1. U.S. Environmental Protection Agency Office of Research and Development Research on Potential Environmental Impacts of Oxy-fuel Combustion at EPA Chun Wai Lee 1, Christopher K. Winterrowd 2, Myrrha Andersen 3, William Linak 1 1 National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 2 ARCADIS U.S. Inc., 3 Department of Mechanical and Aerospace Engineering, North Carolina State University Footnotes Go Here Footnotes Go Here Footnotes Go Here Footnotes Go Here 1U.S Introduction Oxyfuel combustion is a promising technology designed to facilitate carbon capture and sequestration. In oxyfuel combustion, coal is combusted not with ambient air (containing ~79% nitrogen and 21% oxygen) but with an oxygen enriched mixture to generate a concentrated CO 2 exhaust for further processing, compression, and sequestration. The same pollutant species such as sulfur, fuel nitrogen, ash, metals, Hg, potential organic hazardous air pollutants (HAPs), etc. are present in the coal as in air firing, but there is very little information on how these species will behave and be transformed under the unique conditions of oxyfuel combustion and also the effects of this unique environment on the performance of existing pollution control devices. Further, the combustion flue gas is processed in such a way that pollutants which would normally escape controls and be released as air emissions now may be shifted to solid and liquid waste streams, or may be compressed and sequestered with the CO 2 and affect its chemistry during transport and in geological storage. The application of this emerging technology might result in changes in process chemistry of coal combustion that could lead to the formation of chemical species that pose different health risks relative to those currently observed. Research to evaluate the potential environmental impacts of oxy-fuel combustion has been initiated at EPA. The effect of oxy-coal combustion on the formation and behavior of pollutants and the effect of oxy-fuel combustion environment on the performance of existing pollution control devices will be investigated. Potential environmental issues pertaining to the operation of CPUs and how pollutants are partitioned between various effluents will also be studied through an existing Cooperative Research and Development Agreement (CRADA) with Air Liquide. Research Objectives Evaluate the changes in emissions during oxyfuel combustion Identify the associated effects of changes in emissions on the operation of pollution control equipment Examine how pollutant species partition to the effluent streams of CPUs Approach Integrating a laboratory scale oxyfuel combustion system with a CO 2 CPU unit To better simulate actual boiler conditions in the field and evaluate emissions and control under oxy-coal combustion A bench scale drop tube furnace is converted to operate under simulated oxy- coal conditions To examine how oxy-coal operation affects pollutant formation, especially fine particle formation and trace metal behavior An existing laboratory-scale combustor has been modified for performing oxy- natural gas and oxy-coal experiments by adding O 2 operation and flue gas recycling capabilities. The combustor has previously been used in research studies to characterize air pollutants similar to those produced in utility boilers.. The Facility Modified for Oxyfuel Combustion Research A refractory lined vertical furnace (4 m in length, 0.2 m I.D.) with evenly spaced sampling ports for gas and aerosol sampling/temperature measurements. 35 kW nominal firing rate, 0.8 m 3 /min total flue gas flow for air firing, 0.16 m 3 /min for oxy-coal firing New burner, flue gas moisture condenser, flue gas reheater, recycle blower, and flow controls New supervisory control and data acquisition (SCADA) system for monitoring and controlling all process streams New ESP to remove PM prior to flue gas recycling Existing air pollution control equipment includes baghouse, wet FGD, and SCR CEMs for O 2, CO, CO 2, NO, NOx, SO 2 and PM CPU design completed, procurement of equipment in progress Research Facility Ongoing Work Chun Wai Lee lee.chun-wai@epa.gov l 919-541-7663 PHOTO PHOOPHOTO Furnace top section (coal feeder, burner, oxygen supply, recycled flue gas, flame monitoring and safety system) Furnace bottom section (temperature and pressure monitoring, heat exchanger, ductwork routed to ESP PHOTO Modification of the combustion facility for oxy-natural gas and oxy-coal firing completed recently System startup, shakedown, and trouble shooting Examine methods of oxygen addition on coal flame stability Evaluate ESP PM control Initial experiments to evaluate the effect of oxyfuel combustion environment on pollutant formation, e.g., carbon burnt-out, PM particle size distribution, VOC characteristics Major focus on trace HAPs such as heavy metals, fine PM, VOCs, and soot Diagram of the Facility 3 Oxygen supply and control unitFlue gas recycling (moisture condenser, reheater, blower, flow monitoring and control) Flue gas sampling duct and continuous monitoring (O 2, CO 2, CO, SO 2, NO x, H 2 O, PM,) Supervisory control and data acquisition (SCADA) system Disclaimer The views expressed in this poster are those of individual authors and do not necessary reflect the views and policies of the U.S. Environmental Protection Agency Acknowledgment The oxyfuel combustion research is a collaboration with Air Liquide through a Cooperative Research and Development Agreement