CN111517528A - Device and method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method - Google Patents

Abstract

The invention discloses a device and a method for treating ammonia nitrogen in desulfurization wastewater by a membrane absorption method, wherein the device comprises the following components: an alkaline agent adding device is arranged at the top end of the alkali adjusting tank; an organic sulfur feeding device is arranged at the top end of the heavy removal tank, the inlet end of the heavy removal tank is connected with the outlet end of the alkali adjusting tank, and the outlet end of the heavy removal tank is connected with the inlet end of the clarification tank; the inlet end of the middle water tank is connected with the outlet end of the clarification tank, and the outlet end of the middle water tank is connected with the first inlet end of the membrane absorption assembly; the inlet end of the absorption liquid pool is connected with the first outlet end of the membrane absorption assembly, and the outlet end of the absorption liquid pool is connected with the second inlet end of the membrane absorption assembly. The method comprises the following steps: adding an alkaline medicament to adjust the pH value of the desulfurization wastewater to 11-13; organic sulfur is added to remove heavy metals in the desulfurization wastewater; removing suspended matters in the desulfurization wastewater through flocculation and clarification; the supernatant enters an intermediate water tank; separating ammonia nitrogen in the desulfurization wastewater through a separation membrane and absorbing the ammonia nitrogen by absorption liquid to remove the ammonia nitrogen.

Description

Device and method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method

technical field

The invention relates to the technical field of desulfurization wastewater treatment, in particular to a device and method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method.

Background technique

With the continuous improvement of my country's environmental protection requirements, limestone-gypsum wet desulfurization technology is widely used in flue gas desulfurization in coal-fired power plants, steel mills and other fields due to its high desulfurization efficiency and stable operation. In the limestone-gypsum wet desulfurization process, in order to ensure gypsum quality and desulfurization efficiency, a certain amount of desulfurization slurry needs to be discharged, and finally desulfurization wastewater is generated. The composition of desulfurization wastewater is complex and contains high concentrations of suspended solids, ammonia nitrogen, sulfate, calcium and magnesium ions, chloride ions and various heavy metals. Large-scale application of denitrification process, excessive ammonia injection is common, resulting in a significant increase in ammonia nitrogen in wastewater, up to 5000mg/L. At present, the desulfurization wastewater is mainly treated by the triple box process, mainly for the removal of suspended solids and heavy metals in the wastewater, and has no obvious removal effect on ammonia nitrogen, so the ammonia nitrogen exceeds the standard seriously.

High ammonia wastewater has a wide range of sources in actual production, such as coking, petrochemical, pharmaceutical production, aquaculture, fertilizer and meat processing industries, as well as garbage permeate and animal waste. For the treatment of wastewater containing high concentrations of ammonia nitrogen, it is difficult to obtain a better removal effect directly by biological treatment. In addition, as an important chemical raw material, ammonia nitrogen in high-ammonia wastewater is converted into nitrogen gas and discharged into the atmosphere through biological treatment, which is also a waste of resources and does not conform to the concept of circular economy. Therefore, most of the actual high ammonia wastewater is pretreated by physicochemical method first, and then the subsequent biological treatment is carried out according to the actual situation. At present, the commonly used treatment methods of high-concentration ammonia nitrogen wastewater mainly include chemical precipitation method and stripping method.

The chemical precipitation method mainly refers to the Magnesium Ammonium Phosphate (Magnesium Ammonium Phosphate, referred to as MAP) method. This method utilizes the insoluble nature of magnesium ammonium phosphate in water to add chemicals containing PO ₄ ³⁺ and Mg ²⁺ ions to the wastewater. The NH ₄ ⁺ in the wastewater reacts with PO ₄ ³⁺ and Mg ²⁺ ions to form magnesium ammonium phosphate precipitation, and finally the ammonia in the wastewater is removed. The chemical precipitation method has many disadvantages, mainly including a large amount of sediment sludge and serious secondary pollution; a large amount of precipitation chemicals is added, and the cost of the chemicals is high.

The stripping method is that the wastewater is under alkaline conditions (usually the pH is adjusted to about 11.0), and then air or steam is introduced into the wastewater. Under the agitation and entrainment of the air, free molecular ammonia overflows from the wastewater. The overflowing mixed gas is then absorbed by acid liquid, thereby removing ammonia in the wastewater and recovering the ammonia in the form of ammonium salts. When dealing with high concentrations of ammonia nitrogen in wastewater, the stripping method has the advantages of high efficiency, strong adaptability to changes in water quality, and the ability to recover ammonia in wastewater. However, the stripping method also has many shortcomings. For example, when the pressurized air stripping is used at room temperature, not only the removal effect of ammonia nitrogen is poor, but also the air demand is large; when the steam stripping is used, the energy consumption is high. The condensation effect of steam will also cause a significant increase in the volume of wastewater; in addition, the stripping method also has the problems of easy scaling of the equipment and inconvenient operation and maintenance of the device.

