Ammonium phosphate ammonia washing absorption tower

Abstract

The utility model provides an ammonium phosphate ammonia washing absorption tower, the inside of the tower is sequentially provided with an absorption section and an acidification section from bottom to top, the absorption section comprises three continuous absorption sections, namely an upper absorption section, a middle absorption section and a lower absorption section, and ammonia-containing process gas flows through the absorption sections one by one and is in countercurrent contact with ammonium phosphate barren liquor sprayed downwards; therefore, quenching dust removal of process gas and effective absorption of ammonia gas are realized. Then the gas continuously rises to the acidification section, and sulfuric acid is used for secondarily absorbing residual ammonia gas in the gas subjected to absorption treatment in the section, so that the ammonia gas is extracted to the maximum extent, the waste of the ammonia gas is reduced, the concentration of the ammonia gas discharged from the tower top is ensured to reach an extremely low standard, the discharge amount of the ammonia gas is remarkably reduced, and the recovery efficiency of the ammonia gas is improved. In addition, the absorption section and the acidification section are integrated into the same absorption tower, so that the occupied area of equipment is reduced, and the construction cost is also reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of ammonia-containing process gas purification, and particularly relates to an ammonium phosphate washing ammonia absorption tower. BACKGROUND

[0002] The phosphoric acid absorption method is a technology for absorbing and recovering ammonia from process gas. In this process, phosphoric acid reacts with ammonia to form monoammonium phosphate, and then continues to react to form diammonium phosphate. Under high temperature conditions, diammonium phosphate decomposes back into monoammonium phosphate. By utilizing the mutual conversion characteristics between monoammonium phosphate and diammonium phosphate, ammonia in the process gas is absorbed and recovered through low-temperature absorption and high-temperature desorption. The production of anhydrous ammonia by the phosphoric acid absorption method involves three key processes: absorption, desorption, and rectification. Specifically, ammonium phosphate solution is used to absorb ammonia in process gas, the ammonia-rich solution is then desorbed, and finally the ammonia water obtained by desorption is rectified.

[0003] The absorption process plays a crucial role in the production of anhydrous ammonia. It is mainly used to remove the ammonia-rich gas from the outlet of process gases such as coke oven gas and hydrogen cyanide reactor. The ammonia-containing process gas is introduced from the bottom of the absorption tower and is in counter-current contact with the circulating sprayed ammonium phosphate lean solution, selectively absorbing ammonia gas. The absorption tower is generally designed to include upper, middle, and lower spray absorption zones to optimize ammonia absorption efficiency. The purified gas after absorption is returned to the front-end main device or downstream unit for recycling. During the absorption process, the ammonium phosphate lean solution captures ammonia gas and is converted into ammonium phosphate rich solution, which is then transported from the bottom of the absorption tower to the subsequent ammonium phosphate desorption tower. After the desorption process is completed, the lean solution is cooled and recycled back to the absorption tower to achieve the recycling of the solution.

[0004] The existing absorption tower operation adjusts the concentration of ammonia in the tower top purified gas by precisely controlling the temperature of different spray sections, the concentration of ammonium phosphate lean solution, the molar ratio of monoammonium phosphate to diammonium phosphate in the lean solution, and the liquid-gas ratio. However, in actual operation, the absorption tower is often limited by the gas-liquid equilibrium between ammonia and ammonium phosphate solution and the energy consumption of the device, making it difficult to achieve ultra-low ammonia emission concentration in the tower top gas, resulting in waste of ammonia.

