(678a) Economic Feasibility Analysis of Coal-Direct Chemical Looping

Coal-direct chemical looping (CDCL) is an advanced oxy-combustion technology that has the potential to enable substantial savings in the cost and energy penalty associated with carbon dioxide (CO₂) capture from coal-fired power plants. The CDCL utilizes an iron (III)-based oxygen carrier (Fe₂O₃) to supply oxygen for coal combustion.  The process consists of a unique moving bed reactor, namely the reducer, where pulverized or crushed coal is fully converted with the reduction of iron-based oxygen carrier particles. The oxygen carrier is reduced from Fe₂O₃ to a mixture of FeO and Fe, while the flue gas leaving the reducer is a stream mainly composed of CO₂ that can be sequestered.  The oxygen carrier particles contain reduced iron oxide (FeO and Fe) which are then re-oxidized to Fe₂O₃ in the combustor with air, liberating heat to produce steam for power generation.

The iron-based CDCL process has shown the potential for lower capital and operating costs as compared to first generation carbon capture technologies, such as an amine-based solvent system or traditional oxy-combustion system. Further, CDCL does not require an air separation unit (ASU).  Eliminating the ASU results in a significant reduction in capital and operating costs.  Through collaborative efforts, Babcock & Wilcox Power Generation Group, Inc. (B&W PGG) and The Ohio State University (OSU) have developed a preliminary design and operating philosophy for a 550 MWe commercial scale CDCL power plant.  Based on the results of a techno-economic evaluation, B&W PGG estimates that the CDCL process will achieve 96.5% CO₂ capture with only a 26.8% increase in the cost of electricity (COE) when compared to a supercritical pulverized coal-fired power plant. Results of this the techno-economic analysis exceed the U.S. Department of Energy’s (DOE) goal of 90% CO₂ capture at a less than 35% increase in COE. The preliminary design, the latest experimental data, and results from the techno-economic study are presented and discussed.