Compact ultralow-emission desulfurizing tower

Abstract

The utility model discloses a compact ultralow-emission desulfurizing tower. A tower body is provided with a slurry tank, a flue gas inlet and a flue gas outlet; a lower-layer gas-liquid distributor, a lower-layer spraying layer, an upper-layer gas-liquid distributor, an upper-layer spraying layer, a liquid holding layer and a plurality of layers of ridge type demisters are arranged in the tower body in sequence from low to high in an area between the flue gas inlet and the flue gas outlet; a plurality of layers of supporting beams are arranged in the tower body, and the lower spraying layer, the upper gas-liquid distributor, the liquid distribution pipe in the liquid holding layer, the lowest ridge type demister and the rest two adjacent layers of ridge type demisters are fixed on the same layer of supporting beams; the lower spraying layer and the upper spraying layer are both connected with the slurry tank to form a circulation loop, a liquid holding layer circulation box is further arranged outside the tower body, and the liquid holding layer and the liquid holding layer circulation box form a circulation loop. The ultra-low emission is realized, the height of the tower is at least reduced by more than 10m, a demister outside the tower does not need to be arranged, and the construction cost and the design difficulty are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to waste gas treatment technical field, concretely relates to compact type ultra -low emission desulfurizer. BACKGROUND

[0002] Coal-fired power generation is the "cleanest" way of coal resource utilization, and concentrating the use of coal in electric coal is undoubtedly the most correct choice. The application of ultra-low emission technology in coal-fired power plants has achieved remarkable results. After the ultra-low emission transformation, the gas pollutant emission concentration of the power plant basically reaches the emission limit value of gas turbine unit, the smoke dust is less than or equal to 10 mg / Nm 3 , SO2 is less than or equal to 35 mg / Nm 3 , NO x is less than or equal to 50 mg / Nm 3 , which greatly improves the public's confidence in clean coal utilization.

[0003] To achieve more stringent emission standards, the current main methods are to increase the number of spray layers of the desulfurizer and the circulating flow of the slurry in the spray layer, to set single-tower double circulation or double-tower double circulation. Although this scheme meets the requirements of ultra-low or ultra-ultra-low emission of sulfur dioxide and dust, it significantly increases the height or arrangement space of the desulfurizer, greatly increases the investment cost and design difficulty, and is difficult to implement efficiency improvement transformation for some existing units with limited tower height or tower external arrangement space.

[0004] The prior art discloses a high-efficiency gradual change grading composite desulfurizer, which comprises a tower body, the tower body comprises an oxidation crystallization section, a rough desulfurization and dust removal section, a fine desulfurization and dust removal section and a horizontal demisting section from bottom to top; the oxidation crystallization section comprises a slurry pool and a separation mechanism arranged in the slurry pool and dividing the slurry pool into two upper and lower zones; the rough desulfurization and dust removal section comprises a gas distribution plate arranged above a flue gas inlet and a plurality of spray layers connected with the slurry pool; the fine desulfurization and dust removal section comprises a tubular demister, a flushing layer, a thin film liquid holding layer and a liquid holding layer circulating tank, and the PH value of the slurry in the liquid holding layer circulating tank is greater than that of the slurry in the slurry pool. The utility model is used for treating medium-high sulfur coal and high-sulfur coal flue gas, has very high desulfurization efficiency and dust removal performance, and the desulfurization efficiency is more than 99%. The flue gas passes through the plurality of spray layers and the variable-diameter liquid holding layer, so that the purpose of ultra-low emission of outlet flue gas is achieved. However, the plurality of spray layers and the variable-diameter liquid holding layer significantly increase the tower height, and the tower outlet flue gas demister occupies the external arrangement space of the tower. SUMMARY

[0005] In view of the above defects in the prior art, a compact type ultra-low emission desulfurizer is provided, which realizes ultra-low emission of sulfur dioxide and dust through single-tower double circulation and tower internals, and at the same time realizes ultra-low emission, the tower height is reduced by at least more than 10 m, and there is no need to set a tower external demister, which reduces the engineering cost and design difficulty, and is particularly suitable for transformation projects with limited tower height or limited external arrangement.

