CN110026036A - Flue gas aerosol removing means - Google Patents

Abstract

The invention provides a flue gas aerosol removing device. The device includes a humidification unit and an aerosol removal tower, the humidification unit has a clean flue gas inlet of the desulfurization tower; the aerosol removal tower includes a first aerosol water washing section, a second aerosol water washing section and a mist eliminator in sequence from bottom to top , the lower part of the first aerosol water washing section is provided with a humidified flue gas inlet, which is connected with the outlet of the humidification unit. The humidification unit first humidifies the desulfurized clean flue gas, which can make the flue gas reach a supersaturated state. After the flue gas is supersaturated, the diameter of a small amount of dust and slurry particles in the flue gas will increase, and the increased diameter particles are easily dissolved and absorbed by the circulating aqueous solution. Then, the humidified flue gas is washed twice by the aerosol removal tower, and the aerosol in the flue gas is dissolved into the aqueous solution in the gas-liquid collision contact and removed. Using the above device to remove aerosols in the desulfurization flue gas has the advantages of simple overall process, small investment, short construction period and ultra-low emission of aerosols.

Description

Flue gas aerosol removal device

technical field

The invention relates to the technical field of flue gas purification, in particular to a flue gas aerosol removal device.

Background technique

With the increasing improvement of national environmental protection standards, the flue gas of in-use boiler flue gas desulfurization devices has been subjected to desulfurization and denitrification transformation. The desulfurization process can basically be divided into dry, semi-dry and wet processes. Most factories sample the wet desulfurization process. , Large-scale power plants mainly use limestone gypsum method, and small and medium-sized boilers use ammonia desulfurization technology. Due to the defects of some ammonia desulfurization technology in the early stage, the emission concentration of flue gas aerosol after desulfurization remains high, causing new environmental pollution. .

Using ammonia desulfurization process, the flue gas is sprayed and absorbed by multi-stage slurry, purified and then discharged to the atmosphere through the chimney. Due to the controlled fluctuation of the desulfurization process spray absorption slurry pH, slurry concentration, spray density, oxidation degree and other indicators, the unremoved SO ₂ and escaped free NH ₃ will form aerosols with extremely small particle size in the flue gas At the same time, the flue gas passes through the spray layer, and the extremely fine slurry droplets atomized by the nozzle are entrained by the airflow. The diameter of the particles in the form of aerosols in the flue gas is generally less than 0.1 microns, which cannot be placed on the top of the tower. Conventional defogging removed by the device and discharged into the atmosphere.

In the conventional ammonia desulfurization process, a mist eliminator is designed on the upper part of the spray absorption layer, but the mist eliminator can only remove large particles above 15 microns, and the aerosol cannot be removed; some advanced ammonia desulfurization processes control the top layer by controlling the mist eliminator. The pH of the sprayed slurry in the absorption section is acidic, which prevents the escape of ammonia and reduces the generation of aerosols, but the efficiency is limited, and the fine slurry particles entrained in the gas phase cannot be prevented; there is a desulfurization process in the lower part of the tower. Diameter section, which increases the diameter of some fine particles and is removed by the mist eliminator, but the efficiency is generally only 30%, which cannot effectively reduce the concentration of aerosol in the exhaust gas.

In another process, an electrostatic precipitator is installed after the desulfurization tower, which has a high removal rate of aerosols. However, to achieve ultra-clean emission, the electrostatic precipitator is large in scale, high in investment cost, huge in power consumption and complicated in maintenance.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a flue gas aerosol removal device, so as to solve the problems of low removal rate of flue gas aerosol after desulfurization, complicated procedures and high cost in the prior art.

In order to achieve the above object, according to an aspect of the present invention, a flue gas aerosol removal device is provided, which includes: a humidification unit, which has a clean flue gas inlet of a desulfurization tower; an aerosol removal tower, which sequentially includes from bottom to top The first aerosol water washing section, the second aerosol water washing section and the demister are provided with a humidified flue gas inlet at the lower part of the first aerosol water washing section, which is connected with the outlet of the humidification unit.

