Influence Of Low NOx Burner Transformation On Boiler Operation


Influence Of Low NOx Burner Transformation On Boiler Operation

Under the requirements of environmental protection policies, the industry now also attaches great importance to energy conservation and emission reduction measures. Low nitrogen combustion technology has certain advantages in environmental protection, but it also has a certain impact on the operation of boilers. Therefore, it is necessary to further strengthen the measures to deal with the problems of new environmental protection technology and strive for the maximum environmental protection mechanism for the sustainable development of the industry. This paper discusses the relevant content, which has a certain practical significance.

Influence Of Low NOx Burner Transformation On Boiler Operation
1. Connotation analysis of burner
Burners are the main combustion equipment of boilers in fuel power plants. The stove is installed on the four corners or walls of the boiler furnace. The burner injects various fuels and the air required for combustion into the furnace in a certain way so that the fuel and air are fully mixed in the furnace, and ignite rapidly under a certain airflow structure to maintain stable combustion. Burner is a kind of electromechanical equipment with a high degree of automation, mainly including air supply, ignition, monitoring, fuel, and electrical control system. According to the type of fuel, the burner can be divided into pulverized coal burner, gas burner, and fuel burner. The burner uses primary air and secondary air to inject pulverized coal fuel into the furnace. When the mixed fuel is mixed with air, a special airflow structure is formed to make the fuel stable and burn fully. The secondary air rotating jet is used to make the rotating jet combine with the rotating jet and the surrounding medium, so as to enhance the ignition characteristics of pulverized coal flow.

2. Influence analysis of low NOx burner transformation on boiler
(1) The influence of combustion stability and the stability of the boiler is reflected in many aspects, the most important of which is the stability of temperature and the stability during operation. The low NOx burner is equipped with a combination of concentration and dilution at the primary air jet and uses heat reflux relay combustion and other technologies. During the combustion process, it is designed according to the principle of asymmetry between heat and power. The pulverized coal at the pyrolysis air jet is connected with the composite air jet vortex in the center of the boiler. The high reflux rate of heat reflux carbon powder extends the residence time and improves 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. Because the number of oxygen is controlled, the generation of heat is restrained, which affects the operation of the boiler. These two operation modes have an impact on the stable operation of the boiler.

(2) The influence of the internal environment of the boiler on the nozzle of the low NOx burner is less than that of the traditional burner, so the flame generated by the fuel also moves. The reduction of combustion area will reduce the acceptance of temperature by the boiler, and the pressure state generated inside the boiler will also change, resulting in disharmony. The transformation of low NOx burner equipment has changed various parts of the boiler, and the operation is also different. The transformation of the low NOx burner has affected the oxygen content inside the boiler to a certain extent. There are usually the maximum operating oxygen content and the minimum operating oxygen content. The adjustment of the unit can not keep up with the adjustment of the oxygen content and produce negative oxygen. The change of oxygen content and the change of combustion degree change the internal and external pressure of the boiler and change the internal environment. Relevant personnel needs to adjust the oxygen content and directly carry out air supply operation.

(3) The reheating temperature of the boiler is affected. The elevation of the original burner is reduced after the transformation of the low NOx burner, which has a great impact on the reheating temperature. After the burner transformation, the unit coordination is slow, and the boiler pressure tracking and adjustment cannot keep up, which is prone to overshoot and temperature changes. The reformed low NOx burner has a group of oscillating nozzles. When the nozzle swings upward, the temperature of the steam will rise and when the nozzle swings downward, the temperature will fall. However, because there is only one group of oscillating nozzles, the speed of temperature adjustment 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 boiler outlet temperature is within the low load range, the powder manufacturing system must be used, which will lead to the high temperature of the heating surface, which is difficult to overheat. At the same time, the outlet temperature should be controlled within a certain range, which will affect the normal operation of the boiler.

(4) Influence on furnace coking: during the use of a low NOx burner, although the burner will have a coking phenomenon during the operation, especially when starting the lower pulverizing system, it will affect the furnace coking, but during the operation, the burner nozzle still has coking phenomenon, especially when starting the lower pulverizing system, it will significantly affect the negative pressure, indicating that the combustion area is in bad condition, because the main combustion area carries out anoxic combustion, Therefore, there will be cold wall coking near the burner, especially when the lower pulverizing system is started, which will have a significant impact on the combustion condition of the boiler, indicating that the condition of the combustion area is not good, because the main combustion area is anoxic and anoxic, so there will be cold wall coking near the burner, which will affect the coking of the furnace.

(5) The low NOx burner not only reduces the yield of no, but also increases the flammability of slag. Low nitrogen combustion technology adopts low temperature and low oxygen conditions for combustion. The more the temperature in the combustion area decreases, the greater the impact of pulverized coal ignition. The oxygen content in the combustion area decreases, the combustion capacity of pulverized coal decreases, the combustion process also increases, the combustibles in the slag increase, the burner nozzle area changes, and the mixing air is delayed, and the pulverized coal flow in the boiler.

Summary: the advantages and disadvantages of the boiler in operation will be affected by many factors. Although the transformation of the low NOx burner has a certain impact on the boiler operation, in order to keep the energy clean and reduce the harm to the environment, we should optimize the low NOx burner in combination with the actual situation, standardize the transformation process of the low NOx burner, and improve the reliability of the boiler operation.