CN117923514A - Low-energy-consumption and low-material-consumption method and system for ammonia recovery - Google Patents
Low-energy-consumption and low-material-consumption method and system for ammonia recovery Download PDFInfo
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- CN117923514A CN117923514A CN202211317168.6A CN202211317168A CN117923514A CN 117923514 A CN117923514 A CN 117923514A CN 202211317168 A CN202211317168 A CN 202211317168A CN 117923514 A CN117923514 A CN 117923514A
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 256
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 121
- 238000000034 method Methods 0.000 title claims abstract description 42
- 238000011084 recovery Methods 0.000 title claims abstract description 31
- 238000005265 energy consumption Methods 0.000 title claims abstract description 16
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims abstract description 311
- 238000010521 absorption reaction Methods 0.000 claims abstract description 122
- 239000007788 liquid Substances 0.000 claims abstract description 111
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 68
- 230000003647 oxidation Effects 0.000 claims abstract description 58
- 239000003054 catalyst Substances 0.000 claims abstract description 47
- 239000007789 gas Substances 0.000 claims abstract description 43
- 238000009279 wet oxidation reaction Methods 0.000 claims abstract description 36
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000001301 oxygen Substances 0.000 claims abstract description 27
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 27
- 230000001590 oxidative effect Effects 0.000 claims abstract description 26
- 239000007864 aqueous solution Substances 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 21
- 239000000126 substance Substances 0.000 claims abstract description 9
- 239000002253 acid Substances 0.000 claims abstract description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 20
- 239000007800 oxidant agent Substances 0.000 claims description 19
- 238000006243 chemical reaction Methods 0.000 claims description 18
- 238000004821 distillation Methods 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 239000003570 air Substances 0.000 claims description 11
- 239000000243 solution Substances 0.000 claims description 11
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 claims description 8
- 229910000510 noble metal Inorganic materials 0.000 claims description 7
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 5
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 4
- YHWCPXVTRSHPNY-UHFFFAOYSA-N butan-1-olate;titanium(4+) Chemical compound [Ti+4].CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-] YHWCPXVTRSHPNY-UHFFFAOYSA-N 0.000 claims description 4
- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical compound [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 claims description 4
- CFYGEIAZMVFFDE-UHFFFAOYSA-N neodymium(3+);trinitrate Chemical compound [Nd+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O CFYGEIAZMVFFDE-UHFFFAOYSA-N 0.000 claims description 4
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical compound [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 claims description 4
- 150000002910 rare earth metals Chemical class 0.000 claims description 4
- 229910000349 titanium oxysulfate Inorganic materials 0.000 claims description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 3
- YWECOPREQNXXBZ-UHFFFAOYSA-N praseodymium(3+);trinitrate Chemical compound [Pr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O YWECOPREQNXXBZ-UHFFFAOYSA-N 0.000 claims description 3
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 abstract description 6
- 238000001704 evaporation Methods 0.000 abstract description 4
- 230000008020 evaporation Effects 0.000 abstract description 4
- 239000010865 sewage Substances 0.000 abstract description 3
- 239000002250 absorbent Substances 0.000 abstract description 2
- 230000002745 absorbent Effects 0.000 abstract description 2
- -1 amine salt Chemical class 0.000 abstract description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 10
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 10
- 235000011130 ammonium sulphate Nutrition 0.000 description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 230000003197 catalytic effect Effects 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 4
- 239000002351 wastewater Substances 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- 229910010413 TiO 2 Inorganic materials 0.000 description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 3
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 2
- USFZMSVCRYTOJT-UHFFFAOYSA-N Ammonium acetate Chemical compound N.CC(O)=O USFZMSVCRYTOJT-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000005695 Ammonium acetate Substances 0.000 description 1
- 239000004254 Ammonium phosphate Substances 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- GYCMBHHDWRMZGG-UHFFFAOYSA-N Methylacrylonitrile Chemical compound CC(=C)C#N GYCMBHHDWRMZGG-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 241000219793 Trifolium Species 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229940043376 ammonium acetate Drugs 0.000 description 1
