CN117357999A - Instantaneous high-concentration nitrogen oxide flue gas treatment method - Google Patents
Instantaneous high-concentration nitrogen oxide flue gas treatment method Download PDFInfo
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- CN117357999A CN117357999A CN202311644012.3A CN202311644012A CN117357999A CN 117357999 A CN117357999 A CN 117357999A CN 202311644012 A CN202311644012 A CN 202311644012A CN 117357999 A CN117357999 A CN 117357999A
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- 239000003546 flue gas Substances 0.000 title claims abstract description 264
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 263
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 title claims abstract description 168
- 238000000034 method Methods 0.000 title claims abstract description 51
- 230000009467 reduction Effects 0.000 claims abstract description 123
- 238000003860 storage Methods 0.000 claims abstract description 76
- 230000001590 oxidative effect Effects 0.000 claims abstract description 23
- 230000003647 oxidation Effects 0.000 claims abstract description 21
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 21
- 239000007800 oxidant agent Substances 0.000 claims abstract description 20
- 230000005587 bubbling Effects 0.000 claims abstract description 19
- 239000012535 impurity Substances 0.000 claims abstract description 18
- 238000009833 condensation Methods 0.000 claims abstract description 11
- 230000005494 condensation Effects 0.000 claims abstract description 11
- 239000007788 liquid Substances 0.000 claims description 139
- 238000006722 reduction reaction Methods 0.000 claims description 131
- 239000000243 solution Substances 0.000 claims description 88
- 239000007921 spray Substances 0.000 claims description 41
- 239000000203 mixture Substances 0.000 claims description 31
- 238000007599 discharging Methods 0.000 claims description 21
- 239000002253 acid Substances 0.000 claims description 20
- 239000003595 mist Substances 0.000 claims description 20
- 239000007789 gas Substances 0.000 claims description 16
- 238000005086 pumping Methods 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 238000005273 aeration Methods 0.000 claims description 12
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 10
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 8
- 239000004202 carbamide Substances 0.000 claims description 8
- 229910000510 noble metal Inorganic materials 0.000 claims description 7
- 239000011259 mixed solution Substances 0.000 claims description 6
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 5
- 239000000945 filler Substances 0.000 claims description 5
- 230000000712 assembly Effects 0.000 claims description 4
- 238000000429 assembly Methods 0.000 claims description 4
- 239000003517 fume Substances 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 4
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 3
- 239000007791 liquid phase Substances 0.000 claims description 3
- 238000004064 recycling Methods 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 230000001052 transient effect Effects 0.000 claims 4
- 239000000779 smoke Substances 0.000 abstract description 23
- 238000005507 spraying Methods 0.000 abstract description 15
- 230000008569 process Effects 0.000 abstract description 14
- 238000005516 engineering process Methods 0.000 abstract description 7
- 238000002156 mixing Methods 0.000 abstract description 6
- 238000011946 reduction process Methods 0.000 abstract description 5
- 230000002195 synergetic effect Effects 0.000 abstract description 5
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 16
- 239000010931 gold Substances 0.000 description 16
- 229910052737 gold Inorganic materials 0.000 description 16
- 238000006243 chemical reaction Methods 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 230000006872 improvement Effects 0.000 description 8
- 239000002699 waste material Substances 0.000 description 8
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 7
- 229910017604 nitric acid Inorganic materials 0.000 description 7
- 238000012856 packing Methods 0.000 description 6
- 238000003723 Smelting Methods 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 5
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 5
- 241000282414 Homo sapiens Species 0.000 description 3
- 230000003139 buffering effect Effects 0.000 description 3
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 230000003993 interaction Effects 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 239000003513 alkali Substances 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000001502 supplementing effect Effects 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 1
- HXELDDLUAGVKCK-UHFFFAOYSA-N [N]=O.[S] Chemical compound [N]=O.[S] HXELDDLUAGVKCK-UHFFFAOYSA-N 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/002—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by condensation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/75—Multi-step processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/78—Liquid phase processes with gas-liquid contact
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
Abstract
The invention provides a method for treating instantaneous high-concentration nitrogen oxide flue gas, which belongs to the technical field of flue gas treatment, adopts the process technology of condensation, pre-oxidation, slow release and normal temperature reduction, firstly condenses the flue gas to be treated to remove impurities, and then carries out pre-oxidation in a bubbling buffer tank containing oxidant solution to fully and maximally oxidize NO into NO 2 Then the smoke is stably and quantitatively fed into a reduction system through a slow release system, and the normal temperature reduction process utilizes the mutual synergistic effect of primary mixing reduction of part of smoke in a Venturi mixer, collision re-reduction of two parts of smoke in a reducing solution storage tank at the same time and three spraying reduction of a spraying reduction assembly to generate N 2 、CO 2 And H 2 O is discharged, so that the high-efficiency treatment of the high-concentration nitrogen oxide flue gas is realized, and the discharged flue gas has no white smoke problem.
Description
Technical Field
The invention relates to the technical field of flue gas treatment, in particular to a method for treating instantaneous high-concentration nitrogen oxide flue gas.
Background
Aiming at the gold smelting industry and other industries related to the use of nitric acid, particularly the gold mud 'nitric acid impurity removal' and 'aqua regia' technology in the gold smelting industry, high-concentration nitrogen oxide smoke can be generated, particularly in the early stage of the reaction of the gold mud and nitric acid or aqua regia, the extremely high-concentration nitrogen oxide smoke is instantaneously released, the treatment capacity of environmental protection treatment equipment is extremely easily exceeded, the nitrogen oxide smoke cannot stably reach the emission standard, and more nitrogen oxide smoke is discharged into the atmosphere. The large amount of emission of nitrogen oxide smoke can cause corrosion damage to human organs, and death can be caused when serious; acid rain, acid mist and photochemical smog can also be induced, resulting in global warming; land and water ecosystems can also be destroyed.