Further, the first aerosol washing section is an empty tower distribution washing section or a packing layer washing section; the second aerosol washing section is a packing layer washing section.

Further, the aerosol removal tower also includes a circulating liquid tank located below the first aerosol water washing section.

Further, when the first aerosol washing section is the packing layer washing section, the aerosol removal tower also includes a gas distributor, and the gas distributor is arranged between the first aerosol washing section and the circulating liquid tank, and the gas distributor With humidified flue gas inlet.

Further, the first aerosol washing section includes a first washing water distributor, and the first washing water distributor is arranged on the top of the first aerosol washing section; the second aerosol washing section includes a second washing water distributor, and the second washing water A water distributor is placed on top of the second aerosol water wash section.

Further, when the first aerosol washing section is a packing layer washing section, it further includes a first packing layer disposed below the first washing water distributor and a first supporting portion for supporting the first packing layer; the second The aerosol water washing section further includes a second packing layer located under the second washing water distributor and a second supporting part for supporting the second packing layer.

Further, the first aerosol water washing section further includes a first water washing lift-type liquid collecting tank located below the first support part, and the second aerosol water washing section further includes a second water washing lift-type liquid collecting tank located under the second support part. tank.

Further, the first washing water distributor is provided with a first washing water inlet, the circulating liquid tank is provided with a circulating water outlet, and the circulating water outlet is connected with the first washing water inlet through a first circulating pipeline, and the first circulating pipeline is provided with There is a first circulating pump; the second aerosol washing section is provided with a second washing water inlet, and the second washing water inlet is connected with the outlet of the second washing air-lifting liquid collecting tank through a second circulation pipeline, and the second circulation pipe There is also a second circulating pump on the road.

Further, the aerosol removal tower also includes: a discharge branch pipe, which is connected to the first circulation pipeline, and a drain pump is arranged on the discharge branch pipe; A circulating pipeline is connected, and a third circulating pump is also arranged on the circulating bypass.

Further, the fillers used in the first packing layer and the second packing layer are one or more of spherical packing, saddle ring packing, stepped ring packing and grid packing, and the first packing layer and the second packing layer are respectively It is a bulk packing layer or a structured packing layer.

Further, the humidification unit includes: an intake flue with a clean flue gas inlet of the desulfurization tower, and the outlet of the intake flue is connected to the humidified flue gas inlet; a humidification nozzle is arranged inside the intake flue.

Further, the mist eliminator is a roof type mist eliminator, a wire mesh mist eliminator or a cyclone mist eliminator.

Further, the aerosol removal tower has a top exhaust port, the aerosol removal tower also includes an exhaust flue that is connected to the top exhaust port, and the mist eliminator is vertically arranged above the second aerosol water washing section, or, The mist eliminator is placed horizontally in the exhaust flue.

The flue gas aerosol removal device provided by the present invention includes a humidification unit and an aerosol removal tower. The aerosol removal tower sequentially includes a first aerosol water washing section, a second aerosol water washing section and a mist eliminator from bottom to top. The lower part of an aerosol water washing section is provided with a humidified flue gas inlet, which is connected with the outlet of the humidification unit. The humidification unit first humidifies the desulfurized clean flue gas, which can make the flue gas reach a supersaturated state. After the flue gas is supersaturated, the diameter of a small amount of dust and slurry particles in the flue gas will increase, and the increased diameter particles are easily dissolved and absorbed by the circulating aqueous solution. Then, the humidified flue gas was washed twice by the aerosol removal tower, and the aerosol in the flue gas was dissolved and absorbed into the aqueous solution in the gas-liquid collision contact to be removed. Then, the mist eliminator was used to further remove fog, emission

Using the above device to remove aerosols in the desulfurization flue gas, the overall process is simple, convenient for the transformation of the existing desulfurization process, and can be combined with the existing desulfurization process, the investment is small, the construction period is short, and the ultra-low emission of aerosols is realized. At the same time, the device has a strong ability to adapt to variable loads, removes the aerosol and also removes the dust in the flue gas, and further reduces the SO ₂ concentration of the flue gas.