In order to avoid ensuring the discharge of ammonia nitrogen in desulfurization wastewater up to the standard and to recover ammonia nitrogen resources, in view of the shortcomings and deficiencies of the existing desulfurization wastewater concentration process, the development of new desulfurization wastewater treatment methods has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

In order to solve the above problems, the purpose of the present invention is to provide a device and method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method.

The invention provides a device for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method. The device comprises:

Alkali adjusting tank, the top of which is provided with alkaline agent dosing device;

The deweighting tank is provided with an organic sulfur dosing device at the top, the inlet end of the deweighting tank is connected with the outlet end of the alkali conditioning tank, and the outlet end of the deweighting tank is connected with the inlet end of the clarifier;

an intermediate water tank, the inlet end of which is connected with the outlet end of the clarification tank, the outlet end of the intermediate water tank is connected with the first inlet end of the membrane absorption assembly, and the membrane absorption assembly is provided with a separation membrane;

an absorption liquid pool, the inlet end of which is connected with the first outlet end of the membrane absorption assembly, the outlet end of the absorption liquid pool is connected with the second inlet end of the membrane absorption assembly, and the first inlet of the membrane absorption assembly The end and the second inlet end are located on both sides of the separation membrane. .

As a further improvement of the present invention, the alkali adjusting tank is provided with a first stirring device, the weight removal tank is provided with a second stirring device, and the absorption liquid tank is provided with a third stirring device.

As a further improvement of the present invention, the bottom end of the clarifier is connected to the inlet end of the sludge dehydrator, and the outlet end of the sludge dehydrator is connected to the inlet end of the alkali conditioning tank.

As a further improvement of the present invention, a first water pump is provided between the outlet end of the intermediate water tank and the first inlet end of the membrane absorption assembly; the outlet end of the absorption liquid pool is connected to the second inlet end of the membrane absorption assembly A second water pump is provided between the inlet ends.

As a further improvement of the present invention, the second outlet end of the membrane absorption assembly is provided with a waste liquid output pipeline, and an acid dosing device is provided on the waste liquid output pipeline.

As a further improvement of the present invention, a multi-media filter is provided between the outlet end of the clarifier and the inlet end of the intermediate water tank.

As a further improvement of the present invention, the separation membrane is a hydrophobic membrane, and the separation membrane is one or more of a flat plate type, a hollow fiber type, and a roll type.

The invention also provides a method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method, which comprises the following steps:

Step 1. The desulfurization wastewater enters the alkali adjustment tank, and the alkaline agent is added into the alkali adjustment tank through the alkaline agent dosing device to adjust the pH value of the desulfurization wastewater to 11-13;

Step 2, the desulfurization wastewater enters the deweighting tank, and the organic sulfur is added into the weight removal tank through the organic sulfur dosing device and stirred with the second stirring device, so as to remove the heavy metals in the desulfurization wastewater;

Step 3. The desulfurization wastewater from which heavy metals are removed enters the clarifier, and the suspended solids in the desulfurization wastewater are removed by flocculation and clarification;

Step 4. The supernatant in the clarification tank is filtered and entered into the intermediate tank;

Step 5. The supernatant in the intermediate tank enters one side of the separation membrane in the membrane absorption module, and the ammonia gas in the desulfurization wastewater is separated by the separation membrane and enters the other side of the separation membrane to be absorbed by the acid absorption liquid, thereby removing the desulfurization Ammonia nitrogen in wastewater.

As a further improvement of the present invention, the precipitation after the clarification in step 3 enters the sludge dewatering machine for dehydration treatment, and the dehydrated filtrate water is re-transported to the alkali adjustment tank 1 for treatment.

As a further improvement of the present invention, it also includes step 6: when the ammonia nitrogen content in the desulfurization wastewater reaches the standard, add acid to the desulfurization wastewater to adjust the pH of the desulfurization wastewater to 6-8 and then discharge it through an acid dosing device.

