Research of the Formation of Nitrogen Oxides During the Burning of Ekibastuz Coal

In the experiment, the influence of the shift of the oxidant feed on the processes of formation of nitrogen oxides was studied. In order to do so, a vertical tubular furnace with electric heating was used. The flow of dust of Ekibastuz coal in all experiments was kept constant to 0.042 g/s, the grinding factor was 18% and the excess air ratio 1,2. The temperature in the furnace varied from 500 degrees C to 700 degrees C at an 11% oxygen concentration inside. As a result of the experiments, it is shown that by pyrolysis of coal dust from Ekibastuz coal at temperatures of 500-700 degrees C and the delay of time of air supply to the combustion zone by 0.1 s, under experimental conditions, we were able to reduce the concentration of nitrogen oxides by 3 times, including a 1.25 and 1.9 times reduction due to pyrolysis at temperatures ranging from 500 to 700 degrees C, in addition to a 2.7 and 1.9 times reduction owing to the delay of the air supply introduced. As a result of calculations and experiments, it was shown that the greatest reduction in NOx is achieved by supplying secondary air after the completion of the initial stage of gasification before ignition of volatile ones.