Description of drawings

The accompanying drawings forming a part of the present application are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached image:

FIG. 1 shows a schematic structural diagram of a device for removing flue gas aerosol according to an embodiment of the present invention;

FIG. 2 shows a schematic structural diagram of a device for removing flue gas aerosol according to another embodiment of the present invention; and

FIG. 3 shows a schematic structural diagram of a device for removing flue gas aerosol according to yet another embodiment of the present invention.

Wherein, the above-mentioned drawings include the following reference signs:

10. Humidification unit; 11. Intake flue; 12. Humidification nozzle; 20. Aerosol removal tower; 21. First aerosol washing section; 211. First washing water distributor; 212, First packing layer; 213, the first support part; 214, the first water washing lift-type liquid collecting tank; 22, the second aerosol washing section; 221, the second washing water distributor; 222, the second packing layer; 223, the second Supporting part; 224, the second water-washing lift-type liquid collecting tank; 23, the mist eliminator; 24, the gas distributor; 25, the circulating liquid tank; 26, the exhaust flue; 201, the first circulating pump; 202, the first The second circulation pump; 203, the discharge pump; 204, the third circulation pump;

1. Desulfurization and purification gas exhaust flue; 2. Chimney; 101. The first separator; 3. The second separator; 205, The third separator.

Detailed ways

It should be noted that the embodiments in the present application and the features of the embodiments may be combined with each other in the case of no conflict. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

As described in the background art section, the current flue gas aerosol removal rate after desulfurization is low or the process is complicated and expensive.

In order to solve this problem, the present invention provides a flue gas aerosol removal device, as shown in Figures 1 to 3, the device includes: a humidification unit 10, which has a clean flue gas inlet of a desulfurization tower; an aerosol removal tower 20, including the first aerosol washing section 21, the second aerosol washing section 22 and the mist eliminator 23 in sequence from bottom to top, the lower part of the first aerosol washing section 21 is provided with a humidifying flue gas inlet, which is connected with the humidifying unit 10 connected to the outlet.

The humidification unit 10 first humidifies the desulfurized clean flue gas A, so that the flue gas can reach a supersaturated state. After the flue gas is supersaturated, the diameter of a small amount of dust and slurry particles in the flue gas will increase, and the increased diameter particles are easily dissolved and absorbed by the circulating aqueous solution. Then, the humidified flue gas is washed twice by the aerosol removal tower 20, and the aerosol in the flue gas is dissolved and absorbed into the aqueous solution in the gas-liquid collision contact to be removed, and then the mist eliminator 23 is used. Further defogging, discharge. Using the above device to remove aerosols in the desulfurization flue gas, the overall process is simple, convenient for the transformation of the existing desulfurization process, and can be combined with the existing desulfurization process, the investment is small, the construction period is short, and the ultra-low emission of aerosols is realized. At the same time, the device has a strong ability to adapt to variable loads, removes the aerosol and also removes the dust in the flue gas, and further reduces the SO ₂ concentration of the flue gas.

In a preferred embodiment, the first aerosol washing section 21 is an empty tower distribution washing section (as shown in FIG. 2 ) or a packing layer washing section (as shown in FIG. 1 ); the second aerosol washing section 22 is The packing layer is washed with water. When the first aerosol water washing section 21 is an empty tower distribution water washing section, the humidified flue gas has enough time and space to distribute the gas phase evenly after entering, and the first stage of water washing is completed to remove most of the desulfurization flue gas. Dust, aerosols. Then enter the water washing section of the packing layer in the second stage for further water washing, using the packing layer, the gas-liquid contact is sufficient, the aerosol is fully dissolved, and the secondary entrainment amount is small, which is conducive to further reducing the aerosol content and reducing the impact on the mist eliminator 23. Require. Finally, after the flue gas after the secondary water washing passes through the mist eliminator 23 to remove the droplets carried by the flue gas, the purified gas is discharged. When the first aerosol washing section 21 is a packing layer washing section, the humidified flue gas first enters the packing layer of the first aerosol washing section 21, and the packing layer forms a water film to realize the pre-absorption function of the water film; The gas enters the packing layer of the second aerosol water washing section 22 to realize the fine absorption of the water film.

