Modification Scheme Of 350MW Boiler With Low Nitrogen Burners And Related Performance Test Research

Huaneng Shangan Power Plant No. 1 and No. 2 boiler using the subcritical pressure and manufactured by the Canadian company B & w design, a reheat, natural circulation, double arch type single furnace chamber, "W" flame combustion, tail flue,balanced ventilation, solid state slag, all steel structure, full suspension structure, dew arrangement of coal-fired boiler. At present, under the full load condition, the emission concentration of NO_x is about 1000¹200mg/m3, and there is a big gap between the requirements of the environmental protection standard.In response to the issued by the government of Hebei province Hebei gas Lingban[2015]37 Document No., strict implementation of 50 mg / m3 of ultra low NO_x emission limit values, Huaneng Power Plant of 350 MW "W" flame boiler of low NO_x combustion retrofit project. The operation test of the boiler before reformation shows that the boiler operation condition is better, but the NO_x emission value is higher. Through the analysis and comparison of a variety of transformation scheme, demonstrates the burner, a secondary air distribution, overfire air, lack of steam wind four aspects from the burning system of the boiler transformation of rationality, and from the two aspects of environmental benefit and economic benefit for the transformation to evaluation,demonstrates the feasibility and economic transformation.In order to grasp the renovation of low NO_x combustion boiler operation economic and technical characteristics, determine the rules of boiler burning system, the best operation way and influence factors, No. 2 boiler renovation of low NO_x combustion the combustion adjustment test. Through analyzing the testing data, draw the following conclusions: 1 under the condition of SCR entrance NO_x concentration was less than the SCR entrance NO_x concentration 800mg/Nm3 target value burner transformation, so the best operation oxygen determination in favor of reducing the carbon content of fly ash,improve the efficiency of the boiler; 2 with air gradually burn off and the boiler efficiency to improve, but at the same time SCR entrance average NO_x concentration also increased 3; two with reduced air swirl intensity, reducing the carbon content of fly ash, the boiler efficiency increased, while the SCR entrance average NO_x concentration increases, the maximum is close to 630 mg/Nm3, therefore recommended two air swirl lever position is determined as 50 mm, in order to get a higher efficiency of the boiler; 4with the increase of two times the volume of combustion, the carbon content of fly ash is reduced, the boiler efficiency is improved, and the average NO_x concentration in SCR also increased entrance, maximum close to 720 mg/Nm3. Therefore, it is recommended that boiler operation will wind wheel position as 180 mm. In order to get the high boiler efficiency; 5. ABCD four sets of grinding coal machine operation, the boiler fly ash carbon content is low, boiler operation efficiency is higher, but SCR inlet NO_x concentration also than three sets of grinding coal machine run more close to 800mg/Nm3.After the renovation of low NO_x combustion, boiler running well, the reduction of NO_x emissions and boiler efficiency index of outstanding, will be de NO_x inlet concentration of NO_x emission decreased to about 800 mg, through denitrification system,the chimney inlet NO_x concentration reached 50 mg / m3. However, compared with the former, the high temperature corrosion of the water wall of the furnace under the reformed boiler is heavier, the wall thickness of the wall of the water wall is 6.4mm, and the remaining wall thickness is less than 4.5mm. Through in-depth analysis of high temperature corrosion of that high temperature corrosion is the main reason for reducing atmosphere produced H₂S, the initial solution for the replacement of infiltration aluminum, sprayed with high-temperature, wind powder tune flat, and through the test run prevent high temperature corrosion of optimal combustion adjustment programs.