Main classification of low nitrogen burners


Main classification of low nitrogen burners
1. Heavy oil burner, gas burner, and dual fuel burner (light oil/gas or heavy oil/gas).
2. According to operation and mode of operation, it can be divided into three types: first stage, two-stage, progressive two-stage, and progressive two-stage with proportional regulator (the latter implements proportional regulation operation)
3. Industrial Burner Series: All are high-power burners designed specifically for special industrial applications.
4. Classification based on combustion technologies for reducing NOx
Burners are important equipment on industrial fuel boilers and gas boilers, ensuring stable ignition and complete combustion of fuel. Therefore, to suppress the generation of NOx, it is necessary to start with the burner. According to the combustion technology for reducing NOx, low nitrogen oxide burners can be roughly divided into the following categories:
Stage burner
A stage burner designed based on the principle of staged combustion, which mixes fuel and air in stages for combustion. Due to the deviation of combustion from the theoretical equivalence ratio, it can reduce the generation of NOx.
Self recirculation burner
One method is to use the pressure head of the combustion air to suck back some of the combustion flue gas, which enters the burner and mixes with the air for combustion. Due to flue gas recirculation, the heat capacity of combustion flue gas is large, the combustion temperature decreases, and NOx decreases.
Another type of self recirculation burner is to directly recycle some flue gas into the burner and add it to the combustion process. This type of burner has a dual effect of suppressing nitrogen oxide and saving energy.
Concentrated and Diluted Burner
The principle is to make a portion of the fuel burn too rich and another portion burn too lean, but the overall air volume remains unchanged. Due to the deviation of both parts from the chemical equivalence ratio, NOx is very low, and this type of combustion is also known as deviation combustion or non chemical equivalence combustion.
Split flame type burner
The principle is to divide a flame into several small flames. Due to the large heat dissipation area of the small flames and the lower flame temperature, the “thermal reaction NO” decreases. In addition, a small flame shortens the residence time of gases such as oxygen and nitrogen in the flame, and has a significant inhibitory effect on both “thermal reaction NO” and “fuel NO”.
Mixed promotion burner
The residence time of flue gas in the high-temperature zone is one of the main factors affecting the generation of NOx. Improving the mixing of combustion and air can reduce the thickness of the flame surface. Under constant combustion load, the residence time of flue gas on the flame surface, i.e. in the high-temperature zone, is shortened, resulting in a decrease in the generation of NOx. The mixed promotion burner is designed according to this principle.
Low NOx pre chamber burner
Pre combustion chamber is a high-efficiency and low NOx staged combustion technology developed and researched in China in the past 10 years. The pre combustion chamber is generally composed of primary air (or secondary air) and fuel injection system. The fuel and primary air quickly mix to form a rich fuel mixture in the primary combustion zone of the pre combustion chamber. Due to lack of oxygen, only part of the fuel is burned, and the fuel precipitates volatile matter in the primary flame zone with low oxygen and flame temperature, thereby reducing the generation of NOx.