In view of the harm of nitrogen oxide flue gas to human beings and ecological environment, the control of the standard emission of the nitrogen oxide flue gas is a problem to be solved urgently. At present, the nitrogen oxide flue gas treatment technology mainly comprises a liquid absorption method, a solid adsorption method, a catalytic reaction method, a biological purification method, a low-temperature plasma method and the like. Patent application number CN201911394716.3 discloses a method for treating high concentration nitrogen oxide flue gas, comprising the following steps: s1, hydrogen peroxide catalytic oxidation primary absorption: after the nitrogen oxide sulfur-containing flue gas is subjected to quenching tower, venturi and wet dust removal treatment, the flue gas enters a hydrogen peroxide catalytic oxidation spray absorption system, and SO in the flue gas 2 Conversion to SO 3 And absorbed by the spray liquid to form dilute acid, and part of NO is oxidized into high-valence nitrogen oxides dissolved in water and absorbed by the spray liquid to form dilute acid; s2, enabling the flue gas treated in the step S1 to enter a urea spray absorption system, and enabling residual SO in the flue gas 2 、SO 3 NO, NO and NO 2 The NO generated by the absorption reaction is sprayed by the mixed solution of urea and alkali liquor, and the catalyst makes the urea and nitrogen oxides contained in the flue gas undergo the reduction reaction to reactThen N is generated 2 With water, residual SO 2 、SO 3 、NO 2 Is absorbed by alkali liquor to form sulfate and sulfite. The oxidation process and the reduction process of the treatment process both adopt a single spraying system, and the flue gas treatment effect is limited because the concentration of nitrogen oxides in the flue gas is higher and the flue gas cannot be fully contacted with spraying liquid in the spraying process.
In view of the foregoing, there is a need for an improved method for treating flue gas with high concentration of nitrogen oxides instantaneously to solve the above-mentioned problems.
Disclosure of Invention
The invention aims to provide an instantaneous high-concentration nitrogen oxide flue gas treatment method, which adopts the process technology of condensation, pre-oxidation, slow release and normal temperature reduction, wherein the normal temperature reduction process utilizes the mutual synergistic effect of primary mixing reduction of part of flue gas in a Venturi mixer, collision re-reduction of two parts of flue gas in a reducing solution storage tank and three spraying reduction of a spraying reduction assembly, so that the high-concentration nitrogen oxide flue gas is efficiently treated, and the discharged flue gas has no white smoke problem.
In order to achieve the aim, the invention provides a method for treating instantaneous high-concentration nitrogen oxide flue gas, which sequentially carries out condensation impurity removal, pre-oxidation, slow release and normal-temperature reduction on the flue gas to be treated to generate N 2 、CO 2 And H 2 O；
The pre-oxidation is performed in a bubble buffer tank containing an oxidant solution;
the normal temperature reduction is carried out in a reduction system; the reduction system comprises an air inlet pipe, a reduction tower and a reduction liquid storage tank which are mutually communicated up and down, a venturi mixer is arranged between the air inlet pipe and the reduction liquid storage tank, a flue gas feeding pipe communicated with the air inlet pipe, a reduction liquid feeding pipe communicated with the reduction liquid storage tank and a gas-liquid mixture discharging pipe communicated with the reduction liquid storage tank are arranged on the venturi mixer, and a first pumping device connected with the reduction liquid feeding pipe is arranged in the reduction liquid storage tank; the discharge port end of the air inlet pipe extends into the reducing liquid storage tank, and an aeration head is arranged at the discharge port end of the air inlet pipe; the flue gas feeding pipe is arranged between the feeding port end and the discharging port end of the air inlet pipe and is far away from the discharging port end; a plurality of groups of spray reduction assemblies which are arranged up and down are arranged in the reduction tower, and each spray reduction assembly comprises a spray pipe and a filler layer which are arranged up and down; an air extractor is arranged at the top discharge port of the reduction tower;
a slow release system is arranged between the bubbling buffer tank and the reduction system, so that the flue gas quantitatively and stably enters the reduction system.
As a further improvement of the invention, the flue gas enters the reducing liquid storage tank in two parts; a first part of flue gas enters the reducing liquid storage tank from the flue gas feed pipe through the Venturi mixer and the gas-liquid mixture discharge pipe; the second part of flue gas enters the reducing solution storage tank from the air inlet pipe through the aeration head;
the volume ratio of the first part of flue gas to the second part of flue gas is 20% -40%, 60% -80%.
As a further improvement of the invention, the method comprises the following steps:
s1, condensing and removing impurities: condensing and washing the flue gas to be treated to enable acid mist and noble metal impurities in the flue gas to enter a liquid phase for recycling, so as to obtain impurity-removed flue gas;
s2, pre-oxidation: introducing the impurity-removed flue gas obtained in the step S1 into the bubbling buffer tank containing the oxidant, so that part of NO in the impurity-removed flue gas is converted into NO 2 Obtaining pre-oxidized flue gas;
s3, slow release: carrying out gas quantity control on the pre-oxidized flue gas obtained in the step S2 through the slow release system, so that the pre-oxidized flue gas is slowly and stably conveyed into the reduction system;
s4, normal temperature reduction: the first part of flue gas in the pre-oxidized flue gas enters the venturi mixer through the flue gas feeding pipe, the reducing solution enters the venturi mixer through the reducing solution feeding pipe, the first part of flue gas and the reducing solution are initially mixed in the venturi mixer and undergo a reduction reaction, and the obtained gas-liquid mixture is discharged from the gas-liquid mixtureA pipe enters the reducing liquid storage tank, and the second part of flue gas in the pre-oxidized flue gas enters the reducing liquid storage tank through the air inlet pipe; after two parts of pre-oxidized flue gas entering the reducing solution storage tank are mixed, the mixed pre-oxidized flue gas enters the reducing tower under the driving of the air extractor arranged at the top discharge port of the reducing tower, and is reduced by the spray reducing component to obtain N 2 、CO 2 And H 2 O is discharged from the top discharge port of the reduction tower.
As a further improvement of the invention, the feed inlet of the spray pipe is connected with the reducing solution storage tank; and a second pumping device for pressing the reducing liquid in the reducing liquid storage tank into the spray pipe is arranged at the feed inlet end of the spray pipe.
