Composite phase change heat exchange device for boiler flue gas waste heat recovery

Abstract

The invention discloses a composite phase change heat exchange device for boiler flue gas waste heat recovery. The device comprises an original flue internal device of a boiler, an original flue external device of the boiler, a connecting pipeline of the original flue internal device of the boiler and the original flue external device of the boiler and a control meter valve; and a flue duct is internally provided with one or more than one level-I composite phase change heat exchanger, one or more than one level-II composite phase change heat exchanger and a mixing chamber as well as a matched temperature regulating system and an automatic control device which arte arranged outside the flue duct. According to the invention, through phase change working media between a heat exchange pipe and a sleeve pipe in the composite phase change heat exchanger, the combination of an evaporator and a condenser in one device is realized, the efficient recovery of flue gas exhaust heat is realized, a great amount of water for desulfurization is saved, and the low-temperature corrosion of the flue gas is reduced; and simultaneously, the hot air which is heated by an air preheater is utilized to be partially separated out so as to be mixed with net flue gas after desulfurization and is subjected to temperature rise, the mixed air is emitted into atmosphere after reaching the flue gas emission requirement, the low-temperature corrosion of a net flue gas heater after a wet desulfurization is avoided radically at present, and the damage to the environment caused by the flue gas is relieved.

Description

technical field [0001] The invention relates to a device in the technical field of boiler heat transfer, in particular to a composite phase-change heat device for boiler flue gas waste heat recovery. Background technique [0002] At present, more than 80% of domestic thermal power plants use gas-gas heat exchangers (GGH for short) in the wet flue gas desulfurization (Flue Gas Desulfurization, referred to as FGD). , the direct equipment cost of installing GGH is about 1.1 billion yuan. Other related costs include: increased booster fan due to the installation of GGH, increased control points of the control system, increased flue length, GGH support and corresponding building installation costs, etc., the sum of which accounts for about 15% to 20% of the total investment of FGD . The pressure drop of flue gas when GGH is installed is about 1200Pa. In order to overcome these resistances, the pressure head of the booster fan must be increased, which greatly increases the opera...

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art, to eliminate the defect of GGH by using the clean flue gas after the desulfurization of the hot air, and to solve the difficult problem of arranging the heat exchange circular tube evaporation section in the vertical flue or inclined flue , and the problem that the evaporating section and the condensing section of the phase-change heat exchanger must be arranged separately, realize the integrated and compact arrangement of the evaporating section and the condensing section of the phase-change heat exchanger, and realize a truly integrated composite phase-change heat exchanger. Effectively reduce the flue gas temperature in front of the desulfurization tower, save desulfurization water, and reduce the harm of low-temperature corrosion, so as to achieve the goals of energy saving, water saving and emission reduction

Images