Rotary preheated and tubular preheater coupled air preheating system

Abstract

The invention relates to the field of boiler system air preheating, and discloses a rotary preheated and tubular preheater coupled air preheating system. The rotary preheated and tubular preheater coupled air preheating system comprises a rotary preheater and further comprises a tubular preheater with smoke carrying out heat exchange with air. The rotary preheater is used for heating the air on anoutlet of the tubular preheater, and the tubular preheater is used for heating input air on an inlet of the rotary preheater. The tubular preheater is modularly designed, each module is arranged intoa split area with the heat exchange process capable of independently controlled, dry heating hot smoke/hot air introducing connecting opening is formed in each split area, and drying heating with thetemperature raised to 232 DEG C or above can be independently carried out. According to the rotary preheated and tubular preheater coupled air preheating system, the problem of ammonium bisulfate blocking and low-temperature corrosion of a rotary air preheater can be thoroughly solved, and the rotary preheated and tubular preheater coupled air preheating system is stable in operation and suitablefor new design or transformation of a boiler preheating system.

Description

technical field [0001] The invention relates to the air preheating of the boiler, especially an air preheater which can prevent the rotary preheater from generating NH 4 HSO 4 (ammonium bisulfate) deposition air preheating system. Background technique [0002] For large coal-fired boilers, it is conventional to arrange a rotary preheater behind the economizer / SCR to heat the boiler's air supply, so as to reduce the exhaust gas temperature of the boiler and improve the efficiency of the boiler. Usually, in order to improve boiler efficiency, the exhaust gas temperature is generally designed to be relatively low. [0003] However, for boilers equipped with SCR devices, excessive ammonia injection will interact with SO in the flue gas 3 reaction to form ammonium bisulfate. Ammonium bisulfate is solid below 149°C, liquid between 149°C and 232°C, decomposes and volatilizes from liquid above 232°C, and decomposes into NH 3 +SO 3 +H 2 O. In boiler design, the exhaust gas te...

AI Technical Summary

Problems solved by technology

This solution can basically solve the problem of ammonium bisulfate clogging in the rotary air preheater, and the working temperature of the back-end equipment such as the dust collector is not high, but the heat pipe heat exchanger configured therein may still be clogged with ammonium bisulfate and needs to be shut down for cleaning

[0007] The above technologies are all based on increasing the flue gas temperature at the outlet of the rotary air preheater to prevent the condensation of ammonium bisulfate and avoid the cleaning and maintenance of the rotary air preheater with a complicated structure. temperature, which slows down the corrosion of the cold end of the rotary preheater, but cannot completely remove the clogging and deposition of the rotary ammonium bisulfate

Moreover, after raising the flue gas temperature at the outlet of the rotary air preheater, how to adapt to various working conditions, how to make the follow-up dust collector and other equipment work normally, how to comprehensively utilize the existing boiler equipment and waste heat, etc. Careful consideration, incomplete, necessary for improvement

[0008] Announced on November 22, 2019, the announcement number is CN209672379U, a Chinese utility model patent "a tube-box air preheater". The tube-box air preheater is mainly suitable for boilers with small unit capacity, except for 300MW circulating flow The air preheater of the chemical bed boiler has a tube type air preheater, which is rarely used in pulverized coal boilers of 300MW and above

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