- 235000019257 ammonium acetate Nutrition 0.000 description 1
- 229910000148 ammonium phosphate Inorganic materials 0.000 description 1
- 235000019289 ammonium phosphates Nutrition 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 1
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000012065 filter cake Substances 0.000 description 1
- LAQPNDIUHRHNCV-UHFFFAOYSA-N isophthalonitrile Chemical compound N#CC1=CC=CC(C#N)=C1 LAQPNDIUHRHNCV-UHFFFAOYSA-N 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- PLDDOISOJJCEMH-UHFFFAOYSA-N neodymium oxide Inorganic materials [O-2].[O-2].[O-2].[Nd+3].[Nd+3] PLDDOISOJJCEMH-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 210000002345 respiratory system Anatomy 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 238000010977 unit operation Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a low-energy-consumption and low-material-consumption method and system for ammonia recovery, and belongs to the technical field of ammonia recovery. Absorbing ammonia-containing gas by using an absorption liquid to obtain a high COD (chemical oxygen demand) ammonia-rich acetic acid absorption liquid, oxidizing the high COD ammonia-rich acetic acid absorption liquid to obtain a high acetic acid content absorption liquid, oxidizing the high acetic acid content absorption liquid to obtain an ammonia-containing aqueous solution, and distilling the ammonia-containing aqueous solution; the absorption liquid is absorption liquid with high acetic acid content. The invention adopts the acetic acid generated by high-selectivity oxidation of the specific high-efficiency catalyst in the self process as the absorbent to form the organic amine salt, acid is not required to be added, the material consumption is greatly reduced, and simultaneously, a large amount of heat is generated in the wet oxidation process, thereby solving the problems of secondary pollution caused by a large amount of salt-containing sewage generated in the prior art and high evaporation concentration energy consumption.
Description
Technical Field
The invention belongs to the technical field of ammonia recovery, and particularly relates to a low-energy-consumption and low-material-consumption method and system for ammonia recovery.
Background
Ammonia is a colorless gas at normal temperature and has a strong pungent odor. In the chemical technology related to ammonia, residual ammonia often needs to be separated, if the ammonia is directly discharged, stink is sharp, trees die, the respiratory system and skin of people are damaged, and the local air, environment and production and living modes of residents are influenced. It not only pollutes the atmosphere, but also can eutrophicate the water body after forming rainwater, pollute the water source, cause serious environmental pollution. However, ammonia gas is used as an important chemical raw material, and if recovered, the purpose of saving resources can be achieved. Therefore, the technical level of ammonia-containing tail gas treatment based on environmental protection, energy conservation and consumption reduction is urgently required to be improved.
The most of the excessive ammonia in the existing ammonia oxidation industrial device adopts sulfuric acid to absorb ammonia to form ammonium sulfate, and the technology route of crystallizing to obtain ammonium sulfate, such as an acrylonitrile device, an isophthalonitrile device and the like, generates a large amount of salt-containing sewage, causes secondary pollution and has high evaporation concentration energy consumption.
Chinese patent publication CN1204620a discloses a process for recovering unreacted ammonia from the effluent of a reactor obtained in a reaction zone for producing acrylonitrile or methacrylonitrile, quenching the above reactor effluent with an aqueous solution of ammonium phosphate, and desorbing the obtained absorption liquid at high temperature and high pressure to produce an ammonia-containing vapor stream and a recyclable absorption liquid, which process consumes high energy and inevitably produces phosphorus-containing wastewater during the desorption.
In a word, the prior art has the problems of secondary pollution, high energy consumption, acid consumption and the like caused by the salt-containing sewage.
Disclosure of Invention
The invention aims to solve the problems in the prior art, and provides a low-energy-consumption and low-material-consumption method and system for ammonia recovery.
The invention is realized by the following technical scheme:
In a first aspect of the invention, a low-energy-consumption and low-material-consumption method for ammonia recovery is provided, comprising the steps of absorbing ammonia-containing gas by using absorption liquid to obtain high-COD (chemical oxygen demand) ammonia-rich acetic acid absorption liquid, oxidizing the high-COD ammonia-rich acetic acid absorption liquid to obtain high-acetic acid-content absorption liquid, oxidizing the high-acetic acid-content absorption liquid to obtain ammonia-containing aqueous solution, and distilling the obtained ammonia-containing aqueous solution; the absorption liquid is absorption liquid with high acetic acid content.