In order to collect and recycle the washing water, in a preferred embodiment, the aerosol removal tower 20 further includes a circulating liquid tank 25 located below the first aerosol washing section 21 . More preferably, when the first aerosol washing section 21 is a packing layer washing section, the aerosol removal tower 20 further includes a gas distributor 24, and the gas distributor 24 is arranged in the first aerosol washing section 21 and the circulating liquid tank 25. between, and the gas distributor 24 has a humidified flue gas inlet. The use of the gas distributor 24 enables the humidified flue gas to enter and contact the wash water more uniformly. It should be noted that, when the first aerosol washing section 21 is an empty tower distribution washing section, since the humidified flue gas has enough time and space for uniform gas phase distribution after entering, no gas distributor is required. Moreover, this setting method is more suitable for processing flue gas with low dust content (mainly ammonium sulfate solid colloid). When this method is used, the pressure drop of the aerosol removal tower is lower than that of the two-layer packing with water. This type can be considered when the head margin of the fan is insufficient.

In a preferred embodiment, the first aerosol washing section 21 includes a first washing water distributor 211, and the first washing water distributor 211 is arranged at the top of the first aerosol washing section 21; the second aerosol washing section 22 The second washing water distributor 221 is included, and the second washing water distributor 221 is arranged at the top of the second aerosol washing section 22 . In this way, after the humidified flue gas enters from the bottom of the tower, it is in countercurrent contact with the washing water twice, which is beneficial to further improve the removal effect of aerosol and dust. And the use of the washing water distributor can make the washing water evenly distributed to the packing layer.

Preferably, the first washing water distributor 211 includes a first distribution manifold and a plurality of first distribution branch pipes connected to the first distribution manifold; the second washing water distributor 221 includes a second distribution manifold and a plurality of first distribution manifolds connected to the second distribution manifold A plurality of second distribution branches. Preferably, when the first aerosol washing section 21 is an empty tower distribution washing section, the first distribution branch pipe is a silicon carbide spiral nozzle, which is sprayed downward in the shape of a mist hood to form a spray area with a highly superimposed liquid mist, and the falling water The mist and the rising flue gas form a reverse flow, and the dust (ammonium sulfate colloid) in the flue gas is dissolved and washed by the water mist.

In a preferred embodiment, when the first aerosol washing section 21 is a packing layer washing section, it further includes a first packing layer 212 disposed under the first washing water distributor 211 and a first packing layer 212 for supporting the first packing The first support portion 213 of the layer 212 ; the second aerosol washing section 22 further includes a second packing layer 222 located below the second washing water distributor 221 and a second support portion 223 for supporting the second packing layer 222 . More preferably, the first aerosol washing section 21 further includes a first washing lift-type liquid collecting tank 214 located below the first support portion 213 , and the second aerosol washing section 22 further includes a second aerosol washing section 223 located below the second support portion 223 . Two water-washed lift-type liquid collecting tank 224. In this way, after the humidified flue gas enters, it enters the first packing layer 212 through the first water-washing air-lifting liquid collecting tank 214, and after contacting with the washing water, it further enters the second packing layer 222 and the second packing layer 222 through the second washing water distributor 221. Washing water contact.

In order to recycle the washing water to save energy, in a preferred embodiment, the first washing water distributor 211 is provided with a first washing water inlet, the circulating liquid tank 25 is provided with a circulating water outlet, and the circulating water outlet is connected to the first washing water inlet. The water inlet is connected through a first circulation pipeline, and the first circulation pipeline is provided with a first circulation pump 201; the second aerosol washing section 22 is provided with a second washing water inlet, and the second washing water inlet is connected to the second washing water lift gas The outlet of the liquid collecting tank 224 is connected through a second circulation pipeline, and a second circulation pump 202 is also provided on the second circulation pipeline. In actual operation, the washing water can also be replenished into the circulating liquid tank 25 in real time.

