Experimental study on ultra‐low NOx emissions from pulverized coal preheating combustion

Abstract

AbstractRealizing ultra‐low NOx emissions during coal combustion is currently a development trend and technical bottleneck of coal combustion technology. To further exploit the low‐nitrogen potentialities in preheating combustion technology, the preheating characteristics, combustion characteristics, and NOx emission characteristics of pulverized coal, after changing operating parameters such as the air equivalence ratio of circulating fluidized bed, preheating temperature, combustion temperature, and air equivalence ratio in the reduction zone, are explored. The experimental results show that changing the operating parameters has a great impact on the composition of high‐temperature coal gas, the particle size, apparent morphology, and specific surface area of the high‐temperature preheated char after preheating. Properly adjusting the operating parameters can effectively reduce NOx emissions. Based on the explored principle, experiments were designed, and the goal of reducing the initial NOx emissions from coal combustion to less than 50 mg/m3 (the average emissions were 46 mg/m3 [@ 6% O2]) was successfully achieved. The research of this paper provides the most basic experimental guidance and theoretical support for achieving ultra‐low NOx emissions during the engineering pulverized coal combustion.