The beneficial effects of the present invention are as follows: the present application has the advantages of simple process, low sludge production, high ammonia nitrogen removal efficiency, high recoverable ammonia nitrogen, and low operating cost.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that are required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

FIG. 1 is a schematic structural diagram of a device for treating ammonia nitrogen in desulfurization wastewater by a membrane absorption method according to an embodiment of the present invention.

In the figure,

1. Alkali adjusting tank; 2. The first stirring device; 3. Deweighting tank; 4. The second stirring device; 5. Clarifier; 6. Sludge dehydrator; 10. Separation membrane; 11. Absorption tank; 12. Second water pump; 13. Third stirring device; 14. Alkaline chemical dosing device; 15. Organic sulfur dosing device; 16. Acid dosing add device.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in the embodiments of the present invention, the directional indications are only used to explain a certain posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly.

Also, in the description of the present invention, the terminology used is for the purpose of illustration only, and is not intended to limit the scope of the present invention. The terms "comprising" and/or "comprising" are used to designate the presence of stated elements, steps, operations and/or components, but do not preclude the presence or addition of one or more other elements, steps, operations and/or components . The terms "first," "second," and the like, may be used to describe various elements, do not represent an order, and do not limit the elements. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more. These terms are only used to distinguish one element from another. These and/or other aspects will become apparent, and the description of the described embodiments of the present invention, will be more readily understood by those of ordinary skill in the art in conjunction with the following drawings. The drawings are used to depict the described embodiments of the invention for purposes of illustration only. Those skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods of the present invention may be employed without departing from the principles described herein.

Embodiment 1, as shown in FIG. 1, a device for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method according to the embodiment of the present invention, the device includes:

The alkali adjusting tank 1 is provided with an alkaline agent dosing device 14 at its top. The alkali conditioning tank 1 is a closed reactor, and the alkaline agent dosing device 14 adds alkaline agents to the desulfurization wastewater in the alkali conditioning tank 1 to make the PH value of the desulfurization wastewater at 11-13, so as to ensure sufficient OH in the desulfurization wastewater ^- To ensure that the NH ₄ ⁺ in the desulfurization wastewater can be fully converted into NH ₃ . The alkaline agent to be added can be calcium hydroxide or sodium hydroxide, etc., but is not limited to the above two.

The top of the deweighting tank 3 is provided with an organic sulfur dosing device 15 . The deweighting tank 3 is a closed reactor, and the organic sulfur dosing device 15 adds organic sulfur to the desulfurization wastewater in the deweighting tank 3, so that the organic sulfur reacts with the heavy metals in the desulfurization wastewater to remove heavy metals such as lead and mercury. The clarifier 5 is a closed reactor, and the desulfurization wastewater after removing heavy metals is transported to the clarifier 5 through overflow or pipeline. The clarifier 5 is provided with a flocculant and a flocculant dosing device. Add flocculants and coagulants to precipitate and remove the suspended solids in the wastewater, and the suspended solids will also play an entrainment role during the flocculation process to remove part of the COD in the desulfurization wastewater.

The inlet end of the intermediate water tank 7 is connected to the outlet end of the clarification tank 5 , and the outlet end of the intermediate water tank 7 is connected to the first inlet end of the membrane absorption module 9 , and the membrane absorption module 9 is provided with a separation membrane 10 . The intermediate tank 7 is a closed reactor, and the supernatant in the clarifier 5 enters the membrane absorption module 9 through the intermediate tank 7 . The separation membrane 10 adopts a hydrophobic membrane so that the ammonia gas in the supernatant can be separated and absorbed and removed by the absorption liquid on the other side of the separation membrane 10, so as to achieve the purpose of removing ammonia nitrogen from the desulfurization wastewater.

The inlet end of the absorption liquid pool 11 is connected with the first outlet end of the membrane absorption module 9, the outlet end of the absorption solution pool 11 is connected with the second inlet end of the membrane absorption module 9, and the first inlet end of the membrane absorption module 9 is connected to the second inlet end of the membrane absorption module 9. The two inlet ends are respectively disposed on both sides of the separation membrane 10 . The absorption liquid pool 11 is an acid absorption liquid, and the mass concentration of the acid absorption agent is less than 2%. The acid absorbing liquid enters the membrane absorbing assembly 9 through the second inlet end of the membrane absorbing assembly 9 . After the acid absorbing liquid absorbs ammonia gas, it returns to the absorbing liquid pool 11 through the first outlet end of the membrane absorbing assembly 9 . When the pH of the acid absorbing liquid in the absorbing liquid tank 11 is 6-8, the absorbing liquid is discharged and utilized, and new absorbing liquid is replenished to repeat the above-mentioned membrane absorption process.

