Nozzle-free desulfurization slurry flash evaporation device and working method

Abstract

The invention discloses a nozzle-free desulfurization slurry flash evaporation device and a working method. The nozzle-free desulfurization slurry flash evaporation device comprises a pressure pump, a flash evaporation tank, a slurry main conveying pipeline, a high-pressure pipe bundle, a low-pressure pipe bundle, a demister, a slurry pond and a slurry circulating pump, circulating slurry at the bottom of the desulfurizing tower is pumped out by a booster pump and enters a slurry main conveying pipeline, the desulfurizing slurry sequentially enters a high-pressure tube bundle and a low-pressure tube bundle along the slurry main conveying pipeline to overflow, the slurry flows downwards along the tube wall to form a layer of uniform liquid level, and the desulfurizing slurry at the temperature higher than the saturation temperature is evaporated into water vapor under the negative pressure condition. Steam is discharged from a steam outlet of the flash tower. And deep recovery of flue gas waste heat is achieved, the phenomena of pipeline scaling and blocking are reduced, and waste liquid recovery is more energy-saving and environment-friendly while the system safety is improved.

Description

Technical Field

[0001] The invention relates to the field of waste heat recovery technology of slurry flash evaporation after wet desulfurization in thermal power plants and energy-saving and environmental protection technology, and in particular to a nozzle-free desulfurization slurry flash evaporation device and a working method. Background Art

[0002] For a long time in the future, coal-fired power generation will remain the main form of power generation. Limestone-gypsum wet desulfurization technology is the most commonly used post-combustion flue gas desulfurization technology in coal-fired power plants at this stage. After desulfurization, the flue gas temperature drops from about 110°C to about 55°C, and the slurry temperature rises to about 55°C. The saturated wet steam contained in the flue gas carries a large amount of latent heat of vaporization, which is directly discharged into the air, causing waste of water resources and easily causing environmental problems such as "gypsum rain". The desulfurization slurry flash evaporation heat raising technology is essentially a flue gas waste heat deep recovery technology. This technology uses the characteristic that the boiling point of the slurry after desulfurization decreases with the decrease of ambient pressure. By establishing a vacuum phase change environment, the slurry with a temperature above the saturation temperature under the current negative pressure flashes, thereby transporting the latent heat of vaporization carried by the negative pressure steam to the heat pump to condense and release heat to the low-temperature medium, thereby realizing the deep recovery of flue gas waste heat. This technology can simultaneously achieve multiple purposes such as energy saving, water saving, improving desulfurization efficiency, and flue gas whitening, and can further achieve energy saving and environmental protection goals.

[0003] The commonly used desulfurization slurry flash evaporation device design usually adopts nozzles for slurry spray flash evaporation, and the existing waste heat latent heat utilization method is a continuous operation method. Since the limestone slurry contains more solid particles, the nozzle is prone to scaling and clogging during long-term operation, which affects the flash evaporation efficiency and thus reduces the waste heat recovery effect of the slurry after desulfurization.

[0004] The desulfurization slurry flash device mainly increases the pressure through the slurry circulation pump, so that the slurry overflows directly from the pipe without the need for nozzle spraying. The slurry flows along the pipe to form a liquid film, thereby evaporating and condensing the water in the slurry, realizing deep recovery of flue gas waste heat, reducing pipeline structure, increasing system safety, and making waste liquid recovery more energy-saving and environmentally friendly. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a nozzle-free desulfurization slurry flash evaporation device and a working method. The desulfurization slurry flash evaporation device of the present invention is mainly pressurized by a slurry circulation pressure pump, so that the slurry overflows directly from the pipe without the need for nozzle spraying. The slurry flows along the pipe to form a liquid film, so that the water in the slurry evaporates and condenses, thereby realizing deep recovery of flue gas waste heat, reducing pipeline structure, increasing system safety, and making waste liquid recovery more energy-saving and environmentally friendly.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A nozzle-free desulfurization slurry flash device, comprising a pressure pump, a flash tank, a slurry main conveying pipeline, a high-pressure pipe bundle, a low-pressure pipe bundle, a demister, and a slurry tank;

[0008] The booster pump is located on the main slurry conveying pipeline; the high-pressure tube bundle and the low-pressure tube bundle are connected to the main slurry conveying pipeline, and the high-pressure tube bundle and the low-pressure tube bundle are fixed in the flash tank through the high-pressure tube bundle support plate and the low-pressure tube bundle support plate respectively; the demister is installed on the upper part of the flash tank body to remove the liquid entrained in the flash gas; the slurry pool is located in the lower tank body of the flash tank; the desulfurization slurry at the bottom of the desulfurization tower is pumped out by the booster pump and enters the main slurry conveying pipeline, and the desulfurization slurry enters the high-pressure tube bundle and the low-pressure tube bundle successively along the main slurry conveying pipeline for overflow, and the desulfurization slurry flows down along the tube wall to form a uniform liquid surface, and the desulfurization slurry above the saturation temperature evaporates into water vapor under negative pressure conditions, and the water vapor is discharged from the steam outlet of the flash tower after passing through the demister; the desulfurization slurry flowing out of the high-pressure tube bundle and the low-pressure tube bundle finally flows into the slurry pool, and is pumped out by the desulfurization slurry circulation pump and enters the highest spray layer of the desulfurization tower for spraying.

