Pilot Scale Process Evaluation of Reburning for In-Furnace NOx Reduction

摘要

The report gives results of coal and natural gas reburning application tests to a pilot scale 3.0 MWt furnace to provide the scaling information required for commercial application of reburning to pulverized-coal-fired boilers. Initial parametric studies had been conducted in a 23 kWt bench scale reactor to quantify the impact of fuel and process parameters on reburning effectiveness. The results of this investigation confirm the potential of the reburning process for significant NOx reduction. Process effectiveness depends strongly upon the NOx and O2 concentrations at the end of the main heat release zone; the stoichiometry, temperature, and residence time in the fuel-rich reburning zone; the fuel composition and mixing of the reburning fuel jet; and the temperature of the final burnout zone. The investigation also identifies and defines the optimum design criteria for reburning application and demonstrates that it is possible to scale up the process without losing effectiveness.