A low energy and low material consumption method and system for ammonia recovery

Abstract

The application provides a low-energy and low-material-consumption method and system for ammonia recovery, and belongs to the technical field of ammonia recovery. The method comprises the following steps: ammonia-containing gas is absorbed by an absorption liquid to obtain high-COD ammonia-rich acetic acid absorption liquid; the high-COD ammonia-rich acetic acid absorption liquid is subjected to oxidation to obtain high-acetic-acid-content absorption liquid; then, the high-acetic-acid-content absorption liquid is subjected to oxidation to obtain an ammonia-containing aqueous solution; and the obtained ammonia-containing aqueous solution is subjected to distillation; and the absorption liquid is high-acetic-acid-content absorption liquid. In the application, acetic acid produced by high-selectivity oxidation of a specific high-efficiency catalyst in the process is used as an absorbent to form an organic amine salt, and no acid needs to be supplemented, so that the material consumption is greatly reduced; meanwhile, a large amount of heat is generated in the wet oxidation process, the problems of existing technologies, such as generation of a large amount of salt-containing wastewater, secondary pollution and high energy consumption of evaporation and concentration, are solved.

Description

Technical Field

[0001] This invention belongs to the field of ammonia recovery technology, specifically relating to a low-energy and low-material-consumption method and system for ammonia recovery. Background Technology

[0002] Ammonia is a colorless gas at room temperature with a strong, pungent odor. In chemical processes involving ammonia, residual ammonia often requires separation and treatment. Direct emission of ammonia produces a pungent, foul odor, kills trees, damages the respiratory system and skin, and impacts local air quality, the environment, and residents' lifestyles. It not only pollutes the atmosphere but also causes eutrophication of water bodies and water pollution when it forms rainwater, resulting in serious environmental pollution. However, ammonia is an important chemical raw material, and its recovery can achieve resource conservation. Therefore, based on environmental protection and energy conservation, there is an urgent need to improve the technology for treating ammonia-containing waste gas.

[0003] In existing ammonia oxidation industrial plants, excess ammonia is mostly absorbed by sulfuric acid to form ammonium sulfate, which is then crystallized to obtain ammonium sulfate. Examples of such processes include acrylonitrile plants and isophthalonitrile plants. These technologies generate large amounts of saline wastewater, causing secondary pollution, and the evaporation and concentration processes are energy-intensive.

[0004] Chinese patent publication CN1204620A discloses a method for recovering unreacted ammonia from the reactor effluent obtained from the reaction zone that produces acrylonitrile or methacrylonitrile. The method involves rapidly cooling the reactor effluent with an aqueous solution of ammonium phosphate, and then desorbing the resulting absorbent under high temperature and high pressure to generate an ammonia-containing vapor stream and a recyclable absorbent. This technology has high energy consumption during the desorption process and inevitably generates phosphorus-containing wastewater.

[0005] In summary, all existing technologies suffer from secondary pollution problems caused by saline wastewater, high energy consumption, and cost issues related to acid consumption. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art and provide a low-energy and low-material-consumption method and system for ammonia recovery. This process does not produce saline wastewater and the wet oxidation process can achieve heat self-balancing and even generate heat energy. At the same time, it uses acetic acid produced by the wet oxidation reaction as the absorption acid without the need for addition, which greatly reduces material consumption and solves the problems of generating a large amount of saline wastewater, causing secondary pollution, and high energy consumption for evaporation and concentration in the prior art.

[0007] This invention is achieved through the following technical solution:

[0008] In a first aspect, the present invention provides a low-energy and low-material-consumption method for ammonia recovery, comprising absorbing ammonia-containing gas with an absorbent to obtain a high-COD ammonium-rich acetic acid absorbent, oxidizing the high-COD ammonium-rich acetic acid absorbent to obtain a high-acetic acid content absorbent, then oxidizing the high-acetic acid content absorbent to obtain an ammonia-containing aqueous solution, and distilling the obtained ammonia-containing aqueous solution; wherein the absorbent is a high-acetic acid content absorbent.