[0009] The tubes in the high-pressure tube bundle are arranged in a stepped manner, and the slurry flows along the tube wall for flash evaporation; the tubes in the low-pressure tube bundle are arranged in a stepped manner, and the slurry flows along the tube wall for flash evaporation.

[0010] The high-pressure tube bundle is supported by a high-pressure tube bundle support plate, and the high-pressure tube bundle support plate is connected to the flash tower by welding; the low-pressure tube bundle is supported by a low-pressure tube bundle support plate, and the low-pressure tube bundle support plate is connected to the flash tower by welding.

[0011] The demister is located at the top of the flash tank and before the flash gas outlet.

[0012] The working method of the desulfurization slurry waste heat utilization device based on the capillary structure includes the following processes: the desulfurization slurry at the bottom of the desulfurization tower is pumped out by a pressure pump and enters the slurry main transportation pipeline, the desulfurization slurry enters the high-pressure tube bundle and the low-pressure tube bundle along the slurry main transportation pipeline successively to overflow, the desulfurization slurry flows down along the tube wall to form a uniform liquid surface, the desulfurization slurry above the saturation temperature evaporates under negative pressure conditions to become water vapor, and the water vapor passes through the demister and is discharged from the steam outlet of the flash tank.

[0013] The desulfurization slurry flowing out of the high-pressure tube bundle and the low-pressure tube bundle finally flows into the slurry pool, and is pumped out by the desulfurization slurry circulation pump from the output slurry pipeline connected to the slurry pool into the highest spray layer of the desulfurization tower for spraying.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention utilizes a nozzle-free desulfurization slurry flash evaporation device to perform slurry spray flash evaporation, thereby realizing phase change heat transfer of water in the desulfurization slurry, deeply recovering flue gas waste heat, improving waste heat recovery efficiency, and achieving energy saving; it realizes the recovery of high-cleanliness water in the desulfurization slurry, achieves water saving, and increases the degree and flexibility of waste heat recovery in thermal power plants.

[0016] The present invention adopts a nozzle-free desulfurization slurry spraying device, which increases the pressure through a slurry circulation pump so that the slurry overflows directly from the pipe without the need for nozzle spraying, thus avoiding the problem of nozzle scaling and clogging caused by long-term operation, extending the service life of the equipment, and improving the degree of waste heat recovery of the desulfurization slurry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of a nozzle-free desulfurization slurry flash device of the present invention.

[0018] Figure markings: 1-boosting pump; 2-flash tank; 3-high-pressure tube bundle support plate; 4-first high-pressure pipe; 5-second high-pressure pipe; 6-third high-pressure pipe; 7-fourth high-pressure pipe; 8-fifth high-pressure pipe; 9-first low-pressure pipe; 10-second low-pressure pipe; 11-third low-pressure pipe; 12-fourth low-pressure pipe; 13-fifth low-pressure pipe; 14-low-pressure tube bundle support plate; 15-slurry main conveying pipeline; 16-slurry tank; 17-output slurry pipeline; 18-desulfurization slurry circulation pump; 19-demister. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to the accompanying drawings and implementation examples:

[0020] Please refer to Figure 1 The present embodiment is a nozzle-free desulfurization slurry flash device, comprising a pressure pump 1, a flash tank 2, a high-pressure tube bundle support plate 3, a first high-pressure pipe 4, a second high-pressure pipe 5, a third high-pressure pipe 6, a fourth high-pressure pipe 7, a fifth high-pressure pipe 8, a first low-pressure pipe 9, a second low-pressure pipe 10, a third low-pressure pipe 11, a fourth low-pressure pipe 12, a fifth low-pressure pipe 13, a low-pressure tube bundle support plate 14, a slurry main delivery pipeline 15, a slurry pool 16, an output slurry pipeline 17, a desulfurization slurry circulation pump 18 and a demister 19. The slurry main delivery pipeline 15 is connected to each pressure tube bundle, and the slurry flows along the pipe wall for flash evaporation, and is finally collected in the slurry pool 16. The output slurry pipeline 17 is connected to the slurry pool 16, and the slurry is pumped out of the flash tank 2 by the desulfurization slurry circulation pump 18 to complete a flash evaporation cycle.

