An integrated device of a flash tower and a capillary absorber and a working method thereof

Abstract

The present invention provides an integrated device of a flash tower and a capillary absorber and a working method thereof, comprising a desulfurization tower and a capillary absorber; the desulfurization tower is an inverted U-shaped structure, one side is a desulfurization flash side, and the other side is a solution absorption side; the capillary absorber is located in the solution absorption side, a concentrated solution inlet pipe is arranged above the capillary absorber, and the desulfurization tower is connected with a dilute solution outlet pipe and a vacuum pipe below the capillary absorber; the capillary absorber comprises a top capillary tube sheet and a bottom capillary tube sheet, the top capillary tube sheet and the bottom capillary tube sheet separate the inside of the solution absorption side, a plurality of capillaries are arranged between the top capillary tube sheet and the bottom capillary tube sheet, and the top and bottom ends of the capillaries are connected with the top capillary tube sheet and the bottom capillary tube sheet. The water in the desulfurization slurry after wet desulfurization in the thermal power system is evaporated, and the heat is carried and transported by water vapor in the form of latent heat, and the latent heat of water and water vapor is absorbed and recovered.

Description

Technical Field

[0001] The invention belongs to the field of absorption heat pumps and relates to an integrated device of a flash tower and a capillary absorber and a working method thereof. Background Art

[0002] As a device that uses heat sources to improve heat quality, absorption heat pumps have shown broad application prospects in the recovery and utilization of waste heat in power plants.

[0003] At present, closed absorption heat pumps are mostly used to recover waste heat from flue gas in power plants. Since flue gas contains a large amount of impurities, acidic gases and a high oxygen content, heat pump units are mostly closed to avoid flue gas erosion and corrosion of the absorber; the falling film absorber in the traditional heat pump adopts a single-diameter tube-in-tube structure. In order to avoid pipeline clogging and pipeline erosion damage caused by flue gas impurities, the pipe wall is thicker and the pipe diameter is larger. The closed absorption heat pump system cannot recover moisture in the flue gas. Summary of the invention

[0004] The object of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an integrated device of a flash tower and a capillary absorber and a working method thereof, so as to realize the evaporation of water in the desulfurization slurry after wet desulfurization in a thermal power system, and to carry the heat by water vapor in the form of latent heat, and to use an open absorption heat pump to recover the latent heat of water and water vapor during the absorption process.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An integrated device of a flash tower and a capillary absorber comprises a desulfurization tower and a capillary absorber;

[0007] The desulfurization tower is an inverted U-shaped structure, with one side being the desulfurization flash side and the other side being the solution absorption side; the capillary absorber is located in the solution absorption side, the desulfurization tower is provided with a concentrated solution inlet pipe above the capillary absorber, the desulfurization tower is connected with a dilute solution outlet pipe and a vacuum pipe below the capillary absorber, the vacuum pipe is located outside the desulfurization tower, and a vacuum pump is provided in the vacuum pipe;

[0008] The capillary absorber comprises a top capillary tube sheet and a bottom capillary tube sheet, the sides of which are connected to the inner wall of the solution absorption side to separate the interior of the solution absorption side, a plurality of capillaries are arranged between the top capillary tube sheet and the bottom capillary tube sheet, and the top and bottom ends of the capillaries are connected to the top capillary tube sheet and the bottom capillary tube sheet.

[0009] Preferably, the diameter of the top end of the capillary is smaller than that of the bottom end.

[0010] Preferably, the diameter of the capillary tube is 2 to 5 mm.

[0011] Preferably, a cooling water inlet and a cooling water outlet are provided on the tower wall located in the capillary region on the solution absorption side.

[0012] Preferably, the cooling water inlet is located on one side of the tower wall on the solution absorption side, close to the bottom capillary tube sheet, and the cooling water outlet is located on the other side of the tower wall on the solution absorption side, close to the top capillary tube sheet.

[0013] Preferably, a solution demister is provided at the top of the concentrated solution inlet pipe, and the solution demister completely covers the top area of ​​the concentrated solution inlet pipe.

[0014] Preferably, shielding plates are provided in front and on the top of one end of the vacuum pipe facing the interior of the desulfurization tower.

[0015] Preferably, a lithium bromide solution is provided in the concentrated solution inlet pipe.

