Coal-fueled pressurized chemical looping combustion (PCLC) combinedcycle for power generation and CO2 capture

Coal has been proven for many decades to be the lowest cost fuel for power generation and Kentucky residents have enjoyed the lowest residential electricity rates in the nation, due to the fact that a large part of Kentucky's electricity comes from coal. However, potential legislative controls on CO2 emissions are putting coal at a disadvantage in a carbon-constrained world because coal is the most carbon-intensive fuel for power generation. Most of the current technologies for carbon reduction from coal-fueled power generation, such as post-combustion CO2 separation and oxy-fuel combustion, are costly and energy intensive. This project is targeting to develop an advanced technology to burn coal with in-situ CO2 capture for base-load power generation based on the chemical looping combustion concept and to provide a pathway to maintain and strengthen coal's competitive advantage for Kentucky's energy sector. We propose a coal-fueled pressurized chemical looping combustion (PCLC) integrated with a flue-gas turbine combined cycle for next generation power generation with CO2 capture. The proposed PCLC unit consists of two reactors: 1) an Oxidizer in which oxygen from air is selectively fixed into an oxygen-carrier (OC) structure, and 2) a Reducer (Redox) in which coal is burned by OCs. The PCLC unit will generate two gas streams, (1) a high-temperature, high-pressure, clean gas from the Oxidizer used to drive an aero-turbine followed by a heat-recovery steam generator for Rankie Cycle, and (2) a CO2-enriched stream from the Redox for sequestration. The potential positive impacts from the proposed PCLC for large scale power generation include (1) provision of a higher-efficiency (~48%) alternate technology for electricity generation with CO2 capture; (2) a cost-effective means to control pollutants such as sulfur, Hg and trace metals by their pre-removal into a relatively small volume, N2-free gas stream; (3) NOx free flue gas; and (4) significant reduction to cost of electricity of a commercialized CLC power plant by using relatively high performance and cost-effective iron-based oxygen carriers. An extensive research study on coal-fueled PCLC technology has been conducted here on lab-scale apparatus and is proposed to carry on at a bench-scale on a chemical looping apparatus. The lab-scale study included cost-effective OC development, simulation, and cost-economic analysis of the PCLC process for electricity. The proposed research in this project will focus on bench-scale demonstration and scale-up of work previously done involving cost-effective OC development. OCs developed by UKy-CAER will be used for testing of the bench-scale apparatus. The impact of the initial OC temperature, residence time, operating pressure, solids mixing profile, and gas composition in Redox-M will be studied. Issues such as OC particle agglomeration, de-fluidization and solid movement will be addressed and solved.