CN110465193A - A kind of SCR denitration system - Google Patents
A kind of SCR denitration system Download PDFInfo
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- CN110465193A CN110465193A CN201910807730.5A CN201910807730A CN110465193A CN 110465193 A CN110465193 A CN 110465193A CN 201910807730 A CN201910807730 A CN 201910807730A CN 110465193 A CN110465193 A CN 110465193A
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- Prior art keywords
- flow straightening
- catalyst layer
- straightening grid
- grid
- mixed cell
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- 239000003054 catalyst Substances 0.000 claims abstract description 131
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000003546 flue gas Substances 0.000 claims abstract description 42
- 238000006243 chemical reaction Methods 0.000 claims description 58
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical group N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 51
- 230000003068 static effect Effects 0.000 claims description 21
- 239000000779 smoke Substances 0.000 claims description 12
- 239000003795 chemical substances by application Substances 0.000 claims description 7
- 239000007800 oxidant agent Substances 0.000 claims description 5
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 238000006555 catalytic reaction Methods 0.000 claims description 3
- 239000010410 layer Substances 0.000 claims 15
- 239000011229 interlayer Substances 0.000 claims 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 abstract description 20
- CVTZKFWZDBJAHE-UHFFFAOYSA-N [N].N Chemical compound [N].N CVTZKFWZDBJAHE-UHFFFAOYSA-N 0.000 abstract description 11
- 239000000203 mixture Substances 0.000 abstract description 11
- 229910021529 ammonia Inorganic materials 0.000 description 23
- 239000007789 gas Substances 0.000 description 14
- 230000000694 effects Effects 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 7
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 6
- 230000000903 blocking effect Effects 0.000 description 4
- 230000006378 damage Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 208000027418 Wounds and injury Diseases 0.000 description 2
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 208000014674 injury Diseases 0.000 description 2
- WWILHZQYNPQALT-UHFFFAOYSA-N 2-methyl-2-morpholin-4-ylpropanal Chemical compound O=CC(C)(C)N1CCOCC1 WWILHZQYNPQALT-UHFFFAOYSA-N 0.000 description 1
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8631—Processes characterised by a specific device
-
- 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
- B01D53/86—Catalytic processes
- B01D53/90—Injecting reactants
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
-
- 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 present invention provides a kind of SCR denitration system, the first mixed cell, the first catalyst layer, the second mixed cell, the second catalyst layer are provided in main body, the first mixed cell, the first catalyst layer, the second mixed cell, the second catalyst layer are set gradually along the direction of flow of flue gas.In above system, flue gas flows through the first catalyst layer and is reacted after the mixing of the first mixed cell, unreacted NOx and NH3Flow out the first catalyst layer；Unreacted NOx and NH3With non-uniform Flow Field Distribution and concentration distribution, the setting of second mixed cell mixes flue gas again, to make nitrogen ammonia mixture flow through having more uniform velocity field and concentration field before the second catalyst layer, therefore it can sufficiently be reacted when flowing through the second catalyst layer, the discharge for avoiding a large amount of unreacted nitrogen ammonia mixtures, finally improves the denitration efficiency of entire SCR denitration system.
Description
Technical field
The present invention relates to denitrating flue gas fields, and in particular to a kind of SCR denitration system.
Background technique
Selective catalytic reduction (SCR) technology is that current application is most wide, most effective mainstream denitration technology, and denitration efficiency can
To reach 80% or more.The principle of the technology is: under the effect of the catalyst, spraying into ammonia into 280-420 DEG C of flue gas, makes ammonia
Redox reaction occurs in catalyst surface with nitrogen oxides, is then converted to nontoxic and pollution-free nitrogen and water.Due to this
Reaction is to occur the moment contacted in ammonia, nitrogen oxides with catalyst, and catalyst structure is porous structure, material is more crisp
It is weak, therefore the flow field uniformity of SCR denitration system and velocity flow profile situation are particularly important, directly affect denitration performance and catalyst
Service life.
