CHEMICAL LOOPING-A TRANSFORMATIONAL TECHNOLOGY FOR FOSSIL FUEL UTILIZATION

摘要

Chemical looping is a clean-coal technology which utilizes a solid oxygen carrier to provide oxygen to a fossil fuel conversion (combustion or gasification) process.This breakthrough fuel conversion technology does not require a capital-intensive cryogenic air separation unit and is "transformational" in terms of its overall efficiency and cost.Chemical Looping Combustion (CLC) for steam power is the lowest potential cost (cost-of-electricity) technical approach that Alstom has identified to date for coal power with carbon capture.Chemical looping concept was originally proposed in early 1950s by Lewis and Gilliland (1954) as a method of producing pure CO2 stream for industrial purposes.The renewed interest in the development of chemical looping technology over the last decades is motivated mainly by the need to maintain utilization of fossil fuel (coal and natural gas), an abundant energy source, in electricity production while meeting the growing power generation demands in a cost-effective, environmentally sustainable way.The chemical looping concept is flexible, and can be developed further for other high value-added products.By changing the amount of solid oxygen carriers relative to the fuel in a fuel reactor, for example, high quality syngas can be produced as feedstock for petrochemical/refinery industry.By further processing the syngas, high purity H2 can be produced, which then can be used for ammonia synthesis, petroleum refining, fuel cells or other applications.In this paper, chemical looping development is reviewed in detail with its main focus on power generation from solid fuels.The current developmental status is discussed.This includes Alstom's recent achievement in self-sustained operation of limestone-based CLC process at Alstom's 3-MWth pilot scale test facility in Windsor, CT, USA.This is the first such achievement for chemical looping process in the world.