In a preferred embodiment, the aerosol removal tower 20 further comprises: a discharge branch pipe, which is connected to the first circulation pipe, and a discharge pump 203 is arranged on the discharge branch pipe; a circulation bypass, the inlet of which is connected to the second circulation pipe The pipelines are connected, and the outlet is connected to the first circulation pipeline, and a third circulation pump 204 is also provided on the circulation bypass. In the actual implementation process, when the circulating water in the first aerosol washing section 21 reaches a certain specific gravity, it can be sent to the upstream desulfurization tower system B through the discharge branch pipe, and the specific gravity is preferably controlled between 1.05 and 1.1; the second aerosol After the circulating water in the washing section 22 reaches the specified specific gravity, it can be sent to the first aerosol washing section 21 through the circulating bypass. The specific gravity of the washing water in the second aerosol washing section 22 is preferably controlled between 1.0 and 1.05.

In order to further improve the gas-liquid contact effect and thus further improve the flue gas treatment effect, in a preferred embodiment, the fillers used in the first packing layer 212 and the second packing layer 222 are spherical packing, saddle ring packing, stepped ring packing One or more of packing and grid packing, the first packing layer 212 and the second packing layer 222 are respectively bulk packing layers or structured packing layers.

In a preferred embodiment, the humidification unit 10 includes: an intake flue 11 with a clean flue gas inlet of the desulfurization tower, and the outlet of the intake flue 11 is connected to the humidified flue gas inlet; a humidification nozzle 12, It is arranged inside the intake flue 11 . In actual operation, the intake flue 11 can be connected with the existing desulfurization and purified gas exhaust flue 1 in the existing desulfurization device, so that the desulfurized and purified gas first enters the intake flue 11 of the present invention after humidification. Then enter the aerosol removal tower 20. The treated purified gas is discharged into the existing chimney 2 .

In a preferred embodiment, the mist eliminator 23 is a roof ridge mist eliminator, a wire mesh mist eliminator or a cyclone mist eliminator. More preferably, the aerosol removal tower 20 has a top exhaust port, the aerosol removal tower 20 also includes an exhaust flue 26 connected to the top exhaust port, and the mist eliminator 23 is vertically arranged in the second aerosol water washing section. 22 (as shown in Figures 1 and 2), or, the mist eliminator 23 is arranged horizontally in the exhaust flue (as shown in Figure 3). By using the method of horizontally setting the mist eliminator 23 in the exhaust flue, the tower height can be effectively reduced by about two meters, and the load of the tower can be reduced and the amount of construction work can be reduced at the same time. And after adopting this type of demister arrangement, its internal structure and flushing form are different from the vertical arrangement. The demister 23 is installed on the horizontal flue and needs to be fixed.

Preferably, the above-mentioned intake flue 11 is provided with a first partition 101 , the desulfurized purified gas exhaust flue 1 is provided with a second partition 3 , and the exhaust flue 26 is provided with a third partition 205 . The installation of each partition can facilitate maintenance.

In actual operation, preferably, flushing water C is used to flush the mist eliminator 23 intermittently to flush down the intercepted liquid droplets. After the flushing liquid falls, it enters the second flushing water distributor 221 to participate in the packing water flushing. Of course, if the flue gas leaves the desulfurization tower, and the aerosol quantity and particle size can be removed by the extraction tower, humidification can be disabled to save energy; deactivation of humidification will reduce the water replenishment in the circulation section, so the production water can be used as the circulation Water supply facilities.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (13)

1. a kind of flue gas aerosol removing means characterized by comprising

Humidification unit (10) has the import of desulfurizing tower neat stress；

Aerosol removing tower (20) successively includes the first aerosol washing section (21), the second aerosol washing section from the bottom to top (22) and demister (23), the first aerosol washing section (21) lower part is provided with humidification gas inlet, with the humidification The outlet of unit (10) is connected.