SCR denitration system usually arranges different deflector at reactor inlet horizontal connection flue, and
Supporting beam position is evenly arranged the flow straightening grid of series of identical height on one catalyst layer, and flue gas is made to flow through the first catalyst layer
It is preceding in order to obtain preferable Flow Field Distribution.But during actual motion, which cannot guarantee that flue gas has substantially uniformity
Velocity field and concentration field, therefore still remain unreacted NOx and NH3.Meanwhile unreacted NOx and NH3It is flowed through with flue gas
When the second layer or third layer catalyst, the distribution of ammonia nitrogen molar ratio can be more uneven, makes the NOx and NH of remaining3It cannot be abundant
Reaction, final unreacted NOx and NH3With flue gas emission, denitration efficiency is not only reduced, also causes the escaping of ammonia phenomenon.And escape
Ease ammonia can react with sulfur dioxide generates the ammonium sulfate or ammonium hydrogen sulfate of stickiness, to be stained with to air preheater
Dirt reduces air preheater flow area, causes Ash Blocking in Air Preheater.Ash Blocking in Air Preheater not only significantly reduces boiler
Efficiency has an effect on the safe and stable operation of denitration unit.
Summary of the invention
Therefore, the technical problem to be solved in the present invention is that ammonia nitrogen during SCR denitration is overcome to be unevenly distributed and cause
The defect that denitration efficiency is low, the escaping of ammonia and subsequent air preheater block, to provide a kind of SCR denitration system.
Technical solution provided by the present invention is as follows:
The present invention provides a kind of SCR denitration system, including main body, and the main body includes the circulation section and reaction being sequentially communicated
Section, the one end of the circulation section far from conversion zone is smoke inlet, further includes,
First mixed cell, including the first flow straightening grid and the first static mixer, first flow straightening grid are set to
In the conversion zone, first static mixer is set in the circulation section close to the smoke inlet；
First catalyst layer and the second mixed cell, second mixed cell are set in the conversion zone, and described
First catalyst layer is set between first flow straightening grid and second mixed cell and is located in the conversion zone, institute
Stating the second mixed cell is the second flow straightening grid or the second static mixer；
Second catalyst layer is set in the conversion zone, and relative to second mixed cell far from described first
Catalyst layer setting.
Further, system further includes third catalyst layer, is set in the conversion zone, and is urged relative to described second
Agent layer is arranged far from first catalyst layer.
Further, system further includes third mixed cell, is set in the conversion zone, and is set to described second and urges
Between agent layer and third catalyst layer, the third mixed cell is third flow straightening grid or third static mixer.
Further, in first flow straightening grid hole area of structural unit not less than the second flow straightening grid and/or the
The hole area of structural unit in three flow straightening grids.
Further, the hole area of structural unit is structure list in first flow straightening grid in second flow straightening grid
The 20-100% of first hole area；
The hole area of structural unit is the 20- of structural unit hole area in the first flow straightening grid in third flow straightening grid
100%.
Further, the spacing of second flow straightening grid and second catalyst layer is greater than second flow straightening grid
With the spacing between first catalyst layer；
The spacing of the third flow straightening grid and the third catalyst layer is greater than the third flow straightening grid and described the
Spacing between two catalyst layers.
Further, along conversion zone the advance of flue gas direction, first flow straightening grid is fixed on described first and urges
In front of agent layer at 5-500mm；
Second flow straightening grid is fixed at first catalyst layer rear 5-500mm；
The third flow straightening grid is fixed at second catalyst layer rear 5-500mm.
Further, first flow straightening grid is arranged successively forming array grid, the rectangle by rectangular configuration unit
A length of 100-300mm of structural unit, width 20-200mm；
Second flow straightening grid is arranged successively forming array grid, the right angle trigonometry by triangular structure of right angle unit
The a right-angle side a length of 40-300mm, another a length of 20-200mm of right-angle side of shape structural unit；Or second flow straightening grid by
Rectangular configuration unit is arranged successively forming array grid, a length of 20-300mm of the rectangular configuration unit, width 20-200mm；
The third flow straightening grid is arranged successively forming array grid, the right angle trigonometry by triangular structure of right angle unit
The a right-angle side a length of 40-300mm, another a length of 20-200mm of right-angle side of shape structural unit；Or the third flow straightening grid by
Rectangular configuration unit is arranged successively forming array grid, a length of 20-300mm of the rectangular configuration unit, width 20-200mm.