[0009] A further improvement of the present invention is that:

[0010] The method specifically includes the following steps:

[0011] S1, the ammonia-containing gas is contacted with the high acetic acid content absorbent in the absorption tower to absorb the ammonia in the ammonia-containing gas, and a high COD ammonium-rich acetic acid absorbent and ammonia-free gas flow are obtained.

[0012] S2, after the high COD ammonium-rich acetic acid absorbent is reacted with an oxidant in the first oxidation reactor, a high acetic acid content absorbent is obtained;

[0013] S3, a portion of the high acetic acid content absorbent is returned to the absorption tower, and the remaining high acetic acid content absorbent is reacted with the oxidant in the second oxidation reactor to remove acetic acid and obtain an ammonia-containing aqueous solution;

[0014] S4, the ammonia-containing aqueous solution is distilled in the distillation column, and a crude ammonia gas stream is obtained at the top of the column. Optionally, the acidic bottom liquid is returned to the absorption column.

[0015] A further improvement of the present invention is that:

[0016] The ammonia-containing gas is a gas containing organic matter, preferably a gas in which the organic matter is soluble in water.

[0017] A further improvement of the present invention is that:

[0018] In step S1,

[0019] The high acetic acid content absorbent is circulated in the absorption tower, with a pH value of 2–6.5, preferably 4–6.5; and / or,

[0020] The acetic acid concentration in the high acetic acid content absorbent is 3–20% wt, preferably 5–12% wt; and / or,

[0021] The COD value of the high COD ammonium-rich acetic acid absorbent solution is 40,000–250,000 mg / L, preferably 40,000–150,000 mg / L.

[0022] A further improvement of the present invention is that:

[0023] In steps S2 and S3, the oxidant is an oxygen-containing gas; preferably, the oxygen-containing gas can be pure oxygen, air, or oxygen-enriched air with an oxygen content of 35-50% v%.

[0024] A further improvement of the present invention is that:

[0025] In step S2,

[0026] The volume ratio of oxygen in the oxidant to the high-COD ammonium-rich acetic acid absorption solution is 10–400.

[0027] And / or, the temperature of the reaction is 250–300°C;

[0028] And / or, the pressure of the reaction is 7–12.0 MPa;

[0029] And / or, the residence time of the high COD ammonium-rich acetic acid absorbent in the first oxidation reactor is 10 to 150 minutes, preferably 10 to 120 minutes.

[0030] A further improvement of the present invention is that:

[0031] In step S3,

[0032] The volume ratio of oxygen in the oxidant to the high acetic acid content absorption liquid is 10–400.

[0033] And / or, the temperature of the reaction is 180–300°C;

[0034] And / or, the pressure of the reaction is 3.0 to 12.0 MPa;

[0035] And / or, the residence time of the high acetic acid content absorbent in the second oxidation reactor is 10 to 150 minutes, preferably 10 to 90 minutes.

[0036] A further improvement of the present invention is that:

[0037] The oxidation reaction of the high-COD ammonium-rich acetic acid absorbent to obtain a high-acetic acid content absorbent is a wet oxidation reaction carried out in the presence of a first oxidation catalyst; preferably,

[0038] The first oxidation catalyst is a wet oxidation catalyst, comprising the following components by weight:

[0039] (1) 20-40 parts of nano-titanium dioxide;

[0040] (2) 2 to 10 parts selected from at least one of titanium tetrachloride, titanium oxysulfate and tetrabutyl titanate;

[0041] (3) 0.1 to 5 parts selected from at least one of lanthanum nitrate, cerium nitrate, praseodymium nitrate and neodymium nitrate;

[0042] (4) 45–77.9 parts water;

[0043] And / or,

[0044] The oxidation reaction of the high acetic acid content absorbent to obtain an ammonia-containing aqueous solution is a wet oxidation reaction carried out in the presence of a second oxidation catalyst; preferably,

[0045] The second oxidation catalyst is a wet oxidation catalyst, comprising the following components by weight:

[0046] (1) 96–99.8 portions of the carrier;

[0047] (2) 0.1 to 2 parts of rare earth metal oxides;

[0048] (3) 0.1 to 2 parts of at least one precious metal selected from the platinum group.