[0005] Patent CN216092967U discloses a phosphorus ammonium washing ammonia absorption device that can remove ammonia and acid mist from coke oven gas. However, this device has the problems of large footprint of the split device and high ammonia content in the purified gas of the absorption equipment, which cannot achieve ultra-low ammonia emission in the tower top gas, resulting in waste of ammonia. UTILITY MODEL CONTENTS

[0006] In order to solve the problems of low ammonia gas recovery efficiency of the existing absorption tower, ammonia gas resource waste, and large area occupied by the recovery device to increase the construction cost, the utility model provides an ammonia absorption tower of ammonium phosphate washing, which is internally divided into an absorption section and an acidification section from bottom to top. The absorption section is composed of three absorption sections arranged in sequence from top to bottom. Ammonia-containing process gas flows through the three absorption sections from bottom to top and contacts with the ammonia phosphate lean liquid sprayed in the opposite direction to complete the quenching, dust removal and effective absorption of ammonia gas. Then, the gas enters the acidification section, where sulfuric acid is used to further absorb the residual ammonia in the gas treated by the absorption section, so that the ammonia gas in the process gas can be captured to the maximum extent, the ammonia gas concentration discharged from the tower top can reach an ultra-low level, the waste of ammonia gas is significantly reduced, and the overall recovery efficiency is improved. In addition, the absorption section and the acidification section are integrated in the same absorption tower, which reduces the occupied area and the construction cost.

[0007] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0008] An ammonia absorption tower of ammonium phosphate washing comprises an absorption tower body, an absorption section and an acidification section arranged in sequence from bottom to top in the absorption tower body, the absorption section comprises a lower absorption section, a middle absorption section and an upper absorption section from bottom to top, and the absorption section uses ammonia phosphate lean liquid to perform graded circulating spray treatment on ammonia-containing process gas; the acidification section has a sulfuric acid inlet, and sulfuric acid liquid is introduced from the sulfuric acid inlet to absorb the residual ammonia gas in the gas treated by the absorption section.

[0009] In some embodiments, a liquid collecting device is arranged between the acidification section and the upper absorption section, between the upper absorption section and the middle absorption section, and between the middle absorption section and the lower absorption section; the liquid collecting device comprises a liquid collecting disc, a plurality of gas lifting pipes and a gas lifting cap, the liquid collecting disc is used to collect liquid, one end of the gas lifting pipe is arranged on the liquid collecting disc and the gas flows through the gas lifting pipe, and the gas lifting cap is arranged on the other end of the gas lifting pipe.

[0010] In some embodiments, the ammonia absorption tower of ammonium phosphate washing further comprises a plurality of liquid receiving plates, the liquid receiving plates are arranged between the upper absorption section and the middle absorption section and between the middle absorption section and the lower absorption section; the liquid receiving plate is located below the liquid collecting disc, one end of the liquid receiving plate has an overflow weir to overflow the collected ammonia phosphate lean liquid circulating liquid from the upper absorption section to the lower absorption section, and the other end is used to output the ammonia phosphate lean liquid circulating liquid.

[0011] In some embodiments, the ammonia phosphate lean liquid circulating liquid interface and the ammonia phosphate lean liquid circulating liquid outlet of any absorption section are symmetrically arranged with the ammonia phosphate lean liquid circulating liquid interface and the ammonia phosphate lean liquid circulating liquid outlet of the adjacent absorption section along the central axis of the absorption tower body.

[0012] In some embodiments, the acidification section is a plate column or a packed column, when the acidification section is a plate column, the number of theoretical plates is 2-6 layers; when the acidification section is a packed column, the acidification section comprises packing and a packing support structure, the height of the packing is 2-5 meters.

[0013] In some embodiments, the acidification section further has an ammonium sulfate outlet, which is in communication with a collecting tray arranged between the acidification section and the upper absorption section.

[0014] In some embodiments, the absorption tower is an empty tower, a packed column or a plate column, when the absorption tower is an empty tower, the number of spray layers in the empty tower is 2-4 layers; when the absorption tower is a plate column, the number of theoretical plates is 2-6 layers; when the absorption tower is a packed column, the height of each layer of packing is 2-5 meters.

[0015] In some embodiments, the absorption tower body is provided with a gas inlet interface and a backup gas inlet interface near the tower kettle, and the absorption tower body is provided with a gas distributor in communication with the gas inlet interface and the backup gas inlet interface.

[0016] In some embodiments, the ammonium phosphate washing ammonia absorption tower further comprises: a plurality of demisters, the demisters are arranged between the acidification section and the top outlet of the absorption tower body, and between the upper absorption section and the acidification section; and / or, a single layer or multiple layers of spray layers are arranged in the lower absorption section, the middle absorption section and the upper absorption section, and a plurality of evenly distributed hollow cone nozzles or solid cone nozzles are arranged on each spray layer.

