The core reason for the low nitrogen oxide (NOx) emission of high-speed burner is that it inhibits the generation path of nitrogen oxide by optimizing the combustion dynamics conditions. The following is a specific analysis:

1. Combustion characteristics of high speed burner

1. High speed injection and turbulence enhancement

Gas is injected into the furnace at high speed (usually> 100 m/s), forming strong turbulence, so that fuel and air are quickly and evenly mixed, shorten the combustion time, and avoid the formation of local high temperature areas (the main source of thermal NOx).

2. Reduce the peak flame temperature

High-speed gas flow takes away heat and reduces the temperature of the core of the flame (usually controlled at <1300℃), inhibiting thermal NOx** (the amount of NOx generated is reduced by about 50% for every 100℃ decrease in temperature).

3. Tiered combustion technology

Fuel and air supply in stages:

Primary combustion zone: rich fuel combustion (oxygen deficiency), inhibit NOx generation.

Secondary combustion zone: replenish the remaining air to complete full combustion and avoid high temperature and oxygen deficiency leading to fuel NOx.

Second, the key technology of low nitrogen design

1. Pre-mixed combustion (Premix Combustion)

The fuel and air are fully pre-mixed before combustion to form a uniform mixture, eliminate local high temperature points and reduce thermal NOx.

2. Flue gas recirculation (FGR, Flue Gas Recirculation)

Some low temperature flue gas is mixed into the combustion air to dilute the oxygen concentration and reduce the combustion temperature (the typical FGR ratio is 10%~30%, and the NOx emission reduction rate can reach 30%~60%).

3. Low nitrogen burner structure

Porous vortex design: enhance mixing efficiency, shorten flame length, reduce high temperature residence time.

Cooling wall: protected by water cooling or refractory materials to avoid secondary combustion caused by high temperature radiation from the furnace wall.

4. Practical application effect

Typical emission value:

Conventional burner NOx emission: 150~300 mg/m³ (taking natural gas as an example).

High speed low nitrogen burner NOx emission <30~50 mg/m³ (combined with FGR+ premixing technology).

Industry cases:

Steel heat treatment furnace: high speed burner + staged combustion, NOx reduction of more than 60%.

Glass melting furnace: high speed injection + flue gas recirculation, NOx concentration reduced to 80 mg/m³ or less.

V. Technical limitations and optimization direction

1. Fuel adaptability: high nitrogen fuel (such as pulverized coal) needs to be combined with SNCR/SCR and other post-treatment technologies.

2. Cost and maintenance: the premixed system needs precision control, and the maintenance cost is high.

3. Future trends:

Intelligent control: real-time adjustment of air-fuel ratio and FGR ratio.

Hydrogen fuel adaptation: use zero carbon fuel to further reduce NOx generation.

High-speed burner is the core technology of low nitrogen transformation of industrial furnaces through the three-in-one design of mixing enhancement, temperature control and combustion segmentation, which takes into account both efficient combustion and environmental protection requirements.