The invention further improves that:
The method specifically comprises the following steps:
S1, contacting ammonia-containing gas with an absorbing solution with high acetic acid content in an absorption tower to absorb ammonia in the ammonia-containing gas to obtain an ammonia-rich acetic acid absorbing solution with high COD and an ammonia-free air flow;
s2, carrying out oxidation reaction on the high COD ammonium-rich acetic acid absorption liquid and an oxidant in a first oxidation reactor to obtain a high acetic acid content absorption liquid;
S3, returning part of the absorbing liquid with high acetic acid content to the absorption tower, and carrying out oxidation reaction on the remaining absorbing liquid with high acetic acid content and the oxidant in a second oxidation reactor to remove acetic acid and obtain ammonia-containing aqueous solution;
S4, distilling the ammonia-containing aqueous solution in a distillation tower, obtaining crude ammonia gas flow at the top of the tower, and optionally returning acid tower bottom liquid to the absorption tower.
The invention further improves that:
The ammonia-containing gas is a gas containing an organic substance, preferably a gas in which an organic substance component is dissolved in water.
The invention further improves that:
In the step S1 of the process,
The absorption liquid with high acetic acid content is recycled in the absorption tower, and the pH value is 2-6.5, preferably 4-6.5; and/or the number of the groups of groups,
The concentration of acetic acid in the absorption liquid with high acetic acid content is 3-20% wt, preferably 5-12% wt; and/or the number of the groups of groups,
The COD value in the high COD ammonium-rich acetic acid absorption liquid is 40000-250000 mg/L, preferably 40000-150000 mg/L.
The invention further improves that:
In the step S2 and the step S3, the oxidant is oxygen-containing gas; preferably, the oxygen-containing gas may be pure oxygen, air or oxygen-enriched air having an oxygen content of 35 to 50 v%.
The invention further improves that:
in the step S2 of the process,
The volume ratio of oxygen in the oxidant to the high COD ammonium-rich acetic acid absorption liquid is 10-400;
and/or, the temperature of the reaction is 250-300 ℃;
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 absorption liquid in the first oxidation reactor is 10-150 minutes, preferably 10-120 minutes.
The invention further improves that:
in the step S3 of the process,
The volume ratio of oxygen in the oxidant to the high acetic acid content absorption liquid is 10-400;
And/or, the temperature of the reaction is 180-300 ℃;
and/or the pressure of the reaction is 3.0-12.0 MPa;
and/or the residence time of the high acetic acid content absorption liquid in the second oxidation reactor is 10 to 150 minutes, preferably 10 to 90 minutes.
The invention further improves that:
The oxidation reaction of oxidizing the high COD ammonium-rich acetic acid absorption liquid to obtain the absorption liquid with high acetic acid content is a wet oxidation reaction carried out in the presence of a first oxidation catalyst; preferably, the method comprises the steps of,
The first oxidation catalyst is a wet oxidation catalyst and comprises the following components in parts by weight:
(1) 20-40 parts of nano titanium dioxide;
(2) 2-10 parts of at least one selected from titanium tetrachloride, titanyl sulfate and tetrabutyl titanate;
(3) 0.1-5 parts of at least one selected from lanthanum nitrate, cerium nitrate, praseodymium nitrate and neodymium nitrate;
(4) 45-77.9 parts of water;
And/or the number of the groups of groups,
The oxidation reaction of the absorption liquid with high acetic acid content to obtain ammonia-containing aqueous solution is a wet oxidation reaction carried out in the presence of a second oxidation catalyst; preferably, the method comprises the steps of,
The second oxidation catalyst is a wet oxidation catalyst and comprises the following components in parts by weight:
(1) 96-99.8 parts of carrier;
(2) 0.1 to 2 parts of an oxide of a rare earth metal;
(3) 0.1 to 2 parts of at least one noble metal selected from the platinum group.
The invention further improves that:
the wet oxidation reactions are all carried out in a wet oxidation reactor having a wet oxidation catalyst bed.
The invention further improves that:
the method further comprises the steps of: rectifying the crude ammonia gas obtained in the step S4 to obtain an anhydrous ammonia material flow; or adjusting the rectification efficiency to obtain different ammonia content material flows.
