System for automatically controlling sealing and blocking prevention of air pre-heater and control method

Abstract

The invention discloses a system for automatically controlling sealing and blocking prevention of an air pre-heater and a control method. The system comprises a compressed air system, a heating device, a gas-sealing spraying device and an automatic control system, wherein high-pressure air generated by the compressed air system enters the heating device to heat; heated high-temperature and high-pressure air is guided into the gas-spraying sealing device; a high-temperature high-pressure air curtain is formed at the cold end of the air pre-heater and a hot end fan-shaped plate, so that air is prevented from leaking towards a smoke gas side, and therefore, air leakage of the air pre-heater is reduced; and high-temperature high-pressure air further reaches the inner part of a heat exchange element of the air pre-heater, so that ammonium hydrogen sulfate is heated for being converted into a gas state from a liquid state, and accumulated dust is blown to achieve the purpose of reducing airleakage of the air pre-heater and preventing the air pre-heater from blocking. The system can effectively reduce air leakage of the air pre-heater, prevents the air pre-heater from being blocked and corroded, improves heat exchange ability of the air pre-heater, reduces a smoke discharge temperature, improves boiler efficiency, reduces unit coal consumption, and has relatively good economic benefits.

Description

[0001] 【Technical field】 [0002] The invention belongs to the field of energy saving and environmental protection of thermal power plants, and relates to a system and a control method for automatically controlling the sealing and anti-blocking of an air preheater. [0003] 【Background technique】 [0004] The air preheater uses the heat in the boiler flue gas to heat the air required for combustion, so as to reduce the exhaust gas temperature and increase the air supply temperature. The air preheater has become an indispensable and important part of large-scale power plant boilers. The rotary air preheater has the advantages of compact structure, less metal consumption, light weight, and flexible layout, and is widely used in high-parameter, large-capacity power plant boilers. [0005] There is a certain gap between the rotating rotor and the stationary shell of the rotary air preheater, and there is a large pressure difference between the flue gas side and the air side, and th...

AI Technical Summary

Problems solved by technology

The low-temperature section of the air preheater is just in this temperature range, and the liquid ammonium bisulfate has a strong ability to capture fly ash, which combines with the fly ash particles in the flue gas and adheres to the heat transfer element of the preheater to form molten salt-like ash deposits , causing air preheater corrosion and clogging

Blockage of the air preheater increases the air leakage rate of the air preheater, reduces the heat transfer capacity of the air preheater, leads to an increase in the exhaust gas temperature, increases the power consumption rate of the fan, and even causes the fan to stall, affecting the load capacity of the unit and seriously affecting the safety of the unit , stable and economical operation

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