[0006] The utility model discloses a technical scheme for solving the above technical problems is:

[0007] Compact ultra-low emission desulfurization tower, including tower body, be equipped with slurry pool in the bottom of tower body, be equipped with flue gas inlet on the lateral wall of tower body, be equipped with flue gas outlet in the top of tower body, its characterized in that:

[0008] The region between the flue gas inlet and the flue gas outlet in the tower body is sequentially provided with a lower gas-liquid distributor, a lower spray layer, an upper gas-liquid distributor, an upper spray layer, a liquid holdup layer, and a plurality of ridge-type mist eliminators from low to high. A plurality of support beams are vertically spaced in the tower body. The lower spray layer and the upper gas-liquid distributor are fixed on the same layer of support beams. The liquid distribution pipes in the liquid holdup layer and the lowermost ridge-type mist eliminator are fixed on the same layer of support beams. The remaining ridge-type mist eliminators are fixed on the same layer of support beams.

[0009] The lower spray layer and the upper spray layer are connected to the slurry pool to form a circulation loop. A liquid holdup layer circulation tank is also provided outside the tower body. The liquid holdup layer and the liquid holdup layer circulation tank form a circulation loop. The slurry pool is designed with an expanded diameter.

[0010] According to the above technical scheme, the liquid holdup layer includes liquid distribution pipes, liquid film absorption layers, and liquid collection pipes from top to bottom. The liquid collection pipes are connected to the side wall bottom of the liquid holdup layer circulation tank through a connecting pipeline, and a first circulation pump is provided on the connecting pipeline. The liquid collection pipes are connected to the top of the liquid holdup layer circulation tank. A liquid holdup layer desulfurizer supply pipeline is also provided in the liquid holdup layer circulation tank.

[0011] According to the above technical scheme, the height of the desulfurization slurry on the liquid film absorption layer is 10-150 mm.

[0012] According to the above technical scheme, two branches are provided at the outlet of the liquid holdup layer circulation pump. One branch is connected to the liquid collection pipes, and the other branch is connected to the slurry pool.

[0013] According to the above technical scheme, the ridge-type mist eliminator has three layers. The top layer and the middle layer of the ridge-type mist eliminator are fixed on the same layer of support beams. The bottom layer of the ridge-type mist eliminator is connected to the liquid distribution pipes of the liquid holdup layer.

[0014] According to the above technical scheme, the upper spray layer is connected to the lower side wall of the slurry pool through a pipeline, and a second circulation pump is provided on the pipeline. The lower spray layer is connected to the upper side wall of the slurry pool through a pipeline, and a third circulation pump is provided on the pipeline.

[0015] According to the above technical scheme, the lower spray layer and the upper tower spray layer are at least 1 layer. The nozzles on the spray layer are double-head atomizing nozzles.

[0016] According to the technical scheme, the lower gas-liquid distributor adopts non-uniform hole arrangement, and the upper gas-liquid distributor adopts uniform hole arrangement.

[0017] According to the technical scheme, the pulp tank is provided with a pulp tank stirrer, an oxidation air pipe and a pulp tank gypsum liquid discharge pipeline, wherein the pulp tank stirrer is arranged in the middle of the side wall of the pulp tank in a circumferential interval; the oxidation air pipe is located above the pulp tank stirrer, and the pulp tank gypsum liquid discharge pipeline is located at the bottom of the side wall of the pulp tank.

[0018] According to the technical scheme, the expansion ratio of the pulp tank is 1.2.