In a second aspect of the invention, a low-energy-consumption and low-material-consumption system for ammonia recovery is provided, wherein the system comprises an absorption tower, a first oxidation reactor, a second oxidation reactor and a distillation tower which are sequentially communicated, and the first oxidation reactor and the distillation tower kettle are respectively connected with the absorption tower through a reflux pipeline;
Preferably, the first oxidation reactor and the second oxidation reactor are each wet oxidation reactors having a wet oxidation catalyst bed.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a low-energy consumption and low-material consumption method and a system for ammonia recovery, which adopt acetic acid generated by high-selectivity oxidation of a specific high-efficiency catalyst in a self process as an absorbent to form organic amine salt, acid is not required to be added, material consumption is greatly reduced, a large amount of heat is generated in a wet oxidation process, and compared with the prior art, the energy-saving advantage is outstanding, furthermore, acetate in absorption liquid can be removed after wet oxidation, and no salt-containing wastewater is generated.
Drawings
FIG. 1 is a process flow diagram of a low energy and low material consumption process for ammonia recovery according to the present invention.
In the figure, 1, a first oxidation reactor, 2, a second oxidation reactor, 3, a distillation tower, 4, an absorption tower, 5, ammonia-containing gas, 6, ammonia-free gas flow, 7, high COD (chemical oxygen demand) ammonium-rich acetic acid absorption liquid, 8, partial high acetic acid content absorption liquid, 9, residual high acetic acid content absorption liquid, 10, ammonia-containing aqueous solution, 11, tower bottom liquid, 12 and crude ammonia gas flow.
Detailed Description
The invention is described in further detail below with reference to the attached drawing figures:
In a first aspect of the present invention, there is provided a low-energy-consumption and low-material-consumption method for ammonia recovery, as shown in fig. 1, comprising absorbing ammonia-containing gas with an absorption liquid to obtain a high COD ammonia-rich acetic acid absorption liquid, oxidizing the high COD ammonia-rich acetic acid absorption liquid to obtain a high acetic acid content absorption liquid, oxidizing the high acetic acid content absorption liquid to obtain an ammonia-containing aqueous solution, and distilling the ammonia-containing aqueous solution; the absorption liquid is absorption liquid with high acetic acid content.
The method specifically comprises the following steps:
S1, contacting ammonia-containing gas with an absorbing solution with high acetic acid content in an absorption tower to absorb ammonia in the ammonia-containing gas to obtain an ammonia-rich acetic acid absorbing solution with high COD and an ammonia-free air flow;
The ammonia-containing gas is a gas containing organic matters, preferably a gas in which organic matters are dissolved in water;
the COD value in the high COD ammonium-rich acetic acid absorption liquid is 40000-250000 mg/L, preferably 40000-150000 mg/L;
S2, reacting the high COD ammonium-rich acetic acid absorption liquid with an oxidant in a first oxidation reactor to obtain a high acetic acid content absorption liquid;
S3, returning part of the absorbing liquid with high acetic acid content to the absorption tower, and carrying out oxidation reaction on the remaining absorbing liquid with high acetic acid content and the oxidant in a second oxidation reactor to remove acetic acid and obtain ammonia-containing aqueous solution;
The amount of part of the high acetic acid content absorption liquid 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 absorption liquid, so that the complete absorption of ammonia is ensured, and only the balance between the absorption and the recovery of ammonia is required to be met;
s4, distilling the ammonia-containing aqueous solution in a distillation tower, obtaining crude ammonia gas flow at the top of the tower, and returning the acid tower bottom liquid to the absorption tower.
The first oxidation reactor and the second oxidation reactor are each wet oxidation reactors having a wet oxidation catalyst bed.
In the invention, the method further comprises the following steps: rectifying the crude ammonia gas obtained in the step S4 to obtain an anhydrous ammonia material flow; or adjusting the rectification efficiency to obtain different ammonia content material flows.
In some preferred embodiments of the present invention, in step S1, the high acetic acid content absorption liquid is recycled in the absorption tower, and the pH value is 2 to 6.5, preferably 4 to 6.5;
And/or the acetic acid concentration in the high acetic acid content absorption liquid is 3 to 20% wt, preferably 5 to 12% wt. The absorption liquid solvent with high acetic acid content is water, and the absorption liquid also contains ammonia acetate.