[0017] In some embodiments, the ammonium phosphate washing ammonia absorption tower further comprises: a skirt, which is arranged at the bottom of the absorption tower body.

[0018] Compared with the prior art, the ammonium phosphate washing ammonia absorption tower has the following beneficial effects:

[0019] 1、The ammonium phosphate washing ammonia absorption tower provided by the utility model, the internal structure of which is sequentially divided into an absorption section and an acidification section from bottom to top. In the absorption section, the ammonia-containing process gas passes through the lower, middle and upper three continuous absorption sections in sequence, and is in countercurrent contact with the downwardly sprayed ammonium phosphate lean solution, so that the process gas is rapidly cooled and dedusted, and the ammonia gas is fully absorbed. After this absorption stage, the gas continues to rise to the acidification section, and the gas that has passed through the absorption section but still contains ammonia gas is subjected to secondary absorption by sulfuric acid in the acidification section, so as to realize efficient absorption of ammonia gas and ensure that the ammonia content in the gas discharged from the tower top is minimized, thereby greatly reducing the loss of ammonia gas and improving the overall recovery efficiency.

[0020] 2, the utility model provides an ammonia absorption tower of ammonium phosphate washing adopts integrated design, integrates absorption section and acidification section in same absorption tower structure, absorption section and acidification section are integrated in single absorption tower structure, and this integrated design not only promotes the compactness of equipment, but also optimizes the efficiency of whole ammonia recovery process, makes the tower body realize high -efficient cooperation in the limited space, has excellent ammonia recovery performance, also greatly reduces the land occupation of absorption system, reduces the cost of construction, still have the advantages that simple structure, flexible operation. BRIEF DESCRIPTION OF DRAWINGS

[0021] The utility model is further described below in combination with the drawings and embodiments.

[0022] Figure 1 The structure diagram of the ammonia absorption tower of ammonium phosphate washing provided by the utility model.

[0023] The meanings of the signs in the drawings are as follows:

[0024] 1 - absorption tower body;101 - gas inlet interface;102 - spare gas inlet interface;103 - gas distributor;104 - tower top gas outlet;105 - tower kettle liquid outlet;

[0025] 2 - apron;

[0026] 3 - lower absorption section;301 - lower ammonium phosphate lean liquid circulating liquid interface;

[0027] 4 - middle absorption section;401 - middle ammonium phosphate lean liquid circulating liquid interface;402 - middle ammonium phosphate lean liquid circulating liquid outlet;403 - middle liquid receiving plate;

[0028] 5 - upper absorption section;501 - upper ammonium phosphate lean liquid circulating liquid interface;502 - upper ammonium phosphate lean liquid circulating liquid outlet;503 - upper liquid receiving plate;

[0029] 6 - liquid collecting device;

[0030] 7 - acidification section;701 - sulfuric acid inlet;702 - ammonium sulfate outlet;703 - filler;

[0031] 8 - demister. DETAILED DESCRIPTION

[0032] The utility model is further described below in combination with the drawings and embodiments, but the following description including embodiments is only used for making the ordinary skilled person in the art to which the utility model belongs can more clearly understand the principle and essence of the utility model, does not mean to limit the utility model in any form.

[0033] As Figure 1As shown, the utility model provides a kind of ammonium phosphate wash ammonia absorption tower, including absorption tower body 1, absorption tower body 1 is sequentially laid absorption section and acidification section 7 from bottom to top in it, and the absorption section includes lower absorption section 3, middle absorption section 4 and upper absorption section 5 arranged from bottom to top, absorption section uses ammonium phosphate lean liquid to carry out staged circulation spray treatment to ammonia-containing process gas, ammonia-containing process gas is quenched, dusted, purified, and ammonium phosphate lean liquid absorption enough ammonia gas and generates ammonium phosphate rich liquid and is discharged by external circulating pump, enters rear-end desorption tower.