Further, system further includes spraying ammonia unit, being set in the circulation section, and be set to the smoke inlet
Between first static mixer；
Deflector, the intersection close to the circulation section and conversion zone are set in the circulation section.
Further, the circulation section is connected to form U-shaped main body with conversion zone, and the deflector is set to the U-shaped master
The U-shaped bottom of body；
The deflector includes the first deflector and the second deflector being oppositely arranged, and first deflector is close to described
The side setting for the section that circulates.
Further, the height of first flow straightening grid be 200-1000mm, the edge of first flow straightening grid with
The inner wall of the conversion zone abuts against, so that flue gas all passes through from first flow straightening grid；
The height of second flow straightening grid is 200-1000mm, the edge and the conversion zone of second flow straightening grid
Inner wall abut against so that flue gas all passes through from first flow straightening grid；
The height of the third flow straightening grid is 200-1000mm, the edge and the conversion zone of the third flow straightening grid
Inner wall abut against so that flue gas all passes through from first flow straightening grid.
Technical solution of the present invention has the advantages that
1. SCR denitration system provided by the invention, main body includes the circulation section being sequentially communicated and conversion zone, the circulation section
One end far from conversion zone is smoke inlet, additionally includes the first mixed cell, including the first flow straightening grid and the first static state
Mixer, first flow straightening grid are set in the conversion zone, and first static mixer is close to the smoke inlet
It is set in the circulation section；First catalyst layer and the second mixed cell, second mixed cell are set to the reaction
In section, and first catalyst layer is set between first flow straightening grid and second mixed cell and is located at described
In conversion zone, second mixed cell includes the second flow straightening grid or the second static mixer；Second catalyst layer, is set to
In the conversion zone, and it is arranged relative to second mixed cell far from first catalyst layer.In above system, flue gas
After the mixing of the first mixed cell, flows through the first catalyst layer and reacted, unreacted NOx and NH3The first catalysis of outflow
Oxidant layer；Unreacted NOx and NH3With non-uniform Flow Field Distribution and concentration distribution, the setting of the second mixed cell makes flue gas
It mixes again, to make nitrogen ammonia mixture flow through having more uniform velocity field and concentration field before the second catalyst layer, therefore can
Sufficiently to react when flowing through the second catalyst layer, the discharge of a large amount of unreacted nitrogen ammonia mixtures is avoided, is finally improved entire
The denitration efficiency of SCR denitration system.
2. it is mixed to be arranged second between the first catalyst layer and the second catalyst layer for SCR denitration system provided by the invention
Unit is closed, and third catalyst layer is set far from first catalyst layer relative to second catalyst layer.Flue gas is in
One catalyst layer is reacted, unreacted NOx and NH3It flows out the first catalyst layer and is mixed again in the second mixed cell
Close, uniformly mixed nitrogen ammonia mixture flow through the second catalyst layer secondary response again, for avoid unreacted NOx after the reaction was completed and
NH3It is discharged and third catalyst layer is set, unreacted NOx and NH3It is chemical anti-by that can be carried out again when third catalyst layer
It answers, therefore ammonia spill-out can be reduced, and improve system denitration efficiency.
3. it is mixed to be arranged second between the first catalyst layer and the second catalyst layer for SCR denitration system provided by the invention
Unit is closed, third mixed cell is set between the second catalyst layer and third catalyst layer.It flows through after the first catalyst layer not
The NOx and NH of reaction3By occurring to mix again when the second mixed cell, have when flowing through the second catalyst layer more uniform
Velocity field and concentration field, therefore nitrogen ammonia mixture can sufficiently react；After flowing through the second catalyst layer, exist a small amount of unreacted
NOx and NH3By the mixing again of third mixed cell, third catalyst layer is entered with uniform velocity field and concentration field, from
And improve the reaction efficiency of third catalyst layer.The design of second mixed cell and third mixed cell, which further improves, urges
The denitration efficiency of agent avoids the discharge of unreacted nitrogen ammonia mixture, finally improves the denitration effect of entire SCR denitration system
Rate.