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; may be selected from wet oxidation catalysts known in the art, preferably,
The first catalyst is selected from the catalysts disclosed in chinese patent publication CN104148048 a. CN104148048a is considered to be incorporated in its entirety in the present invention.
Specifically, the first catalyst comprises the following components in parts by weight:
(1) 20-40 parts of nano titanium dioxide;
(2) 2-10 parts of at least one selected from titanium tetrachloride, titanyl sulfate and tetrabutyl titanate;
(3) 0.1-5 parts of at least one selected from lanthanum nitrate, cerium nitrate, praseodymium nitrate and neodymium nitrate;
(4) 45-77.9 parts of water.
In some preferred embodiments of the present invention, in step S3, the second catalyst in the second oxidation reactor is a noble metal catalyst; may be selected from wet oxidation catalysts known in the art, preferably,
The second catalyst is disclosed in Chinese patent publication CN105080540A (most of organic components in acrylic acid wastewater are acetic acid). CN105080540a is considered to be incorporated in its entirety in the present invention.
Specifically, the second catalyst comprises the following components in parts by weight:
(1) 96-99.8 parts of carrier;
(2) 0.1 to 2 parts of an oxide of a rare earth metal;
(3) 0.1 to 2 parts of at least one noble metal selected from the platinum group.
The rare earth metal is at least one selected from La, ce, pr, nd and Eu; the noble metal is preferably at least one of Ru, pd, pt, ir and Rh; the carrier is preferably at least one selected from TiO 2、ZrO2、Al2O3 and SiO 2.
In some preferred embodiments of the present invention, in steps S2, S3, the oxidizing agent is an oxygen-containing gas; preferably, the oxygen-containing gas may be pure oxygen, air or oxygen-enriched air having an oxygen content of 35 to 50 v%.
In 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;
the temperature of the reaction is 250-300 ℃;
the pressure of the reaction is 7-12.0 MPa;
The residence time of the high COD ammonium-rich acetic acid absorption liquid in the first oxidation reactor is 10-150 minutes, preferably 10-120 minutes.
In 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;
The temperature of the reaction is 180-300 ℃;
The pressure of the reaction is 3.0-12.0 MPa;
The residence time of the high acetic acid content absorption liquid in the second oxidation reactor is 10 to 150 minutes, preferably 10 to 90 minutes.
In a second aspect of the present invention, there is provided a low-energy and low-material consumption system for ammonia recovery, as shown in fig. 1, comprising an absorption tower 4, a first oxidation reactor 1, a second oxidation reactor 2 and a distillation tower 3, which are sequentially connected, the first oxidation reactor 1 and the distillation tower 3 being further connected to the absorption tower 4 through reflux pipes, respectively.
The specific flow is as follows:
contacting ammonia-containing gas 5 with an absorption liquid with high acetic acid content in an absorption tower 4, and absorbing ammonia in the gas to obtain a high COD ammonia-rich acetic acid absorption liquid 7 and an ammonia-free gas stream 6;
the high COD ammonia-rich acetic acid absorption liquid 7 reacts with an oxidant in a first oxidation reactor 1 with a wet oxidation catalyst bed to obtain a high acetic acid content absorption liquid; in the first oxidation reactor, the catalyst can oxidize the high COD ammonium-rich acetic acid absorption liquid into acetic acid, and the acetic acid and ammonia generate ammonium acetate;
Returning part of the absorbing liquid 8 with high acetic acid content to the absorption tower 4 through a return pipeline to be used as the absorbing liquid to absorb ammonia in gas, and carrying out catalytic wet oxidation on the remaining absorbing liquid 9 with high acetic acid content and an oxidant in the second oxidation reactor 2 with a wet oxidation catalyst bed to remove acetic acid and obtain ammonia-containing aqueous solution 10; in the second oxidation reactor, the catalyst can oxidize acetic acid (mainly acetate) into carbon dioxide and water, and the catalytic efficiency can be adjusted according to actual conditions to realize the content of the acetic acid in the solution after the reaction;
carrying out distillation operation on the ammonia-containing water solution 10 in a distillation tower 3, obtaining a crude ammonia gas stream 12 at the top of the tower, and returning tower bottom liquid 11 to an absorption tower 4; the crude ammonia stream 12 is rectified to produce an anhydrous ammonia stream or the rectification efficiency is adjusted to produce a stream of varying ammonia content (not shown).