[0049] A further improvement of the present invention is that:

[0050] All wet oxidation reactions are carried out in a wet oxidation reactor equipped with a wet oxidation catalyst bed.

[0051] A further improvement of the present invention is that:

[0052] The method further includes: distilling the crude ammonia gas stream obtained in step S4 to obtain anhydrous ammonia stream; or adjusting the distillation efficiency to obtain streams with different ammonia contents.

[0053] A second aspect of the present invention provides a low-energy and low-material-consumption system for ammonia recovery, the system comprising an absorption tower, a first oxidation reactor, a second oxidation reactor, and a distillation tower connected in sequence, wherein the bottom of the first oxidation reactor and the distillation tower are respectively connected to the absorption tower via reflux pipes.

[0054] Preferably, both the first oxidation reactor and the second oxidation reactor are wet oxidation reactors with a wet oxidation catalyst bed.

[0055] Compared with the prior art, the beneficial effects of the present invention are:

[0056] This invention provides a low-energy and low-material-consumption method and system for ammonia recovery. It uses acetic acid, which is produced by highly selective oxidation of a specific high-efficiency catalyst in its own process, as an absorbent to form organic amine salts. No acid supplementation is required, which greatly reduces material consumption. At the same time, a large amount of heat is generated during the wet oxidation process. Compared with the existing process, the energy-saving advantage is obvious. Furthermore, the acetate ions in the absorbent can be removed by wet oxidation, and no saline wastewater is generated. Attached Figure Description

[0057] Figure 1This is a process flow diagram of a low-energy and low-material-consumption method for ammonia recovery according to the present invention.

[0058] In the diagram, 1 is the first oxidation reactor, 2 is the second oxidation reactor, 3 is the distillation tower, 4 is the absorption tower, 5 is the ammonia-containing gas, 6 is the ammonia-free gas flow, 7 is the high-COD ammonium-rich acetic acid absorbent, 8 is the partially high-acetic acid absorbent, 9 is the remaining high-acetic acid absorbent, 10 is the ammonia-containing aqueous solution, 11 is the bottom liquid of the tower, and 12 is the crude ammonia gas flow. Detailed Implementation

[0059] The present invention will now be described in further detail with reference to the accompanying drawings:

[0060] A first aspect of the present invention provides a low-energy-consumption and low-material-consumption method for ammonia recovery, such as... Figure 1 As shown, the process includes absorbing ammonia-containing gas with an absorbent to obtain a high-COD ammonium-rich acetic acid absorbent, oxidizing the high-COD ammonium-rich acetic acid absorbent to obtain a high-acetic acid content absorbent, then oxidizing the high-acetic acid content absorbent to obtain an ammonia-containing aqueous solution, and distilling the resulting ammonia-containing aqueous solution; the absorbent is a high-acetic acid content absorbent.

[0061] The method of the present invention specifically includes the following steps:

[0062] S1, the ammonia-containing gas is contacted with the high acetic acid content absorbent in the absorption tower to absorb the ammonia in the ammonia-containing gas, and a high COD ammonium-rich acetic acid absorbent and ammonia-free gas flow are obtained.

