Three-dimensional model studies of a pulverized coal corner-fired utility furnace and comparisons with local furnace data and boiler exhaust NO(x)

Due to United States utility deregulation, competition among utilities has increased. Because fuel cost represents the single largest Operation and Maintenance (O&M) expense, burning the least-cost coal for reducing O&M cost becomes a strategy in today's competitive arena. The least-cost coal normally indicates low rank coal. Low rank means a coal with low ash fusion temperature, high slag reflectivity, low heating value, high sulfur content and high ash content. Firing low rank coal increases the Furnace Exit Gas Temperature (FEGT) and increases slag/clinker problems in the upper furnace. As soon as large clinkers fall from the upper furnace, tube leakage in the lower furnace occurs and results in unit forced outage and loss of power generation.; To reduce slag/clinker problems in the upper furnace requires reducing the FEGT. In this research work, the objective is to investigate how to reduce the FEGT by changing boiler operating variables and/or adding wall soot blowers and/or lowering burner elevations. Evaluation of these approaches for reducing the FEGT requires experimental furnace testing and computational furnace modeling.; Local gas temperatures, wall heat flux and stack {dollar}rm NOsb{lcub}x{rcub}{dollar} were measured during furnace tests. These measurements are used for tuning and calibrating the furnace model. The experimental facility is the Fayette Power Project unit 2 boiler of the Lower Colorado River Authority, a Combustion Engineering corner-fired pulverized-coal boiler with a capacity of 606 MWe. The furnace model is based on the PCGC-3 code developed by Brigham Young University.