CN105521709A - SCR (selective catalytic reduction) reaction based low-temperature denitration reactor and method - Google Patents
SCR (selective catalytic reduction) reaction based low-temperature denitration reactor and method Download PDFInfo
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- CN105521709A CN105521709A CN201610077100.3A CN201610077100A CN105521709A CN 105521709 A CN105521709 A CN 105521709A CN 201610077100 A CN201610077100 A CN 201610077100A CN 105521709 A CN105521709 A CN 105521709A
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- reactor
- flue gas
- catalytic reduction
- reduction layer
- denitrating
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- 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
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- 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
- B01D53/76—Gas phase processes, e.g. by using aerosols
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- 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
Abstract
The invention relates to an SCR (selective catalytic reduction) reaction based low-temperature denitration reactor and method. A smoke inlet of the reactor is directly connected to a tail flue of a power station boiler, smoke enters the reactor after flowing out of the tail flue of the boiler and is firstly pre-oxidized through a catalytic oxidation layer in the reactor, a part of NO is converted into NO2, and the pre-oxidized smoke is mixed with NH3 sprayed from a nozzle and has a rapid SCR reaction on the catalytic oxidation layer after being uniformly mixed through a static mixer; the temperature in the reactor is 200-350 DEG C, and the rapid SCR reaction speed is more than 10 times of the standard SCR reaction speed; a prepared catalytic oxidation layer is further arranged at the lower part of the catalytic oxidation layer, the smoke reacting on the catalytic oxidation layer passes by the prepared catalytic oxidation layer, and residual NOx is further reduced into N2. The denitration efficiency of the smoke low-temperature section is greatly improved and can be higher than 98% at the temperature of 200 DEG C.
Description
Technical field
The invention belongs to gas denitrifying technology field, particularly a kind of low-temperature denitration reactor based on SCR reaction and method.
Background technology
Nitrogen oxide is very huge to the harm of environment, and SCR (SCR) technology is exactly utilize reducing agent under the effect of catalyst, and the NOx in flue gas is reduced into N
2, to reduce the environmental pollution that combustion of fossil fuel brings.Mainly 4NH is there is in traditional Benitration reactor
3+ 4NO+O
2→ 4N
2+ 6H
2the chemical reaction of O, if do not introduce catalyst, this reaction more than 900 DEG C just can reach good denitration effect; Having under catalyst existent condition, the temperature required for this reaction is more than 300 DEG C, and the denitration efficiency in low temperature range is less than 50%.
Summary of the invention
Not enough for prior art, the invention provides a kind of low-temperature denitration reactor based on SCR reaction and method.
A kind of low-temperature denitration reactor based on SCR reaction, smoke inlet is located at the top of reactor, exhanst gas outlet is located at the bottom of reactor, reactor head to be inclination angle the be inclined plane of 30 ° ~ 40 °, its inside is followed successively by catalytic oxidation layer 3 from top to bottom, nozzle 5, static mixer 6 and catalytic reduction layer 7, described nozzle 5 stores with ammonia and is connected with spraying system 4; Catalytic oxidation layer 3 and catalytic reduction layer 7 select vanadium titanium system's denitrating catalyst or transition metal modified molecular sieve denitrating catalyst.
Smoke inlet place is provided with entrance guiding plate 2, and the knuckle of described entrance guiding plate 2 is 130 ° ~ 150 °; Smoke outlet is provided with outlet deflector 9, and described outlet deflector 9 is vertical baffle.
Described ammonia stores selects eddy current static mixing type to spray grid with spraying system 4.
Described catalytic reduction layer 7 bottom is provided with preparation catalytic reduction layer 8, and preparation catalytic reduction layer 8 selects vanadium titanium system's denitrating catalyst or transition metal modified molecular sieve denitrating catalyst.
Above-mentioned a kind of low-temperature denitration reactor based on SCR reaction carries out the method for denitrating flue gas, the smoke inlet of reactor is connected directly between on Rear of Utility Boiler flue 1, flue gas enters reactor after being flowed out by boiler back end ductwork 1, first through catalytic oxidation layer 3 pre-oxidation in reactor, part NO is made to be converted into NO
2, the NH that the flue gas of pre-oxidation and nozzle 5 spray into
3mixing, and after static mixer 6 mixes, carry out SCR reaction at catalytic reduction layer 7, SCR key reaction is NO+NO
2+ 2NH
3→ 2N
2+ 4H
2o, reaction rate accurate SCR up to standard reacts 4NH
3+ 4NO+O
2→ 4N
2+ 6H
2more than 10 times of O speed; Temperature in reactor is 200 ~ 350 DEG C.
