What is the central wind during the operation of the rotary kiln burner?

You may not know much about rotary kiln burners, so today I will explain what the central wind is during the operation of rotary kiln burners.

The central air of the rotary kiln burner mainly has the following five functions:

Prevent pulverized coal from flowing back and blocking the outlet of the burner.

The central air volume should not be too large, generally accounting for about 10% of the primary air volume. Excessive air volume not only increases the primary air volume, but also increases the axial velocity at the center of the valley bottom, reducing the velocity difference between the two peaks and the valley bottom in the saddle shape, which is not conducive to the mixing and combustion of pulverized coal.

2. Cool the burner end and protect the nozzle.

The area around the burner is filled with hot gas, and its end face is not protected by refractory materials, completely exposed to the outside. This hinders the high-temperature gas and negative pressure backflow, cooling both the interior of the burner and the end face, thus achieving the purpose of protecting the burner.

3. The flame is more stable

The central air and circulating air injected through the plate-hole flame stabilizer can cause decompression, making the flame more stable and ensuring a long lifespan for the flame stabilizer.

4. Reduce the production of harmful gas nitrogen dioxide

The central area of the flame is where the pulverized coal is concentrated, forming an internal circulation. With very little excess air, complete combustion can be achieved, and the central air is cold wind. After being introduced into the kiln, the attenuation process of the flow field in the kiln is significantly slowed down. The contact area between the pulverized coal contained in the primary air jet and the primary air decreases with increasing time, but the mixing intensity does not weaken. Therefore, it can reduce the content of nitrogen dioxide in the exhaust gas, generally by 80%-60%.

5. Assist in adjusting the flame shape to improve the quality of clinker

Although the central air volume and pressure are not large, they have a certain auxiliary effect on adjusting the shape of the flame.