Method for Separation of Coal Conversion Products from Sorbents/Oxygen Carriers

This SBIR/STTR project targets the development of a technology for segregating fuel-based contaminants char and ash) from oxygen carrier material in the context of chemical looping combustion application. In chemical looping, the well-mixed solids that flow from the fuel reactor consisting of char, ash, and oxygen carrier particles cannot be completely separated into their constituents before they enter the air reactor. The slip of carbon leads to char oxidation in the wrong reactor and poor CO2 separation efficiency. The buildup of ash that is not rejected necessitates rejection of larger quantities of oxygen carrier material, resulting in a high operating cost penalty. An efficient method to separate char and ash from oxygen carrier material is critical for the deployment of chemical looping technology. The proposed project will develop a novel method for char/ash separation from oxygen carrier that is specifically tailored to chemical looping combustion and its unique constraints and process conditions. The proposed segregation system consists of a novel combination of methodologies that together provide very high segregation efficiency, even under the extreme conditions of chemical looping systems. Phase I will involve laboratory-scale testing of the concept at both ambient conditions and at representative elevated temperatures. The components in the novel segregation system will be optimized through parametric evaluation of several process conditions. Following completion of testing, a preliminary design for a scaled-up, integrated, continuously fed segregation system will be developed. The proposed technology will facilitate the development of chemical looping technology which is a potentially attractive approach for carbon dioxide capture and emissions mitigation. Other potential applications exist such as: in the separation of carbon from coal-fired plant ash to generate pozzolanic material to replace cement in concrete; in metallurgical processing direct iron reduction with coal) rendering it more energy efficient; in the recovery of coal and valuable minerals from coal cleaning reject streams; and in post-consumer goods recycling/waste-to-energy based on fragmentation and separation.