The Impact of Low Nitrogen Burner Renovation on Boiler Operation
The Impact of Low Nitrogen Burner Renovation on Boiler Operation
Under the requirements of environmental protection policies, industry now attaches great importance to energy-saving and emission reduction measures. Low nitrogen combustion technology has certain advantages in environmental protection, but at the same time, it also has a certain impact on the operation of boilers. Therefore, it is necessary to further strengthen the measures to deal with problems arising from new environmental protection technologies, and strive for the maximum environmental protection mechanism for sustainable development of industry. This article discusses relevant content and has certain practical significance.
1. Analysis of the connotation of the burner
Burners are the main combustion equipment of boilers in fuel power plants. The furnace is installed on the four corners or walls of the boiler furnace. The burner sprays various fuels and combustion required air into the furnace in a certain way, allowing the fuel and air to fully mix in the furnace, quickly ignite under a certain airflow structure, and maintain stable combustion. A burner is a highly automated electromechanical equipment that mainly includes air supply, ignition, monitoring, fuel, and electrical control systems. According to the type of fuel, burners can be divided into coal powder burners, gas burners, and fuel burners. The burner adopts primary and secondary wind directions to inject coal powder fuel into the furnace. When the mixed fuel is mixed with air, a special airflow structure is formed, which makes the fuel stable and fully burned. Using secondary air to rotate the jet, the rotating jet is combined with the surrounding medium to enhance the ignition characteristics of the coal powder airflow.
2. Analysis of the Impact of Low Nitrogen Burner Renovation on Boilers
(1) The impact of combustion stability is reflected in many aspects of boiler stability, the most important of which is in temperature stability and stability during operation. The low nitrogen burner is equipped with a concentration dilution combination at the primary jet port, utilizing technologies such as thermal reflux relay combustion. During the combustion process, it is designed based on the principle of asymmetry between heat and power. The coal powder at the pyrolysis jet port is connected to the composite jet vortex at the center of the boiler, and the high reflux rate of the thermal reflux carbon powder prolongs the residence time and increases the heat generated by combustion in the vortex. The low nitrogen transformation of the boiler also controls the amount of oxygen, During the combustion process, oxygen needs to meet the combustion conditions to generate heat. As the number of oxygen is controlled, the generation of heat is also suppressed, which affects the operation of the boiler. These two operating modes have an impact on the stable operation of the boiler.
(2) The impact of the internal environment of the boiler on the low nitrogen burner nozzle is smaller than that of traditional burners, so the flame generated by the fuel also moves accordingly. The reduction of combustion area will reduce the boiler's temperature reception, and at the same time, the pressure state generated inside the boiler will also change, leading to disharmony. The modification of low nitrogen burner equipment has changed the various components of the boiler and resulted in different operating conditions. The modification of low nitrogen burners has to some extent affected the oxygen content inside the boiler, usually with the maximum and minimum operating oxygen levels. The adjustment of units cannot keep up with the adjustment of oxygen levels, resulting in negative oxygen. The changes in oxygen levels and combustion levels change the pressure inside and outside the boiler, altering the internal environment. Relevant personnel need to adjust the oxygen level and directly carry out air supply operations.
(3) The reheating temperature of the boiler is affected, and the elevation of the original burner is reduced after the modification of the low nitrogen burner, which has a significant impact on the reheating temperature. After the burner renovation, the coordination of the unit is slow, and the boiler pressure tracking adjustment cannot keep up, which is prone to overshoot and temperature changes. The modified low nitrogen burner has a set of oscillating nozzles. When the nozzle swings upwards, the temperature of the steam will increase, and when the nozzle swings downwards, the temperature will decrease. However, because there is only one set of oscillating nozzles, the temperature adjustment speed is limited. The adjustment time is too long, and the air ratio is controlled by low oxygen conditions, which affects the efficiency of the machine. In order to ensure that the outlet temperature of the boiler is within the low load range, a powder manufacturing system must be used, which will cause the heating surface temperature to be too high and difficult to exceed. At the same time, the outlet temperature should be controlled within a certain range to affect the normal operation of the boiler.
(4) The impact on furnace coking: During the use of low nitrogen burners, although coking may occur during operation, especially when starting the lower level pulverization system, it will affect furnace coking. However, during operation, there is still coking at the burner nozzle, especially when starting the lower level pulverization system, which will significantly affect negative pressure, indicating that the combustion zone is not in good condition because the main combustion zone undergoes anaerobic combustion, Therefore, there will be cold wall coking near the burner, especially when starting the lower level pulverization system, which will have a significant impact on the combustion status of the boiler, indicating that the combustion zone is not in good condition because the main combustion zone is lacking oxygen and oxygen. Therefore, cold wall coking will occur near the burner, which will have an impact on furnace coking.
(5) The low nitrogen burner not only reduces the NO yield, but also increases the combustibility of the slag. Low nitrogen combustion technology adopts low-temperature and low oxygen conditions for combustion. The more the temperature in the combustion zone decreases, the greater the impact of coal powder ignition. The oxygen content in the combustion zone decreases, the combustion ability of coal powder decreases, the combustion process also increases, the amount of combustible materials in the slag increases, the nozzle area of the burner changes, the mixing air is delayed, and the coal powder airflow in the boiler increases.
Summary: The quality of a boiler during operation will be influenced by many factors. Although the transformation of a low nitrogen burner has a certain impact on the operation of the boiler, in order to maintain energy cleanliness and reduce environmental hazards, it is still necessary to optimize the low nitrogen burner in combination with reality, standardize the transformation process of the low nitrogen burner, and improve the reliability of boiler operation.