[0016] A working method of the integrated device of the flash tower and the capillary absorber based on any one of the above items, comprising the following process:

[0017] The vacuum pump draws gas from the capillary and the desulfurization tower through the vacuum pipeline, so that both the desulfurization flash evaporation side and the solution absorption side are in a low-pressure environment; the desulfurization slurry enters the low-pressure environment of the desulfurization flash evaporation side and flashes to become water vapor; the water vapor and the solution injected from the concentrated solution inlet pipeline are mixed and enter the capillary. When the flow rate is low, the solution flows along the inside of the capillary and forms a liquid film on the surface of the capillary; when the water vapor passes through the capillary, the water vapor gas pressure is greater than the saturated vapor pressure on the surface of the solution, a condensation phase change occurs, and the capillary absorber releases heat.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention utilizes low-pressure flash evaporation to extract gas in the capillary and the desulfurization tower through a vacuum pump, so that the desulfurization flash evaporation side and the solution absorption side are both in a low-pressure environment, and the desulfurization slurry flashes in the low-pressure environment to become water vapor, thereby realizing the evaporation of water in the desulfurization slurry after wet desulfurization in the thermal power system, and allowing heat to be carried and transported by water vapor in the form of latent heat, thereby avoiding corrosion of the capillary heat exchanger; the structure of the capillary heat exchanger is adopted as the absorber of the open absorption heat pump, and the latent heat of water and water vapor is recovered during the absorption process, and the pipeline does not require a thick pipe wall and a large pipe diameter to be able to work normally.

[0020] Furthermore, by increasing the diameter of the lower end of the capillary, the heat exchange area between the cooling water at the end of the absorption process and the lithium bromide liquid membrane is expanded, the heat exchange capacity between the low-temperature cooling water at the end of the absorption process and the lithium bromide liquid membrane in the capillary is enhanced, and the temperature of the lithium bromide solution at the end of the absorption process is effectively reduced, thereby enhancing the ability of the lithium bromide solution at the lower end of the capillary to absorb water vapor, thereby ensuring the heat-raising and water-taking effect of the device.

[0021] Furthermore, a smaller tube diameter allows a thinner tube wall to meet the pressure difference requirements inside and outside the tube, so the thermal conductivity resistance of the tube wall is lower and the heat transfer capacity inside and outside is stronger; at the same time, a smaller tube diameter allows more capillaries to be arranged in the same space, and the absorption area is larger, thereby further increasing the absorption capacity of the solution.

[0022] Furthermore, the cooling water can reduce the temperature of the lithium bromide liquid film on the capillary wall, improve the absorption capacity, and after the cooling water is heated, it can be used in other places.

[0023] Furthermore, the purpose of the solution demister is to prevent the concentrated solution flowing into the concentrated solution inlet pipe from entering the desulfurization flash side while ensuring the passage of water vapor.

[0024] Further, the baffle can prevent solution from being sucked into the vacuum line. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the device structure of the present invention.

[0026] Among them: 1-desulfurization tower; 2-desulfurization slurry inlet pipe; 3-slurry nozzle; 4-slurry demister; 5-cold slurry collection pipe; 6-water vapor transport pipeline; 7-solution demister; 8-concentrated solution inlet pipe; 9-top capillary tube sheet; 10-capillary; 11-cooling water inlet; 12-cooling water outlet; 13-bottom capillary tube sheet; 14-shield; 15-vacuum pipe; 16-vacuum pump; 17-dilute solution outlet pipe. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0028] like Figure 1 As shown, the integrated device of the flash tower and the capillary absorber of the present invention comprises a desulfurization tower 1 and a capillary absorber.

[0029] The desulfurization tower 1 is an inverted U-shaped structure, consisting of a desulfurization slurry flash evaporation part on the left, a water vapor transport part on the top, and an open absorption heat pump solution absorption part on the right.

[0030] The left side desulfurization slurry flash part is the desulfurization flash side, including a desulfurization slurry inlet pipe 2, a slurry nozzle 3, a slurry demister 4 and a cold slurry collecting pipe 5; the desulfurization slurry inlet pipe 2 is located near the bottom of the desulfurization flash side, horizontally extending into the interior of the desulfurization flash side, the slurry nozzle 3 is distributed on the upper side of the desulfurization slurry inlet pipe 2, the slurry demister 4 is located above the desulfurization slurry inlet pipe 2, the purpose of setting the slurry demister 4 is to prevent the desulfurization slurry splashed from the slurry nozzle 3 from entering the water vapor transport pipeline 6 while ensuring the passage of water vapor; the cold slurry collecting pipe 5 is located at the bottom of the desulfurization flash side.

[0031] The top side water vapor transport part is a water vapor transport pipeline 6, and a solution demister 7 is arranged on the water vapor transport pipeline 6. The demister 7 separates the top side water vapor transport part and the right side open absorption heat pump solution absorption part.

