(419b) SO3 Emissions From a Tangentially-Fired Pilot Scale Boiler Operating Under Oxy-Combustion Conditions

Oxy-combustion of pulverized coal (PC) is a promising near-term technology for CO2 capture and sequestration from utility boilers. With support from DOE, ALSTOM Power is executing an oxy-combustion test program utilizing the 15 MWth tangentially-fired Boiler Simulation Facility (BSF), in Windsor, CT, USA. The objectives of this program are to design and develop an innovative oxyfuel system for T-fired boiler units, evaluate the performance of the oxyfuel T-fired boiler system in pilot-scale tests, and address technical gaps for commercial design of oxyfuel systems for T-fired utility boilers. In evaluating the oxyfuel system, detailed measurements from the pilot-scale tests will aid in understanding furnace heat absorption, ash deposition, material corrosion, combustion, and pollutant formation and destruction in the oxyfuel T-fired process. This presentation will focus on the effort to understand the fate of SO3 under oxy-combustion conditions. Measurements were taken at various locations on the BSF during air-fired baseline condition and during two different oxy-combustion conditions to quantify the impact of flue gas recycle (FGR) on SO3 formation. Two different FGR conditions were evaluated for oxy-combustion operation: one with high SO2 in the FGR and one with very low SO2 in the FGR. Measurements of SO3 concentration were obtained by applying a controlled condensation method with flue gas sample extraction via an inertial separation probe. Insights into the formation and fate of SO3 under oxy-combustion conditions will be discussed.