A nozzle-free desulfurization slurry flash evaporation device and its working method

Abstract

This invention discloses a nozzle-free desulfurization slurry flash evaporation device and its operating method. The device includes a pressurizing pump, a flash tank, a main slurry delivery pipeline, a high-pressure tube bundle, a low-pressure tube bundle, a demister, a slurry pool, and a slurry circulation pump. The circulating slurry at the bottom of the desulfurization tower is drawn from the pressurizing pump into the main slurry delivery pipeline. The desulfurization slurry flows along the main slurry delivery pipeline, successively entering the high-pressure and low-pressure tube bundles for overflow. The slurry flows down the pipe walls, forming a uniform liquid surface. The desulfurization slurry, above its saturation temperature, evaporates into water vapor under negative pressure, and the water vapor is discharged from the steam outlet of the flash tower. This achieves deep recovery of flue gas waste heat, reduces pipe scaling and blockage, increases system safety, and makes waste liquid recovery more energy-efficient and environmentally friendly.

Description

Technical Field

[0001] This invention relates to the technology of waste heat recovery from flash evaporation of slurry after wet desulfurization in thermal power plants and the field of energy conservation and environmental protection technology, specifically to a nozzle-free flash evaporation device for desulfurization slurry and its working method. Background Technology

[0002] For a considerable period in the future, coal-fired power generation will remain the primary form of electricity production. Limestone-gypsum wet desulfurization technology is currently the most commonly used post-combustion flue gas desulfurization technology in coal-fired power plants. After desulfurization, the flue gas temperature drops from approximately 110°C to around 55°C, while the slurry temperature rises to around 55°C. The saturated wet steam contained in the flue gas carries a large amount of latent heat of vaporization. Direct emission into the air wastes water resources and can easily lead to environmental problems such as "gypsum rain." Desulfurization slurry flash evaporation and heat recovery technology is essentially a deep flue gas waste heat recovery technology. This technology utilizes the characteristic that the boiling point of the desulfurized slurry decreases with decreasing ambient pressure. By establishing a vacuum phase change environment, the slurry, whose temperature is above the saturation temperature under the current negative pressure, undergoes flash evaporation. This transfers the latent heat of vaporization carried by the negative pressure steam to a heat pump for condensation and heat release into a low-temperature medium, thus achieving deep recovery of flue gas waste heat. This technology can simultaneously achieve multiple objectives such as energy saving, water saving, improved desulfurization efficiency, and flue gas whitening, and can further achieve energy conservation and environmental protection goals.

[0003] Currently, commonly used desulfurization slurry flash evaporation devices typically employ nozzles for slurry spraying and flash evaporation. However, existing methods for utilizing latent heat are based on continuous operation. Since limestone slurry contains a large number of solid particles, long-term operation can easily lead to scaling and clogging of the nozzles, affecting flash evaporation efficiency and thus reducing the waste heat recovery effect of the slurry after desulfurization.

[0004] This desulfurization slurry flash evaporation device mainly uses a slurry circulation pump to pressurize the slurry, causing it to overflow directly from the pipe without the need for spraying nozzles. The slurry flows along the pipe to form a liquid film, thereby evaporating and condensing the water in the slurry, achieving deep recovery of waste heat from the flue gas, reducing pipeline structure, increasing system safety, and making waste liquid recovery more energy-efficient and environmentally friendly. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a nozzle-free desulfurization slurry flash evaporation device and its operating method. The desulfurization slurry flash evaporation device of the present invention mainly uses a slurry circulation pressurization pump to pressurize the slurry, causing it to overflow 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, achieving deep recovery of waste heat from flue gas, reducing pipeline structure, increasing system safety, and making waste liquid recovery more energy-efficient and environmentally friendly.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A nozzle-free desulfurization slurry flash evaporation device includes a pressurization pump, a flash tank, a main slurry delivery pipeline, a high-pressure tube bundle, a low-pressure tube bundle, a demister, and a slurry pool.

[0008] The pressurizing pump is located on the main slurry delivery pipeline; the high-pressure tube bundle and the low-pressure tube bundle are connected to the main slurry delivery pipeline, and the high-pressure tube bundle and the low-pressure tube bundle are fixed in the flash tank by 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 to remove liquid entrained in the flash vapor; the slurry pool is located in the lower part of the flash tank; the desulfurization slurry at the bottom of the desulfurization tower is drawn out by the pressurizing pump and enters the main slurry delivery pipeline, and the desulfurization slurry flows into the high-pressure tube bundle and the low-pressure tube bundle successively along the main slurry delivery pipeline for overflow, and the desulfurization slurry flows down the pipe wall to form a uniform liquid surface. The desulfurization slurry above the saturation temperature evaporates into water vapor under negative pressure, 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 drawn out by the desulfurization slurry circulation pump to enter 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, which is welded to the flash tower; the low-pressure tube bundle is supported by a low-pressure tube bundle support plate, which is welded to the flash tower.

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

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

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

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

[0015] This invention utilizes a nozzle-less desulfurization slurry flash evaporation device to perform slurry spray flash evaporation, achieving phase change heat transfer of water in the desulfurization slurry, deeply recovering waste heat from flue gas, improving waste heat recovery efficiency, and achieving energy saving; it also achieves the recovery of high-cleanliness water in the desulfurization slurry, thus saving water and increasing the degree and flexibility of waste heat recovery in thermal power plants.