As a further improvement of the invention, a heat exchange tube is arranged in the reducing liquid storage tank, and a temperature control heat exchanger which is connected with the heat exchange tube in an electrified way is arranged on the outer wall of the reducing liquid storage tank.
As a further improvement of the invention, a demisting layer is arranged at the discharge port end of the reduction tower.
As a further improvement of the present invention, the method further comprises the steps of:
s5, flue gas defogging: step S4 is carried out to obtain N 2 、CO 2 And H 2 O passes through the defogging layer, after removing moisture, follow the reduction tower the top discharge gate discharges.
As a further improvement of the invention, in the step S2, the oxidant solution is one of a hydrogen peroxide solution and an ozone water solution; in the step S4, the reducing solution is a mixed solution of urea and liquid ammonia, the pH value of the reducing solution is 0.5-5, the concentration is 5-25 wt%, the temperature is 10-35 ℃, and the spray liquid-gas ratio is 10L/m 3 ~100L/m 3 The residence time of the pre-oxidized flue gas in the reduction tower is more than 12s.
As a further development of the invention, in step S1, the condensation is carried out in a condenser pipe, which is connected to a refrigerator; the flue gas treated by the condensing pipe is subjected to impurity removal by a steam-water separator.
As a further improvement of the invention, the air inlet pipe, the flue gas feeding pipe, the reducing liquid feeding pipe and the gas-liquid mixture discharging pipe are all provided with air valves; the flue gas feeding pipe is arranged between the feeding hole of the air inlet pipe and the air valve on the air inlet pipe.
The beneficial effects of the invention are as follows:
the instantaneous high-concentration nitrogen oxide fume treating process includes condensing fume to be treated to eliminate impurity, pre-oxidizing in bubbling buffering tank with oxidant solution to oxidize NO into NO fully and maximally 2 Then the smoke is enabled to enter the reduction system stably and quantitatively through the slow release system.
In the reduction system, a part of the pre-oxidized flue gas (namely, a first part of flue gas) is controlled to enter a venturi mixer through a flue gas feeding pipe, and the pre-oxidized flue gas is primarily reduced in the venturi mixer and then enters a reducing liquid storage tank. The other part (namely second part of flue gas) directly enters the reducing solution storage tank through the air inlet pipe and contacts with the reducing solution through the aeration head, and the aeration head not only can enable the second part of flue gas to rapidly enter the reducing solution with larger impulsive force and fully contact with the reducing solution to perform preliminary reduction, but also can increase the contact area of the flue gas and the reducing solution, and further enables the flue gas to fully contact with the reducing solution to perform preliminary reduction. Meanwhile, the second part of flue gas rapidly enters the reducing liquid with larger impulsive force to enable the reducing liquid to be in a rapid tumbling (boiling) state all the time, the gas-liquid mixture entering the reducing liquid from the Venturi mixer through the gas-liquid mixture discharging pipe collides with the second part of flue gas directly entering the reducing liquid from the air inlet pipe and is further mixed in the tumbling reducing liquid, so that the preoxidized flue gas in the reducing liquid is uniformly distributed, and the secondary reduction is realized to the greatest extent.
The gas-liquid mixture entering the reducing liquid storage tank is driven by an air extractor arranged at the top discharge port of the reducing tower to enter the reducing tower upwards, and fully contacts with the reducing liquid sprayed by the spray pipe in the packing layer to realize three-time spray reduction, thereby generating N 2 、CO 2 And H 2 And after O, removing water mist through a demisting layer, and discharging from a top discharge port of the reduction tower.
According to the invention, the mutual synergistic effect of primary mixing reduction of a part of flue gas in a Venturi mixer, collision and secondary reduction of two parts of flue gas in a reducing solution storage tank and three spraying reduction of a spraying reduction assembly is utilized, so that high-efficiency treatment of high-concentration nitrogen oxide flue gas is realized, the problem of white smoke is avoided in the discharged flue gas, the damage of nitrogen oxides to human living, production environment and natural ecological environment is avoided, the green development of gold smelting industry and other industries related to nitric acid use is promoted, and the concept of 'green water Qingshan mountain is Jin Shanyin mountain' is practiced.
Drawings
FIG. 1 is a process flow diagram of the instant high concentration nitrogen oxide flue gas treatment method of the present invention.
FIG. 2 is a schematic diagram of a reduction system according to the present invention.
Reference numerals
1-an air inlet pipe; 2-a reduction tower; 3-a reducing solution storage tank; a 4-venturi mixer; 5-an air valve; 21-a spray pipe; 22-a filler layer; 23-a top discharge port; 24-defogging layer; 25-spraying heads; 31-a first pumping device; 32-an aeration head; 33-a second pumping device; 34-heat exchange tubes; 35-a temperature control heat exchanger; 36-liquid outlet; 37-a reducing solution feed port; 41-a flue gas feed pipe; 42-reducing liquid feeding pipe; 43-gas-liquid mixture discharging pipe.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
It should be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and/or processing steps closely related to aspects of the present invention are shown in the drawings, and other details not greatly related to the present invention are omitted.
In addition, it should be further noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The invention provides a method for treating instantaneous high-concentration nitrogen oxide flue gas, which adopts the process technology of condensation, pre-oxidation, slow release and normal temperature reduction, and the flue gas to be treated is subjected to condensation impurity removal, pre-oxidation, slow release and normal temperature reduction in sequence, and acid mist and noble metal carried by the flue gas to be treated are recovered through condensation; pre-oxidizing the flue gas to convert part of NO into NO 2 Afterwards; further reducing at normal temperature after slow release, and reacting the reducing agent with nitrogen oxides to generate N 2 、CO 2 And H 2 And O, realizing stable standard emission of the instantaneous high-concentration nitrogen oxide flue gas.