The innovation point of the invention is as follows:
(1) In the invention, the high-content acetic acid absorption liquid generated by high-selectivity oxidation of the high-efficiency catalyst in the first oxidation reactor 1 is used as the absorption liquid for absorbing ammonia in ammonia-containing gas, acid is not required to be added, and the material consumption is greatly reduced.
(2) The high-efficiency noble metal catalyst in the second oxidation reactor 2 is used for removing the acetate in the absorption liquid with high acetic acid content to obtain an ammonia-containing aqueous solution so as to realize the recovery of ammonia, the acetate is treated by the wet oxidation catalyst to directly generate CO 2, and the solution is purer ammonia water, so that the subsequent treatment is facilitated, and no salt-containing wastewater is generated.
(3) In the invention, in the wet oxidation process of the high COD ammonium-rich absorption liquid in the first oxidation reactor, a large amount of heat is generated besides the high-content acetic acid absorption liquid for absorbing ammonia, and the heat can be supplied to the raw materials of the first oxidation reactor and the second oxidation reactor for preheating by utilizing the existing heat exchange means, so that the external heat supplement is not needed in the reaction process, and the method has the energy-saving advantage compared with the crystallization and evaporation of a large amount of heat required in the ammonium salt production in the prior art.
The embodiments of the present invention all comprise four main steps: ammonia absorption, catalytic wet oxidation to produce acetic acid, and distillation and rectification to recover ammonia and ammonia by catalytic wet oxidation. Since the distillation and rectification operation of ammonia belongs to a simple basic chemical unit operation, this will not be described in detail in the examples.
The ammonia-containing gas in the embodiment of the invention is reaction gas obtained after the ammonia oxidation reaction of propylene in a laboratory, and the oxidizing agents used in the wet oxidation reaction process in the first oxidation reactor and the second oxidation reactor are all pure oxygen.
[ Example 1]
1. Preparation of the first catalyst
220G of nano titanium dioxide (rutile type with the specific surface area of 22m 2/g and the particle size of 82 nm), 40g of titanyl sulfate, 20g of tetrabutyl titanate, 6g of lanthanum nitrate, 10g of cerium nitrate and 10g of neodymium nitrate are dissolved in 500mL of water; dropwise adding 65mL of 17% ammonia water into the mixed material under intense stirring at 40 ℃, continuously stirring for 2h, and carrying out suction filtration; extruding the filter cake into clover shape by a die, drying at room temperature, roasting the formed product at 750 ℃ in air atmosphere for 4 hours to obtain a titanium dioxide carrier containing rare earth elements, wherein the strength is 87N/mm, and the catalyst is the first catalyst C-01.
The first catalyst C-01 above and its preparation are from example 9 of the patent application publication No. CN 104148048A.
2. Preparation of the second catalyst
TiO 2:CeO2:Nd2O3:Ru 98.4:0.4:0.8:0.4 by weight.
1.1 Preparation of the vector: mixing and kneading 240g of nano TiO 2 powder, 0.98gCeO 2 powder, 1.92g of nano Nd 2O3 powder, 80g of water and 4g of carboxymethyl cellulose for 2 hours, extruding and molding, drying the molded product at room temperature, and roasting at 700 ℃ for 2 hours;
1.2 noble metal loading: 199.0g of the molded carrier was immersed in an aqueous solution containing 2.16g of hydrated RuCl 3 at room temperature overnight, dried at 80℃and reduced under a hydrogen atmosphere (hydrogen-nitrogen mixture having a hydrogen content of 4%) at 400℃for 4 hours to give a noble metal-supported catalyst, referred to as second catalyst C-02.
The above second catalyst C-02 and its preparation are from example 3 of the patent application publication No. CN 105080540A.