[0034] And acidification section 7 has sulfuric acid inlet 701, sulfuric acid liquid is imported from sulfuric acid inlet 701, to carry out absorption to the ammonia gas remaining in the gas after being treated by absorption section, and the purified gas obtained is discharged from the outlet at the top of tower.

[0035] Further, the ammonium phosphate wash ammonia absorption tower further includes: a skirt 2 arranged at the bottom of the absorption tower body 1, which provides solid support for the absorption tower body 1.

[0036] Further, the lower absorption section 3, the middle absorption section 4 and the upper absorption section 5 are each provided with an ammonium phosphate lean liquid circulation liquid interface and an ammonium phosphate lean liquid circulation liquid outlet, which are respectively a lower ammonium phosphate lean liquid circulation liquid interface 301, a lower ammonium phosphate lean liquid circulation liquid outlet (which can be omitted, the ammonium phosphate lean liquid sprayed in the lower absorption section 3 directly falls into the tower kettle, which can be discharged through the outlet of the tower kettle), a middle ammonium phosphate lean liquid circulation liquid interface 401, a middle ammonium phosphate lean liquid circulation liquid outlet 402, an upper ammonium phosphate lean liquid circulation liquid interface 501 and an upper ammonium phosphate lean liquid circulation liquid outlet 502.

[0037] Preferably, the ammonium phosphate lean liquid circulation liquid interface and the ammonium phosphate lean liquid circulation liquid outlet of any absorption section are arranged in a staggered manner along the central axis of the tower body with the ammonium phosphate lean liquid circulation liquid interface and the ammonium phosphate lean liquid circulation liquid outlet of the adjacent absorption section.

[0038] More preferably, the ammonium phosphate lean liquid circulation liquid interface and the ammonium phosphate lean liquid circulation liquid outlet of the adjacent absorption section are symmetrically arranged on both sides of the tower body along the central axis of the tower body. Figure 1 As shown, the upper ammonium phosphate lean liquid circulation liquid interface 501, the upper ammonium phosphate lean liquid circulation liquid outlet 502 and the lower ammonium phosphate lean liquid circulation liquid interface 301 are arranged on the left side of the absorption tower body 1, and the middle ammonium phosphate lean liquid circulation liquid interface 401 and the middle ammonium phosphate lean liquid circulation liquid outlet 402 are arranged on the right side of the tower body.

[0039] Further, the lower absorption section 3, the middle absorption section 4 and the upper absorption section 5 are each provided with a single or multiple spray layer, and a plurality of hollow cone nozzles or solid cone nozzles are arranged on each spray layer in a uniform manner, and each spray layer is in communication with the ammonium phosphate lean liquid circulation liquid interface.

[0040] In some embodiments, asFigure 1 As shown, the liquid collecting device is arranged between the acidification section 7 and the upper absorption section 5, between the upper absorption section 5 and the middle absorption section 4, and between the middle absorption section 4 and the lower absorption section 3.

[0041] The liquid collecting device 6 comprises a liquid collecting tray for collecting liquid, a plurality of gas lifting pipes, and a gas lifting cap. One end of the gas lifting pipe is arranged in the liquid collecting tray and allows gas to flow through the gas lifting pipe, and the gas lifting cap is arranged at the other end of the gas lifting pipe.

[0042] Further, the ammonium phosphate washing ammonia absorption tower described above further comprises a plurality of liquid receiving plates, and the liquid receiving plates are arranged between the upper absorption section 5 and the middle absorption section 4, and between the middle absorption section 4 and the lower absorption section 3. The liquid receiving plate is located below the liquid collecting tray, and one end of the liquid receiving plate has an overflow weir to overflow the collected ammonium phosphate lean liquid circulating liquid from the upper absorption section to the lower absorption section, and the other end is used to communicate with the ammonium phosphate lean liquid circulating liquid outlet of the absorption section to output the ammonium phosphate lean liquid circulating liquid.