[0032] The solution absorption part of the open absorption heat pump on the right side is the solution absorption side, including a concentrated solution inlet pipe 8, a capillary absorber, a cooling water inlet 11, a cooling water outlet 12, a baffle 14, a vacuum pipe 15, a vacuum pump 16 and a dilute solution outlet pipe 17.

[0033] The concentrated solution inlet pipe 8 is arranged above the capillary absorber, the dilute solution outlet pipe 17 and the vacuum pipe 15 are arranged below the capillary absorber, the vacuum pipe 15 is arranged outside the desulfurization tower 1, and a vacuum pump 16 is arranged inside the vacuum pipe 15. A shielding plate 14 is arranged in front of and on the top of one end of the vacuum pipe 15 facing the inside of the desulfurization tower 1.

[0034] The capillary absorber includes a top capillary tube sheet 9, capillaries 10 and a bottom capillary tube sheet 13. The sides of the top capillary tube sheet 9 and the bottom capillary tube sheet 13 are connected to the inner wall of the solution absorption side to separate the interior of the solution absorption side. A plurality of capillaries 10 are arranged between the top capillary tube sheet 9 and the bottom capillary tube sheet 13. The top and bottom ends of the capillaries 10 are connected to the top capillary tube sheet 9 and the bottom capillary tube sheet 13. The two ends of the capillaries 10 are respectively welded to the top capillary tube sheet 9 and the bottom capillary tube sheet 13 by vacuum brazing or laser welding. The top diameter of the capillary 10 is smaller than the bottom diameter, and the smallest diameter is about 2 mm.

[0035] A cooling water inlet 11 and a cooling water outlet 12 are provided on the tower wall in the capillary 10 area on the solution absorption side. The cooling water inlet 11 is located on one side of the tower wall on the solution absorption side, close to the bottom capillary tube sheet 13, and the cooling water outlet 12 is located on the other side of the tower wall on the solution absorption side, close to the top capillary tube sheet 9.

[0036] The present invention mainly realizes two functions. The first function converts the water in the desulfurization slurry into water vapor carrying latent heat by low-pressure flash evaporation. The vacuum pump 16 extracts the gas in the capillary 10 and the desulfurization tower 1 through the vacuum pipe 15, so that the desulfurization slurry inlet pipe 2 and the slurry nozzle 3 are in a low-pressure environment. The baffle 14 is to prevent the lithium bromide solution from being sucked into the vacuum pipe 15. The desulfurization slurry enters the slurry nozzle 3 along the desulfurization slurry inlet pipe 2, enters the low-pressure environment, and flashes and turns into water vapor. The slurry after flashing converges to the lower part under the action of gravity and is recycled through the cold slurry outlet pipe 5.

[0037] The function of the second part is to use an open absorption heat pump capillary absorber to absorb and utilize the flash steam latent heat and recover water. The water vapor flashed by the slurry nozzle 3 enters the capillary 10 through the water vapor transport pipeline 6, and the lithium bromide concentrated solution enters the capillary 10 through the concentrated solution inlet pipeline 8. The purpose of the solution demister 7 is to prevent the concentrated solution flowing into the concentrated solution inlet pipeline 8 from entering the left desulfurization part while ensuring the passage of water vapor. The purpose of the top capillary tube sheet 9 and the bottom capillary tube sheet 13 is to prevent the lithium bromide concentrated solution and water vapor from entering the outside of the capillary 10 and mixing with the cooling water.

[0038] The lithium bromide concentrated solution enters the capillary 10. When the flow rate is low, the lithium bromide concentrated solution flows along the inner side of the capillary 10 and forms a liquid film on the surface of the tube. When water vapor passes through the capillary 10, the water vapor gas pressure is greater than the saturated vapor pressure on the surface of the lithium bromide concentrated solution, so the water vapor enters the solution and undergoes a condensation phase change. As the solution absorbs water vapor, the concentration of the solution gradually decreases. Under the condition of constant temperature, the saturated vapor pressure on the surface of the solution gradually increases. Due to the influence of the vacuuming process, the vacuum degree in the capillary 10 becomes higher and higher, that is, the water vapor partial pressure in the tube gradually decreases. Therefore, it is necessary to adopt a cooling method to further reduce the temperature of the lithium bromide liquid film on the wall of the capillary 10 and improve the absorption capacity. Cooling water enters from the cooling water inlet 11 and forms a countercurrent flow with the liquid film in the capillary 10.

[0039] At the same time, by increasing the diameter of the lower end of the capillary 10, the heat exchange area between the cooling water at the end of the absorption process and the lithium bromide liquid membrane is expanded, the heat exchange capacity between the low-temperature cooling water at the end of the absorption process and the lithium bromide liquid membrane in the capillary 10 is enhanced, and the temperature of the lithium bromide solution at the end of the absorption process is effectively reduced, thereby enhancing the ability of the lithium bromide solution at the lower end of the capillary 10 to absorb water vapor, thereby ensuring the heat-raising and water-taking effect of the device.