[0019] The utility model has the following beneficial effects:

[0020] 1、Pulp tank adopts expansion design, absorption area includes two layers of gas-liquid distributor and multiple spray layers, two layers of gas-liquid distributor are inserted into lower part of spray layer and between spray layers respectively without increasing the height of absorption area, the lowermost spray layer shares a support beam with upper gas-liquid distributor, liquid holding layer is equal in diameter with absorption area; the lowermost demister and liquid distribution pipe of liquid holding layer share a support beam, and the rest of the demisters are arranged in a diamond shape and share a support beam. The above-mentioned desulfurization tower realizes ultra-low emission of sulfur dioxide and dust through single tower double circulation and tower internals, and at the same time of realizing ultra-low emission, the height of the tower is reduced by at least 10m or more, and there is no need to set up tower outer demister, which reduces engineering cost and design difficulty, and is especially suitable for transformation projects with limited tower height or limited tower outer arrangement.

[0021] 2、Liquid holding layer is provided with a layer of liquid film (liquid film absorption layer), and limestone slurry or lime slurry and other desulfurizing agents are added in the liquid film, which covers the entire flow cross section. When the flue gas passes through the liquid film, the flue gas is disturbed and fully contacts with the liquid film, and the sulfur dioxide in the flue gas is absorbed by the desulfurizing agent, which further improves the desulfurization efficiency.

[0022] 3、The spray section is divided into two stages by using the gas-liquid distributor, the lower spray layer directly sprays the slurry of the pulp tank to remove the sulfur dioxide in the flue gas; the upper spray layer adds limestone slurry at the inlet of the circulating pump through the desulfurizing agent supply pipeline, which improves the pH value of the spray slurry and removes the flue gas. The pH value of the spray section is divided in this embodiment, which significantly improves the desulfurization efficiency compared with the conventional spray section.

[0023] 4、The lower gas-liquid distributor adopts non-uniform hole arrangement, and the hole arrangement is adapted to the flue gas distribution, which can effectively distribute the flue gas and solve the problem of flue gas deflection, further improving the desulfurization performance. At the same time, the gas-liquid distributor increases the residence time of the slurry, strengthens the gas-liquid mass transfer, and therefore improves the SO2 removal efficiency.

[0024] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the description, the following is a detailed description of the preferred embodiments of the present invention with the accompanying drawings. The specific implementation methods of the present invention are given in detail in the following embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0026] Figure 1 It is a structural schematic diagram of an embodiment provided by the utility model;

[0027] In the figure, 1. tower body; 2. slurry pool; 3. flue gas inlet; 4. flue gas outlet; 5. lower gas-liquid distributor; 6. lower spray layer; 7. upper gas-liquid distributor; 8. upper spray layer; 9. ridge-type demister; 10. support beam; 11. liquid holding layer circulation box; 12. liquid distribution pipe; 13. liquid film absorption layer; 14. liquid collecting pipe; 15. first circulation pump; 16. liquid holding layer circulating slurry discharge pipe; 17. second circulation pump; 18. desulfurizer supply pipe; 19. slurry pool agitator; 20. oxidation air pipe; 21. slurry pool gypsum liquid discharge pipe; 22. third circulation pump; 23. liquid holding layer desulfurizer supply pipe. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1 The principles and features of the present invention are described, and the examples provided are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are greatly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0029] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a central component. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. The use herein of the terms "and / or" includes a set of one or more associated listed items.

[0031] Referring to Figure 1 The compact ultra-low emission desulfurization tower provided by the application.

[0032] Embodiment 1

[0033] The tower body 1 is provided with a slurry pool 2 at the bottom, a flue gas inlet 3 on the sidewall, and a flue gas outlet 4 at the top.

[0034] The region between the flue gas inlet and the flue gas outlet in the tower body is provided with, from low to high, a lower gas-liquid distributor 5, a lower spray layer 6, an upper gas-liquid distributor 7, an upper spray layer 8, a liquid holding layer 12 / 13 / 14, and a plurality of ridge-type mist eliminators 9; and a plurality of support beams 10 are provided in the tower body in the vertical direction at intervals, wherein the lower spray layer and the upper gas-liquid distributor are fixed on the same layer of support beams, the liquid distribution pipes in the liquid holding layer and the lowest ridge-type mist eliminator are fixed on the same layer of support beams, and the remaining ridge-type mist eliminators are fixed on the same layer of support beams in adjacent two layers.