[0063] The ammonia-containing gas is a gas containing organic matter, preferably a gas in which the organic matter is soluble in water;

[0064] The COD value of the high COD ammonium-rich acetic acid absorbent solution is 40,000–250,000 mg / L, preferably 40,000–150,000 mg / L;

[0065] S2, after reacting the high COD ammonium-rich acetic acid absorbent with the oxidant in the first oxidation reactor, a high acetic acid content absorbent is obtained;

[0066] S3, a portion of the high acetic acid content absorbent is returned to the absorption tower, and the remaining high acetic acid content absorbent is reacted with the oxidant in the second oxidation reactor to remove acetic acid and obtain an ammonia-containing aqueous solution;

[0067] The amount of high acetic acid content absorbent returned to the absorption tower is determined by the ammonia content in the ammonia-containing gas and the acetic acid content in the high acetic acid content absorbent. Based on ensuring complete ammonia absorption, it is only necessary to meet the balance between ammonia absorption and recovery.

[0068] S4, the ammonia-containing aqueous solution is distilled in the distillation column, and a crude ammonia gas stream is obtained at the top of the column. Preferably, the acidic bottom liquid is returned to the absorption column.

[0069] Both the first and second oxidation reactors are wet oxidation reactors with wet oxidation catalyst beds.

[0070] In this invention, the method further includes: distilling the crude ammonia gas stream obtained in step S4 to obtain anhydrous ammonia stream; or adjusting the distillation efficiency to obtain streams with different ammonia contents.

[0071] In some preferred embodiments of the present invention, in step S1, the high acetic acid content absorbent is circulated in the absorption tower, and the pH value is 2 to 6.5, preferably 4 to 6.5;

[0072] And / or, the acetic acid concentration in the high acetic acid content absorbent is 3–20% wt, preferably 5–12% wt. The solvent of the high acetic acid content absorbent is water, and the absorbent also contains ammonium acetate.

[0073] In some preferred embodiments of the present invention, in step S2, the first catalyst in the first oxidation reactor is a composite metal oxide catalyst; it can be selected from existing wet oxidation catalysts in the prior art, preferably...

[0074] The first catalyst is selected from the catalyst disclosed in Chinese Patent Publication CN104148048A. CN104148048A is considered to be incorporated herein by reference in its entirety.

[0075] Specifically, the first catalyst comprises the following components in parts by weight:

[0076] (1) 20-40 parts of nano-titanium dioxide;

[0077] (2) 2 to 10 parts selected from at least one of titanium tetrachloride, titanium oxysulfate and tetrabutyl titanate;

[0078] (3) 0.1 to 5 parts selected from at least one of lanthanum nitrate, cerium nitrate, praseodymium nitrate and neodymium nitrate;

[0079] (4) 45 to 77.9 parts water.

[0080] In some preferred embodiments of the present invention, in step S3, the second catalyst in the second oxidation reactor is a noble metal catalyst; it can be selected from existing wet oxidation catalysts in the prior art, preferably...

[0081] The second catalyst is described in Chinese Patent Publication CN105080540A (The majority of organic components in acrylic acid wastewater are acetic acid). CN105080540A is incorporated herein by reference in its entirety.

[0082] Specifically, the second catalyst comprises, by weight, the following components:

[0083] (1) 96–99.8 portions of the carrier;

[0084] (2) 0.1 to 2 parts of rare earth metal oxides;

[0085] (3) 0.1 to 2 parts of at least one precious metal selected from the platinum group.

[0086] The rare earth metal is selected from at least one of La, Ce, Pr, Nd and Eu; the noble metal is preferably selected from at least one of Ru, Pd, Pt, Ir and Rh; the support is preferably selected from at least one of TiO2, ZrO2, Al2O3 and SiO2.

[0087] In some preferred embodiments of the present invention, in steps S2 and S3, the oxidant is an oxygen-containing gas; preferably, the oxygen-containing gas can be pure oxygen, air, or oxygen-enriched air with an oxygen content of 35-50%v%.

[0088] In some other embodiments of the present invention, in step S2, the volume ratio of oxygen in the oxidant to the high COD ammonium-rich acetic acid absorption liquid is 10 to 400.

[0089] The reaction temperature is 250–300°C;

[0090] The reaction pressure is 7–12.0 MPa;

[0091] The residence time of the high-COD ammonium-rich acetic acid absorbent in the first oxidation reactor is 10 to 150 minutes, preferably 10 to 120 minutes.

