Development and Demonstration of Large Scale Industrial Low Emission Radiation Stabilized Burners

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and 70 ppm. Two other data points had C O emissions between 10 and 30 ppm. All other points had C O emissions less than 10 ppm. Because C O emissions in nearly all cases are well below our current targets, no test data are shown. Tabulated data from the complete test program, and a more detailed evaluation of the results are presented in Reference 2. 4. PERFORMANCE MODELING Results of test program previously described were modeled after the completion of testing to achieve two objectives. The first objective was to better understand the parameters that control N O x emissions from the RSB. The second objective was to demonstrate the accuracy and the limitations of the models so that the models can be used reliably in the future to model R S B performance in other boiler geometries. Computational Fluid Dynamics (CFD) modeling was conducted by B & W . In a parallel effort, Alzeta used in-house codes to separately complete thermal modeling and emissions modeling. The modeling tools used in this project are described below. The software used by B&W for burner and furnace models was the B&W proprietary COmbustion MOdel (COMO). This code is a general purpose flow and combustion code capable of axisymetric, cylindrical, two-dimensional, and three dimensional geometries. The flow portion of the code is based on the incompressible Navier-Stokes equations, turbulence is modeled using the k-e turbulence model with the law-of-the-wall functions at the boundary layers. Gas phase chemistry is described in an Eulerian reference. Particles can be described in either Eulerian or Lagrangian coordinates. Alzeta used a plug-flow model to predict the thermodynamics of the boiler firebox. The firebox was divided into cylindrical slices along the length of the firebox, and energy and mass balances were maintained for each cylindrical slice of the entire volume. The energy balance accounted for both gas phase and burner radiation to the tube walls; convective heat transfer to the tube walls was included also. The combination of the gas phase emittance and the total energy balance required an iterative procedure to determine the temperature of each cell. This simple 5