Study On Coal Combustion And NO Emission In Different Atmosphere

Coal as the main energy of the current China, the pollution is obvious, how use of coal efficient and clean is an urgent need to study. as a new generation of coal combustion technology, O₂/CO₂ combustion technology has broad application prospects,but the mechanism of coal combustion in O₂/CO₂ atmosphere is not entirely clear; on the other hand, as a new combustion technology, coal combustion under the O₂/CO₂ atmosphere or the air which one more energy-efficient remains controversial;at the same time coal at O₂/CO₂ atmosphere appeared unstable combustion phenomenon,temperature and particle size have a significant impact on coal combustion characteristics.In this paper,the conventional pulverized and superfine pulverized used in this experiments to study the process of coal combustion and particle size affect the atmosphere of the combustion process, and to explore different sizes in different atmosphere interaction on pulverized coal combustion to improve combustion characteristics and reducing NO generated effects.Through tube furnace experiments, research 16?m and 82?m pulverized coal and pulverized coal combustion characteristics of both mixed in air and O₂/CO₂ atmosphere.The results show that: in the coal combustion process, NO concentration was increased first peak and then gradually decline into the process of zero;high temperature of furnace to produce SO₂,so SO₂ generation was little,high temperature conducive to volatile nitrogen oxidation of NO; particle size have a greater impact on NO production,pulverized mass fraction of 16?m larger peak CO greater,but smaller peak effect on NO; the greater the mass fraction of superfine pulverized coal,NO reduce is more obvious.under O₂/CO₂ atmosphere pulverized coal combustion CO generation amount higher than the air atmosphere,NO peak under O₂/CO₂ atmosphere generated by the combustion of pulverized coal is much lower than the air atmosphere;and at higher furnace temperature,the cumulative amount of NO higher than lower temperatures under O₂/CO₂ atmosphere,temperature has greater impact on the NO production.By steady state simulation,pulverized coal combustion under different conditionswere simulated under different atmospheres, analysis of pulverized coal in air and O₂/CO₂ combustion atmosphere different results show that: the furnace temperature increases could reduce NO emissions,the furnace temperature higher,the NO emission at the outlet lower;small particle size of pulverized coal can effectively reduce NO emissions;the oxygen-rich atmosphere could effectively inhibit the production of NO,O₂ concentration increase has little effect on reducing NO emissions under oxygen-rich atmosphere;the excess air coefficient increasing is reduced NO emissions.Through unsteady simulation of coal combustion results are as follows:16?m pulverized effectively improve the performance of pulverized coal combustion,coal ignition time and location in advance;with increase 16?m pulverized coal mass fraction,pulverized coal combustion performance have a substantial increase,at the same time,NO concentration peak increases, the small size pulverized coal increasing makes volatile nitrogen and char nitrogen more easy to precipitate and oxidation,NO concentration at the exit decreased.