Specifically, the pre-oxidation is performed in a bubble buffer tank containing an oxidant solution. Compared with spraying the oxidizing liquid on the flue gas, the flue gas is introduced into the bubbling buffer tank, and the flue gas is buffered on one side; on the other hand, the flue gas can be fully contacted with the oxidant solution in the bubbling buffer tank and fully and maximally oxidize NO into NO 2 The content of refractory NO in the flue gas is reduced, and the residual NO reduces the subsequent reduction process to N 2 。
The normal temperature reduction is performed in a reduction system. As shown in fig. 2, the reducing system comprises an air inlet pipe 1, a reducing tower 2 and a reducing liquid storage tank 3 which are mutually communicated up and down, a venturi mixer 4 is arranged between the air inlet pipe 1 and the reducing liquid storage tank 3, a flue gas feeding pipe 41 communicated with the air inlet pipe 1, a reducing liquid feeding pipe 42 communicated with the reducing liquid storage tank 3 and a gas-liquid mixture discharging pipe 43 communicated with the reducing liquid storage tank 3 are arranged on the venturi mixer 4, and a first pumping device 31 connected with the reducing liquid feeding pipe 42 is arranged in the reducing liquid storage tank 3; the discharge port end of the air inlet pipe 1 extends into the reducing liquid storage tank 3, and the discharge port end of the air inlet pipe 1 is provided with an aeration head 32; the flue gas feeding pipe 41 is arranged between the feeding port end and the discharging port end of the air inlet pipe 1 and is far away from the discharging port end. A plurality of groups of spray reduction assemblies which are arranged up and down are arranged in the reduction tower 2, and each spray reduction assembly comprises an upper part and a lower partA shower pipe 21 and a filler layer 22 are arranged; an air extractor (not shown) is arranged at the top discharge hole 23 of the reduction tower 2. So configured, a part of the pre-oxidized flue gas (i.e., a first part of the flue gas) enters the venturi mixer 4 through the flue gas feed pipe 41, at the same time, the reducing liquid in the reducing liquid storage tank 3 is pumped into the venturi mixer 4 through the reducing liquid feed pipe 42 by the first pumping device 31, the first part of the flue gas and the reducing liquid are primarily mixed in the venturi mixer 4 and undergo a reduction reaction, so that part of nitrogen oxides are reduced, and the obtained gas-liquid mixture reenters the reducing liquid storage tank 3 from the gas-liquid mixture discharge pipe 43 (the first part of the flue gas enters the venturi mixer 4 through the flue gas feed pipe 41, the reducing liquid enters the venturi mixer 4 through the reducing liquid feed pipe 42, and the gas-liquid mixture enters the reducing liquid storage tank 3 through the gas-liquid mixture discharge pipe 43 are synchronous and continuous); the other part of the pre-oxidized flue gas (namely, the second part of the flue gas) directly enters the reducing liquid storage tank 3 through the air inlet pipe 1 to be contacted with the reducing liquid, and the aeration head 32 is arranged, so that the second part of the flue gas can rapidly enter the reducing liquid with larger impulsive force to be fully contacted with the reducing liquid and be subjected to preliminary reduction, the contact area of the flue gas and the reducing liquid can be increased, and the flue gas can be further fully contacted with the reducing liquid and be subjected to preliminary reduction; in addition, the second part of flue gas quickly enters the reducing liquid with larger impulsive force to enable the reducing liquid to be in a quick-rising state all the time, the gas-liquid mixture entering the reducing liquid from the Venturi mixer 4 through the gas-liquid mixture discharging pipe 43 collides with the second part of flue gas directly entering the reducing liquid from the air inlet pipe 1 and the reducing liquid and is further mixed, so that the pre-oxidized flue gas in the reducing liquid is uniformly distributed, and the re-reduction is realized to the greatest extent. The gas-liquid mixture (mainly refers to the pre-oxidized flue gas of which part is reduced) entering the reducing liquid storage tank 3 upwards enters the reducing tower 2 under the driving of an air extractor (which can be a draught fan) arranged at a discharge port 23 at the top of the reducing tower 2, and is subjected to three-time spray reduction by a spray reduction assembly to generate N 2 、CO 2 And H 2 And after O, discharging from a top discharge hole 23 of the reduction tower 2, so as to realize stable standard discharge of the instantaneous high-concentration nitrogen oxide flue gas. The book is provided withAccording to the invention, the high-efficiency treatment of the high-concentration nitrogen oxide flue gas is realized by utilizing the mutual synergistic effect of primary mixing reduction of a part of flue gas in a Venturi mixer, collision and secondary reduction of two parts of flue gas in a reducing solution storage tank and three spraying reduction of a spraying reduction assembly, so that the discharged flue gas has no white smoke problem.
Preferably, the volume ratio of the first part of flue gas to the second part of flue gas is 20% -40%, namely 60% -80%. The volumes of the first part of flue gas and the second part of flue gas can be controlled in a split manner through the electromagnetic valve, namely, the electromagnetic valve is arranged on the air inlet pipe 1, the opening angle of the electromagnetic valve is controlled through a control program, and the volume ratio of the first part of flue gas to the second part of flue gas is accurately controlled.
The number of the venturi mixers 4 can be freely set according to the treated flue gas amount, and a plurality of the venturi mixers 4 can be arranged at different positions of the same air inlet pipe 1 (each venturi mixer 4 is independently corresponding to one flue gas inlet pipe 41, one reducing liquid inlet pipe 42 and one gas-liquid mixture outlet pipe 43). The air valve 5 is arranged on the air inlet pipe 1, and the flue gas feeding pipe 41 is arranged between the feeding hole of the air inlet pipe 1 and the air valve 5, so that the air valve 5 can be closed, and flue gas can only enter the Venturi mixer 4 through the flue gas feeding pipe 41. The flue gas feeding pipe 41, the reducing liquid feeding pipe 42 and the gas-liquid mixture discharging pipe 43 are also provided with a gas valve 5, and the flue gas can enter the channel selectively through the switch of the gas valve 5.
