CN107485988A - A kind of SCR denitration method - Google Patents
A kind of SCR denitration method Download PDFInfo
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- CN107485988A CN107485988A CN201710978973.6A CN201710978973A CN107485988A CN 107485988 A CN107485988 A CN 107485988A CN 201710978973 A CN201710978973 A CN 201710978973A CN 107485988 A CN107485988 A CN 107485988A
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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
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
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- 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
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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
- B01D53/77—Liquid phase processes
- B01D53/79—Injecting reactants
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D2251/404—Alkaline earth metal or magnesium compounds of calcium
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- B—PERFORMING OPERATIONS; TRANSPORTING
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Abstract
The invention belongs to denitration field, more particularly to a kind of SCR denitration method, method of denitration provided by the invention comprises the following steps：A), flue gas flows through boiler flue；Wherein, before corresponding to the section of afterbody superheater in flue, in and after be disposed with first, second, and third hydrogen peroxide solution spray site；The hydrogen peroxide solution injection situation of each hydrogen peroxide solution spray site of temperature control of each hydrogen peroxide solution spray site is flowed through according to flue gas；Flue gas obtains aoxidizing flue gas after spraying hydrogen peroxide solution；B), the scrubbed liquid washing of the oxidation flue gas, obtains denitration flue gas；H is added with the cleaning solution2O2, organic sulfoxide or sulphite.Method provided by the invention can keep higher denitration efficiency during ignition of the boiler and underrun.
Description
Technical field
The invention belongs to denitration field, more particularly to a kind of SCR denitration method.
Background technology
NOxIt is a kind of main Air Pollutants, it can cause photochemistry with hydrocarbon under strong light action
Pollution；The NO being discharged into airxIt is the main reason for forming acid rain, seriously endangers ecological environment.
The denitration mode that general thermal power plant uses at present is SCR (selective catalytic reduction) denitration, flue gas during igniting
NO when temperature does not reach SCR input conditionsxDischarge exceeded；After boiler possesses denitration input condition, ammonia is sprayed by increasing denitration
Amount, reduces overall NOxDischarge, ensure that denitration annual average is qualified.Coal-burning power plant is in underload, because SCR inlet cigarette temperature is less than
Proper catalyst operation temperature window and cause denitrating system not put into operation, minimum discharge requirement can not be met.Use SCR denitration
The fundamental prerequisite to put into operation is the minimum operating temperature that cigarette temperature will reach catalyst, even with low temperature catalyst, it is also desirable to
The process of one raising flue-gas temperature.Oxidizing process denitration due to that need not use catalyst, is aoxidized with strong oxidizer activation
NO, it is allowed to generate the NO of high-valence state2、N2O5Etc. water-soluble generation HNO2And HNO3, can be put into igniting and low load stage
Use.The technique for carrying out oxidation and denitration at present, generally plus after boiler induced-draft fan, before desulfurization entrance, hydrogen peroxide oxidation NOx's
Efficiency comparison is poor.Need to add other energy or activating agent carrys out stimulating activity molecule to improve oxygenation efficiency.Use ozone oxidation
Observable index is higher, and operating cost is bigger.Soluble NO at high pricexInto downstream wet desulphurization equipment, with water or alkali liquor absorption, this
When desulphurization plant should be noted that monitoring adjustment slurry pH value, ensure desulphurization plant normal operation.Common absorbing liquid has Ca (OH)2、
The alkali lye such as NaOH, removal effect caused by different absorbents have certain difference, absorbing liquid consumption in various degree be present
The problem of big, while part NO be present2The problem of being then reduced into NO, overall denitration efficiency is caused to decline about 1/3rd.
The content of the invention
In view of this, it is an object of the invention to provide a kind of SCR denitration method, this method is in ignition of the boiler and underload
There is higher denitration efficiency during operation.
The invention provides a kind of SCR denitration method, comprise the following steps：
A), flue gas flows through boiler flue；Wherein, in flue between afterbody superheater and upper level superheater
The first hydrogen peroxide solution spray site is provided with section, is corresponded in flue and second pair is provided with the section of afterbody superheater
Oxygen aqueous solution spray site, section of the flue between afterbody superheater and economizer is provided with the 3rd hydrogen peroxide solution
Spray site；
When the flue-gas temperature of the first hydrogen peroxide solution spray site is in preset temperature range, sprayed in the first hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the first hydrogen peroxide solution spray site is outside preset temperature range, the
One hydrogen peroxide solution spray site stops spray hydrogen peroxide solution；
When the flue-gas temperature of the second hydrogen peroxide solution spray site is in preset temperature range, sprayed in the second hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the second hydrogen peroxide solution spray site is outside preset temperature range, the
Two hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution；
When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is in preset temperature range, sprayed in the 3rd hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is less than preset temperature range, the
Three hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is higher than default temperature
When spending scope, all hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution；
Flue gas obtains aoxidizing flue gas after spraying hydrogen peroxide solution；
B), the scrubbed liquid washing of the oxidation flue gas, obtains denitration flue gas；H is added with the cleaning solution2O2, You Jiya
Sulfone or sulphite.