[0016] The present invention employs a nozzle-free desulfurization slurry spraying device, which pressurizes the slurry by a slurry circulation pump, allowing the slurry to overflow directly from the pipe without the need for nozzle spraying. This avoids the problem of nozzle scaling and clogging caused by long-term operation, extends the service life of the equipment, and improves the degree of waste heat recovery of the desulfurization slurry. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a nozzle-less desulfurization slurry flash evaporation device according to the present invention.

[0018] Reference numerals in the attached drawings: 1-Pressure 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-Main slurry delivery pipeline; 16-Slurry tank; 17-Output slurry pipeline; 18-Desulfurization slurry circulation pump; 19-Demister. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0020] Please refer to the following: Figure 1 This embodiment discloses a nozzle-free desulfurization slurry flash evaporation device, comprising a pressurizing 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 main slurry delivery pipeline 15, a slurry pool 16, an output slurry pipeline 17, a desulfurization slurry circulation pump 18, and a demister 19. The main slurry delivery pipeline 15 is connected to each pressure tube bundle, and the slurry flows along the pipe wall for flash evaporation, finally being collected in the slurry pool 16. The output slurry pipeline 17 is connected to the slurry pool 16, and the slurry is drawn out of the flash tank 2 by the desulfurization slurry circulation pump 18, completing one flash evaporation cycle.

[0021] Figure 1This is a schematic diagram of a nozzle-free desulfurization slurry flash evaporation device. The device, designed to improve slurry flash evaporation efficiency while preventing scaling and clogging in the flash tank, includes: a high-pressure tube bundle 4-8 connected to the main slurry delivery pipeline 16, with each tube arranged in a stepped manner to form a stepped overflow; a low-pressure tube bundle 9-14 connected to the main slurry delivery pipeline 15, with each tube 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, respectively connected to the high-pressure tube bundle 4-8 and the low-pressure tube bundle 9-13; and a demister 19 located on the upper part of the flash tank body 2 to remove liquid entrained in the flash vapor.

[0022] When the device of the present invention is in use, the main slurry conveying pipeline 15 is connected to the limestone slurry conveying mechanism. Through the operation of the limestone slurry conveying mechanism and the pressurizing pump 1, the limestone slurry in the desulfurization tower is conveyed to the high-pressure tube bundle 4-8 and the low-pressure tube bundle 9-13 through the main slurry conveying pipeline 15. Then the limestone slurry overflows from the high-pressure tube bundle 4-8 and the low-pressure tube bundle 9-13. The limestone slurry is flashed in the flash tank 2. After flashing, the limestone slurry falls into the slurry pool 16 at the bottom of the flash tank 2, realizing slurry flashing without nozzles, preventing clogging and scaling and improving the efficiency of slurry flashing.

[0023] It should also be noted that the slurry tank 16 is located at the bottom of the flash tank 2. The limestone slurry that falls into the slurry tank 16 after flashing can be extracted by the desulfurization slurry circulation pump 18. This allows the low-temperature slurry after flashing to enter the upper desulfurization spray tower through the slurry output pipeline 17, realizing the recycling of slurry. At the same time, it makes full use of the waste heat of the desulfurization slurry, achieving 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 welded to the body of the flash tank 2. The plates have openings and fit tightly with the high-pressure tube bundle and the low-pressure tube bundle to prevent vibration caused by slurry pressurization overflow and to ensure stable operation of the slurry.

[0025] refer to Figure 1 As shown, a demister 19 is installed inside the flash tank 2, and the demister 19 is located above the flash tank 2. The demister removes liquid droplets carried in the flash vapor, which helps to obtain relatively clean and dry flash vapor.

[0026] The above are merely embodiments of the present invention and do not limit the scope of the present invention. Any equivalent structural or procedural transformations made using the present invention and its drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of the present invention.

Claims

1. A nozzle-free desulfurization slurry flash evaporation device, characterized in that, Includes a booster pump, flash tank, main slurry delivery pipeline, high-pressure tube bundle, low-pressure tube bundle, demister, and slurry tank; The pressurizing pump is located on the main slurry delivery pipeline; the high-pressure tube bundle and the low-pressure tube bundle are connected to the main slurry delivery pipeline, and the high-pressure tube bundle and the low-pressure tube bundle are fixed in the flash tank by 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 to remove liquid entrained in the flash vapor; the slurry pool is located in the lower part of the flash tank; the slurry overflows from the high-pressure tube bundle and the low-pressure tube bundle.

2. The nozzle-free desulfurization slurry flash evaporation device as described 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. The nozzle-less desulfurization slurry flash evaporation device as described in claim 1, characterized in that, The high-pressure tube bundle is supported by a high-pressure tube bundle support plate, which is connected to the flash tower by welding. The low-pressure tube bundle is supported by a low-pressure tube bundle support plate, which is connected to the flash tower by welding.

4. The nozzle-less desulfurization slurry flash evaporation device as described in claim 1, characterized in that, The demister is located at the top of the flash tank, before the flash vapor outlet.

5. A method for operating a nozzleless desulfurization slurry flash evaporation device according to any one of claims 1-4, characterized in that, The process includes the following steps: the desulfurization slurry at the bottom of the desulfurization tower is pumped out by a pressurized pump and enters the main slurry delivery pipeline. The desulfurization slurry flows into the high-pressure tube bundle and the low-pressure tube bundle along the main slurry delivery pipeline for overflow. The desulfurization slurry flows down the pipe wall to form a uniform liquid surface. The desulfurization slurry above the saturation temperature evaporates into water vapor under negative pressure. The water vapor passes through the demister and is discharged from the steam outlet of the flash tank.

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

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