Flue gas afterheat recovery system

Abstract

The invention provides a flue gas afterheat recovery system comprising a phase-change exchanger and an automatic control device which is mounted on the phase-change exchanger. The phase-change exchanger comprises a phase-change upper section and a phase-change lower section which are communicated; the phase-change upper section of the phase-change exchanger is communicated with a main condensate pipeline in a low-pressure regenerative heating system; the phase-change lower section of the phase-change exchanger is arranged in a flue gas channel; a wall temperature tester is mounted on the phase-change lower section; a signal of the wall temperature tester controls the flow of condensate entering the low-pressure regenerative heating system of the phase-change upper section of the phase-change exchanger by the automatic control device; the condensate in the automatic control device is heated after entering the phase-change upper section of the phase-change exchanger, and the heated condensate enters the main condensate pipeline in the automatic control device again. The invention saves energy and effectively utilizes flue gas afterheat to heat the condensate.

Description

technical field [0001] The invention relates to a flue gas waste heat recovery 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 condensed water. 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] At present, the waste heat of the flue gas at the tail of the boiler is widely used to heat air and water, such as heating the cold air entering the boiler air preheater, or heating the condensed water in other equipment or devices. For the condense...

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Problems solved by technology

[0007] The technical problem to be solved by this invention is how to effectively use the waste heat of flue gas at the tail of the boiler to partially replace the problem of energy waste caused by the need for steam turbine extraction to do work for traditional low-pressure heaters

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