[0035] The lower spray layer and the upper spray layer are connected with the slurry pool to form a circulation loop, and a liquid holding layer circulation tank 11 is further provided outside the tower body, and the liquid holding layer and the liquid holding layer circulation tank form a circulation loop; the slurry pool adopts an expanded diameter design.

[0036] In this embodiment, the desulfurization tower absorption section is composed of a gas-liquid distributor, a spray layer, a liquid holding layer, and a mist eliminator, the spray section and the liquid holding layer are two independent circulation systems, both have desulfurization function, the mist eliminator has mist elimination function, and the three sections all have synergistic dust removal function, so the desulfurization tower has both desulfurization and dust removal functions. The above device realizes ultra-low emission of flue gas multi-pollutants through two independent circulation and tower internals, and meets the outlet SO2<20mg / m 3 , and smoke dust <3mg / m 3 .

[0037] In addition, the pulp pool adopts an expanded diameter design, the absorption zone includes two layers of gas-liquid distributors and multiple spray layers, the two layers of gas-liquid distributors are respectively inserted into the lower part of the spray layer and between the spray layers without increasing the height of the absorption zone, the lowermost spray layer shares a support beam with the upper gas-liquid distributor, the liquid holding layer has the same diameter as the absorption zone; the lowermost demister and the liquid distribution pipe of the liquid holding layer share a support beam, and the remaining demisters are arranged in a diamond shape and share a support beam. The above desulfurization tower realizes ultra-low emission of sulfur dioxide and dust through single-tower double circulation and tower internals, and at the same time of realizing ultra-low emission, the tower height is reduced by at least 10 m or more, and there is no need to set a demister outside the tower, thereby reducing the engineering cost and design difficulty, and being particularly suitable for transformation projects with limited tower height or limited external arrangement.

[0038] Example 2

[0039] The structure and principle of Example 2 are close to those of Example 1, and the difference lies in that a holding layer arrangement form is given. The holding layer includes, from top to bottom, a liquid distribution pipe 12, a liquid film absorption layer 13, and a liquid collection pipe 14, the liquid collection pipe and a holding layer circulation tank side wall bottom are connected through a connecting pipe, and a first circulation pump 15 is arranged on the connecting pipe; the liquid collection pipe and the top of the holding layer circulation tank are connected; a holding layer desulfurization agent supply pipe 23 is further arranged in the holding layer circulation tank. Preferably, the height of the desulfurization slurry on the liquid film absorption layer is 10-150 mm.

[0040] The holding layer is provided with a liquid film (liquid film absorption layer), and a desulfurization agent such as limestone slurry or lime slurry is added in the liquid film, which covers the entire flow cross section. When the flue gas passes through the liquid film, the flue gas is disturbed and fully contacts the liquid film, and the sulfur dioxide in the flue gas is absorbed by the desulfurization agent, further improving the desulfurization efficiency.

[0041] In Example 2, two branches are arranged at the outlet of the holding layer circulation pump, one branch is connected with the liquid collection pipe, and the other branch is connected with the pulp pool, as shown in the figure, and the other branch is a holding layer circulation slurry discharge pipe 16.

[0042] In Examples 1-2, the ridge-type demister is provided with three layers, the top ridge-type demister and the middle ridge-type demister are fixed on the same support beam, and the bottom ridge-type demister is connected with the liquid distribution pipe of the holding layer.

[0043] Example 3

[0044] The structure and principle of embodiment 3 are similar to those of embodiment 1, except that the upper spray layer is connected to the lower sidewall of the slurry pool through a pipeline, and a second circulating pump 17 is arranged on the pipeline; the lower spray layer is connected to the upper sidewall of the slurry pool through a pipeline, and a third circulating pump 22 is arranged on the pipeline. In order to ensure the desulfurization effect of the upper spray layer, a desulfurizer supplement pipeline 18 is arranged on the pipeline at the inlet of the second circulating pump.