4. SCR denitration system provided by the invention, the hole area of the first flow straightening grid is not less than the second flow straightening grid and the
The structural unit of the hole area of three flow straightening grids, the second flow straightening grid and third flow straightening grid is rectangle or right angled triangle.It closes
The hole area of reason can be such that gas passes through, and avoid gas and damage to main body and catalyst.First honeycomb screen simultaneously
The hole area of grid is not less than the hole area of the second flow straightening grid and third flow straightening grid, can increase the complete flue gas containing ammonia of unreacted
Probability and the increase flue gas containing ammonia contacted with flow straightening grid then increases from the first catalyst layer to the path of the second catalyst layer
The mixability of the flue gas containing ammonia, and the mixed effect of the second flow straightening grid and the smaller flue gas of hole area of third flow straightening grid is got over
It is good, so that gas is reached the second catalyst layer and participate in that there is uniform flow field when reaction, avoids flue gas containing ammonia since flow field is uneven
Lead to the situation not sufficiently reactive in the second catalyst layer, may finally reach and increase denitration efficiency and reduction Blocking in Air Preheater
The effect of plug.
5. SCR denitration system provided by the invention, the spacing between second flow straightening grid and second catalyst layer
Greater than the spacing between second flow straightening grid and first catalyst layer, the third flow straightening grid and the third are catalyzed
Spacing between oxidant layer is greater than the spacing between the third flow straightening grid and second catalyst layer.As the complete NOx of unreacted
And NH3When being flowed out from catalyst, that is, enter the second flow straightening grid and/or third flow straightening grid and mixed again, flows out the
The gas of two flow straightening grids and/or third flow straightening grid occurs further to mix in sufficiently long region, makes the temperature of flue gas
Field and velocity field are more uniform.The mixing effect of the second flow straightening grid and/or third flow straightening grid can be improved by designing above
Fruit improves gas in the extent of reaction of catalyst surface, and mitigates the injury to catalyst, then improves SCR denitration system
Denitration efficiency.
Detailed description of the invention
It, below will be to specific in order to illustrate more clearly of the specific embodiment of the invention or technical solution in the prior art
Embodiment or attached drawing needed to be used in the description of the prior art be briefly described, it should be apparent that, it is described below
Attached drawing is some embodiments of the present invention, for those of ordinary skill in the art, before not making the creative labor
It puts, is also possible to obtain other drawings based on these drawings.
Fig. 1 is the structural schematic diagram of SCR denitration system in the embodiment of the present invention；
Fig. 2 is that structural unit is that the flow straightening grid of rectangle is illustrated perpendicular to the section of main body inner wall in the embodiment of the present invention
Figure；
Fig. 3 is section of the flow straightening grid perpendicular to main body inner wall that structural unit is right angled triangle in the embodiment of the present invention
Schematic diagram.
Appended drawing reference:
1- smoke inlet；2- main body；3- sprays ammonia unit；The first static mixer of 4-；5- deflector；The first honeycomb screen of 6-
Grid；The first catalyst layer of 7-；The second mixed cell of 8-；The second catalyst layer of 9-；10- third mixed cell；11- third catalyst
Layer；12- rectangular configuration unit；13- triangular structure of right angle unit.
Specific embodiment
Technical solution of the present invention is clearly and completely described below in conjunction with attached drawing, it is clear that described implementation
Example is a part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, ordinary skill
Personnel's every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that term " center ", "upper", "lower", "left", "right", "vertical",
The orientation or positional relationship of the instructions such as "horizontal", "inner", "outside" be based on the orientation or positional relationship shown in the drawings, merely to
Convenient for description the present invention and simplify description, rather than the device or element of indication or suggestion meaning must have a particular orientation,
It is constructed and operated in a specific orientation, therefore is not considered as limiting the invention.In addition, term " first ", " second ",
" third " is used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance.
In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, term " installation ", " phase
Even ", " connection " shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or be integrally connected；It can
To be mechanical connection, it is also possible to be electrically connected；It can be directly connected, can also can be indirectly connected through an intermediary
Connection inside two elements.For the ordinary skill in the art, above-mentioned term can be understood at this with concrete condition
Concrete meaning in invention.