3. Recovery of ammonia
S1, contacting ammonia-containing gas with an absorption liquid with high acetic acid content in an absorption tower to absorb ammonia in the gas, so as to obtain a high COD (chemical oxygen demand) ammonia-rich acetic acid absorption liquid and an ammonia-free gas flow;
S2, reacting the high COD ammonium-rich acetic acid absorption liquid with oxygen in a first oxidation reactor with a first catalyst C-01 to obtain a high acetic acid content absorption liquid;
S3, returning part of the absorbing liquid with high acetic acid content to the absorption tower through a return pipeline to serve as the absorbing liquid to absorb ammonia in the gas, and carrying out catalytic wet oxidation on the remaining absorbing liquid with high acetic acid content and oxidant oxygen in a second oxidation reactor with a second catalyst C-02 to remove acetic acid and obtain ammonia-containing aqueous solution.
The reaction conditions and the results are shown in Table 1 and Table 2.
The experimental steps from example 2 to example 8 are the same as those from example 1, and specific reaction conditions and results are shown in tables 1 and 2.
[ Comparative example 1]
The existing ammonium sulfate recovery process was used in comparison with example 1.
1. Absorbing ammonia-containing gas by using absorption liquid with the mass concentration of sulfuric acid of 5% to obtain high COD ammonium sulfate absorption liquid;
2. And distilling the high COD ammonium sulfate absorption liquid to obtain ammonium sulfate crystals and distillate.
[ Comparative example 2]
Comparative example 2 the same experimental conditions as in example 1 were used, with the difference from example 1:
S1, absorbing ammonia-containing gas by using absorption liquid with the mass concentration of sulfuric acid of 5% to obtain high COD ammonium sulfate absorption liquid;
s2, carrying out wet oxidation reaction on the high COD ammonium sulfate absorption liquid and oxygen in a first oxidation reactor to obtain a high acetic acid content absorption liquid;
S3, returning part of the absorbing liquid with high acetic acid content to the absorption tower through a return pipeline for absorbing ammonia in the ammonia-containing gas, and carrying out catalytic wet oxidation on the remaining absorbing liquid with high acetic acid content and oxygen in the second oxidation reactor to obtain an ammonia-containing aqueous solution.
The reaction conditions and the results are shown in Table 1 and Table 2.
TABLE 1
TABLE 2
The ammonia absorption and the ammonia recovery can be realized in all the examples 1 to 8, the salt content in the ammonia-containing aqueous solution is extremely low and even 0, and the comparative example 1 is the existing ammonium sulfate recovery process, compared with the invention, sulfuric acid is required to be lost, and the evaporation and crystallization energy consumption of ammonium sulfate is high; comparative example 2 was conducted in the same manner as in example 1 except that the ammonia concentration in the aqueous ammonia-containing solution was far lower than in example, recovery of ammonia could not be achieved, and there was also a problem of brine waste.
Finally, it should be noted that the above-mentioned technical solution is only one embodiment of the present invention, and various modifications and variations can be easily made by those skilled in the art based on the application methods and principles disclosed in the present invention, and are not limited to the methods described in the above-mentioned specific embodiments of the present invention, therefore, the foregoing description is only preferred, and not meant to be limiting.
Claims (11)
1. The low-energy consumption and low-material consumption method for ammonia recovery comprises the steps of absorbing ammonia-containing gas by using absorption liquid to obtain high-COD (chemical oxygen demand) ammonium-rich acetic acid absorption liquid, oxidizing the high-COD ammonium-rich acetic acid absorption liquid to obtain high-acetic acid content absorption liquid, oxidizing the high-acetic acid content absorption liquid to obtain ammonia-containing aqueous solution, and distilling the ammonia-containing aqueous solution; the absorption liquid is absorption liquid with high acetic acid content.
2. The low energy and low material consumption process for ammonia recovery according to claim 1, characterized in that it comprises in particular the following steps:
S1, contacting ammonia-containing gas with an absorbing solution with high acetic acid content in an absorption tower to absorb ammonia in the ammonia-containing gas to obtain an ammonia-rich acetic acid absorbing solution with high COD and an ammonia-free air flow;
s2, carrying out oxidation reaction on the high COD ammonium-rich acetic acid absorption liquid and an oxidant in a first oxidation reactor to obtain a high acetic acid content absorption liquid;
S3, returning part of the absorbing liquid with high acetic acid content to the absorption tower, and carrying out oxidation reaction on the remaining absorbing liquid with high acetic acid content and the oxidant in a second oxidation reactor to remove acetic acid and obtain ammonia-containing aqueous solution;
S4, distilling the ammonia-containing aqueous solution in a distillation tower, obtaining crude ammonia gas flow at the top of the tower, and optionally returning acid tower bottom liquid to the absorption tower.