[0043] Preferably, the liquid receiving plate arranged between the upper absorption section 5 and the middle absorption section 4 is referred to as the upper liquid receiving plate 503, and the liquid receiving plate arranged between the middle absorption section 4 and the lower absorption section 3 is referred to as the middle liquid receiving plate 403. The arrangement position of the liquid receiving plate is the same as the arrangement structure of the ammonium phosphate lean liquid circulating liquid interface and the ammonium phosphate lean liquid circulating liquid outlet of the absorption section, and the liquid receiving plates of adjacent absorption sections are symmetrically arranged on both sides of the tower body along the central axis of the tower body, i.e., the upper ammonium phosphate liquid receiving plate and the upper section ammonium phosphate lean liquid circulating liquid interface, the upper section ammonium phosphate lean liquid circulating liquid outlet, and the lower section ammonium phosphate lean liquid circulating liquid interface are arranged on the left side of the tower body, and the middle ammonium phosphate liquid receiving plate and the middle section ammonium phosphate lean liquid circulating liquid interface and the middle section ammonium phosphate lean liquid circulating liquid outlet are arranged on the right side.

[0044] The operation process in the absorption section is as follows:

[0045] The ammonium phosphate lean liquid from the rear-end desorption tower is pumped out by the desorption tower kettle liquid pump, enters from the upper section ammonium phosphate lean liquid circulating liquid interface, and absorbs the ammonia gas flowing into the upper absorption section 5 in the process of downward spraying of the ammonium phosphate lean liquid. The absorbed ammonium phosphate lean liquid falls on the liquid receiving plate of the middle absorption section 4, flows into the upper liquid receiving plate 503, a part of which flows out through the upper section ammonium phosphate lean liquid circulating liquid outlet, the circulating liquid flows out through the external circulating pump, is cooled after heat exchange, and then flows back to the upper section ammonium phosphate lean liquid circulating liquid interface, and the other part flows into the middle absorption section 4 through the upper ammonium phosphate liquid receiving plate to overflow into the middle absorption section 4, and participates in the circulation absorption of the middle absorption section 4 as the ammonium phosphate lean liquid of the middle absorption section 4.

[0046] The ammonium phosphate lean solution in the middle absorption section 4 is circulated by an external circulation pump, and after heat exchange and cooling, it enters the middle absorption section from the middle section ammonium phosphate lean solution circulation liquid interface, absorbs the ammonia gas entering the middle absorption section 4 in the process of downward spraying, and then falls onto the middle absorption section 4 liquid collecting plate and flows into the middle liquid receiving plate 403. Part of the ammonium phosphate lean solution flows out through the middle section ammonium phosphate lean solution circulation liquid outlet, continues to be sprayed and circulated, and the other part overflows into the lower absorption section 3 through the middle liquid receiving plate 403, and participates in the circulation and absorption of the lower absorption section 3 as the ammonium phosphate lean solution of the lower absorption section 3.

[0047] The ammonium phosphate lean solution in the lower absorption section 3 is circulated by an external circulation pump, enters from the lower section ammonium phosphate lean solution circulation liquid interface, absorbs the ammonia gas in the lower absorption section 3 in the process of downward spraying, and then enters the tower kettle. The ammonium phosphate lean solution after absorption flows out through the tower kettle liquid outlet 105, is backflowed to the lower section ammonium phosphate lean solution circulation liquid interface by an external circulation pump, and continues to circulate in the lower absorption section 3. When the ammonium phosphate lean solution absorbs enough ammonia gas to become ammonium phosphate rich solution, the ammonium phosphate rich solution is discharged by an external circulation pump and enters the rear-end desorption tower.

[0048] In some embodiments, the acidification section 7 also has an ammonium sulfate outlet 702 which communicates with the liquid collecting tray arranged between the acidification section 7 and the upper absorption section 5.

[0049] In some embodiments, the acidification section 7 can be a plate column or a packed column. When the acidification section 7 is a plate column, the number of theoretical plates is 2-6 layers. When the acidification section 7 is a packed column, the acidification section 7 includes packing 703 and a packing support structure, and the height of the packing 703 is 2-5 meters.

