What are the main classifications of low NOx burners?
What are the main classifications of low NOx burners?
1. Heavy oil burner, gas burner, and dual fuel burner (light oil/gas or heavy oil/gas)
2. According to operating and operating mode: Omb burners have one stage, two stages, progressive two stages, and progressive two stages with proportional regulators (the latter realizes proportional regulation operation)
Industrial burner series: All large power burners are designed specifically for special industrial applications.
3. Based on the classification of combustion technology to reduce NOx.
4. The burner is an important device for industrial fuel boilers and gas boilers. It ensures stable combustion and complete combustion of fuel. Therefore, in order to inhibit the generation of NOx, it must start from the burner. According to the combustion technology for reducing NOx, low NOx burners are roughly classified into the following categories:
Staged Burner
A staged combustion chamber designed according to the principle of staged combustion makes fuel and air mix and burn in stages. Since the combustion deviates from the theoretical equivalence ratio, NOx generation can be reduced.
Self-circulation Burner
One type uses the pressure head of combustion air to draw back some combustion flue gas into the burner and mix it with air to burn. Due to the flue gas recirculation, the heat capacity of the combustion flue gas is larger, the combustion temperature is reduced, and NOx is reduced.
Another type of self-circulation burner directly recirculates some flue gas in the burner and adds it to the combustion process. This burner has the dual effects of inhibiting NOx and energy saving.
Enriched Combustion Burner
Its principle is to fully burn a portion of the fuel and burn the other portion too lightly but keep the total air volume constant. Since both parts are burning away from the stoichiometric ratio, the NOx is very low. This combustion is also called deviation combustion or non-stoichiometric combustion.
Striated Burner
Its principle is to divide the flame into several small flames. Because the surface area of the smaller flame is larger, the flame temperature is lower, thereby reducing “thermal NO”. In addition, the small flame shortens the residence time of oxygen, nitrogen, and other gases in the flame, and has a significant inhibitory effect on “thermal NO” and “fuel NO”.
Mixed Promoter Burner
The residence time of flue gas in the high-temperature zone is one of the main factors affecting the amount of NOx generated. Improve the mixing of fuel and air, thereby reducing the thickness of the flame surface. Under the condition that the combustion load remains unchanged, the flue gas is in a high-temperature state at the surface of the flame. Shorten the residence time in this area to reduce the amount of NOx generated. The mixed promoter burner is designed based on this principle.
Low NOx Pre-combustion Chamber Burner
The pre-combustion chamber is a high-efficiency, low-NOx staged combustion technology developed and researched by China over the past decade. The pre-combustion chamber is usually composed of primary air (or secondary air) and a fuel injection system. Fuel and primary air quickly mix. A rich fuel mixture is formed in the main combustion zone of the pre-combustion chamber. Due to the lack of oxygen, only a portion of the fuel is burned. Fuel releases volatile substances in the first flame zone, and the oxygen content is low, the flame temperature is low, and therefore reduces the generation of NOx.