As long as in addition, the non-structure each other of technical characteristic involved in invention described below different embodiments
It can be combined with each other at conflict.
Embodiment 1
The present embodiment provides a kind of SCR denitration systems, as shown in Figure 1, including main body 2, main body 2 includes the stream being sequentially communicated
Logical section and conversion zone, the one end of circulation section far from conversion zone is smoke inlet 1, and conversion zone goes out far from one end of circulation section for flue gas
Mouthful.Further include,
First mixed cell, including the first flow straightening grid 6 and the first static mixer 4, the first flow straightening grid 6 are set to instead
It answers in section, the first static mixer 4 is set in circulation section close to smoke inlet 1；
First catalyst layer 7 and the second mixed cell 8, the second mixed cell 8 is set in conversion zone, and the first catalyst
Layer 7 is set between the first flow straightening grid 6 and the second mixed cell 8 and is located in conversion zone, and the second mixed cell 8 is second whole
Flow grid or the second static mixer；In the present embodiment, the second static mixer includes and is not limited to rectangular blade or circle
Blade mixer；
Second catalyst layer 9, is set in conversion zone, and sets relative to the second mixed cell 8 far from the first catalyst layer 7
It sets.
In above-mentioned SCR denitration system, flue gas flows through the first catalyst layer 7 and carries out instead after the mixing of the first mixed cell
It answers, unreacted NOx and NH3Flow out the first catalyst layer 7；Unreacted NOx and NH3With non-uniform Flow Field Distribution and dense
Degree distribution, the setting of the second mixed cell 8 mixes flue gas again, thus make nitrogen ammonia mixture flow through the second catalyst layer 9 before
It with more uniform velocity field and concentration field, therefore can sufficiently react, avoid a large amount of not anti-when flowing through the second catalyst layer
The discharge for answering nitrogen ammonia mixture finally improves the denitration efficiency of entire SCR denitration system.
In one embodiment, the hole area of structural unit is not less than in the second flow straightening grid in the first flow straightening grid 6
The hole area of structural unit；Specifically, the hole area of structural unit is structure list in the first flow straightening grid 6 in the second flow straightening grid
The 20-100% of first hole area；As shown in Fig. 2, the first flow straightening grid 6 is arranged successively forming array lattice by rectangular configuration unit 12
Grid, a length of 100-300mm of rectangular configuration unit 12, width 20-200mm；Second flow straightening grid is by triangular structure of right angle list
Member 13 forms rectangular configuration, and is arranged successively forming array grid, a length of 40- of a right-angle side of triangular structure of right angle unit 13
300mm, another a length of 20-200mm of right-angle side.Certainly, as the embodiment of deformation, as shown in figure 3, the second flow straightening grid can
To be arranged successively forming array grid, a length of 20-300mm of rectangular configuration unit 12, width 20- by rectangular configuration unit 12
200mm.The reasonable hole area of flow straightening grid can be such that gas passes through, and avoid gas and cause to hurt to main body and catalyst
Evil.The hole area of the first flow straightening grid 6 is not less than the hole area of the second flow straightening grid and third flow straightening grid simultaneously, can increase
The probability and increase flue gas containing ammonia that the complete flue gas containing ammonia of unreacted is contacted with flow straightening grid are catalyzed from the first catalyst layer to second
The path of oxidant layer then increases the mixability of the flue gas containing ammonia, and the hole area of the second flow straightening grid and third flow straightening grid is got over
The mixed effect of small flue gas is better, so that gas is reached the second catalyst layer and participates in having uniform flow field when reaction, avoids containing ammonia
Flue gas may finally reach increase denitration efficiency since flow field unevenly leads to the situation not sufficiently reactive in the second catalyst layer
With the effect for reducing air preheater blocking.
