Flue gas heater by evaporative cooling

Abstract

The invention relates to an evaporation and cooling gas heater, comprising original smoke heat exchanger (1) and purified smoke heat exchanger (2), steam dome (3), by which two heat exchangers are connected. At the side of original smoke heat exchanger (1), the quantity of heat of original smoke is transferred to the cycling medium (11) in heat exchanging pipe (6) at original smoke side. The cycling medium (11) is evaporated by heating and formed steam enters in heat exchanging pipe (7) at purified smoke side. In the heat exchanging pipe (7), the quantity of heat of steam is transferred to the purified smoke and the purified smoke is condensed into liquid. Under the effect of gravity, liquid medium returns into the heat exchanging pipe (6) at the original smoke side through steam dome (3). By the cycling, the purpose that the quantity of heat of original is used to heat the purified smoke is realized. Steam even-pressure room (5) at the purified smoke side is connected with vacuum pump (10) outside so as to control the pressure in evaporating and cooling system and the boiling point of cycling medium. The invention can adopt multiple groups of smoke heater in parallel. By controlling the pressure in each heat exchanger, multi-step temperature difference heat exchanger is realized. The invention is provided with no leakage of smoke, strong applicable ability to load variety of mainframe, and no operation consumption.

Description

technical field [0001] The invention relates to a flue gas heater used in the field of wet desulfurization in thermal power plants, in particular to an evaporation cooling flue gas heater. Background technique [0002] At present, there are two types of flue gas heaters (GGH) commonly used in this field, rotary GGH and water medium GGH. The rotary GGH system has strong adaptability to flue gas, and has the characteristics of more convenient layout and more performance. Leakage of net flue gas, which will lead to a reduction in desulfurization efficiency. In addition, the rotary GGH has a lot of auxiliary equipment and complex control system, which generally has the disadvantages of high energy consumption and difficult operation and maintenance. The water-medium GGH does not have the problem of flue gas leakage, but the energy consumption of the water pump with large circulating water flow and high head is still high. Contents of the invention [0003] The purpose of th...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the shortcomings of GGH gas leakage and high energy consumption in the prior art, and propose a safe, efficient and controllable economical flue gas heater using evaporative cooling. The invention can realize energy-free operation

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