[0092] In some other embodiments of the present invention, in step S3, the volume ratio of oxygen in the oxidant to the high acetic acid content absorption liquid is 10 to 400.

[0093] The reaction temperature is 180–300°C;

[0094] The reaction pressure is 3.0–12.0 MPa;

[0095] The residence time of the high acetic acid content absorbent in the second oxidation reactor is 10 to 150 minutes, preferably 10 to 90 minutes.

[0096] In a second aspect, the present invention provides a low-energy-consumption and low-material-consumption system for ammonia recovery, such as... Figure 1 As shown, the system includes an absorption tower 4, a first oxidation reactor 1, a second oxidation reactor 2, and a distillation tower 3 connected in sequence. The first oxidation reactor 1 and the distillation tower 3 are also connected to the absorption tower 4 through reflux pipes.

[0097] The specific process is as follows:

[0098] Ammonia-containing gas 5 is contacted with a high-acetic acid content absorbent in the absorption tower 4 to absorb the ammonia in the gas, resulting in a high-COD ammonium-rich acetic acid absorbent 7 and an ammonia-free gas stream 6.

[0099] After reacting the high COD ammonium-rich acetic acid absorbent 7 with an oxidant in a first oxidation reactor 1 with a wet oxidation catalyst bed, a high acetic acid content absorbent is obtained; in the first oxidation reactor, the catalyst can oxidize the high COD ammonium-rich acetic acid absorbent into acetic acid, and the acetic acid reacts with ammonia to form ammonium acetate;

[0100] A portion of the high-acetic acid content absorbent liquid 8 is returned to the absorption tower 4 via a reflux pipe to absorb ammonia in the gas. The remaining high-acetic acid content absorbent liquid 9 is reacted with an oxidant in a second oxidation reactor 2 with a wet oxidation catalyst bed to remove acetic acid and obtain an ammonia-containing aqueous solution 10. In the second oxidation reactor, the catalyst can oxidize acetic acid (mainly acetate ions) into carbon dioxide and water. The catalytic efficiency can be adjusted according to the actual situation to achieve the desired acetic acid content in the solution after the reaction.

[0101] An ammonia-containing aqueous solution 10 is distilled in a distillation column 3, and a crude ammonia gas stream 12 is obtained at the top of the column, while the bottom liquid 11 is returned to the absorption column 4. The crude ammonia gas stream 12 is then purified to obtain an anhydrous ammonia stream, or the purification efficiency is adjusted to obtain streams with different ammonia contents (not listed).

[0102] Innovation of this invention:

[0103] (1) In this invention, the high-content acetic acid absorbent produced by the high-efficiency catalyst in the first oxidation reactor 1 is used as the absorbent to absorb ammonia in the ammonia-containing gas. No acid needs to be added, and the material consumption is greatly reduced.

[0104] (2) After removing acetate ions from the high acetic acid content absorption liquid with the high-efficiency precious metal catalyst in the second oxidation reactor 2, an ammonia-containing aqueous solution is obtained, thereby realizing the recovery of ammonia. Furthermore, after the acetate ions are treated with the wet oxidation catalyst, CO2 is directly generated, and the solution is a relatively pure ammonia solution, which is beneficial for subsequent treatment and no saline wastewater is generated.

[0105] (3) In the wet oxidation process of the high COD ammonium-rich absorbent in the first oxidation reactor, in addition to generating a high content acetic acid absorbent for absorbing ammonia, a large amount of heat is also generated. This heat can be supplied to the raw materials of the first oxidation reactor and the second oxidation reactor for preheating using existing heat exchange methods. Therefore, no external heat is required during the reaction process, which has an energy-saving advantage compared with the existing technology of ammonium salt production which requires a large amount of heat for crystallization and evaporation.

[0106] The embodiments listed in this invention all include four main steps: ammonia absorption, catalytic wet oxidation to produce acetic acid, ammonia recovery via catalytic wet oxidation, and ammonia distillation. Since ammonia distillation is a simple, basic chemical unit operation, it will not be described in detail in the embodiments.

