Alstom's Chemical Looping Technology Program Update

摘要

Alstom Power is developing Chemical Looping Processes utilizing limestone or metal oxides (MeOx) as oxygen carriers to transport oxygen from air to the fuel. These technologies have the capability to capture CO_2 from new and existing coal-fired power plants while maintaining relatively higher plant power generation efficiency compared to competing technologies. The power plant concept is based on a hybrid gasification-combustion process utilizing high temperature chemical and thermal looping technology. The chemical and thermal looping technology can also be configured as a gasification process producing a syngas or hydrogen for various applications while also producing a separate stream of CO_2 for use or sequestration. Currently, testing of MeOx concept continues under the EU-funded ACCLAIM program using the 100 kW flexible pilots at Chalmers University, Goteborg, Sweden, for long term testing of alternative oxygen carriers such as manganese ore and iron ore and the 1 MWth prototype at Darmstadt University, Germany, for the goal of reaching autothermal operation. Both of these pilot facilities were built under the ECLAIR EU-program and are based on circulating fluidized bed (CFB) technology. The limestone chemical looping concept is now in the advanced stages of testing at the 3-MWth prototype facility in Windsor, CT, after achieving over 350 hours of operation including 75 hours self-sustained, autothermal operation. Cold flow models (CFMs) of various sizes including the prototype size were built in parallel to the hot test facilities on both programs and successfully operated. These CFMs along with CFD model studies using state-of-the-art software have helped investigate the solids transport mechanisms, and develop a list of critical operating parameters and operator training for the prototypes. Operation of these facilities will lead to further characterization of performance and development of design information for scale-up and demonstration. The progress to date of the MeOx and Limestone based chemical looping programs is reported in this paper. This includes an overview of the results obtained in the MeOx based ECLAIR and ACCLAIM programs, which has received financial co-funding support from the European Union - Research Fund for Coal and Steel (RFCS) and the Limestone program is currently co-funded by the DOE National Energy Technology Laboratory's Advanced Energy System program along with additional funding from North Dakota Industrial Commission and Illinois Clean Coal Institute.