2. flue gas aerosol removing means according to claim 1, which is characterized in that the first aerosol washing section (21) washing section or packing layer washing section are distributed for void tower；The second aerosol washing section (22) is packing layer washing section.

3. flue gas aerosol removing means according to claim 2, which is characterized in that the aerosol removing tower (20) is also Including being located at the circulation liquid bath (25) below the first aerosol washing section (21).

4. flue gas aerosol removing means according to claim 3, which is characterized in that when the first aerosol washing section (21) when being described filler layer washing section, the aerosol removing tower (20) further includes gas distributor (24), the gas point Cloth device (24) is arranged between the first aerosol washing section (21) and the circulation liquid bath (25), and the gas distributor (24) there is the humidification gas inlet.

5. flue gas aerosol removing means according to claim 3 or 4, which is characterized in that the first aerosol washing Section (21) includes the first washing water distributor (211), and first washing water distributor (211) is arranged in first aerosol At the top of washing section (21)；The second aerosol washing section (22) includes the second washing water distributor (221), second washing Water distributor (221) setting is at the top of the second aerosol washing section (22).

6. flue gas aerosol removing means according to claim 5, which is characterized in that when the first aerosol washing section It (21) further include setting first filling out below first washing water distributor (211) when being described filler layer washing section The bed of material (212) and the first support portion (213) for being used to support first packing layer (212)；The second aerosol washing section (22) further include the second packing layer (222) below second washing water distributor (221) and be used to support described the The second support portion (223) of two packing layers (222).

7. flue gas aerosol removing means according to claim 6, which is characterized in that the first aerosol washing section It (21) further include that the first washing being located at below first support portion (213) rises gas formula collecting tank (214), second gas is molten Glue washing section (22) further includes that the second washing below second support portion (223) rises gas formula collecting tank (224).

8. flue gas aerosol removing means according to claim 7, which is characterized in that the first washing water distributor (211) it is provided with the first washing water inlet, the circulation liquid bath (25) is provided with circulating water outlet, the circulating water outlet and institute It states the first washing water inlet to be connected by first circulation pipeline, and is provided with first circulation pump on the first circulation pipeline (201)；The second aerosol washing section (22) is provided with the second washing water inlet, the second washing water inlet and described the The outlet that two washings rise gas formula collecting tank (224) is connected by second circulation pipeline, and is also set up on the second circulation pipeline There is second circulation to pump (202).

9. flue gas aerosol removing means according to claim 8, which is characterized in that the aerosol removing tower (20) is also Include:

Bleeder is connected with the first circulation pipeline, and positive displacement pump (203) are provided on the bleeder；

Circulation bypass, import are connected with the second circulation pipeline, and outlet is connected with the first circulation pipeline, and described Third circulating pump (204) are additionally provided in circulation bypass.

10. flue gas aerosol removing means according to claim 6, which is characterized in that first packing layer (212) and The filler used in second packing layer (222) is in Ball-type packing, Intalox metal tower packing, ladder ring packing, grid packing One or more, first packing layer (212) and second packing layer (222) are respectively bulk type packing layer or regular type Packing layer.

11. flue gas aerosol removing means according to claim 1, which is characterized in that the humidification unit (10) includes:

Inlet air stack (11) has the desulfurizing tower neat stress import, and the outlet of the inlet air stack (11) and the humidification Gas inlet is connected；

It is humidified spray head (12), is arranged in the inside of the inlet air stack (11).

12. flue gas aerosol removing means according to claim 1, which is characterized in that the demister (23) is ridge Formula demister, mesh mist eliminator or spiral-flow type demister.

13. flue gas aerosol removing means according to claim 12, which is characterized in that the aerosol removing tower (20) With top vent, the aerosol removing tower (20) further includes the exhaust uptake (26) being connected with the top vent, The demister (23) is vertically set on the top of the second aerosol washing section (22), alternatively, the demister (23) water It is flat to be arranged in the exhaust uptake (26).