Preferably, a slow release system is arranged between the bubbling buffer tank and the reduction system so as to quantitatively and stably enter the reduction system through the pre-oxidized flue gas. The technology of condensation, pre-oxidation, slow release and normal temperature reduction is adopted, so that the instantaneous treatment of the high-concentration nitrogen oxide flue gas is efficiently realized. In some embodiments, the slow release system is that an electromagnetic valve is arranged on a communicating pipeline of the bubbling buffer tank and the reduction system, and the opening angle of the electromagnetic valve is controlled by a control program, so that the flue gas in the bubbling buffer tank stably and quantitatively enters the reduction system.
The reducing solution storage tank 3 is internally provided with a heat exchange tube 34, and the outer wall is provided with a temperature control heat exchanger 35 which is connected with the heat exchange tube 34 in an electrified way and controls the temperature of the heat exchange tube 34. In this way, the reducing solution is controlled at a proper temperature, so that the rapid progress of the reduction reaction is promoted.
The bottom of the reducing solution storage tank 3 is also provided with a liquid outlet 36 for discharging the reducing solution in the reducing solution storage tank 3, and cleaning or maintaining the reducing solution storage tank 3.
The top of the reducing solution storage tank 3 is also provided with a reducing solution feed port 37 for timely supplementing the reducing solution into the reducing solution storage tank 3.
A liquid level detector is arranged at the position, close to the top 1/3, of the reducing liquid storage tank 3, and is used for monitoring the amount of the reducing liquid in the reducing liquid storage tank 3 (monitoring the liquid level of the reducing liquid in a steady state before the reduction reaction is carried out), and reminding a worker of supplementing the reducing liquid when the liquid level is lower than the liquid level.
As shown in fig. 2, the feed port of the shower pipe 21 is connected to the reducing solution storage tank 3; the feed port end of the shower pipe 21 is provided with a second pumping means 33 for pressing the reducing liquid in the reducing liquid storage tank 3 into the shower pipe 21.
The first pumping means 31 is a jet pump; the second pumping means 33 is a shower pump.
The number of spray reduction assemblies can be freely set according to the height of the reduction tower 2. Each spray pipe 21 is provided with a plurality of spray heads 25, preferably atomizing spray heads, and a packing layer 22 is positioned below the spray heads 25. The filler layer 22 is used for increasing the contact area between the flue gas and the reducing solution, so that the reduction reaction is fully performed.
The discharge port end of the reduction tower 2 is also provided with a defogging layer 24. The mist eliminator 24 is located above the spray reduction assembly. The mist removing layer 24 is used for removing H in the product 2 O, thereby N is generated 2 And CO 2 And (5) discharging. The composition of packing layer 22 is pall rings.
The invention also provides a method for treating the instantaneous high-concentration nitrogen oxide flue gas, which comprises the following steps:
s1, condensing and removing impurities:
condensing and washing high-concentration nitrogen oxide flue gas (namely flue gas to be treated, NOx flue gas for short) generated by the reaction of gold mud and nitric acid or aqua regia to enable acid mist and noble metal impurities in the flue gas to enter a liquid phase for recycling, so as to obtain impurity-removing flue gas.
Arranging a condensing pipe at the outlet of a reaction kettle of gold mud and nitric acid or aqua regia, condensing in the condensing pipe, connecting the condensing pipe with a refrigerator, controlling acid mist in flue gas to be cooled to the dew point, forming gaseous flue gas, liquid acid mist and solid noble metal in the flue gas to be treated, and then enabling the noble metal carried in the acid mist and the acid mist to enter a smelting waste liquid gold recovery system through a steam-water separator to remove impurities and obtain impurity-removed flue gas; meanwhile, the waste acid is recovered, and the loss of noble metals is avoided.
S2, pre-oxidation:
pressing the impurity-removed flue gas obtained in the step S1 into a bubbling buffer tank containing oxidant solution for buffering through high pressure or negative pressure of a compression fan, and simultaneously reacting the impurity-removed flue gas with the oxidant to oxidize NO into NO to the greatest extent 2 The content of NO which is difficult to treat in the flue gas is reduced, and the pre-oxidized flue gas is obtained.
Specifically, the oxidant solution is one of a hydrogen peroxide solution and an ozone water solution, and is preferably a hydrogen peroxide solution.
An aeration head is arranged at the air inlet of the bubbling buffer tank and used for quickly flushing impurity-removed flue gas into the bubbling buffer tank with high impact force, and meanwhile, the contact area of the impurity-removed flue gas and oxidant solution is enlarged, so that the oxidation effect is improved. The bubbling buffer tank is internally provided with a smoke concentration detector, a pressure gauge, a safe pressure relief system and the like.
S3, slow release:
and (3) controlling the gas quantity of the pre-oxidized flue gas obtained in the step (S2) through a slow release system, so that the pre-oxidized flue gas is slowly and stably conveyed into a reduction system.
S4, normal temperature reduction:
a part of the pre-oxidized flue gas (i.e., a first part of the flue gas) enters the venturi mixer 4 through a flue gas feeding pipe 41, the reducing solution enters the venturi mixer 4 through a reducing solution feeding pipe 42, the first part of the flue gas and the reducing solution are initially mixed in the venturi mixer 4 and undergo a reduction reaction, and the obtained gas-liquid mixture enters the reducing solution storage tank 3 from a gas-liquid mixture discharging pipe 43. The other part of pre-oxidized smoke (namely, the second part of smoke) directly enters the reducing solution storage tank 3 through the air inlet pipe 1, and the two parts of smoke are fully collided and mixed in the reducing solution storage tank 3, so that the reducing solution in the reducing solution storage tank 3 is in a tumbling state, and the reducing reaction is further fully carried out in the tumbling state.