Smoke inlet place, the angle of flow of flue gas direction and vertical direction is 45 °-65 °.
After pre-oxidation, NO and NO in flue gas
2mol ratio be (0.8-1.2): 1.
NH
3in straying quatity and flue gas, the mol ratio of NOx is (0.9-1.05): 1.
Described catalytic reduction layer 7 bottom is provided with preparation catalytic reduction layer 8, and the flue gas reacted through catalytic reduction layer 7 passes through preparation catalytic reduction layer 8, further the NOx of remnants is reduced into N
2.
In reactor, the air speed size of flue gas is 20000 ~ 40000h
-1; Inside reactor flue gas flow rate is even, and the velocity of flue gas relative standard deviation of each layer catalyst surface is less than 6%.
Beneficial effect of the present invention is New-type boiler denitration reaction device designed by the present invention, by changing the position of spray ammonia system, introduce quick SCR reaction process, the catalyst layer of two kinds of difference in functionalitys is set at inside reactor, make flue gas in reactor after initial oxidation the process of catalytic reduction, make denitration key reaction by 4NH
3+ 4NO+O
2→ 4N
2+ 6H
2o changes NO+NO into
2+ 2NH
3→ 2N
2+ 4H
2o, substantially increases the denitration efficiency of flue gas low-temperature section, can reach more than 98% in the efficiency of about 200 DEG C denitrations.
Accompanying drawing explanation
Fig. 1 is a kind of schematic diagram of the low-temperature denitration reactor based on SCR reaction;
Label declaration: 1-boiler back end ductwork, 2-entrance guiding plate, 3-catalytic oxidation layer, 4-ammonia store and export deflector, 10-reactor outlet flue with spraying system, 5-nozzle, 6-static mixer, 7-catalytic reduction layer, 8-preparation catalytic reduction layer, 9-.
Detailed description of the invention
Below in conjunction with the drawings and specific embodiments, the present invention will be further described.It is emphasized that following explanation is only exemplary, instead of in order to limit the scope of the invention and apply.
A kind of low-temperature denitration reactor based on SCR reaction as shown in Figure 1, reactor head to be inclination angle the be inclined plane of 30 ° ~ 40 °, smoke inlet is located at the top of reactor, and smoke inlet place is evenly distributed with entrance guiding plate 2, and the knuckle of entrance guiding plate 2 is 130 ° ~ 150 °; Exhanst gas outlet is located at the bottom of reactor, and 4 vertical baffle 9 of smoke outlet distribution can improve the distributed effect of flue gas, eliminate the dust deposit in actual moving process.Inside reactor is followed successively by catalytic oxidation layer 3 from top to bottom, nozzle 5, static mixer 6, catalytic reduction layer 7 and preparation catalytic reduction layer 8, described nozzle 5 stores with ammonia and is connected with spraying system 4, and wherein ammonia stores and selects eddy current static mixing type to spray grid with spraying system 4; Reactor outer cladding insulation material, thus the loss reducing whole denitrification process heat, be conducive to maintaining reaction temperature.Described catalytic oxidation layer 3, catalytic reduction layer 7 and preparation catalytic reduction layer 8 all select conventional scr denitrating catalyst, comprise vanadium titanium system's denitrating catalyst or transition metal modified molecular sieve denitrating catalyst.
Above-mentioned a kind of low-temperature denitration reactor based on SCR reaction carries out the method for denitrating flue gas:
O in simulated flue gas
2volume fraction is 3%, NO concentration 2000ppm, and Balance Air is N
2, its air speed is 25000h
-1, flue gas flow 8L/min, space velocity size is 20000 ~ 40000h
-1, inside reactor flue gas flow rate is even, and the velocity of flue gas relative standard deviation of each layer catalyst surface is less than 6%.Catalytic oxidation layer 3, catalytic reduction layer 7 and preparation catalytic reduction layer 8 all select Mn-Ce-ZSM-5 composite molecular sieve catalyst.The time of contact controlling flue gas and catalyst layer is about 200ms, is conducive to the diffusion of reacting gas in catalyst micropore, absorption, the desorb of reaction and product gas and diffusion.
