1. Material Due to the relatively high working temperature of the denitration spray gun (the flue gas temperature is 850 ℃-1100 ℃), and the flue gas flow rate is also fast, a large amount of dust is entrained in the flue gas, and the wear of the spray gun is also very serious. Therefore, the spray gun needs: high temperature resistance, wear resistance and corrosion resistance. The key parts of the spray gun, such as the spray gun rod, are made of inconel600, which can maintain high strength and corrosion resistance under the environment of no higher than 1200 ℃. The nozzle is made of Hastelloy C-276, which can maintain high strength and Corrosion resistance and high wear resistance ensure a constant balance of the ammonia spray area.
2. The mixing uniformity of the spray and the flue gas The spray angle of the denitrification spray gun ranges from 10°-150°. The spray gun with a small angle has strong penetrating ability, and the spray gun with a large angle covers a large area. The length of the spray gun and the spray point extending into the furnace Depth also varies. A variety of spray guns with different angles and positions are used to achieve the best design through CFD flow field simulation analysis combined with on-site measurement, and can achieve high denitrification efficiency.
3. Adjustment ability The denitration spray gun has telescopic adjustment ability. When there is a small difference between the on-site working conditions and the design, the position of the spray gun can be partially adjusted to ensure the denitration efficiency. At the same time, if the spray gun is not used for a period, it can be withdrawn from the furnace to prolong the service life of the spray gun.
4. Atomized particle size The atomized particles of the denitration spray gun are not like flue gas cooling, the finer the better, but the particles should be moderate. If the particles are too fine, the penetration will be too poor and the denitration efficiency will be reduced. If the particles are too coarse, the overall surface area of the particles will be too small, which will also reduce the denitration efficiency, and if the particles are too large, due to the fast flow rate of the flue gas, the spray particles will not be completely gasified in a short time, and sometimes droplets will be produced, resulting in Furnace burst. According to the specific project, the design selects the best atomized particle size.
5. Position determination The position of the spray gun mainly considers the gas temperature inside the boiler. If urea solution is used, try to set the position within the temperature range of 950±50°C. For ammonia solution, try to set it within the range of 900±50°C to avoid flames. place. Generally, a reaction time of more than 0.5 seconds must be guaranteed, and the mixing degree must be good. Whether the location of the spray gun is suitable or not directly determines the level of denitration efficiency. The choice of gun location is the most critical part of the whole system. The spray gun should be installed with a slight downward slope and must be extended into the furnace for a safe distance.