(172b) COAL Direct Chemical Looping Process: Metallurigical Coke and PRB COAL Conversions

As a novel oxy-combustion approach for CO₂ capture from coal power plants, the chemical looping processes have been extensively studied. The chemical looping process can easily extract highly concentrated CO₂ and efficiently recover heat, which has exhibited the promising economic and technical feasibility to capture CO₂ from the coal conversion processes.

At the Ohio State University, Coal-Direct Chemical Looping (CDCL) process using iron-based oxygen carriers has been developed for the application to the power generation with in-situ CO₂ capture. The iron-based oxygen carrier particles can undergo extensive characteristic and performance tests for the application in the chemical looping processes. These oxygen carrier particles are consisted of reactive metal oxides, Fe₂O₃ and inert supports. The study of particular oxygen carrier particle shows that the particle can be regenerable under reduction-oxidation conditions for more than 100 cycles. Also, these particles are capable to convert various fuels such as methane, syngas and solid fuels to generate hydrogen and/or heat. In this study, a 2.5 kW_th bench unit and a 25 kW_th sub-pilot demonstration unit for the CDCL process are presented. Design, construction and operation of CDCL sub-pilot unit are discussed. The sub-pilot unit was successfully operated in the integrated and continuous manner with different types of solid fuels such as metallurgical coke and PRB coal.