Main classifications of low nitrogen burners

1. Heavy oil burners, gas burners and dual fuel burners (light oil/gas or heavy oil/gas).

2. According to the operation and operation mode, it is divided into: Orient burner has one-stage, two-stage, progressive two-stage and progressive two-stage with proportional regulator, etc. (the latter implements proportional adjustment operation)

3. Industrial burner series: all are high-power burners, designed for special industrial applications.

4. Classification according to NOx reduction combustion technology

The burner is an important equipment on the industrial oil-fired boilers and gas-fired boilers. It ensures the stable combustion of the fuel and the complete combustion of the fuel. Therefore, to suppress the generation of NOx, the burner must be started. According to the combustion technology to reduce NOx, low NOx burners are roughly divided into the following categories:

a. Stage burner

The stage burner designed according to the principle of staged combustion makes the fuel and air mixed and combusted in stages. Since the combustion deviates from the theoretical equivalence ratio, the generation of NOx can be reduced.

b. Self-recirculating burners

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 type of self-recirculating burner is to directly recirculate part of the flue gas 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.

c. 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.

d. Split flame 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".

e. Mixing promotion type burner

The residence time of the flue gas in the high temperature area is one of the main factors affecting the amount of NOx generation. Improving the mixing of combustion and air can reduce the thickness of the flame surface. Under the condition of constant combustion load, the flue gas is at high temperature on the flame surface. The residence time in the zone is shortened, thereby reducing the amount of NOx generated. Mixing-promoting burners are designed according to this principle.

f. Low NOx pre-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 a fuel injection system. The fuel and the primary air are rapidly mixed. A fuel-rich mixture is formed in the primary combustion zone in the pre-combustor. Due to lack of oxygen, only part of the fuel is burned, and the fuel precipitates volatiles in the primary flame zone with lean oxygen and lower flame temperature, thus reducing the generation of NOx.