[0050] In some embodiments, the absorption tower can be a void tower, a packed column or a plate column. When the absorption tower is a void tower, the number of spray layers in the void tower is 2-4 layers. When the absorption tower is a plate column, the number of theoretical plates in each absorption section is 2-6 layers. When the absorption tower is a packed column, the height of each layer of packing in each absorption section is 2-5 meters.

[0051] In some embodiments, the absorption tower body 1 is provided with a gas inlet interface 101 and a standby gas inlet interface 102 near the tower kettle. The main function of the two gas inlet interfaces is to ensure that the gas can smoothly and efficiently enter the absorption tower,

[0052] The absorption tower body 1 is provided with a gas distributor 103 which communicates with the gas inlet interface 101 and the standby gas inlet interface 102, which is designed to optimize the distribution and flow of gas in the tower, and ensures uniform distribution of gas in the tower. After the ammonia-containing process gas is uniformly distributed by the gas distributor 103, it is in countercurrent contact with the ammonium phosphate lean solution in the absorption section, thereby efficiently absorbing the ammonia gas therein.

[0053] In some embodiments, the ammonia absorption tower for ammonium phosphate washing further comprises: a plurality of demisters 8, which are arranged between the acidification section 7 and the top outlet of the absorption tower body 1 and between the upper absorption section 5 and the acidification section 7, and the presence of the demisters 8 can effectively remove the foam generated in the gas treatment process, thereby ensuring the purity of the gas and the stable operation of the absorption tower.

[0054] Preferably, double-layer demisters 8 are arranged between the acidification section 7 and the top outlet of the absorption tower body 1.

[0055] In some embodiments, because the absorption tower process gas has an inlet gas pressure, a safety valve interface is arranged at the top of the absorption tower body 1.

[0056] The operation process of the ammonia absorption tower for ammonium phosphate washing is as follows:

[0057] The process gas from the hydrocyanic acid device enters the absorption tower body 1 from the inlet interface 101, is uniformly distributed in the tower by the gas distributor 103, is reversely contacted with the ammonium phosphate lean liquid in the lower absorption section 3, and the temperature is rapidly reduced, so that the dust in the process gas is adsorbed and purified, and part of the ammonia in the process gas is absorbed, and then the process gas enters the middle absorption section 4 through the steam cap of the lower absorption section 3, is reversely contacted with the ammonium phosphate lean liquid in the middle absorption section 4, and the ammonia in the process gas is further absorbed, and then the process gas enters the upper absorption section 5 through the steam cap of the middle absorption section 4, is reversely contacted with the ammonium phosphate lean liquid in the upper absorption section 5, and the ammonia in the process gas is further absorbed, and then the process gas is defoamed through the upper demister 8, and then enters the acidification section 7 through the steam cap of the upper absorption section 5.

[0058] The sulfuric acid liquid from the sulfuric acid system is delivered by a sulfuric acid pump, enters the acidification section 7 from the sulfuric acid interface at the top of the tower, is reversely contacted with the process gas after the steam cap of the upper absorption section 5 at the filler 703, and the sulfuric acid liquid fully absorbs the ammonia to form ammonium sulfate liquid, the ammonium sulfate liquid flows out through the ammonium sulfate liquid outlet, is circulated by an external sulfuric acid pump, is cooled after heat exchange, and is returned to the sulfuric acid interface to re-enter the acidification section 7, and when the ammonium sulfate liquid forms saturated ammonium sulfate liquid, the saturated ammonium sulfate liquid passes through the ammonium sulfate liquid outlet and is discharged to the front-end acrylonitrile system by the external sulfuric acid pump. The process gas after sulfuric acid purification is discharged from the tower body through the top gas outlet 104 and enters the front-end acrylonitrile system.

[0059] The concentration of ammonia in the gas phase entering the acidification section 7 can be adjusted by controlling the absorption section temperature, the ammonium phosphate lean liquid concentration, the ammonium phosphate lean liquid molar ratio and the liquid-gas ratio, and the ammonia concentration of the outlet gas at the top of the tower can be controlled by controlling the acidification section 7 temperature and the reflux ratio.

[0060] The ideal embodiments of the utility model are inspired, and through the above description, relevant staff can make various changes and modifications without deviating from the technical idea of the utility model.

