1. Oxy Coal Combustion at the US EPA Myrrha Andersen, Bill Roberts, MAE NCSU Bill Linak, C.W. Lee, NRMRL US EPA Chris Winterowd, Daniel Janek, ARCADIS Jost Went, CE U of Utah Coal Abundant reserves Competitively low prices for base load power generation According to data from 2009, 29.4% of the world’s energy consumption came from coal generated electricity Abundant reserves Competitively low prices for base load power generation According to data from 2009, 29.4% of the world’s energy consumption came from coal generated electricity Oxy Coal Combustion Drop Tube Furnace Innovative Furnace Reactor (IFR) Furnace Coal Combustion Carbon dioxide (CO 2 ) is a major byproduct of coal combustion CO 2 is a greenhouse gas that contributes to global warming Other byproducts of coal combustion include: PM, NO X, SO X Carbon dioxide (CO 2 ) is a major byproduct of coal combustion CO 2 is a greenhouse gas that contributes to global warming Other byproducts of coal combustion include: PM, NO X, SO X Carbon Capture and Sequestration (CCS) Capturing the CO 2 that is emitted from coal combustion and storing it underground This allows for the continued use of a cheap power source while stopping its contribution to global warming In order to store the CO 2 underground it must be compressed Capturing the CO 2 that is emitted from coal combustion and storing it underground This allows for the continued use of a cheap power source while stopping its contribution to global warming In order to store the CO 2 underground it must be compressed Carbon Capture Technologies Instead of using air as an oxidizer pure O 2 is mixed with recycled flue gases (mostly CO 2 ) this generates a high concentration of CO 2 in the product gases. This high concentration of CO 2 in the product gases makes the compression that is necessary for CCS more financially viable. This research was supported in part by an appointment to the Research Participation Program for the U.S. Environmental Protection Agency, Office of Research and Development administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and EPA Acknowledgements Oxy Coal Oxy Coal technology could be implemented as a retrofits to existing coal fired power plants as well as newly built plants In order for existing boilers and pollution control technologies to be retrofitted for oxy coal combustion similar combustion temperatures must be reached. This is achieved by recycling the flue gases back to the burner. Innovative Furnace Reactor –35 kW th, 15 lb/hr coal –SCR, FF, wet FGD for emission controls Modifications needed for oxy-coal firing: –O 2 supply –Flue gas recirculation loop (ductwork) –Dryer for flue gas moisture removal –Blower –Pre-heater –Flue gas composition monitoring system –Recirculation flow control –ESP Flue gas volume reduced by 80% CO 2 Concentration increased from 15% in air-firing to 80% in oxygen- firing The drop tube is located in the EPA’s High Bay Building. Is used to simulate oxy coal combustion environments. The alumina tube is externally heated to 1400°C by three zones of resistance heaters. The coal is feed by an AccuRate single screw feeder, mounted above the furnace. We are feeding between ~1 g/min of coal and running at ~20% excess air conditions. The goal is to match realistic boiler conditions in a drop tube furnace. Examine ash behavior, trace element partitioning, speciation Process variables – O 2, CO 2, moisture, temperature Does oxy-coal combustion affect the partitioning of trace elements and their control through ESPs and FFs? Does oxy-coal combustion affect trace element speciation (e.g Hg)? In order to match the adiabatic flame temperature of an oxy coal flame with that of air-fired combustion, the overall oxygen mole fraction in the burner inlet should be ~28% or ~35% for wet and dry recycle, respectively, to compensate for the effects of the higher molar heat capacities of H 2 O and CO 2. Natural Gas Coal Oil HistoricProjected Pre-Combustion Capture Fuel is gasified or reformed into a syngas (CO 2 and H 2 ), the CO 2 is then removed from the syngas. If then burned in a gas and then steam turbine the system is called Integrated Gasification Combined Cycles (IGCC) Post-Combustion Capture CO 2 separated from flue gas using chemical solvents, sorbents and membranes. Oxy-fuel Combustion Coal Post Combustion CO 2 Separation ------------------- IGCC: Pre-combustion CO 2 removal -------------------- Post Oxy-fuel Combustion CO 2 Removal Evolution of Utility Air Pollution Control NOx Understand the effect of CO 2 environment on formation of pollutant species (metals, Hg, organics) Understand the requirements for further processing of gas effluent composed of CO 2 and pollutant species (SO 2, NO x, PM) before the CO 2 can be compressed, transported, and sequestered Operation of ESPs, SCR units, and acid gas scrubbers Control of HAPs (metals, Hg, HCl, organics, etc.) Understand the purity requirements of CO 2 stream to ensure safe long term GS Potential for trace levels of sulfuric and nitric acids and other organic impurities to be compressed and sequestered with the CO 2 Characteristics of the fly ash and volatile metals (Hg and Se) that may be compressed and sequestered with the CO 2 Project Objectives Develop oxy-fuel research capabilities Combustion & CPU Bench & laboratory scale Bench Convert drop tube furnace for one pass O2/CO2 1-3 g/min coal,1 cfm Transition from one-pass to recycle Design/build 1 cfm CPU Laboratory Convert IFR to oxy-gas and then oxy-coal (2011 cap eq) 5-10 lb/hr coal, 6-10 cfm Develop CRADA (Air Liquide) 10 cfm CPU Approach Coal & Primary Gas Secondary Gas Experimental Goals Burner Design Compression and Purification Research A compression and purification unit (CPU) will be designed and built for conducting research on treating CO 2 concentrated flue gas generated by IFR Includes flue gas pretreatment/conditioning, compressor, chiller and heat exchangers Will characterize trace flue gas components partitioning between sequestration, condensation, and emission streams Negotiating with Air Liquide for CPU testing through a CRADA