Then, under the drive of an air extractor arranged at the top discharge port 23 of the reduction tower 2, the pre-oxidized flue gas enters the multi-stage efficient reduction tower 2, and under the interaction of the spray pipe 21 and the packing layer 22, the mass transfer process is strengthened, and the partially reduced pre-oxidized flue gas is fully contacted with the reduction solution to be further reduced, so that N is obtained 2 、CO 2 And H 2 O。
Specifically, the reducing solution is a mixed solution of urea and liquid ammonia, the pH value of the reducing solution is 0.5-5, the concentration is 5-25 wt%, the temperature is 10-35 ℃, and the spray liquid-gas ratio is 10L/m 3 ~100L/m 3 The residence time of the pre-oxidized flue gas in the reduction tower 2 is more than 12s.
S5, flue gas defogging:
step S4 to obtain N 2 、CO 2 And H 2 O further passes through the mist removing layer 24, and after moisture is removed, is discharged from the top discharge port 23 of the reduction tower 2.
The present invention will be described in detail with reference to the following examples.
Example 1
A method for treating instantaneous high-concentration nitrogen oxide flue gas comprises the following steps:
s1, condensing and removing impurities:
and (3) enabling high-concentration NOx flue gas generated by the reaction of the gold mud and the nitric acid to pass through a condensing pipe, wherein the condensed water temperature is less than 5 ℃, cooling and condensing acid mist and gold carried in the NOx flue gas, and then, returning a part of the acid mist and gold to a reaction kettle, enabling the flue gas to pass through a gas-liquid separator, further separating waste acid and gold in the flue gas, and pumping the separated waste acid into a waste liquid treatment system to obtain impurity-removed flue gas. Wherein the concentration of NOx is 47891mg/m 3 The air quantity is 1000m 3 /h。
S2, pre-oxidation:
the impurity-removed flue gas obtained in the step S1 is pressed into a bubbling buffer tank containing oxidant solution to be buffered by a negative pressure of a compression fan, and at the same time, the impurity is removedThe flue gas reacts with the oxidant, and NO is oxidized into NO to the maximum extent 2 The content of NO which is difficult to treat in the flue gas is reduced, and the pre-oxidized flue gas is obtained.
Specifically, the oxidant solution is a hydrogen peroxide solution. The bubbling buffer tank pressure was 0.3MPa.
S3, slow release:
and (3) controlling the gas quantity of the pre-oxidized flue gas obtained in the step (S2) through a slow release system, so that the pre-oxidized flue gas is slowly and stably conveyed into a reduction system.
S4, normal temperature reduction:
a part of the pre-oxidized flue gas (first part of flue gas) enters the venturi mixer 4 through a flue gas feed pipe 41, the reducing liquid enters the venturi mixer 4 through a reducing liquid feed pipe 42, the first part of flue gas and the reducing liquid are initially mixed in the venturi mixer 4 and undergo a reduction reaction, and the obtained gas-liquid mixture enters a reducing liquid storage tank from a gas-liquid mixture discharge pipe 43. The other part of pre-oxidized flue gas (second part of flue gas) directly enters the reducing solution storage tank 3 through the air inlet pipe 1, and the two parts of flue gas are fully collided and mixed in the reducing solution storage tank 3, so that the reducing solution in the reducing solution storage tank 3 is in a tumbling state, and the reducing reaction is further fully carried out in the tumbling state. The volume ratio of the first part of flue gas to the second part of flue gas is 30 percent to 70 percent.
Then, under the drive of an air extractor arranged at the top discharge hole 23 of the reduction tower 2, the flue gas enters the five-stage efficient reduction tower 2 (namely, a spray reduction assembly is of a 5-layer structure arranged up and down), the mass transfer process is enhanced under the interaction of the spray pipe 21 and the packing layer 22, and the flue gas is fully contacted with the reduction liquid to be further reduced to obtain N 2 、CO 2 And H 2 O。
Specifically, the reducing solution is a mixed solution of urea and liquid ammonia, the pH value of the reducing solution is 4.5, the concentration is 15wt%, the temperature is 20 ℃, and the spray liquid-gas ratio is 80L/m 3 The residence time of the flue gas in the reduction column 2 was 20s.
S5, flue gas defogging:
step S4 to obtain N 2 、CO 2 And H 2 O further passes through the mist elimination layer 24, after removal of moisture,is discharged from a top discharge port 23 of the reduction tower 2.
The content of NOx in the discharged flue gas is 98mg/m 3 ，NOx＜240mg/m 3 Reaching the integrated emission standard of atmospheric pollutants (GB 16297-1996).
Examples 2 to 5
The difference between the instantaneous high-concentration nitrogen oxide flue gas treatment method and the embodiment 1 is that in the step S1, the concentration of NOx in the treated nitrogen oxide flue gas is different, and the other steps are substantially the same as those in the embodiment 1, and are not described herein.
The concentration of NOx in the products obtained in examples 1-5 is shown in Table 1.
TABLE 1 concentration of NOx in the products obtained in examples 1-5
| Examples | Peak NOx concentration (mg/m) in flue gas to be treated 3 ） | Concentration of NOx discharged from treated flue gas (mg/m) 3 ） |
| Example 1 | 47891 | 98 |
| Example 2 | 46900 | 104 |
| Example 3 | 48020 | 131 |
| Example 4 | 48157 | 123 |
| Example 5 | 48032 | 116 |
As can be seen from Table 1, the NOx concentrations in the flue gases discharged in examples 1-5 were all less than 240mg/m 3 The technical scheme of the invention can ensure that the instantaneous high-concentration nitrogen oxide smelting flue gas stably reaches the standard of emission of atmospheric pollutants (GB 16297-1996).
Example 6
A method for treating instantaneous high-concentration nitrogen oxide flue gas comprises the following steps:
s1, condensing and removing impurities:
and (3) enabling high-concentration NOx smoke generated by the reaction of the gold mud and the aqua regia to pass through a condensing pipe, wherein the condensed water temperature is less than 5 ℃, cooling and condensing acid mist and gold carried in the NOx smoke, and then, returning a part of the acid mist and gold to a reaction kettle, enabling the smoke to pass through a gas-liquid separator, further separating waste acid and gold in the smoke, and pumping the separated waste acid into a waste liquid treatment system to obtain impurity-removed smoke. Wherein the concentration of NOx is 45000mg/m 3 The air quantity is 2000m 3 /h。
S2, pre-oxidation:
the impurity-removed flue gas obtained in the step S1 is pressed into a bubbling buffer tank containing oxidant solution through a negative pressure of a compression fan for buffering, and meanwhile, the impurity-removed flue gas reacts with the oxidant, and NO is oxidized into NO to the greatest extent 2 The content of NO which is difficult to treat in the flue gas is reduced, and the pre-oxidized flue gas is obtained.
