(199c) Pilot-Scale Investigation of Heat Flux, Radiation and CO Distribution from an Oxy-Coal Flame

The Carbon-Capture Multidisciplinary Simulation Center (CCMSC) at the University of Utah is a 5-year US$16M research program funded by the U.S. Department of Energy through the Predictive Science Academic Alliance Program. The objective of the center is to demonstrate that exascale computing, coupled with formalized Verification & Validation with Uncertainty Quantification (V&V/UQ), can be used to more rapidly deploy new technologies for achieving low cost, low emission, coal-fired power generation. We are using a hierarchical validation approach to obtain simultaneous consistency between a set of selected experiments and simulations at several different scales (0.1 KWth, 100 KWth, 1.5 MWth and 15 MWth) that embody the key physics components (large eddy simulations, multiphase flow, particle combustion and radiation) to predict performance in an industrial-scale facility, which for this project is a 350MWe oxy-fired boiler.

As a portion of the first year activities of this program, oxy-combustion with flue gas recycle (FGR) experiments were performed in the University of Utah’s 1.5 MWth pulverized coal furnace (L1500). The furnace was configured with heat flux probes, radiometers and additional temperature measurements. Throughout a week period, operating conditions in the furnace were replicated each day for two burner swirl conditions, thus providing multiple data sets for uncertainty quantification of the data and for validation/uncertainty quantification (V/UQ) of the Large Eddy Simulation (LES) tool that will be used in this program.

For these tests the furnace was fitted with 8 water cooled tube bundles in the first four sections of the reactor.  The temperature of the water in and out and the temperature of tube surface were measured, along with the cooling water flow rate.  A set of three radiometers were installed in the near flame region.  These devices were configured to differentiate between radiation from the hot refractory walls and from the coal flame.  From these data the heat flux could be determined by multiple methods at four axial locations relative to the flame.  Close scrutiny of the heat flux and radiometer data indicate that these techniques are sensitive enough to resolve changes in burner operating conditions.  However the magnitude of the heat transfer is not constant throughout a test period due to accumulation of ash on heat transfer and background surfaces.

Measurements of gas composition, including O₂ and CO were performed as part of these measurements.  Extractive samples of gas were collected from three radial positions at seven axial location downstream of the flame.  These data compare CO profiles in the furnace for swirled vs. non-swirled flames and will be used to validate char oxidation kinetics and in the model.