Writer： admin Time：2021-06-10 00:00 Browse：℃
Fuel gas burner is natural gas, when we use gas burner requires attention to what? Explore the problem of low nitrogen burner operation that appears with the view adjustment
Adjusting for low nitrogen burners problem occurred in operation
Energy conservation is a long-term development strategy for the sustainable development of our country, it is my country's basic national policy. Currently, the goal to achieve energy saving facing a very serious situation. Nitrogen oxides are one of the air pollutants emission power plant boiler. Run a large number of boiler emissions of nitrogen oxides, boiler after use low nitrogen burners transformation are still many problems to be solved in the operation. Let's explore Adjustment low nitrogen burners appear during operation. 1, fully understand the mechanism of reducing NOx generated mainly two: the primary combustion zone to reduce combustion temperatures and low oxygen; fully grasp the principle of low nitrogen burners, regardless of the level of load, can be adjusted significantly. The degree of opening of the secondary air shutter opening large load appropriately bottom (AA level), such as when the shutter opening 180MW AA layer is large from 55% to 65%, while the powder in the holder lower portion of the primary combustion zone is reduced as far as possible complete combustion slag containing carbon, while the big open top of the secondary air damper primary combustion zone (OFA layer) and four baffle overfire air, down the center of the flame reduce thermal NOx generation. 2, the air volume provided by the milling system hot secondary air, the furnace design to reduce the blowing wind causes serious shortage milling system, controlled by the manufacturer to design requirements about 3.0 when the amount of oxygen to the coal pulverizing system to reduce average speed 100rpm. At this time, the second air pressure adjustment, change the milling system operation method has become the only way to solve. Using temporary furnace output characteristics inverted powder powder, to maintain a high system load multi-unit conversion powder at two different load units, down to the low dust load units, thus reducing milling systems on and off, to reduce the number of sets Pulverized System to maintain a high air volume milling system, effectively reducing the power consumption rate. 3. To recognize the NOx reduction will inevitably lead to reduced boiler efficiency, the best to find a balance point, we can not pursue low NOx. Daily adjustment, as long as the NOx is not too high to meet environmental requirements, can increase the secondary air to improve combustion efficiency. 4, from the viewpoint of NOx control speaking, staged combustion, intake air classification is good. When blending in practice, the sealing lip with low-grade coal bunker B power corresponding to the upper layer to the powder, A long flame coal bunker with a powder corresponding to the lower layer, the effect of steady combustion play. Because most lower secondary air baffle running in full or opening, much larger than the other layers, the bottom of the burner is generally not the lack of wind, with the wind at the time, suitable for inverted pagoda with the wind, on the one hand help to raise flame center, so that the steam temperature increase at low load, on the other hand also in line with the wind NOx reduction strategy, i.e., the primary combustion zone hypoxia combustion. 5, when the condition is satisfied, the lower burner should be used, without the influence of the load belt, the upper part of the burner outage, the lower layer to the powder to increase the speed, the lower the air volume slightly larger because this is also advantageous coal burnout and improve combustion efficiency. Down and because the center of the flame, the furnace temperature was lowered center, help reduce the formation of NOx; to extend the combustion zone between the reduction zone overfire air, and help re portion of NOx is reduced. 6, a low nitrogen burner primary combustion zone hypoxia combustion, combustion in order to ensure safety, the value of not less than 3% oxygen; when a substantial increase in speed to the powder layer should be properly corresponding to large secondary air baffle opening in order to avoid excessive primary combustion zone pulverized coal, a serious lack of wind caused the fire, deflagration. Only when the speed stable powder machine, only gradually turn down the corresponding secondary air baffle to reduce NOx. 7, can be suitably adjusted Classifier tailgate, fine tune moderate fineness of pulverized coal, although the milling system output decreased, but the unburned carbon is reduced, the loss is reduced. Can first be adjusted to observe a fine coal fineness pulverizing system, unburned carbon is increased by 1%, standard coal increased from about 1.0 ~ 1.3g / KWH of view, the means needed to reduce ash or combustible it is worth it. 8, an appropriate increase in secondary pressure, ensure proper secondary wind speed and improve the penetration of secondary air to facilitate combustion. After the increase overfire air, the second overall pressure drop. According to the original design, more than 80% load, the second bellows differential pressure should ensure 1.0KPa, secondary wind speed in order to make a reasonable range, but the transformation is far less than the design pressure 0.8KPa highest value. It can be taken to increase when the NOx content meet the requirements of the total air volume, turn down the secondary air baffle, turn down the method of adjusting the overfire air. 9, a perimeter wind serve to strengthen the rigidity of the wind, to prevent the gas flow deflection preventing wall-flame coal and the pulverized coal is separated from the gas stream; pulverized coal after the ignition, a small amount of secondary air can be supplied in time, in favor the development of the combustion process. For low nitrogen burners, the pulverized coal concentration, easy to form the pulverized coal combustion hypoxic environment is conducive to reducing the generation of NOx, and the amount of perimeter air after the transformation has increased compared with the original design, it should be opening perimeter air with powder machine speed moderate to open big. 10, concerned about the furnace, milling system leakage. Cold air into the furnace will increase the exhaust gas temperature, reduce boiler efficiency, detrimental. Furnace slag hopper bottom seal should be sealed to see the tap hole, fire-hole look at the furnace should be inspected regularly to ensure close. Leak milling system to promptly contact process, wood splitter comprising a lid, cover, etc. to the coal should be sealed well. 11, low wind load should be increased moderately combustion zone, to facilitate burn pulverized coal, but will reduce excessive wind furnace temperature, the furnace load is low due to the low temperature level, if the secondary air to penetrate easily cause too strong fire, affect safety; moderately high load can reduce the amount of combustion air zone, in order to improve the economy, but the air volume is too small, the air preheater heat exchanger decreases, will cause the exhaust gas temperature is high, the loss increases.
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