Specifically, the oxidant solution is a hydrogen peroxide solution. The pressure of the bubbling buffer tank was 0.1MPa.
S3, slow release:
and (3) controlling the gas quantity of the pre-oxidized flue gas obtained in the step (S2) through a slow release system, so that the pre-oxidized flue gas is slowly and stably conveyed into a reduction system.
S4, normal temperature reduction:
a part of the pre-oxidized flue gas (first part of flue gas) enters the venturi mixer 4 through a flue gas feed pipe 41, the reducing liquid enters the venturi mixer 4 through a reducing liquid feed pipe 42, the first part of flue gas and the reducing liquid are initially mixed in the venturi mixer 4 and undergo a reduction reaction, and the obtained gas-liquid mixture enters a reducing liquid storage tank from a gas-liquid mixture discharge pipe 43. The other part of pre-oxidized flue gas (second part of flue gas) directly enters the reducing solution storage tank 3 through the air inlet pipe 1, and the two parts of flue gas are fully collided and mixed in the reducing solution storage tank 3, so that the reducing solution in the reducing solution storage tank 3 is in a tumbling state, and the reducing reaction is further fully carried out in the tumbling state. The volume ratio of the first part of flue gas to the second part of flue gas is 30 percent to 70 percent.
Then, under the drive of an air extractor arranged at the top discharge hole 23 of the reduction tower 2, the flue gas enters the four-stage efficient reduction tower 2 (namely, a spray reduction assembly is of a 4-layer structure arranged up and down), the mass transfer process is enhanced under the interaction of the spray pipe 21 and the packing layer 22, and the flue gas is fully contacted with the reduction liquid to be further reduced to obtain N 2 、CO 2 And H 2 O。
Specifically, the reducing solution is a mixed solution of urea and liquid ammonia, the pH value of the reducing solution is 4.5, the concentration is 15wt%, the temperature is 20 ℃, and the spray liquid-gas ratio is 80L/m 3 The residence time of the flue gas in the reduction column 2 was 20s.
S5, flue gas defogging:
step S4 to obtain N 2 、CO 2 And H 2 O further passes through the mist removing layer 24, and after moisture is removed, is discharged from the top discharge port 23 of the reduction tower 2.
The content of NOx in the discharged flue gas is 115mg/m 3 ，NOx＜240mg/m 3 Reaching the integrated emission standard of atmospheric pollutants (GB 16297-1996).
Comparative example 1
The instantaneous high-concentration nitrogen oxide flue gas treatment method is different from the embodiment 1 in that the flue gas to be treated is all introduced into the reducing liquid storage tank 3 through the venturi mixers 4 via the gas-liquid mixture discharging pipe 43, the number of the venturi mixers 4 to be operated is 3 (the number of the venturi mixers 4 to be operated in the embodiment 1 is 1, the number of the venturi mixers 4 can be infinite, the number of the venturi mixers 4 to be selectively opened is the same), the gas flow rate in each venturi mixer 4 is 33% of the total volume (i.e. the gas flow rate in each venturi mixer 4 is approximately the same as that in the embodiment 1), and the other steps are approximately the same as those in the embodiment 1, and are not repeated here.
Comparative example 2
Compared with the embodiment 1, the instantaneous high-concentration nitrogen oxide flue gas treatment method is different in that the flue gas to be treated is all introduced into the reducing solution storage tank 3 through the air inlet pipe 1 and the aeration head 32, the concentration of NOx in the treated nitrogen oxide flue gas is different, and the other is substantially the same as the embodiment 1, and the description is omitted.
Comparative example 3
The instantaneous high-concentration nitrogen oxide flue gas treatment method is different from the embodiment 1 in that the volume ratio of the first portion flue gas to the second portion flue gas is 70% to 30%, the number of the venturi mixers 4 operated in the comparative example 3 is 2, the gas flow rate in each venturi mixer 4 is 35% of the total volume (i.e. the gas flow rate in each venturi mixer 4 is approximately the same as that in the embodiment 1), and the other portions are approximately the same as in the embodiment 1, and are not repeated here.
The NOx concentrations in the products obtained in example 1 and comparative examples 1-3 are shown in Table 2.
TABLE 2 concentration of NOx in the products obtained in example 1 and comparative examples 1-3
| Examples | Peak NOx concentration (mg/m) in flue gas to be treated 3 ） | Emission concentration of NOx in treated flue gas（mg/m 3 ） |
| Example 1 | 47891 | 98 |
| Comparative example 1 | 47891 | 127 |
| Comparative example 2 | 47891 | 176 |
| Comparative example 3 | 47891 | 132 |
As can be seen from table 2, under the condition that the flue gas concentration is the same, the gas-liquid intensified mixing mode of the embodiment 1 makes the flue gas emission concentration lowest, and the comparative embodiment 2 makes the flue gas enter the reducing solution only by the aeration mode, and finally the flue gas emission concentration highest, thereby further explaining the technical scheme of the invention, the stable standard-reaching emission of the instantaneous high-concentration nitrogen oxide flue gas can be ensured, and the treatment effect is best.
In summary, the invention provides a method for treating instantaneous high-concentration nitrogen oxide flue gas, which adopts the process technology of condensation, pre-oxidation, slow release and normal temperature reduction, and the normal temperature reduction process utilizes the mutual synergistic effect of primary mixing reduction of part of flue gas in a Venturi mixer, collision re-reduction of two parts of flue gas in a reducing solution storage tank and three spraying reduction of a spraying reduction assembly, so that the high-efficiency treatment of the high-concentration nitrogen oxide flue gas is realized, and the discharged flue gas has no white smoke problem.
