantage of molecular oxygen uncoupling (CLOU); (ii) the mixed oxides concept, using mainly non-nickel materials with high reactivity towards CO/H2, together with a minor fraction of particles of reduced nickel content acting as reforming catalyst (i.e. transferring CH4 to CO/H2). Oxygen carrier particles will be prepared and investigated using available laboratory reactor equipment. Subsequently, production of large batches will be investigated for the most promising candidates. Existing CLC units at a scale of 10-200 kW will be used to investigate real life performance and operation stability.
Professor vid Chalmers, Space, Earth and Environment, Energy Technology
London, United Kingdom
The Hague, Netherlands
Funding Chalmers participation during 2010–2015