[0107] In this embodiment of the invention, the ammonia-containing gas is the reaction gas obtained after the laboratory ammoxidation reaction of propylene, and the oxidant used in the wet oxidation reaction in the first oxidation reactor and the second oxidation reactor is pure oxygen.

[0108]

Example 1

[0109] 1. Preparation of the first catalyst

[0110] 220g nano titanium dioxide (rutile type, specific surface area 22m²) 2 / g (particle size 82nm), 40g titanium oxysulfate, 20g tetrabutyl titanate, 6g lanthanum nitrate, 10g cerium nitrate, and 10g neodymium nitrate were dissolved in 500mL of water; under vigorous stirring at 40℃, 65mL of 17% ammonia water was added dropwise to the mixture, and stirring was continued for 2h, followed by filtration; the filter cake was extruded into a clover shape using a mold, dried at room temperature, and the molded material was calcined at 750℃ in air for 4h to obtain a titanium dioxide support containing rare earth elements with a strength of 87N / mm, which was designated as the first catalyst C-01.

[0111] The above-mentioned first catalyst C-01 and its preparation are from Example 9 of the patent application with publication number CN104148048A.

[0112] 2. Preparation of the second catalyst

[0113] The weight ratio of TiO2:CeO2:Nd2O3:Ru is 98.4:0.4:0.8:0.4.

[0114] 1.1 Preparation of the carrier: 240g of nano TiO2 powder, 0.98g of CeO2 powder, 1.92g of nano Nd2O3 powder, 80g of water and 4g of carboxymethyl cellulose were mixed and kneaded for 2 hours, then extruded into strips. After drying the strips at room temperature, they were calcined at 700℃ for 2 hours.

[0115] 1.2 Noble metal supported: 199.0 g of the molded support was immersed overnight in an aqueous solution containing 2.16 g of hydrated RuCl3 at room temperature, dried at 80 °C, and then reduced at 400 °C in a hydrogen atmosphere (a hydrogen-nitrogen mixture with a hydrogen content of 4%) for 4 hours to obtain a noble metal supported catalyst, which was designated as the second catalyst C-02.

[0116] The above-mentioned second catalyst C-02 and its preparation are from Example 3 of the patent application with publication number CN105080540A.

[0117] 3. Ammonia recovery

[0118] S1. Ammonia-containing gas is contacted with a high-acetic acid content absorbent in an absorption tower to absorb ammonia from the gas, resulting in a high-COD ammonium-rich acetic acid absorbent and an ammonia-free gas stream.

[0119] S2. After reacting the high COD ammonium-rich acetic acid absorbent with oxygen in a first oxidation reactor with a first catalyst C-01, a high acetic acid content absorbent is obtained.

[0120] S3. A portion of the high acetic acid content absorbent is returned to the absorption tower via a reflux pipe to absorb ammonia in the gas. The remaining high acetic acid content absorbent and oxygen oxidant are subjected to catalytic wet oxidation in a second oxidation reactor with a second catalyst C-O2 to remove acetic acid and obtain an ammonia-containing aqueous solution.

[0121] The reaction conditions and results are shown in Tables 1 and 2.

[0122] The experimental steps for

Example 2

Example 8

Example 1

[0123]

Comparative Example 1

[0124] The existing ammonium sulfate recovery process was compared with that in Example 1.

[0125] 1. Ammonia-containing gas is absorbed by an absorbent solution with a sulfuric acid mass concentration of 5% to obtain a high COD ammonium sulfate absorbent solution;

[0126] 2. High COD ammonium sulfate absorbent solution was distilled to obtain ammonium sulfate crystals and distillate.

