Boiler smoke discharging condensed water heat-carrying circulation based three incorporated tower heat exchange method and device

Abstract

The invention discloses a boiler smoke discharging condensed water heat-carrying circulation based three incorporated tower heat exchange method and device and belongs to the technical field of exhaust air heat recovery and boiler heating. By adopting a spray tower heat exchange structure with three incorporated towers, the device is divided into an air heating and humidification region, a smoke high-temperature heat exchange region and a smoke low-temperature heat exchange region from bottom to top. Smoke enters the high-temperature heat exchange region from the middle part of the tower, performs heat exchange with high-temperature waste heat circulation water, then rises to the low-temperature heat exchange region and is exhausted from the tower top after performing heat exchange with low-temperature waste heat circulation water; the low-temperature waste heat circulation water is sprayed from a low-temperature spraying device for heat exchange, is supplied to an air heating and humidification section for spraying heat exchange after passing through a water-air separator and heats inlet air of a boiler or directly descends to the high-temperature heat exchange region; and the high-temperature waste heat circulation water is sent into the high-temperature heat exchange region from a high-temperature spraying device for heat exchange and is supplied outside and heats heating net water after gathering in a pool at the tower bottom. A set of system can realize a main heat exchange process required for smoke recovery and heating, so that the system flow is greatly improved, the equipment amount and the occupying space are reduced, and investment and energy consumption are lowered.

Description

technical field [0001] The invention relates to a three-tower-in-one heat exchange method and device based on boiler exhaust gas condensate water heat-carrying cycle, and belongs to the technical fields of exhaust air heat recovery and boiler heat supply. Background technique [0002] There is a large amount of water vapor in the exhaust smoke of boilers that use coal, natural gas and other fuels for heating. The exhaust air of many processes also contains a large amount of water vapor. A large amount of latent heat and sensible heat are lost in smoke or exhaust air. In order to recover such high-humidity flue gas or air waste heat in depth, the currently commonly used waste heat utilization methods include: partition-type condensation heat recovery device, flue gas condensation heat recovery device based on absorption heat pump heat exchange, etc., but the former has corrosion problems, replacement The high cost of the hot zone, the latter has problems such as the high cost...

AI Technical Summary

Problems solved by technology

In order to recover such high-humidity flue gas or air waste heat in depth, the currently commonly used waste heat utilization methods include: partition-type condensation heat recovery device, flue gas condensation heat recovery device based on absorption heat pump heat exchange, etc., but the former has corrosion problems, replacement The high cost of the hot zone, the latter has problems such as the high cost of the absorption heat pump, which often leads to a long payback period

[0003] Tsinghua University has developed a number of innovative boiler exhaust gas deep condensation heat recovery technology methods, including "direct recovery method and device for boiler exhaust heat and humidity based on steam heat transfer cycle" (2017104371042), "a kind of smoke tower integrated Boiler exhaust fume total heat recovery and flue gas whitening device" (2017206805342), etc., use the waste heat recovered from the low-temperature section of the flue gas to heat the low-temperature waste water, and use it to heat and humidify the boiler inlet air to increase the moisture content of the exhaust smoke and its dew point The method of recovering waste heat from the high-temperature section of the flue gas to heat the low-temperature waste water such as the return water of the heating network has achieved the purpose of greatly reducing the exhaust gas temperature to 20-30°C and fully recovering its sensible heat and latent heat. Among them, the exhaust heat recovery process is decomposed into two interconnected but independent processes and devices, the high-temperature section and the low-temperature section, plus the air spray heating and humidifying device, which has the disadvantages of taking up a large space and complicating the system flow. Too many supporting equipment components lead to too many failure points, the large resistance of the water and air system will increase the power consumption, and the initial investment is still high, so the heat exchange method and equipment system need to be further optimized

[0004] The process exhaust air of many industrial enterprises contains a large amount of water vapor, usually because it contains impurities, waste gas and other components that are easy to corrode and scale, and the existing technology is often difficult to effectively recycle and utilize the remaining heat resources

[0005] In addition, the obvious white smoke (white mist) phenomenon caused by the large amount of water vapor contained in the chimney is currently considered to be an important pollution problem, so "whitening" treatment is required

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