Local temperatures and gas concentrations were measured in a 17 MW top-fired pulverized coal furnace. A specially designed suction pyrometer was used for thermocouple temperature measurements as well as withdrawal of gas samples from the furnace. The gas sampling system was carefully tested to make sure that the sample gas was efficiently quenched. Gas samples were analysed for O2, CO, CO2, NO, NO2 and SO2. The effects of furnace load, primary:secondary air ratio and total excess air level were investigated. NO emission increased with the total excess air level, but was less sensitive to variations in load and in distribution of combustion air. These results are discussed in terms of NO formation mechanisms as well as burner and furnace characteristics. The experimental data provide good possibilities for scaling and modelling studies, in that they characterize a full-scale, single-burner pulverized coal system with a simple geometry.
- Nitrogen oxides
- Pulverized coal