[0127] [Comparative Example 2]

[0128] Comparative Example 2 used the same experimental conditions as Example 1, but differed from Example 1 in that:

[0129] S1. Absorb ammonia-containing gas with an absorbent solution containing 5% sulfuric acid to obtain a high-COD ammonium sulfate absorbent solution;

[0130] S2. The high COD ammonium sulfate absorbent solution undergoes a wet oxidation reaction with oxygen in the first oxidation reactor to obtain an absorbent solution with a high acetic acid content;

[0131] S3. A portion of the high acetic acid content absorbent is returned to the absorption tower through a reflux pipe to absorb ammonia from the ammonia-containing gas. The remaining high acetic acid content absorbent is subjected to catalytic wet oxidation with oxygen in the second oxidation reactor to obtain an ammonia-containing aqueous solution.

[0132] The reaction conditions and results are shown in Tables 1 and 2.

[0133] Table 1

[0134]

[0135]

[0136] Table 2

[0137]

[0138] Examples 1-8 can all achieve ammonia absorption and recovery, and the salt content in the ammonia-containing aqueous solution is extremely low or even 0. However, Comparative Example 1 is an existing ammonium sulfate recovery process, which requires the loss of sulfuric acid and has high energy consumption for ammonium sulfate evaporation and crystallization compared with the present invention. Comparative Example 2 operates in the same way as Example 1, but the ammonia concentration in the ammonia-containing aqueous solution is much lower than that in the examples, so ammonia recovery cannot be achieved, and the problem of saline wastewater also exists.

[0139] Finally, it should be noted that the above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the above specific embodiments of the present invention. Therefore, the methods described above are only preferred and have no limiting significance.

Claims

1. A low-energy and low-material-consumption method for ammonia recovery, comprising: absorbing ammonia-containing gas with an absorbent to obtain a high-COD ammonium-rich acetic acid absorbent, wherein the COD value of the high-COD ammonium-rich acetic acid absorbent is 40,000–250,000 mg / L; subjecting the high-COD ammonium-rich acetic acid absorbent to a wet oxidation reaction in the presence of a first oxidation catalyst to obtain a high-acetic acid content absorbent, wherein the acetic acid concentration in the high-acetic acid content absorbent is 3–20% wt; subsequently, a portion of the high-acetic acid content absorbent is returned as an ammonia-containing gas absorbent; and the remaining portion of the high-acetic acid content absorbent is subject to a wet oxidation reaction in the presence of a second oxidation catalyst to obtain an ammonia-containing aqueous solution; the obtained ammonia-containing aqueous solution is then distilled; wherein the absorbent is a high-acetic acid content absorbent.

2. The low-energy and low-material-consumption method for ammonia recovery according to claim 1, characterized in that, The method specifically includes the following steps: S1, the ammonia-containing gas is contacted with the high acetic acid content absorbent in the absorption tower to absorb the ammonia in the ammonia-containing gas, and a high COD ammonium-rich acetic acid absorbent and ammonia-free gas flow are obtained. S2, after the high COD ammonium-rich acetic acid absorbent is reacted with an oxidant in the first oxidation reactor, a high acetic acid content absorbent is obtained; S3, a portion of the high acetic acid content absorbent is returned to the absorption tower, and the remaining high acetic acid content absorbent is reacted with the oxidant in the second oxidation reactor to remove acetic acid and obtain an ammonia-containing aqueous solution; S4, the ammonia-containing aqueous solution is distilled in the distillation tower, and a crude ammonia gas stream is obtained at the top of the tower. The acidic bottom liquid is returned to the absorption tower.

3. The low-energy and low-material-consumption method for ammonia recovery according to claim 2, characterized in that, The ammonia-containing gas is a gas containing organic matter.

4. The low-energy and low-material-consumption method for ammonia recovery according to claim 2, characterized in that, In step S1, the high acetic acid content absorbent is circulated in the absorption tower, with a pH value of 2–6.5; and / or, The acetic acid concentration in the high acetic acid content absorption solution is 5–12% wt; and / or, The COD value of the high COD ammonium-rich acetic acid absorbent solution is 40,000–150,000 mg / L.