[0045] The spray section is divided into two stages by using a gas-liquid distributor. The lower spray layer directly uses the slurry of the slurry pool for spraying, and the sulfur dioxide in the flue gas is preliminarily removed. The upper spray layer adds limestone slurry through a desulfurizer supplement pipeline at the inlet of the circulating pump, which increases the pH value of the spray slurry and performs fine removal on the flue gas. This embodiment realizes pH value zoning in the spray section, which significantly improves the desulfurization efficiency compared with the conventional spray section.

[0046] Preferably, the lower spray layer and the upper tower spray layer are each at least one layer, and the nozzles on the spray layer are double-head atomizing nozzles. The lower gas-liquid distributor adopts a non-uniform opening arrangement, and the upper gas-liquid distributor adopts a uniform opening arrangement.

[0047] The lower gas-liquid distributor adopts a non-uniform opening arrangement, which is adapted to the flue gas distribution and can effectively distribute the flue gas, solve the flue gas deflection problem, and further improve the desulfurization performance. At the same time, the gas-liquid distributor increases the slurry residence time and strengthens the gas-liquid mass transfer, thereby improving the SO2 removal efficiency.

[0048] Embodiment 4

[0049] The structure and principle of embodiment 4 are similar to those of embodiment 1, except that a slurry pool agitator 19, an oxidation air pipe 20, and a slurry pool gypsum liquid discharge pipeline 21 are arranged in the slurry pool, wherein the slurry pool agitator is arranged in the middle of the sidewall of the slurry pool in a circumferential direction; the oxidation air pipe is located above the slurry pool agitator, and the slurry pool gypsum liquid discharge pipeline is located at the bottom of the sidewall of the slurry pool.

[0050] Preferably, the expansion ratio of the slurry pool is at least 1.2.

[0051] In addition, the device also has a synergistic dust removal function: the spraying section, the liquid holding layer and the demisting section all have a synergistic dust removal function. The slurry of the spraying section is sprayed out by multiple nozzles of each spraying layer, moves downward, and contacts the flue gas in counterflow, so that the dust particles in the gas flow and the liquid droplets have inertia collision, interception, diffusion, coagulation and gravity settling, etc., so that the dust is captured. The gas-liquid distributor uniformly distributes the flue gas, and the flue gas and the slurry are fully mixed and contacted on the device, thereby improving the dust removal efficiency. However, the desulfurization section has a relatively low dust removal efficiency for fine dust in the flue gas, especially PM2.5 and finer dust. The liquid holding layer has a liquid film, and the flue gas enters the liquid film to generate a large number of bubbles to form a foam layer. The smoke dust is disturbed by the foam under the action of inertia and diffusion, and constantly changes direction, thereby increasing the contact probability of the smoke dust and the liquid, and the flue gas is further purified. The dust removal effect of the bubble type dust collector is higher than that of the spray tower dust collector, especially in removing PM2.5 and finer dust, which is much higher than the dust removal efficiency of the spraying layer. In addition, the temperature of the circulating liquid of the liquid film is lower than the temperature of the flue gas, and the flue gas is cooled after entering the liquid film. In the process of condensing the water vapor in the flue gas into liquid droplets, fine dust, including part of the aerosol, is wrapped to form larger liquid droplets, so that they can be removed by the liquid film or the subsequent demister, thereby further improving the overall dust removal efficiency.

[0052] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any person skilled in the art can easily implement the present application according to the above description and the drawings. However, any equivalent changes, modifications and evolution of the above-mentioned technical content within the scope of the technical scheme of the present application are also equivalent embodiments of the present application. Meanwhile, any equivalent changes, modifications and evolution of the above-mentioned technical content within the scope of the technical scheme of the present application are also equivalent embodiments of the present application.