The smoke inlet of reactor is connected directly between on Rear of Utility Boiler flue 1, flue gas flow to low-temperature denitration reactor by boiler back end ductwork 1, the flow of flue gas direction at reactor smoke inlet place and the angle of vertical direction are 45 °-65 °, flue gas enters reactor after entrance guiding plate 2 water conservancy diversion, flue gas first through catalytic oxidation layer 3 pre-oxidation, makes part NO be converted into NO in reactor
2, when reaction temperature is increased to 200 DEG C, find through flue gas analyzer test, in flue gas, NO is oxidized to NO
2efficiency be approximately 50%.NH
3/ N
2the nozzle 5 of gaseous mixture through spraying grid sprays in reactor, NH
3in straying quatity and flue gas, the mol ratio of NOx is (0.9-1.05): 1, in the flue of certain length with the flue gas after catalytic oxidation through static mixer 6 is full and uniform mix after, quick SCR reaction is there is, more than 10 times of quick SCR reaction rate accurate SCR reaction rate up to standard on the reducing catalyst surface of catalytic reduction layer 7; During reaction temperature 200 DEG C, the conversion ratio of NOx gas is up to more than 98%, and the denitration efficiency under flue gas low-temperature condition obtains great lifting.The NOx of remnants, before SCR reactor outlet is discharged, by preparation catalytic reduction layer 8, is reduced into N by flue gas further
2, the conversion ratio of NOx gas brings up to more than 99%.After denitration completes, flue gas discharges the outlet section of SCR reactor through vertical baffle 9 water conservancy diversion, and the whole flue gas low-temperature denitration reaction reacted based on quick SCR completes.
SCR low-temperature denitration reactor can be applicable to station boiler well fast above, and can directly transform and come into operation on the basis of existing power station SCR denitration device, improvement cost be low, and operating cost is low, and substantially increases the denitration efficiency of flue gas in low-temperature zone.
Claims (10)
1. the low-temperature denitration reactor based on SCR reaction, it is characterized in that, smoke inlet is located at the top of reactor, exhanst gas outlet is located at the bottom of reactor, reactor head to be inclination angle the be inclined plane of 30 ° ~ 40 °, its inside is followed successively by catalytic oxidation layer (3) from top to bottom, nozzle (5), static mixer (6) and catalytic reduction layer (7), described nozzle (5) and ammonia store and are connected with spraying system (4); Catalytic oxidation layer (3) and catalytic reduction layer (7) select vanadium titanium system's denitrating catalyst or transition metal modified molecular sieve denitrating catalyst.
2. according to claim 1 a kind of based on SCR reaction low-temperature denitration reactor, it is characterized in that, smoke inlet place is provided with entrance guiding plate (2), and the knuckle of described entrance guiding plate (2) is 130 ° ~ 150 °; Smoke outlet is provided with outlet deflector (9), and described outlet deflector (9) is vertical baffle.
3. a kind of low-temperature denitration reactor based on SCR reaction according to claim 1, it is characterized in that, described ammonia stores selects eddy current static mixing type to spray grid with spraying system (4).
4. according to claim 1 a kind of based on SCR reaction low-temperature denitration reactor, it is characterized in that, described catalytic reduction layer (7) bottom is provided with preparation catalytic reduction layer (8), and vanadium titanium system's denitrating catalyst or transition metal modified molecular sieve denitrating catalyst are selected in preparation catalytic reduction layer (8).
5. described in the arbitrary claim of claim 1-4, a kind of low-temperature denitration reactor based on SCR reaction carries out the method for denitrating flue gas, it is characterized in that, the smoke inlet of reactor is connected directly between on Rear of Utility Boiler flue (1), flue gas enters reactor after being flowed out by boiler back end ductwork (1), first through catalytic oxidation layer (3) pre-oxidation in reactor, part NO is made to be converted into NO
2, the NH that the flue gas of pre-oxidation and nozzle (5) spray into
3mixing, and after static mixer (6) mixes, carry out SCR reaction at catalytic reduction layer (7); Temperature in reactor is 200 ~ 350 DEG C.
6. the method for a kind of denitrating flue gas according to claim 5, it is characterized in that, smoke inlet place, the angle of flow of flue gas direction and vertical direction is 45 °-65 °.
7. the method for a kind of denitrating flue gas according to claim 5, is characterized in that, after pre-oxidation, and NO and NO in flue gas
2mol ratio be (0.8-1.2): 1.