Further, along conversion zone the advance of flue gas direction, before the first flow straightening grid 6 is fixed on the first catalyst layer
At square 5-500mm；Second flow straightening grid is fixed at the first catalyst layer rear 5-500mm, and the second flow straightening grid is urged with second
The spacing of agent layer 9 is greater than the spacing of the second flow straightening grid and the first catalyst layer 7.As unreacted complete NOx and NH3From urging
It when being flowed out in agent, immediately enters the second flow straightening grid and is mixed again, flow out the gas of the second flow straightening grid in long enough
Region in occur further mixing, keep the temperature field of flue gas and velocity field more uniform, to improve gas in catalyst
The extent of reaction on surface, and mitigate the injury to catalyst, then improve the denitration efficiency of SCR denitration system.
Further, the height of the first flow straightening grid 6 is 200-1000mm, the edge and conversion zone of the first flow straightening grid 6
Inner wall abut against so that flue gas all passes through from the first flow straightening grid 6.The height of second flow straightening grid is 200-1000mm,
The edge of second flow straightening grid and the inner wall of conversion zone abut against, so that flue gas all passes through from the first flow straightening grid 6.When not anti-
Answer complete NOx and NH3When being flowed out from catalyst, that is, enters the second flow straightening grid and mixed again, the second flow straightening grid
Suitable height sufficiently long path can be provided for gas mixing, while not increasing cost；The cross section of second flow straightening grid
It is identical as main body inner wall size, pass through unreacted gas all, so that all gas be made to occur to mix again, then mentions
The mixed effect of high second flow straightening grid improves gas in the extent of reaction of catalyst surface, then improves SCR denitration system
Denitration efficiency.
Further, circulation section is connected to form U-shaped main body with conversion zone.
Further, system further includes spraying ammonia unit 3, is set in circulation section, and be set to smoke inlet 1 and first
Between static mixer 4；
Deflector 5 is set to the U-shaped bottom of U-shaped main body including the first deflector and the second deflector being oppositely arranged, tool
Body, the first deflector is close to the side setting of circulation section, and the second deflector is close to the setting of the side of conversion zone.
Embodiment 2
The present embodiment provides a kind of SCR denitration systems, and on the basis of above-described embodiment 1, system further includes third catalysis
Oxidant layer 11, is set in conversion zone, and is arranged relative to the second catalyst layer 9 far from the first catalyst layer 7.By the way that third is arranged
Catalyst layer 11 makes by the first catalyst layer 7,9 unreacted NOx and NH of the second catalyst layer3In third catalyst layer 11
It is reacted again, to avoid unreacted NOx and NH3It is expelled directly out, effectively reduces ammonia spill-out, and improve system denitration
Efficiency.
Embodiment 3
The present embodiment provides a kind of SCR denitration systems, as shown in Figure 1, system is also wrapped on the basis of above-described embodiment 2
Third mixed cell 10 is included, is set in conversion zone, and is set between the second catalyst layer and third catalyst layer, third is mixed
Closing unit 10 is third flow straightening grid or third static mixer.In the present embodiment, the second static mixer includes and unlimited
In rectangular blade or circular blade mixer.
In above-mentioned SCR denitration system, the second mixed cell 8 is set between first catalyst layer 7 and the second catalyst layer 9,
Third mixed cell 10 is set between second catalyst layer 9 and third catalyst layer 11.Flow through unreacted after the first catalyst layer
NOx and NH3By occurring to mix again when the second mixed cell 8, there is more uniform speed when flowing through the second catalyst layer 9
Field and concentration field are spent, therefore nitrogen ammonia mixture can sufficiently react；After flowing through the second catalyst layer 9, exist a small amount of unreacted
NOx and NH3By the mixing again of third mixed cell 10, third catalyst layer is entered with uniform velocity field and concentration field
11, to improve the reaction efficiency of third catalyst layer 11.The design of second mixed cell 8 and third mixed cell 10 is into one
Step improves the denitration efficiency of catalyst, avoids the discharge of unreacted nitrogen ammonia mixture, finally improves entire SCR denitration system
The denitration efficiency of system.
Further, the hole area of structural unit is not less than structural unit in third flow straightening grid in the first flow straightening grid 6
Hole area；Specifically, the hole area of structural unit is structural unit hole area in the first flow straightening grid 6 in third flow straightening grid
20-100%.
