Study On Optimization Of Atomizing Nozzle For SNCR In CFBs

China is a big country of coal production and consumption, and the burning of coal will produce large amounts of NOx emissions, of which thermal power plant is an important source of NOx emissions, so it is necessary to carry out denitrification transformation of boiler in thermal power plant. This paper carries on the transformation to the boiler through the selective non catalytic reduction method, and the performance of reducing agent spray gun is an important factor influencing the denitrification efficiency, this paper mainly research on optimization of the reducing agent spray gun for denitration. The research mainly from three aspects, the experimental study, industrial experimental study and numerical simulation.Firstly, by establishing a cold state test bench, we did laboratory research for the flow characteristics, atomized particle size distribution and exit velocity distribution of conical spray gun, fan spray gun and the efferevescent atomization spray gun, and we got the data above of different pressure.Secondly, a power plant SNCR denitration test was carried out in CFBs, the study show, the 100 kg/h fan spray gun had a denitration efficiency which was 7.7%~10% higher than 60 kg/h fan spray gun. The 135 kg/h conical spray gun had a denitration efficiency which was 4.9%~9.3% higher than 80kg/h conical spray gun. The 80 kg/h fan spray gun had a denitration efficiency which was 8.8%~10.9% higher than 80kg/h conical spray gun. At last, engineering application chose fan spray gun for its denitration efficiency was higher with the same NSR. Combined with laboratory test results, the denitration efficiency of fan spray gun was better because fan spray gun had fast exit velocity and suitable particle size.Finally, SNCR denitration numerical were simulated in the cyclone separator, calculation results show : when the reaction temperature is 950 ℃, ammonia nitrogen ratio was 2, atomized particle size was 200~300μm, the injection speed was 40 m/s and the number of gun was 8, it’s was conducive to improve the denitration efficiency. Under the same conditions, simulation calculation of denitration efficiency was 14.4%~18.2% higher than filed test, this is because the calculation was carried out in an ideal situation, and filed test result was affected by boiler loads, temperature and so many other factors.