The above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present invention.
Claims (10)
1. A method for treating instantaneous high-concentration nitrogen oxide fume is characterized in that fume to be treated is subjected to condensation impurity removal, pre-oxidation, slow release and normal-temperature reduction in sequence to generate N 2 、CO 2 And H 2 O；
The pre-oxidation is performed in a bubble buffer tank containing an oxidant solution;
the normal temperature reduction is carried out in a reduction system; the reduction system comprises an air inlet pipe, a reduction tower and a reduction liquid storage tank which are mutually communicated up and down, a venturi mixer is arranged between the air inlet pipe and the reduction liquid storage tank, a flue gas feeding pipe communicated with the air inlet pipe, a reduction liquid feeding pipe communicated with the reduction liquid storage tank and a gas-liquid mixture discharging pipe communicated with the reduction liquid storage tank are arranged on the venturi mixer, and a first pumping device connected with the reduction liquid feeding pipe is arranged in the reduction liquid storage tank; the discharge port end of the air inlet pipe extends into the reducing liquid storage tank, and an aeration head is arranged at the discharge port end of the air inlet pipe; the flue gas feeding pipe is arranged between the feeding port end and the discharging port end of the air inlet pipe and is far away from the discharging port end; a plurality of groups of spray reduction assemblies which are arranged up and down are arranged in the reduction tower, and each spray reduction assembly comprises a spray pipe and a filler layer which are arranged up and down; an air extractor is arranged at the top discharge port of the reduction tower;
a slow release system is arranged between the bubbling buffer tank and the reduction system, so that the flue gas quantitatively and stably enters the reduction system.
2. The method for treating transient high concentration nitrogen oxide flue gas according to claim 1, wherein flue gas enters the reducing solution storage tank in two parts; a first part of flue gas enters the reducing liquid storage tank from the flue gas feed pipe through the Venturi mixer and the gas-liquid mixture discharge pipe; the second part of flue gas enters the reducing solution storage tank from the air inlet pipe through the aeration head;
the volume ratio of the first part of flue gas to the second part of flue gas is 20% -40%, 60% -80%.
3. The method for treating instantaneous high-concentration nitrogen oxide flue gas according to claim 2, comprising the steps of:
s1, condensing and removing impurities: condensing and washing the flue gas to be treated to enable acid mist and noble metal impurities in the flue gas to enter a liquid phase for recycling, so as to obtain impurity-removed flue gas;
s2, pre-oxidation: introducing the impurity-removed flue gas obtained in the step S1 into the bubbling buffer tank containing the oxidant, so that part of NO in the impurity-removed flue gas is converted into NO 2 Obtaining pre-oxidized flue gas;
s3, slow release: carrying out gas quantity control on the pre-oxidized flue gas obtained in the step S2 through the slow release system, so that the pre-oxidized flue gas is slowly and stably conveyed into the reduction system;
s4, normal temperature reduction: the first part of flue gas in the pre-oxidized flue gas enters the venturi mixer through the flue gas feeding pipe, the reducing solution enters the venturi mixer through the reducing solution feeding pipe, the first part of flue gas and the reducing solution are initially mixed in the venturi mixer and undergo a reduction reaction, the obtained gas-liquid mixture enters the reducing solution storage tank from the gas-liquid mixture discharging pipe, and the second part of flue gas in the pre-oxidized flue gas enters the reducing solution storage tank through the air inlet pipe; after two parts of pre-oxidized flue gas entering the reducing solution storage tank are mixed, the mixed pre-oxidized flue gas enters the reducing tower under the driving of the air extractor arranged at the top discharge port of the reducing tower, and is reduced by the spray reducing component to obtain N 2 、CO 2 And H 2 O is discharged from the top discharge port of the reduction tower.
4. The method for treating transient high concentration nitrogen oxide flue gas according to claim 3, wherein a feed inlet of the spray pipe is connected with the reducing solution storage tank; and a second pumping device for pressing the reducing liquid in the reducing liquid storage tank into the spray pipe is arranged at the feed inlet end of the spray pipe.
5. The method for treating the instantaneous high-concentration nitrogen oxide flue gas according to claim 3, wherein a heat exchange tube is arranged in the reducing liquid storage tank, and a temperature control heat exchanger which is electrically connected with the heat exchange tube is arranged on the outer wall of the reducing liquid storage tank.
6. The method for treating instantaneous high-concentration nitrogen oxide flue gas according to claim 3, wherein a mist removing layer is arranged at the discharge port end of the reduction tower.
7. The method for treating transient high concentration nitrogen oxide flue gas of claim 6, further comprising the steps of:
s5, flue gas defogging: step S4 is carried out to obtain N 2 、CO 2 And H 2 O passes through the defogging layer, after removing moisture, follow the reduction tower the top discharge gate discharges.
8. The method for treating flue gas containing nitrogen oxides with high concentration at the moment according to claim 3, wherein in the step S2, the oxidant solution is one of hydrogen peroxide solution and ozone water solution; in the step S4, the reducing solution is a mixed solution of urea and liquid ammonia, the pH value of the reducing solution is 0.5-5, the concentration is 5-25 wt%, the temperature is 10-35 ℃, and the spray liquid-gas ratio is 10L/m 3 ~100L/m 3 The residence time of the pre-oxidized flue gas in the reduction tower is more than 12s.
9. A method for treating flue gas containing transient high concentration of nitrogen oxides according to claim 3, wherein in step S1, the condensation is performed in a condenser tube, and the condenser tube is connected to a refrigerator; and the flue gas treated by the condensing pipe is subjected to impurity removal through a steam-water separator.
10. The instantaneous high-concentration nitrogen oxide flue gas treatment method according to claim 3, wherein air valves are arranged on the air inlet pipe, the flue gas inlet pipe, the reducing liquid inlet pipe and the gas-liquid mixture outlet pipe; the flue gas feeding pipe is arranged between the feeding hole of the air inlet pipe and the air valve on the air inlet pipe.
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