[0021] Figure 1It is a schematic diagram of the structure of a nozzle-free desulfurization slurry flash evaporation device, which improves the slurry flash evaporation efficiency and prevents scaling and clogging of the flash tank, including: a high-pressure tube bundle 4-8, wherein the high-pressure tube bundle 4-8 is connected to the main slurry conveying pipeline 16, and the tubes in the tube bundle are arranged in a stepped manner to form a stepped overflow; a low-pressure tube bundle 9-14, wherein the low-pressure tube bundle 9-14 is connected to the main slurry conveying pipeline 15, and the tubes in the tube bundle are arranged in a stepped manner to form a stepped overflow; a high-pressure tube bundle support plate 3 and a low-pressure tube bundle support plate 14, which are respectively connected to the high-pressure tube bundle 4-8 and the low-pressure tube bundle 9-13; a demister 19 is located on the upper part of the flash tank body 2 to meet the need to remove liquid entrained in the flash gas.

[0022] When the device of the present invention is in use, the main slurry delivery pipeline 15 is connected to the limestone slurry delivery mechanism, and the limestone slurry in the desulfurization tower is delivered to the high-pressure tube bundle 4-8 and the low-pressure tube bundle 9-13 through the main slurry delivery pipeline 15 through the operation of the limestone slurry delivery mechanism and the booster pump 1, and then the limestone slurry overflows the high-pressure tube bundle 4-8 and the low-pressure tube bundle 9-13, and the limestone slurry is flashed in the flash tank 2, and the flashed limestone slurry falls into the slurry pool 16 at the bottom of the flash tank 2, so as to realize the slurry flashing without nozzles, prevent clogging and scaling, and improve the efficiency of slurry flashing;

[0023] It is also necessary to explain that the slurry pool 16 is located at the bottom of the flash tank 2. The desulfurization slurry circulation pump 18 can be used to extract the limestone slurry that falls into the slurry pool 16 after flash evaporation, so that the low-temperature slurry after flash evaporation enters the upper desulfurization spray tower through the output slurry pipeline 17, thereby realizing the slurry recycling and making full use of the waste heat of the desulfurization slurry to achieve the purpose of energy saving and consumption reduction.

[0024] refer to Figure 1 As shown, the high-pressure tube bundle support plate 3 and the low-pressure tube bundle support plate 14 are connected to the flash tank 2 by welding. Holes are opened on the plates, and they closely match the high-pressure tube bundle and the low-pressure tube bundle, which is beneficial to preventing vibration caused by slurry pressurization overflow and ensuring stable operation of the slurry.

[0025] refer to Figure 1 As shown, a demister 19 is installed in the flash tank 2, and the demister 19 is located above the flash tank 2. The demister plays a role in removing droplets carried in the flash gas, which is conducive to obtaining relatively clean and dry flash gas.

[0026] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the present invention and the drawings, or directly or indirectly applied in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A nozzle-free desulfurization slurry flash device, characterized in that: Including booster pump, flash tank, slurry main delivery pipeline, high pressure pipe bundle, low pressure pipe bundle, demister, slurry tank; The booster pump is located on the main slurry conveying pipeline; the high-pressure tube bundle and the low-pressure tube bundle are connected to the main slurry conveying pipeline, and the high-pressure tube bundle and the low-pressure tube bundle are respectively fixed in the flash tank through the high-pressure tube bundle support plate and the low-pressure tube bundle support plate; the demister is installed on the upper part of the flash tank body to remove the liquid entrained in the flash gas; the slurry pool is located in the lower tank body of the flash tank.

2. A nozzle-free desulfurization slurry flash device as claimed in claim 1, characterized in that: The tubes in the high-pressure tube bundle are arranged in a stepped manner, and the slurry flows along the tube wall for flash evaporation; the tubes in the low-pressure tube bundle are arranged in a stepped manner, and the slurry flows along the tube wall for flash evaporation.

3. A nozzle-free desulfurization slurry flash device as claimed in claim 1, characterized in that: The high-pressure tube bundle is supported by a high-pressure tube bundle support plate, and the high-pressure tube bundle support plate is connected to the flash tower by welding; The low-pressure tube bundle is supported by a low-pressure tube bundle support plate, and the low-pressure tube bundle support plate is connected to the flash tower by welding.

4. A nozzle-free desulfurization slurry flash device as claimed in claim 1, characterized in that: The demister is located at the top of the flash tank and before the flash gas outlet.

5. A working method of the desulfurization slurry waste heat utilization device based on the capillary structure according to any one of claims 1 to 5, characterized in that: The process includes the following: the desulfurization slurry at the bottom of the desulfurization tower is pumped out by a pressure pump and enters the main slurry transportation pipeline. The desulfurization slurry enters the high-pressure tube bundle and the low-pressure tube bundle along the main slurry transportation pipeline to overflow. The desulfurization slurry flows down along the tube wall to form a uniform liquid surface. The desulfurization slurry above the saturation temperature evaporates into water vapor under negative pressure conditions. The water vapor passes through the demister and is discharged from the steam outlet of the flash tank.

6. The working method according to claim 5, characterized in that: The desulfurization slurry flowing out of the high-pressure tube bundle and the low-pressure tube bundle finally flows into the slurry pool, and is pumped out by the desulfurization slurry circulation pump from the output slurry pipeline connected to the slurry pool into the highest spray layer of the desulfurization tower for spraying.

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