Further, the alkali adjusting tank 1 is provided with a first stirring device 2 , the weight removing tank 3 is provided with a second stirring device 4 , and the absorption liquid tank 11 is provided with a third stirring device 13 . The first stirring device 2 , the second stirring device 4 and the third stirring device 13 play a stirring effect on the solutions in the alkali adjusting tank 1 , the weight removing tank 3 and the hand soap tank 11 respectively, so that the solutions inside are evenly mixed and fully reacted.

Further, the bottom end of the clarification tank 5 is connected to the inlet end of the sludge dehydrator 6 , and the outlet end of the sludge dehydrator 6 is connected to the inlet end of the alkali conditioning tank 1 . The precipitate generated by the suspended matter in the clarifier 5 enters the sludge dewatering machine 6, and the precipitate is dewatered and discharged for subsequent treatment.

Further, a first water pump 8 is provided between the outlet end of the intermediate water tank 7 and the first inlet end of the membrane absorption assembly 9; Two water pumps 12 . The first water pump 8 transports the desulfurized wastewater in the intermediate water tank 7 to the membrane absorption assembly 9 , and the second water pump 12 transports the acid absorption liquid in the absorption liquid tank 11 to the membrane absorption assembly 9 .

Further, the second outlet end of the membrane absorption assembly 9 is provided with a waste liquid output pipeline, and an acid dosing device 16 is provided on the waste liquid output pipeline. When the ammonia nitrogen concentration in the desulfurization wastewater reaches the standard, it needs to be discharged, and before discharge, it is necessary to add acid agent to the desulfurization wastewater through the acid adding device 16 to make the pH value between 6-8 to be discharged. During the application process, a PH detection device can be set up on the waste liquid output pipeline for real-time detection of the PH of the deamination wastewater.

Further, a multi-media filter is provided between the outlet end of the clarification tank 5 and the inlet end of the intermediate water tank 7 . The multi-media filter filters the supernatant in the clarification tank 5, and then transports the filtered supernatant to the intermediate tank 7 to ensure that the suspended solids concentration in the desulfurization wastewater entering the intermediate tank 7 is less than 5mg/ L, thereby preventing the separation membrane 10 from being fouled or the membrane pores of the separation membrane 10 from being blocked.

Further, the separation membrane 10 is a hydrophobic membrane, and the separation membrane 10 is one or more of a flat plate type, a hollow fiber type, and a roll type. A hydrophobic membrane is selected for the separation membrane 10, so that the ammonia gas in the desulfurization wastewater can be separated, and absorbed and removed by the sulfurous acid absorption liquid on the other side of the separation membrane 10. The liquid water and other non-volatile substances in the desulfurization wastewater are trapped in the desulfurization wastewater, and the desulfurization wastewater after deamination is returned to the intermediate pool 7 . In application, the separation membrane 10 can be a flat type, a hollow fiber type, or a roll type, but it is not limited to the hydrophobic membranes of the above-mentioned structures, and the specific structure can be selected according to the actual situation.

Embodiment 2, the present invention also provides a method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method, and the method comprises the following steps:

Step 1. The desulfurization wastewater enters the alkali adjustment tank 1, and the alkaline agent is added into the alkali adjustment tank 1 through the alkaline agent dosing device 14 to adjust the pH value of the desulfurization wastewater to 11-13. Ensuring that there are enough hydroxides to promote the conversion of ammonium ions in the wastewater into molecular ammonia, and adjusting the pH of the desulfurization wastewater to alkaline, can remove some heavy metals in the desulfurization wastewater.

In step 2, the desulfurization wastewater enters the deweighting tank 3, and the organic sulfur is added into the weight removal tank 3 through the organic sulfur dosing device 15 and stirred with the second stirring device 4 for removing heavy metals in the desulfurization wastewater. The organic sulfur reagent reacts with the heavy metals in the desulfurization wastewater to remove heavy metal ions such as lead and mercury.

Step 3. The desulfurization wastewater from which heavy metals have been removed enters the clarifier 5, and the suspended solids in the desulfurization wastewater are removed through flocculation and clarification. Through flocculation and clarification, the suspended solids in the desulfurization wastewater can be removed, and at the same time, part of the COD in the desulfurization wastewater can be removed through the entrainment of the suspended solids.