Claims

1. A compact ultra-low emission desulfurization tower, comprising a tower body, a slurry pool arranged at the bottom of the tower body, a flue gas inlet arranged on the sidewall of the tower body, and a flue gas outlet arranged at the top of the tower body; characterized in that: a region between the flue gas inlet and the flue gas outlet in the tower body is sequentially provided with a lower gas-liquid distributor, a lower spray layer, an upper gas-liquid distributor, an upper spray layer, a liquid holdup layer, and a plurality of ridge-type mist eliminators from low to high; and a plurality of support beams are arranged in the tower body in the vertical direction at intervals, wherein the lower spray layer and the upper gas-liquid distributor are fixed on the same layer of support beams, the liquid distribution pipe in the liquid holdup layer and the lowest ridge-type mist eliminator are fixed on the same layer of support beams, and the remaining ridge-type mist eliminators are fixed on the same layer of support beams in adjacent two layers. The lower spray layer and the upper spray layer are connected with the slurry pool to form a circulation loop, and a liquid holdup layer circulation tank is further arranged outside the tower body, and the liquid holdup layer and the liquid holdup layer circulation tank form a circulation loop; the slurry pool is designed with an expanded diameter. The liquid holdup layer comprises a liquid distribution pipe, a liquid film absorption layer, and a liquid collection pipe from top to bottom, the liquid collection pipe and the sidewall bottom of the liquid holdup layer circulation tank are connected through a connecting pipeline, and a first circulation pump is arranged on the connecting pipeline; the liquid collection pipe and the top of the liquid holdup layer circulation tank are connected; and a liquid holdup layer desulfurization agent supply pipeline is further arranged in the liquid holdup layer circulation tank.

2. The compact ultra-low emission desulphurization tower according to claim 1, characterized in that: The height of the desulfurization slurry on the liquid film absorption layer is 10-150 mm.

3. The compact ultra-low emission sulphur removal tower according to claim 1, wherein: Two branches are arranged at the outlet of the liquid holdup layer circulation pump, one branch is connected with the liquid collection pipe, and the other branch is connected with the slurry pool.

4. The compact ultra-low emission sulphur removal tower according to claim 2, wherein: The ridge-type mist eliminator is provided with three layers, the top layer and the middle layer of the ridge-type mist eliminator are fixed on the same layer of support beams, and the bottom layer of the ridge-type mist eliminator is connected with the liquid distribution pipe of the liquid holdup layer.

5. The compact ultra-low emission sulphur removal tower according to claim 1, wherein: The upper spray layer is connected with the lower sidewall of the slurry pool through a pipeline, and a second circulation pump is arranged on the pipeline; and the lower spray layer is connected with the upper sidewall of the slurry pool through a pipeline, and a third circulation pump is arranged on the pipeline.

6. The compact ultra-low emission sulphur removal tower according to claim 1, characterized in that: The lower spray layer and the upper spray layer are each at least one layer, and the nozzles on the spray layer are double-head atomizing nozzles.

7. The compact ultra-low emission desulphurization tower according to claim 1 or 6, characterized in that: The lower gas-liquid distributor is arranged with non-uniform openings, and the upper gas-liquid distributor is arranged with uniform openings.

8. The compact ultra-low emission sulphur removal tower according to claim 1, characterized in that: A slurry pool agitator, an oxidation air pipe, and a slurry pool gypsum liquid discharge pipeline are arranged in the slurry pool, wherein the slurry pool agitator is circumferentially arranged at intervals on the middle part of the sidewall of the slurry pool; the oxidation air pipe is located above the slurry pool agitator, and the slurry pool gypsum liquid discharge pipeline is located at the bottom of the sidewall of the slurry pool.

9. The compact ultra-low emission sulphur removal tower according to claim 1, characterized in that: The expansion ratio of the slurry pool is at least 1.

2.

10. The compact ultra-low emission sulphur removal tower according to claim 1, characterized in that: ​

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