[0061] The technical scope of the present application is not limited to the content of the specification, and must be determined based on the scope of the claims.

Claims

1. An ammonium phosphate scrubber ammonia absorber tower characterized by, Comprise: an absorption tower body, an acidification section arranged in sequence from bottom to top in the absorption tower body, the absorption section comprises a lower absorption section, a middle absorption section and an upper absorption section from bottom to top, and the absorption section uses ammonium phosphate lean liquid to treat ammonia-containing process gas by graded circulation spray; the acidification section has a sulfuric acid inlet, and sulfuric acid liquid is introduced from the sulfuric acid inlet to absorb residual ammonia gas in the gas treated by the absorption section.

2. The ammonium phosphate ammonia washing absorption tower according to claim 1, wherein, a liquid collecting device is arranged between the acidification section and the upper absorption section, between the upper absorption section and the middle absorption section, and between the middle absorption section and the lower absorption section; the liquid collecting device comprises a liquid collecting disc, a plurality of gas lifting pipes and a gas lifting cap, the liquid collecting disc is used to collect liquid; one end of the gas lifting pipe is arranged in the liquid collecting disc and the gas flows through the gas lifting pipe, and the gas lifting cap is arranged at the other end of the gas lifting pipe.

3. The ammonium phosphate ammonia washing absorption tower according to claim 2, further comprising: a plurality of liquid receiving plates, the liquid receiving plates are arranged between the upper absorption section and the middle absorption section and between the middle absorption section and the lower absorption section; the liquid receiving plate is located at the lower part of the liquid collecting disc, and one end of the liquid receiving plate has an overflow weir to overflow the collected ammonium phosphate lean liquid circulation liquid from the upper absorption section to the lower absorption section, and the other end is used to output the ammonium phosphate lean liquid circulation liquid.

4. The ammonium phosphate ammonia washing absorption tower according to claim 1, wherein, the ammonium phosphate lean liquid circulation liquid interface and the ammonium phosphate lean liquid circulation liquid outlet of any absorption section are symmetrically arranged with the ammonium phosphate lean liquid circulation liquid interface and the ammonium phosphate lean liquid circulation liquid outlet of the adjacent absorption section along the central axis of the absorption tower body.

5. The ammonium phosphate ammonia washing absorption tower according to claim 1, wherein, the acidification section is a plate tower or a packed tower, when the acidification section is a plate tower, the theoretical plate number is 2-6 layers; when the acidification section is a packed tower, the acidification section comprises packing and a packing support structure, and the height of the packing is 2-5 meters.

6. The ammonium phosphate ammonia washing absorption tower according to claim 2, wherein, the acidification section further has an ammonium sulfate outlet which communicates with the liquid collecting disc arranged between the acidification section and the upper absorption section.

7. The ammonium phosphate ammonia washing absorption tower according to claim 1, wherein, the absorption tower is an empty tower, a packed tower or a plate tower, when the absorption tower is an empty tower, the number of spray layers in the empty tower is 2-4 layers; when the absorption tower is a plate tower, the theoretical plate number is 2-6 layers; when the absorption tower is a packed tower, the height of each layer of packing is 2-5 meters.

8. The ammonium phosphate ammonia washing absorption tower according to claim 1, wherein, the absorption tower body is provided with a gas inlet interface and a standby gas inlet interface near the tower kettle, the absorption tower body is provided with a gas distributor which communicates with the gas inlet interface and the standby gas inlet interface.

9. The ammonium phosphate ammonia washing absorption tower according to any one of claims 1-8, wherein, ​ Also comprising: a plurality of demisters, the demisters being arranged between the acidification section and the top outlet of the absorption tower body, and between the upper absorption section and the acidification section; and / or, a single or multiple spray layers are arranged in the lower absorption section, the middle absorption section and the upper absorption section, and a plurality of hollow cone nozzles or solid cone nozzles are arranged on each spray layer.

10. The ammonium phosphate washing ammonia absorption tower according to claim 1, characterized in that, Also comprising: a skirt arranged at the bottom of the absorption tower body.

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