Classification of low nitrogen burners
Nov 18, 2022
What categories can low nitrogen burners be divided into according to the principle?
Low NOx burners refer to burners with low NOx emissions during fuel combustion. The NOx emission of traditional natural gas boiler burners is usually around 120~150mg/m3. The NOx emission of low nitrogen burners is usually around 30~80mg/m3. NOx emissions below 30mg/m3 are usually called ultra-low nitrogen burners. At present, low-nitrogen burners can be roughly divided into the following categories according to the principle:
1) Stage burner
The stage burner designed according to the principle of staged combustion makes the fuel and air mix and burn in stages. Since the combustion deviates from the theoretical equivalence ratio, it can reduce the generation of nitrogen. 2) Self-recirculating 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 and burn with the air. Due to flue gas recirculation, the heat capacity of the combustion flue gas is large, the combustion temperature is reduced, and the NOx is reduced. Another kind of self-recirculation burner is to recirculate part of the flue gas directly in the burner and add it to the combustion process. This kind of burner has the dual effects of suppressing nitrogen oxides and saving energy.
3) Concentration burner
The principle is to make part of the fuel burn too rich and the other part burn too lean, but the overall air volume remains unchanged. Since both parts are burned off-stoichiometric, the NOx is very low. This type of combustion is also known as off-stoichiometric or non-stoichiometric combustion.
4) 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, the small flame shortens the residence time of oxygen, nitrogen and other gases in the flame, and has obvious inhibitory effects on "thermal reaction NO" and "fuel NO".
