Major categories of oxide low nitrogen burners

The low nitrogen oxides burner is an important equipment for industrial furnaces. It ensures the stable ignition and combustion of fuel and the complete combustion of fuel. Therefore, to suppress the generation of NOx, it is necessary to start with the burner. According to the combustion technology to reduce NOx, oxide low nitrogen burners are roughly divided into the following categories:

1. Stage burner The stage burner designed according to the principle of staged combustion makes the fuel and air mixed and burned in stages. Because the combustion violates the theoretical equivalence ratio, it can reduce the generation of NOx.

2. Self-recirculation burner: One is to use the pressure head of the combustion air to suck back part of the combustion flue gas, enter the burner, and mix with the air for combustion. Because the flue gas is recirculated, the heat capacity of the combustion flue gas is large, the combustion temperature is reduced, and NOx is reduced. Another self-recirculation burner is to recirculate part of the flue gas directly in the burner and add it to the combustion process. This burner has the dual functions of suppressing nitrogen oxides and saving energy.
3. Rich-lean type burner: Its principle is to make part of the fuel burn in an over-rich manner and the other part of the fuel burn in an over-lean manner, but the overall air volume remains unchanged. Because both parts are burning in violation of the chemical equivalent ratio, NOx is very low. This combustion is also called violation combustion or non-chemical equivalent combustion.
4. Cutting flame type burner: Its principle is to divide a flame into several small flames. Because the small flame has a large heat dissipation area and a low flame temperature, the "thermal reaction NO" is reduced. In addition, the small flame shortens the residence time of gases such as oxygen and nitrogen in the flame, which has a significant inhibitory effect on "thermal reaction NO" and "fuel NO". 5. Mixing 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 the condition of unchanged combustion load, the residence time of flue gas in the flame surface, i.e. the high temperature zone, is shortened, thereby reducing the generation of NOx. Mixing promotion burners are designed according to this principle. 6. Low NOx pre-combustion chamber burner The pre-combustion chamber is a high-efficiency, low-NOx staged combustion technology developed and researched in my country 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 are quickly mixed to form a fuel-rich mixture in the primary combustion zone of the pre-combustion chamber. Due to lack of oxygen, only part of the fuel is burned. The fuel separates volatiles in the primary flame zone with low oxygen and flame temperature, thereby reducing the generation of NOx.