There is an alternating process of heat and cold source between the boiler and the burner. The temperature of the hot flue gas in the furnace can be as high as 800°C to 1000°C, the combustion-supporting gas should be a high-temperature gas turbine exhaust temperature of 500°C, and the temperature of the air used for combustion is only 25°C to 50°C, which stimulates the potential for vibration. Why does the burner accessory vibrate during operation?
The lower part of the furnace of the boiler is the combustion zone, and the upper part communicates with the flue. During operation, the furnace is filled with continuously flowing combustion gas, and the entire furnace space forms a gas flow field.
The inner side of the furnace wall is affected by the dynamic pressure of the gas flow field in the furnace, and the outer side is affected by the atmospheric pressure. When the gas flow pressure in the furnace fluctuates, it will excite the vibration of the furnace wall. In actual production, the boiler gas pressure fluctuates greatly, resulting in unstable combustion, large fluctuations in the negative pressure of the furnace dome, and frequent changes in the pressure difference between the inner and outer sides. Causes the boiler wall to vibrate. The furnace wall vibration caused by combustion dynamics is inevitable. The function of the rigid beam is to protect the furnace and flue from damage under furnace operating pressure or deflagration conditions, that is, to increase the rigidity of the furnace wall by adding rigid beams. Insufficient rigidity of rigid beams or failure of installation to meet the design requirements will cause serious furnace wall vibration.
Change the natural frequency of the combustor and the frequency of the vortex generated by the combustion at the periphery of the combustor throat. In order to prevent the flame swing from stimulating the low-frequency vibration of the flue gas column, the burner structure and combustion conditions should be improved.
It can change the natural vibration frequency of combustion in the furnace pit, such as retrofitting double-sided water wall, large exhibition, horizontal superheater, etc. Improve the combustor to match the air regulator and wind box structure, such as installing a burner stabilizer, air baffle, etc. It is necessary to reasonably design and arrange the flue gas recirculation inlet position and adjust the control method to prevent the occurrence of abnormal phenomena such as short-circuit flue gas. Then, the reason for the vibration of the burner accessories may be the above reasons.