3. The low energy and low material consumption process for ammonia recovery according to claim 2, wherein the ammonia containing gas is an organic containing gas, preferably a gas in which organic components are dissolved in water.
4. The low energy and low material consumption process for ammonia recovery according to claim 2, wherein in step S1,
The absorption liquid with high acetic acid content is recycled in the absorption tower, and the pH value is 2-6.5, preferably 4-6.5; and/or the number of the groups of groups,
The concentration of acetic acid in the absorption liquid with high acetic acid content is 3-20% wt, preferably 5-12% wt; and/or the number of the groups of groups,
The COD value in the high COD ammonium-rich acetic acid absorption liquid is 40000-250000 mg/L, preferably 40000-150000 mg/L.
5. The low energy and low material consumption method for ammonia recovery according to claim 2, wherein in step S2 and step S3, the oxidizing agent is an oxygen-containing gas; preferably, the oxygen-containing gas may be pure oxygen, air or oxygen-enriched air having an oxygen content of 35 to 50 v%.
6. The process for ammonia recovery according to claim 5, wherein in step S2,
The volume ratio of oxygen in the oxidant to the high COD ammonium-rich acetic acid absorption liquid is 10-400;
and/or, the temperature of the reaction is 250-300 ℃;
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 absorption liquid in the first oxidation reactor is 10-150 minutes, preferably 10-120 minutes.
7. The low energy and low material consumption method for ammonia recovery according to claim 5, wherein in step S3,
The volume ratio of oxygen in the oxidant to the high acetic acid content absorption liquid is 10-400;
And/or, the temperature of the reaction is 180-300 ℃;
and/or the pressure of the reaction is 3.0-12.0 MPa;
and/or the residence time of the high acetic acid content absorption liquid in the second oxidation reactor is 10 to 150 minutes, preferably 10 to 90 minutes.
8. A low-energy and low-material-consumption process for ammonia recovery according to any one of claims 1-7,
The oxidation reaction of oxidizing the high COD ammonium-rich acetic acid absorption liquid to obtain the absorption liquid with high acetic acid content is a wet oxidation reaction carried out in the presence of a first oxidation catalyst; preferably, the method comprises the steps of,
The first oxidation catalyst is a wet oxidation catalyst and comprises the following components in parts by weight:
(1) 20-40 parts of nano titanium dioxide;
(2) 2-10 parts of at least one selected from titanium tetrachloride, titanyl sulfate and tetrabutyl titanate;
(3) 0.1-5 parts of at least one selected from lanthanum nitrate, cerium nitrate, praseodymium nitrate and neodymium nitrate;
(4) 45-77.9 parts of water;
And/or the number of the groups of groups,
The oxidation reaction of the absorption liquid with high acetic acid content to obtain ammonia-containing aqueous solution is a wet oxidation reaction carried out in the presence of a second oxidation catalyst; preferably, the method comprises the steps of,
The second oxidation catalyst is a wet oxidation catalyst and comprises the following components in parts by weight:
(1) 96-99.8 parts of carrier;
(2) 0.1 to 2 parts of an oxide of a rare earth metal;
(3) 0.1 to 2 parts of at least one noble metal selected from the platinum group.
9. The low energy and low material consumption process for ammonia recovery according to claim 8, wherein the wet oxidation reactions are each carried out in a wet oxidation reactor having a wet oxidation catalyst bed.
10. The low energy and low material consumption process for ammonia recovery of claim 2, further comprising: rectifying the crude ammonia gas obtained in the step S4 to obtain an anhydrous ammonia material flow; or adjusting the rectification efficiency to obtain different ammonia content material flows.
11. The low-energy-consumption low-material-consumption system for ammonia recovery is characterized by comprising an absorption tower, a first oxidation reactor, a second oxidation reactor and a distillation tower which are sequentially communicated, wherein the first oxidation reactor and the distillation tower kettle are also respectively connected with the absorption tower through a return pipeline;
Preferably, the first oxidation reactor and the second oxidation reactor are each wet oxidation reactors having a wet oxidation catalyst bed.
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