Further, third flow straightening grid is fixed at the second catalyst layer rear 5-500mm, third flow straightening grid and
The spacing of three catalyst layers 11 is greater than the spacing between third flow straightening grid and the second catalyst layer 9.
Further, third flow straightening grid is arranged successively forming array grid, right angle by triangular structure of right angle unit 13
The a right-angle side a length of 40-300mm, another a length of 20-200mm of right-angle side of triangular structure unit 13；Certainly, as deformation
Embodiment, third flow straightening grid can be arranged successively forming array grid, rectangular configuration unit 12 by rectangular configuration unit 12
A length of 20-300mm, width 20-200mm.
Further, the height of third flow straightening grid is 200-1000mm, the edge of third flow straightening grid and conversion zone
Inner wall abuts against, so that flue gas all passes through from the first flow straightening grid 6.
Comparative example 1
This comparative example provides a kind of SCR denitration system, with embodiment 1, only difference is that: the system is not related to
Second mixed cell 8.
Comparative example 2
This comparative example provides a kind of SCR denitration system, with embodiment 2, only difference is that: the system is not related to
Second mixed cell 8.
Test example 1
Performance test has been carried out to the SCR denitration system in above-described embodiment 1-3 and comparative example 1-3.Test result such as table 1
It is shown.Wherein flue gas flow rate is 15m/s, and flue-gas temperature is 350 DEG C, denitrating system entrance NOxMass concentration is 400ppm.
Table 1
| Number | Denitration efficiency (%) | Export NOxIt is worth (ppm) | The escaping of ammonia (ppm) |
| Embodiment 1 | 93.00 | 28 | 4 |
| Embodiment 2 | 94.25 | 23 | 3 |
| Embodiment 3 | 95.50 | 18 | 2 |
| Comparative example 1 | 85.00 | 60 | 5 |
| Comparative example 2 | 86.50 | 54 | 5 |
As it can be seen from table 1 increasing the unreacted after the first catalyst layer by the second mixed cell of setting and containing ammonia
The uniformity coefficient of flue gas mixing, improves unreacted flue gas containing ammonia in the extent of reaction of the second catalyst layer surface, to increase
Denitration efficiency, while reducing amount of ammonia slip, reduce the stopping state of air preheater.By the way that third catalyst is arranged
Layer, makes by the first catalyst layer, the second catalyst layer unreacted NOx and NH3It is reacted again in third catalyst layer,
Ammonia spill-out is effectively reduced, and improves system denitration efficiency.The setting of third mixed cell can be further increased by
The uniformity coefficient that unreacted flue gas containing ammonia mixes after two catalyst layers, improves unreacted flue gas containing ammonia in third catalyst layer table
The extent of reaction in face to further increase denitration efficiency, and reduces the stopping state of air preheater.
Obviously, the above embodiments are merely examples for clarifying the description, and does not limit the embodiments.It is right
For those of ordinary skill in the art, can also make on the basis of the above description it is other it is various forms of variation or
It changes.There is no necessity and possibility to exhaust all the enbodiments.And it is extended from this it is obvious variation or
It changes still within the protection scope of the invention.
Claims (10)
1. a kind of SCR denitration system, including main body, the main body includes the circulation section being sequentially communicated and conversion zone, the circulation
The one end of section far from conversion zone is smoke inlet, which is characterized in that further include,
First mixed cell, including the first flow straightening grid and the first static mixer, first flow straightening grid are set to described
In conversion zone, first static mixer is set in the circulation section close to the smoke inlet；
First catalyst layer and the second mixed cell, second mixed cell are set in the conversion zone, and described first
Catalyst layer is set between first flow straightening grid and second mixed cell and is located in the conversion zone, and described the
Two mixed cells are the second flow straightening grid or the second static mixer；
Second catalyst layer is set in the conversion zone, and relative to second mixed cell far from first catalysis
Oxidant layer setting.
2. system according to claim 1, which is characterized in that further include third catalyst layer, be set to the conversion zone
It is interior, and be arranged relative to second catalyst layer far from first catalyst layer.
3. system according to claim 2, which is characterized in that further include third mixed cell, be set to the conversion zone
It is interior, and be set between second catalyst layer and third catalyst layer, the third mixed cell is third flow straightening grid
Or third static mixer.
