Studies On The Impact Of Pulverized Coal Concentration Rate On The Combustion Characteristics Of Central Fuel Rich Swirl Burner

The Central-fuel-rich （CFR） swirl burner is a new combustion technology ofhigh efficiency, low NO_xemissions taking the advantage of pulverized coalconcentration, air classification technology. Due to the unique efficient and stablecombustion with low NO_x emission characteristics of the high concentration ofpulverized coal combustion, a lot of research have been done on the swirl burnerpulverized coal combustion technology at home and abroad, but most of which juststay in the theoretical studies or coal static combustion analysis, also little related tothe NO_Xrelease mechanism or thermal experiments, little part of the thermalexperiments are less related to the combustion and NO_Xemission characteristics ofthe swirl burner under the different pulverized coal concentration distribution in theprimary air. This article made some rearch on the impact of the pulverized coalconcentration rate on the combustion characteristics of the combustion region nearthe burner and the entire internal furnace, on a0.5MW hot-state test bed of the CFRswirl burner, the conclusions are as follows.This article firstly made a debugging on the0.5MW hot-state test bed of theCFR swirl burner, after the debugging and improvement, The system parametersmet the designed requirements, air leakage coefficient less than4%, the system hasa good sealing performance and a long and stable operation, also has a goodreproducibility of the test results, that provided a guarantee for a comprehensiveand detailed study on the combustion performance of the CFR swirl burner.The experimental study on the combustion region near the CFR swirl burnershow that, the pulverized coal concentration rate has a significant effect on flamestructure, temperature of inner flame, composition of flue gas and NO_x emissioncharacteristics, has a less effect on the burnout rate of C in the flame region. Withthe pulverized coal concentration rate increased, the temperature in the flame regiondecreased; the dispersion angle of pulverized coal flame decreased, the length offlame increased; the concentration of O₂in flue gas of inner flame decreased, theconcentration of CO increased; the concentration of NO_x and peak of concentrationboth decreased; the burnout rate of C in the flame region decreased. The experimental study on the CFR swirl burner furnace center region showthat, the pulverized coal concentration rate has some effect on the temperature inthe and the composition of flue gas, has a significant effect on the NO_x emission inthe flue gas at the exit of furnace, has a less effect on the burnout rate of C in theentire furnace. With the pulverized coal concentration rate increased, thetemperature in the center region increased, but the gas temperature become in thesame line at the exit of furnace; reducing atmosphere in the inner flame is greatlyenhanced, but the concentration of O₂and CO in flue gas become in the same lineat the exit of furnace; With the pulverized coal concentration rate increased from1to5, the concentration of NO_x dropped from1182mg/m³to861mg/m³in the fluegas at the exit of furnace, decreasing by27.15%; at the upper furnace, the burnoutrate of C decreased in the0≤Z≤2500mm region.