8. the method for a kind of denitrating flue gas according to claim 5, is characterized in that, NH
3in straying quatity and flue gas, the mol ratio of NOx is (0.9-1.05): 1.
9. the method for a kind of denitrating flue gas according to claim 5, it is characterized in that, described catalytic reduction layer (7) bottom is provided with preparation catalytic reduction layer (8), the flue gas reacted through catalytic reduction layer (7) passes through preparation catalytic reduction layer (8), further the NOx of remnants is reduced into N
2.
10. the method for a kind of denitrating flue gas according to claim 5, it is characterized in that, in reactor, the air speed size of flue gas is 20000 ~ 40000h
-1; Inside reactor flue gas flow rate is even, and the velocity of flue gas relative standard deviation of each layer catalyst surface is less than 6%.
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|---|---|---|---|
| CN201610077100.3A CN105521709B (en) | 2016-02-03 | 2016-02-03 | A kind of low-temperature denitration reactor and method based on SCR reactions |
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|---|---|---|---|
| CN201610077100.3A CN105521709B (en) | 2016-02-03 | 2016-02-03 | A kind of low-temperature denitration reactor and method based on SCR reactions |
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| CN105521709B CN105521709B (en) | 2018-01-23 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107051203A (en) * | 2017-06-21 | 2017-08-18 | 重庆大学 | A kind of middle low temperature sulfur-containing smoke gas efficient denitrifying device and method based on Fast SCR reactions |
| CN107930387A (en) * | 2017-12-01 | 2018-04-20 | 江苏新中金环保科技股份有限公司 | A kind of coke oven flue gas integration desulfurization denitration system |
| CN107983146A (en) * | 2017-12-01 | 2018-05-04 | 江苏新中金环保科技股份有限公司 | A kind of coke oven flue gas desulfurization and denitrification integral process |
| CN108404653A (en) * | 2018-03-30 | 2018-08-17 | 西安热工研究院有限公司 | A kind of flue gas SCR denitration puies forward effect system and method |
| TWI673101B (en) * | 2017-09-15 | 2019-10-01 | 日商三菱日立電力系統股份有限公司 | Denitration device for coal-fired boiler |
| CN113750783A (en) * | 2021-08-24 | 2021-12-07 | 福建华电可门发电有限公司 | Method of two-section type SCR reaction device suitable for wide-temperature-zone denitration |
| CN114570195A (en) * | 2022-03-14 | 2022-06-03 | 大唐环境产业集团股份有限公司 | SCR reactor, catalyst and preparation method thereof |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107051203A (en) * | 2017-06-21 | 2017-08-18 | 重庆大学 | A kind of middle low temperature sulfur-containing smoke gas efficient denitrifying device and method based on Fast SCR reactions |
| TWI673101B (en) * | 2017-09-15 | 2019-10-01 | 日商三菱日立電力系統股份有限公司 | Denitration device for coal-fired boiler |
| CN107930387A (en) * | 2017-12-01 | 2018-04-20 | 江苏新中金环保科技股份有限公司 | A kind of coke oven flue gas integration desulfurization denitration system |
| CN107983146A (en) * | 2017-12-01 | 2018-05-04 | 江苏新中金环保科技股份有限公司 | A kind of coke oven flue gas desulfurization and denitrification integral process |
| CN107983146B (en) * | 2017-12-01 | 2021-04-20 | 江苏新中金环保科技股份有限公司 | Coke oven flue gas desulfurization and denitrification integrated process |
| CN108404653A (en) * | 2018-03-30 | 2018-08-17 | 西安热工研究院有限公司 | A kind of flue gas SCR denitration puies forward effect system and method |
| CN113750783A (en) * | 2021-08-24 | 2021-12-07 | 福建华电可门发电有限公司 | Method of two-section type SCR reaction device suitable for wide-temperature-zone denitration |
| CN114570195A (en) * | 2022-03-14 | 2022-06-03 | 大唐环境产业集团股份有限公司 | SCR reactor, catalyst and preparation method thereof |
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| CN105521709B (en) | 2018-01-23 |
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Inventor after: Wang Tao Inventor after: Wan Zhentian Inventor after: Yang Xiaochu Inventor after: Xiao Haiping Inventor after: Sun Baomin Inventor after: Dai Yukun Inventor before: Wan Zhentian Inventor before: Yang Xiaochu Inventor before: Wang Tao Inventor before: Xiao Haiping Inventor before: Sun Baomin Inventor before: Dai Yukun |
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