short description:

The main function of the silicon carbide nozzle of the burner is to inject the pulverized coal air mixture (primary air) supplied by the pulverized coal preparation system and the secondary air required for combustion into the furnace at a certain concentration and speed, respectively, so as to achieve stable ignition and combustion in the suspended state.

• 1. The structure of silicon carbide nozzle must be simple, not easy to block, easy to repair and replace, long service life, and improve economic efficiency.
• 2. The silicon carbide nozzle adopts an integrated casting molding process, which is high temperature resistant, wear-resistant and reduces maintenance costs.

The burner nozzles of power plant generally adopts cast steel structure. The proper swing of the burner nozzle can change the position of the flame center to adjust the reheat steam temperature level; The thick and thin pulverized coal burner can prevent furnace coking and high-temperature corrosion, and has the characteristics of stable ignition, good combustion stability at low load, and low NOx emission. After the primary air cast steel nozzle of the burner is burnt and deformed, the deviation between the furnace flame center and the design value is large, and the deviation between the nozzle size and the original size is large. The initial momentum of the jet is reduced compared with that before the burning loss, the range is shorter, and the rigidity is poor. The pulverized coal ignites near the nozzle, and the temperature near the nozzle is high, which is easy to produce slagging. The primary air nozzle of the burner needs to be replaced after it is burnt. During the replacement, the powder pipes connected to the outside of the burner need to be disconnected, the primary air nozzle of the burner and the nozzle should be pulled out together, then replaced, and then loaded. The workload is large, the environment is poor, and it costs labor, time, and money, resulting in great economic losses.

The silicon carbide nozzle of the burner produced by our company is wear-resistant, high-temperature resistant, non-deformable, and its service life is 3-5 times that of the cast steel nozzle, which improves the boiler efficiency, reduces NOX emissions, saves energy and environmental protection, reduces maintenance costs, and improves economic benefits.

It adopts integrated molding process, which is resistant to high temperature, abrasion and deformation.

The defects of cast steel nozzle mainly include the following aspects. 

1. The nozzle of cast steel is not wear-resistant, corrosion resistant, high temperature resistant and has short service life. The boiler needs to be shut down for replacement, resulting in great economic losses.

2. The cast steel nozzle is easy to be damaged during the operation of the unit, and the blunt body of the nozzle often falls off, threatening the operation of the burner and the safe operation of the slag extractor.

3. Because the nozzle material is G40Cr20Ni5, which works under high temperature for a long time, when the combustion of pulverized coal is unstable, it will cause uneven temperature distribution in the furnace or coking at the nozzle, resulting in thermal stress at the nozzle due to temperature difference, resulting in serious local deformation of the nozzle, short range of primary air, poor rigidity, pulverized coal ignition near the nozzle, high temperature near the nozzle, and local additional stress in the component. When the temperature fluctuation is large, The thermal stress changes greatly, causing thermal fatigue cracks on the nozzle surface, which will cause the burner nozzle and nozzle to burn over a long period of time.

4. Because the primary air flow is a high-speed gas-solid two-phase flow, the uneven scouring of pulverized coal particles leads to serious local wear of the blunt body and even wear off the blunt body. The nozzle and the blunt body are integrated. On the other hand, the thermal stress at high temperature is easy to cause serious deformation of the nozzle, even burning out, so the nozzle can not play its due role.