4. system according to claim 3, which is characterized in that the hole area of structural unit is not in first flow straightening grid
Less than the hole area of structural unit in the second flow straightening grid and/or third flow straightening grid.
5. system according to claim 4, which is characterized in that the hole area of structural unit is in second flow straightening grid
The 20-100% of structural unit hole area in first flow straightening grid；
The hole area of structural unit is the 20-100% of structural unit hole area in the first flow straightening grid in third flow straightening grid.
6. the system according to any one of claim 3-5, which is characterized in that second flow straightening grid and described second
The spacing of catalyst layer is greater than the spacing between second flow straightening grid and first catalyst layer；
The spacing of the third flow straightening grid and the third catalyst layer is greater than the third flow straightening grid and urges with described second
The spacing of agent interlayer.
7. system according to claim 6, which is characterized in that the direction of the advance of flue gas along conversion zone,
First flow straightening grid is fixed in front of first catalyst layer at 5-500mm；
Second flow straightening grid is fixed at first catalyst layer rear 5-500mm；
The third flow straightening grid is fixed at second catalyst layer rear 5-500mm.
8. the system according to any one of claim 3-5, which is characterized in that first flow straightening grid is by rectangular configuration
Unit is arranged successively forming array grid, a length of 100-300mm of the rectangular configuration unit, width 20-200mm；
Second flow straightening grid is arranged successively forming array grid, the right angled triangle knot by triangular structure of right angle unit
The a right-angle side a length of 40-300mm, another a length of 20-200mm of right-angle side of structure unit；Or second flow straightening grid is by rectangle
Structural unit is arranged successively forming array grid, a length of 20-300mm of the rectangular configuration unit, width 20-200mm；
The third flow straightening grid is arranged successively forming array grid, the right angled triangle knot by triangular structure of right angle unit
The a right-angle side a length of 40-300mm, another a length of 20-200mm of right-angle side of structure unit；Or the third flow straightening grid is by rectangle
Structural unit is arranged successively forming array grid, a length of 20-300mm of the rectangular configuration unit, width 20-200mm.
9. system described in any one of -2 according to claim 1, which is characterized in that further include,
Ammonia unit is sprayed, is set in the circulation section, and be set between the smoke inlet and first static mixer；
Deflector, the intersection close to the circulation section and conversion zone are set in the circulation section.
10. system according to claim 9, which is characterized in that the circulation section is connected to form U-shaped main body with conversion zone,
The deflector is set to the U-shaped bottom of the U-shaped main body；
The deflector includes the first deflector and the second deflector being oppositely arranged, and first deflector is close to the circulation
The side setting of section.
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| CN113426288A (en) * | 2021-06-25 | 2021-09-24 | 华能(大连)热电有限责任公司 | Method for improving denitration efficiency and ammonia escape rate detection and calculation accuracy of coal-fired power plant |
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| CN106178949A (en) * | 2016-08-25 | 2016-12-07 | 华电电力科学研究院 | A kind of efficient SCR denitration device of stepped mixing |
| CN109647193A (en) * | 2018-12-28 | 2019-04-19 | 浙江天蓝环保技术股份有限公司 | A kind of SCR denitration method and device of ammonia segmentation supply |
| CN210752095U (en) * | 2019-08-29 | 2020-06-16 | 中国华电科工集团有限公司 | SCR denitration system |
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| CN106178949A (en) * | 2016-08-25 | 2016-12-07 | 华电电力科学研究院 | A kind of efficient SCR denitration device of stepped mixing |
| CN109647193A (en) * | 2018-12-28 | 2019-04-19 | 浙江天蓝环保技术股份有限公司 | A kind of SCR denitration method and device of ammonia segmentation supply |
| CN210752095U (en) * | 2019-08-29 | 2020-06-16 | 中国华电科工集团有限公司 | SCR denitration system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113426288A (en) * | 2021-06-25 | 2021-09-24 | 华能(大连)热电有限责任公司 | Method for improving denitration efficiency and ammonia escape rate detection and calculation accuracy of coal-fired power plant |
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