Step 4. The supernatant in the clarification tank 5 is filtered and then enters the intermediate tank 7 to ensure that the concentration of the suspended solids in the desulfurization wastewater in the intermediate tank 7 is less than 5 mg/L.

Step 5. The supernatant in the intermediate tank 7 enters one side of the separation membrane 10 in the membrane absorption module 9, and the ammonia gas in the desulfurization wastewater is separated by the separation membrane 10 and enters the other side of the separation membrane 10 to be absorbed by the acid absorption liquid. Absorption to remove ammonia nitrogen in desulfurization wastewater. The acid absorption liquid in the absorption liquid pool 11 enters the membrane absorption assembly 9 , flows out of the membrane absorption assembly 9 after absorbing ammonia gas, and returns to the absorption liquid pool 11 . With the progress of deamination, when the pH of the acid absorption liquid in the absorption liquid tank 11 is 6-8, the absorption liquid is discharged for use, and new absorption liquid is replenished to repeat the above-mentioned membrane absorption process.

Further, the precipitation after the clarification in step 3 enters the sludge dewatering machine 6 for dehydration treatment, and the dehydrated filtrate water is re-transported to the alkali adjustment tank 1 for treatment.

Further, it also includes step 6: when the ammonia nitrogen content in the desulfurization wastewater reaches the standard, add acid to the desulfurization wastewater to adjust the pH of the desulfurization wastewater to 6-8 through the acid dosing device 16 and then discharge it.

In this application, taking the raw water of desulfurization wastewater from a power plant (wastewater cyclone overflow), the alkaline agent used is lime milk, and the acid absorption liquid is sulfuric acid solution as an example, the main water quality parameters of the desulfurization wastewater used are as follows:

index unit Numerical value SS mg/L 4573 pH mg/L 6.1 Ammonia nitrogen mg/L 4736 TDS mg/L 24364

The desulfurization wastewater first enters the alkali adjustment tank 1, and the lime milk with a mass fraction of 3% is added into the alkali adjustment tank 1 through the alkaline agent dosing device 14, and the pH of the wastewater is adjusted to 12. After 30 minutes of reaction, the alkali adjustment tank 1 The intermediate wastewater enters the deweighting tank 3 through overflow, and organic sulfur is added to the deweighting tank 3 to remove heavy metals such as mercury and lead in the wastewater.

After the stirring reaction for 30 minutes, the waste water in the deweighting tank 3 enters the clarification tank 5 through the overflow, and in the clarification tank 5, polyferric chloride and PAM (concentrations are 30mg/L and 6mg/L respectively) are added, and the flocculation clarification effect is carried out. , to remove suspended solids in wastewater. The sediment produced in the clarification tank 5 enters the sludge dewatering machine 6, and the filtrate water produced by the sludge dewatering machine 6 is returned to the alkali adjusting tank 1 to repeat the above treatment process.

The concentration of suspended solids in the supernatant of clarifier 5 was about 35 mg/L. In order to avoid the pollution of the separation membrane 10, after the supernatant of the clarification tank 5 is filtered by a multi-media filter, the concentration of suspended solids in the wastewater is reduced to about 2 mg/L, and then enters the intermediate tank 7, and the wastewater in the intermediate tank 7 enters the membrane. In the absorption module, ammonia in the wastewater in the membrane absorption module 9 volatilizes in the form of ammonia gas through the separation membrane 10 and is absorbed by the 2% sulfuric acid absorption liquid on the other side of the membrane, thereby achieving the purpose of ammonia nitrogen removal. The sulfuric acid absorption liquid in the absorption liquid pool 11 enters the membrane absorption component 9 , flows out of the membrane absorption component 9 after absorbing ammonia gas, and flows back into the absorption liquid pool 11 .

When the pH of the sulfuric acid absorption liquid in the absorption liquid tank 11 is 7, the absorption liquid is discharged for use, and new absorption liquid is replenished to repeat the above-mentioned membrane absorption process. Experiments show that after membrane absorption treatment, the ammonia nitrogen concentration in wastewater is reduced to 9 mg/L, and the removal rate exceeds 99.8%, which is lower than the national first-class discharge standard.

In the description provided herein, numerous specific details are set forth. It will be understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Furthermore, it will be understood by those of ordinary skill in the art that although some of the embodiments described herein include certain features, but not others, included in other embodiments, that combinations of features of different embodiments are intended to be within the scope of the invention within and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

It will be understood by those skilled in the art that although the invention has been described with reference to exemplary embodiments, various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, the inventions are not to be limited to the particular embodiments disclosed, but the inventions are to include all embodiments falling within the scope of the appended claims.

