Factors Affecting the Effect of Low-Nitrogen Combustion Transformation
Factors Affecting the Effect of Low-Nitrogen Combustion Transformation
1、 Research and analysis on the influence of superheated and reheated steam temperature.
After the transformation of the low nitrogen burner, the nozzle of the low nitrogen burner is about 1m lower than the original one. In the process of analysis, based on the bottom burner, the height of the remaining burners moves downward, resulting in the simultaneous drop of the flame center and the reduction of the heat absorbed by all heating surfaces, thus reducing the outlet smoke temperature. The revamped low nitrogen burner has a great impact on the reheat steam temperature. Due to the slow coordination of boiler units and the uncoordinated pressure tracking and adjustment, it is easy to cause the problem of excessive adjustment, and also lead to the instability of steam temperature.
In addition, due to the low oxygen combustion during the primary and secondary air ratio, the steam temperature adjustment will be limited to a certain extent, the entire adjustment time cannot be shortened, and the unit operation efficiency cannot be improved. In order to ensure that the outlet temperature is within the standard range, the upper powder manufacturing system can be used at the low load stage, and the height of the nozzle can be appropriately increased. However, this adjustment can make the low nitrogen steam enter the standard range, which becomes an important problem in the transformation of the low nitrogen burner.
During the transformation process, the nozzle of the burnout air can be adjusted appropriately. If the nozzle of the burnout air is adjusted to swing upward, the temperature of the reheated steam will be in a rising state. If the nozzle of the burnout air is adjusted to swing downward, the temperature of the reheated steam will be reduced until it is within the standard range. Therefore, Through this principle, the low nitrogen burner can be properly adjusted during boiler operation.
2、 The boiler coking and fire extinguishing are caused by the blending of coal into the boiler.
Slag and high temperature corrosion are the problems that have always existed in coal-fired boilers in power stations, and their severity even affects the safe operation of boilers. With the application of low NOX combustion technology, deoxidization atmosphere is formed in the main combustion zone due to lack of oxygen, which reduces the ash melting point and causes slag and high-temperature corrosion; At the same time, the staged combustion in the furnace leads to flame extension, coke combustion difficulty, and heating surface slag at the furnace outlet. The melting point temperature of coal ash affects the performance of boiler slag. For boilers burning low ash melting point coal, most of the low nitrogen burners will have slagging problems after transformation, even affecting the safe operation of the boiler.
3、 Boiler fire extinguishing is caused by boiler design.
The horizontal tangential angle of the boiler burner at the initial stage of design can be adjusted. According to some test results of the boiler, the boiler layer A after the low nitrogen transformation will have a reverse tangential effect, resulting in the turbulence of the rotating air flow in the boiler and the abnormal change of the wind speed. The stability of the boiler during combustion is not as good as before, resulting in flameout in the bore. The burner reconstruction project is unreasonable, and the design error of the reverse tangent angle of the combustion separator is too large; The original imaginary circle was destroyed in the reconstruction design, which was specifically manifested by the large tangential edge of the secondary air. Due to the change of horizontal and vertical bluff bodies during the transformation process, the rotating power of secondary air is insufficient to maintain the stability of domestic flame, and the anti-interference ability is weak, which is easy to cause flame jumping and wall sticking.