Natural circulation indirect flue gas reheater

Abstract

The invention provides a natural circulation indirect type flue gas reheater which comprises a heat absorption section, a first heat emission section, a second heat emission section and a control system, wherein the heat absorption section and the first heat emission section are arranged in flues, and the second heat emission section is arranged outside the flues and used for heating condensate water. The heat absorption section is arranged in the high-temperature flue in front of a desulfurizing tower, the first heat emission section is arranged in the low-temperature flue in back of the desulfurizing tower, the first heat emission section and the second heat emission section are connected with the heat absorption section respectively through circulating pipes, and heat-transfer media are arranged in the circulating pipes. A flow regulating valve is arranged on a condensate water pipeline entering the second heat emission section, the first heat emission section and the heat absorption section are respectively provided with a temperature sensor, and the flow regulating valve and the temperature sensors are all connected with the control system. According to the natural circulation indirect type flue gas reheater, the method that clean flue gas after desulfuration is directly heated by recycling heat of flue gas before desulfuration is adopted and different from the method that the clean flue gas after desulfuration is heated by directly carrying out heat exchange on the flue gas before desulfuration and the clean flue gas after desulfuration through a traditional GGH, the problems of corrosion and leakage of an original GGH system and other problems are solved, and the instability of the traditional GGH system is improved.

Description

technical field [0001] The invention relates to the field of reheating net flue gas after wet desulfurization, in particular to a natural circulation indirect flue gas reheater. Background technique [0002] Sulfur dioxide is contained in boiler flue gas, and direct discharge will form acid rain and cause serious environmental pollution; especially the treatment of sulfur dioxide in thermal power plants has attracted widespread attention, and domestic power plants have now adopted effective devices for sulfur dioxide treatment. At present, the most widely used desulfurization method in China is flue gas wet desulfurization, especially limestone (or lime)-gypsum wet desulfurization. Limestone (or lime)-gypsum wet desulfurization uses limestone (or lime) as an absorbent to wash sulfur dioxide in the flue gas to generate calcium sulfite, and then oxidize it with the added air to finally generate gypsum, remove sulfur dioxide, and purify the flue gas . The whole reaction proce...

AI Technical Summary

Problems solved by technology

However, in this technology, the heat medium needs to be transported by a heat pump when running in the system, which consumes a lot of energy to assist the operation of the system, resulting in a large increase in operating costs.

[0006] Chinese patent ZL200610169891.9 discloses an evaporative cooling flue gas heater, which is also a heat exchanger that replaces the traditional GGH. It connects the original flue gas heat exchanger and the clean flue gas heat exchanger through a steam chamber, and uses a vacuum pump To control the internal pressure of the heat exchanger to adjust the wall temperature, but because the original flue gas heat exchange tube and the clean flue gas heat exchange tube are directly connected through the steam chamber, the circulation of the medium cannot be carried out smoothly, and the wall temperature is controlled by a vacuum pump. In the actual implementation process, the pressure sensor will encounter inaccurate pressure measurement, which will cause the control system to fail to work effectively, resulting in unstable operation of the entire system

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