Flue-gas waste heat reclaiming system

Abstract

The invention provides a flue-gas waste heat reclaiming system which comprises a phase-change heat exchanger and an automatic control device, wherein the phase-change heat exchanger comprises a phase-change upper section and a phase-change lower section, and the automatic control device is arranged on the phase-change heat exchanger; the phase-change upper section of the phase-change heat exchanger is arranged in an air passage at the front of an inlet of an air preheater, and the phase-change lower section of the phase-change heat exchanger is arranged in a flue-gas passage; and the flow rate of air that enters into the phase-change upper section of the phase-change heat exchanger can be regulated by the automatic control device. On the one hand, the flue-gas waste heat reclaiming system utilizes flue-gas waste heat, instead of a heat source in the traditional air heater, to heat air, thereby saving energy sources; and on the other hand, the flue-gas waste heating reclaiming system regulates the air flow rate by the automatic control device and ensures that the wall temperature of the phase-change heat exchanger is always higher than the flue-gas acid dew point, thereby avoiding the low-temperature corrosion of the air preheater and the phase-change heat exchanger.

Description

technical field [0001] The invention relates to a flue gas waste heat recovery energy-saving system, in particular to a flue gas waste heat recovery system which utilizes the waste heat of flue gas at the tail of a boiler to heat cold air. Background technique [0002] As we all know, if the high-temperature flue gas discharged from the tail flue of the boiler is directly discharged to the atmosphere, it will not only pollute the environment, but also fail to meet the current requirements for boiler energy saving. Therefore, how to effectively utilize the high-temperature flue gas discharged from the tail flue of the boiler to provide an energy-saving and environment-friendly boiler has become a concern of people in the field. [0003] However, while cooling the high-temperature flue gas and effectively utilizing its heat, the problem of low-temperature corrosion in boiler equipment must also be considered. [0004] Since the condensation problem of the low-temperature heat...

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Problems solved by technology

[0007] The technical problem to be solved by the present invention is how to effectively utilize the waste heat of the flue gas at the tail of the boiler to replace the traditional air heater, which needs to use the steam extraction or exhaust steam of the steam turbine as the heat source, so as to avoid wasting energy

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