[0040] The diameter of the capillary tube 10 is about 2 to 5 mm. The smaller tube diameter allows a thinner tube wall to meet the pressure difference requirement inside and outside the tube, so the thermal conductivity resistance of the tube wall is lower and the heat transfer capacity inside and outside is stronger; at the same time, the smaller tube diameter allows more capillaries 10 to be arranged in the same space, and the absorption area is larger, thereby further increasing the absorption capacity of the solution.

[0041] On the one hand, the present invention utilizes a low-pressure flash evaporation method to realize the evaporation of water in the desulfurization slurry after wet desulfurization in the thermal power system, and allows the heat to be carried and transported by water vapor in the form of latent heat; on the other hand, a heat exchanger with a capillary 10 as the main body is adopted to increase the membrane area and heat exchange area of ​​the absorber, and by changing the diameter distribution of the capillary 10, the heat exchange area between the end solution of the absorption process and the cooling water is increased, the heat exchange capacity is improved, the temperature of the end solution of the absorption process is effectively reduced, and the saturated vapor pressure of the end solution of the absorption process is reduced, thereby ensuring the absorption capacity of the end solution of the absorption process for water.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A working method of an integrated device of a flash tower and a capillary absorber, characterized in that: The integrated device comprises a desulfurization tower (1) and a capillary absorber; The desulfurization tower (1) is an inverted U-shaped structure, one side of which is a desulfurization flash side, and the other side of which is a solution absorption side; the capillary absorber is located in the solution absorption side; the desulfurization tower (1) is provided with a concentrated solution inlet pipe (8) above the capillary absorber; the desulfurization tower (1) is connected with a dilute solution outlet pipe (17) and a vacuum pipe (15) below the capillary absorber; the vacuum pipe (15) is located outside the desulfurization tower (1), and a vacuum pump (16) is provided in the vacuum pipe (15); The capillary absorber comprises a top capillary tube sheet (9) and a bottom capillary tube sheet (13); the sides of the top capillary tube sheet (9) and the bottom capillary tube sheet (13) are connected to the inner wall of the solution absorption side to separate the interior of the solution absorption side; a plurality of capillaries (10) are arranged between the top capillary tube sheet (9) and the bottom capillary tube sheet (13); the top and bottom ends of the capillaries (10) are connected to the top capillary tube sheet (9) and the bottom capillary tube sheet (13); The cooling water inlet (11) is located on one side of the tower wall on the solution absorption side, close to the bottom capillary tube sheet (13), and the cooling water outlet (12) is located on the other side of the tower wall on the solution absorption side, close to the top capillary tube sheet (9); A solution demister (7) is provided at the top of the concentrated solution inlet pipe (8), and the solution demister (7) completely wraps the top area of ​​the concentrated solution inlet pipe (8); The working method comprises the following processes: a vacuum pump (16) extracts gas from the capillary (10) and the desulfurization tower (1) through a vacuum pipe (15), so that both the desulfurization flash side and the solution absorption side are in a low-pressure environment; the desulfurization slurry enters the low-pressure environment of the desulfurization flash side and flashes to become water vapor; the water vapor and the solution injected from the concentrated solution inlet pipe (8) are mixed and then enter the capillary (10); when the flow rate is low, the solution flows along the inner side of the capillary (10) and forms a liquid film on the surface of the capillary (10); when the water vapor passes through the capillary (10), the water vapor gas pressure is greater than the saturated vapor pressure on the surface of the solution, a condensation phase change occurs, and the capillary absorber releases heat.

2. The working method of the integrated device of flash tower and capillary absorber according to claim 1, characterized in that: The diameter of the top end of the capillary (10) is smaller than the diameter of the bottom end.

3. The working method of the integrated device of flash tower and capillary absorber according to claim 1, characterized in that: The diameter of the capillary tube (10) is 2-5 mm.

4. The working method of the integrated device of flash tower and capillary absorber according to claim 1, characterized in that: A cooling water inlet (11) and a cooling water outlet (12) are provided on the tower wall located in the capillary tube (10) region on the solution absorption side.

5. The working method of the integrated device of flash tower and capillary absorber according to claim 1, characterized in that: A shielding plate (14) is provided in front of and on the top of one end of the vacuum pipe (15) facing the interior of the desulfurization tower (1).

6. The working method of the integrated device of flash tower and capillary absorber according to claim 1, characterized in that: A lithium bromide solution is provided in the concentrated solution inlet pipe (8).

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