5. The low-energy and low-material-consumption method for ammonia recovery according to claim 4, characterized in that, In step S1, the high acetic acid content absorbent is circulated in the absorption tower, with a pH value of 4 to 6.

5.

6. The low-energy and low-material-consumption method for ammonia recovery according to claim 2, characterized in that, In steps S2 and S3, the oxidant is an oxygen-containing gas; the oxygen-containing gas is oxygen-enriched air with an oxygen content of 35-50%v.

7. The low-energy and low-material-consumption method for ammonia recovery according to claim 2, characterized in that, In steps S2 and S3, the oxidant is pure oxygen or air.

8. The low-energy and low-material-consumption method for ammonia recovery according to claim 5, characterized in that, In step S2, the volume ratio of oxygen in the oxidant to the high COD ammonium-rich acetic acid absorption liquid is 10 to 400. And / or, the temperature of the reaction is 250–300°C; And / or, the pressure of the reaction is 7–12.0 MPa; And / or, the residence time of the high COD ammonium-rich acetic acid absorbent in the first oxidation reactor is 10 to 150 minutes.

9. The low-energy and low-material-consumption method for ammonia recovery according to claim 8, characterized in that, The residence time of the high-COD ammonium-rich acetic acid absorbent in the first oxidation reactor is 10–120 minutes.

10. The low-energy and low-material-consumption method for ammonia recovery according to claim 5, characterized in that, In step S3, the volume ratio of oxygen in the oxidant to the high acetic acid content absorption liquid is 10 to 400. And / or, the temperature of the reaction is 180–300°C; And / or, the pressure of the reaction is 3.0 to 12.0 MPa; And / or, the residence time of the high acetic acid content absorbent in the second oxidation reactor is 10 to 150 minutes.

11. The low-energy and low-material-consumption method for ammonia recovery according to claim 10, characterized in that, The residence time of the high acetic acid content absorbent in the second oxidation reactor is 10–90 minutes.

12. According to claim 1 The low-energy and low-material-consumption method for ammonia recovery according to any one of the 11 claims is characterized in that, The first oxidation catalyst is a wet oxidation catalyst, comprising the following components by weight: (1) 20-40 parts of nano-titanium dioxide; (2) 2 to 10 parts selected from at least one of titanium tetrachloride, titanium oxysulfate and tetrabutyl titanate; (3) 0.1 to 5 parts selected from at least one of lanthanum nitrate, cerium nitrate, praseodymium nitrate and neodymium nitrate; (4) 45–77.9 parts water; And / or, The second oxidation catalyst is a wet oxidation catalyst, comprising the following components by weight: (1) 96–99.8 portions of the carrier; (2) 0.1 to 2 parts of rare earth metal oxides; (3) 0.1 to 2 parts of at least one precious metal selected from the platinum group.

13. The low-energy and low-material-consumption method for ammonia recovery according to claim 1, characterized in that, All wet oxidation reactions are carried out in a wet oxidation reactor equipped with a wet oxidation catalyst bed.

14. The low-energy and low-material-consumption method for ammonia recovery according to claim 2, characterized in that, The method further includes: distilling the crude ammonia gas stream obtained in step S4 to obtain anhydrous ammonia stream; or adjusting the distillation efficiency to obtain streams with different ammonia contents.

15. A low-energy-consumption and low-material-consumption system for ammonia recovery, characterized in that, The system is used to perform the low-energy and low-material-consumption method for ammonia recovery as described in any one of claims 1-14. The system includes an absorption tower, a first oxidation reactor, a second oxidation reactor, and a distillation tower connected in sequence. The bottoms of the first oxidation reactor and the distillation tower are also connected to the absorption tower via reflux pipes.

16. The low-energy-consumption and low-material-consumption system for ammonia recovery according to claim 15, characterized in that, Both the first oxidation reactor and the second oxidation reactor are wet oxidation reactors with wet oxidation catalyst beds.

Images