Claims (10)

1. a device for the treatment of ammonia nitrogen in the desulfurization wastewater by membrane absorption method, is characterized in that, comprises: an alkali adjusting tank (1), the top of which is provided with an alkaline agent dosing device (14); The weight removal tank (3) is provided with an organic sulfur dosing device (15) at the top, and the inlet end of the weight removal tank (3) is connected with the outlet end of the alkali adjustment tank (1). The outlet end of (3) is connected with the inlet end of the clarifier (5); An intermediate water tank (7), the inlet end of which is connected with the outlet end of the clarifier (5), and the outlet end of the intermediate water tank (7) is connected with the first inlet end of the membrane absorption assembly (9), the membrane absorption A separation membrane (10) is arranged inside the component (9); an absorption liquid pool (11), the inlet end of which is connected with the first outlet end of the membrane absorption assembly (9), and the outlet end of the absorption liquid pool (11) is connected with the second inlet of the membrane absorption assembly (9) The ends are connected, and the first inlet end and the second inlet end of the membrane absorption assembly (9) are respectively arranged on both sides of the separation membrane (10). 2. The device for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method according to claim 1, characterized in that, the alkali adjusting tank (1) is provided with a first stirring device (2), and the deweighting tank (3) is provided with a first stirring device (2). ) is provided with a second stirring device (4), and the absorption liquid pool (11) is provided with a third stirring device (13). 3. The device for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method according to claim 1, wherein the bottom end of the clarifier (5) is connected with the inlet end of the sludge dewatering machine (6), and the sewage The outlet end of the mud dehydrator (6) is connected with the inlet end of the alkali conditioning tank (1). 4. The device for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method according to claim 1, characterized in that, between the outlet end of the intermediate pool (7) and the first inlet end of the membrane absorption module (9) A first water pump (8) is provided; a second water pump (12) is provided between the outlet end of the absorption liquid pool (11) and the second inlet end of the membrane absorption assembly (9). 5. The device for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method according to claim 1, wherein the second outlet end of the membrane absorption assembly (9) is also connected with a waste liquid output pipeline, and the waste liquid output An acid dosing device (16) is arranged on the pipeline. 6 . The device for treating ammonia nitrogen in desulfurized wastewater by membrane absorption method according to claim 1 , characterized in that, between the outlet end of the clarifier (5) and the inlet end of the intermediate pool (7), there are multiple media filter. 7 . The device for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method according to claim 1 , wherein the separation membrane ( 10 ) is a hydrophobic membrane, and the separation membrane ( 10 ) is a flat plate type or a hollow fiber type. 8 . , one or more of the roll type. 8. A method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method of the membrane absorption method for treating ammonia nitrogen in desulfurization wastewater according to any one of claims 1-7, wherein the method comprises the following steps: Step 1, the desulfurization wastewater enters the alkali adjustment tank (1), and the alkaline agent is added into the alkali adjustment tank (1) through the alkaline agent dosing device (14) to adjust the pH value of the desulfurization wastewater to 11-13; In step 2, the desulfurization wastewater enters the deweighting tank (3), and the organic sulfur is added to the deweighting tank (3) through the organic sulfur dosing device (15) and stirred with the second stirring device (4) for removing desulfurization Heavy metals in wastewater; Step 3, the desulfurization wastewater from which heavy metals are removed enters the clarifier (5), and the suspended solids in the desulfurization wastewater are removed by flocculation and clarification; Step 4, the supernatant in the clarification tank (5) is filtered into the intermediate water tank (7); Step 5. The supernatant in the intermediate pool (7) enters the side of the separation membrane (10) in the membrane absorption module (9), and the ammonia gas in the desulfurization wastewater is separated by the separation membrane (10) and enters the separation membrane (10). The other side of 10) is absorbed by the acid absorption liquid, thereby removing ammonia nitrogen in the desulfurization wastewater. 9. The method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method according to claim 8, wherein the precipitation after the clarification in the step 3 enters the sludge dewatering machine (6) to be dewatered, and the dewatered The filtrate water is re-transported to the alkali adjusting tank (1) for treatment. 10. The method for treating ammonia nitrogen in desulfurization wastewater by membrane absorption method according to claim 8, characterized in that, further comprising step 6, when the ammonia nitrogen content in the desulfurization wastewater reaches the standard, adding to it by the acid dosing device (16). The pH of the acid-regulated desulfurization wastewater is 6-8 and then discharged.

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