Preferably, the first hydrogen peroxide solution spray site, the second hydrogen peroxide solution spray site and the injection of the 3rd hydrogen peroxide solution
The preset temperature range of point is 400~500 DEG C.
Preferably, the second hydrogen peroxide solution spray site is arranged in the section that flue corresponds to afterbody superheater
Between position.
Preferably, along flow of flue gas direction, the first hydrogen peroxide solution spray site and afterbody superheater top
Distance is 2~5m, and the 3rd hydrogen peroxide solution spray site and the distance of afterbody superheater end are 1~12m.
Preferably, the afterbody superheater is located at below the reversal chamber of flue.
Preferably, H in the hydrogen peroxide solution2O2Concentration be 20~30wt%；Each hydrogen peroxide solution spray site
H2O2NO in flue gas when emitted dose flows through the spray site with flue gasxThe mol ratio of content is 2~3.
Preferably, the H2O2, the addition of organic sulfoxide or sulphite in cleaning solution be more than 0.1mol/L.
Preferably, the pH value of the cleaning solution is 3~6.
Preferably, the mode of the washing is spray；During washing the cleaning solution and the liquid-gas ratio of oxidation flue gas for 3~
8L/m3。
Compared with prior art, the invention provides a kind of SCR denitration method.Method provided by the invention includes following step
Suddenly：A), flue gas flows through boiler flue；Wherein, the section in flue between afterbody superheater and upper level superheater
The first hydrogen peroxide solution spray site is inside provided with, is corresponded in flue and the second hydrogen peroxide is provided with the section of afterbody superheater
Solution spray site, section of the flue between afterbody superheater and economizer is provided with the injection of the 3rd hydrogen peroxide solution
Point；When the flue-gas temperature of the first hydrogen peroxide solution spray site is in preset temperature range, in the first hydrogen peroxide solution spray site
Hydrogen peroxide solution is sprayed to flue gas；When the flue-gas temperature of the first hydrogen peroxide solution spray site is outside preset temperature range, first pair
Oxygen aqueous solution spray site stops spray hydrogen peroxide solution；When the flue-gas temperature of the second hydrogen peroxide solution spray site is in preset temperature range
When interior, hydrogen peroxide solution is sprayed to flue gas in the second hydrogen peroxide solution spray site；When the flue gas temperature of the second hydrogen peroxide solution spray site
When degree is outside preset temperature range, the second hydrogen peroxide solution spray site stops spray hydrogen peroxide solution；When the 3rd hydrogen peroxide solution sprays
When the flue-gas temperature of exit point is in preset temperature range, hydrogen peroxide solution is sprayed to flue gas in the 3rd hydrogen peroxide solution spray site；When
When the flue-gas temperature of 3rd hydrogen peroxide solution spray site is less than preset temperature range, it is double that the 3rd hydrogen peroxide solution spray site stops spray
The oxygen aqueous solution；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is higher than preset temperature range, all hydrogen peroxide solution sprays
Exit point stops spray hydrogen peroxide solution；Flue gas obtains aoxidizing flue gas after spraying hydrogen peroxide solution；B), the oxidation flue gas is scrubbed
Liquid washs, and obtains denitration flue gas；H is added with the cleaning solution2O2, organic sulfoxide or sulphite.The present invention is with temperature data
Based on, during boiler startup process or underrun, according to hydrogen peroxide solution in flue gas to the NO in flue gasxEnter
The optimum temperature section of row oxidation, subregion are controlled penetrating hydrogen peroxide solution, excited using fume high-temperature in hydrogen peroxide solution in real time
H2O2Produce OH and HO2Etc. strong oxidizing property group, make the NO in flue gasxRapid oxidation generates the soluble NO of high-valence statex；
Washed afterwards by cleaning solution, will the soluble NO of high pricexAbsorbed with cleaning solution, and by adding organic Asia in cleaning solution
Sulfone, sulphite or H2O2, suppress the soluble NO of high pricexNO is then reduced into, so that method provided by the invention keeps higher
Denitration efficiency.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
There is the required accompanying drawing used in technology description to be briefly described, it should be apparent that, drawings in the following description are only this
The embodiment of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can also basis
The accompanying drawing of offer obtains other accompanying drawings.
Fig. 1 is hydrogen peroxide solution spray site set location schematic diagram provided in an embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation describes, it is clear that described embodiment is only part of the embodiment of the present invention, rather than whole embodiments.It is based on
Embodiment in the present invention, those of ordinary skill in the art are obtained every other under the premise of creative work is not made
Embodiment, belong to the scope of protection of the invention.
The invention provides a kind of SCR denitration method, comprise the following steps：
A), flue gas flows through boiler flue；Wherein, in flue between afterbody superheater and upper level superheater
The first hydrogen peroxide solution spray site is provided with section, is corresponded in flue and second pair is provided with the section of afterbody superheater
Oxygen aqueous solution spray site, section of the flue between afterbody superheater and economizer is provided with the 3rd hydrogen peroxide solution
Spray site；
When the flue-gas temperature of the first hydrogen peroxide solution spray site is in preset temperature range, sprayed in the first hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the first hydrogen peroxide solution spray site is outside preset temperature range, the
One hydrogen peroxide solution spray site stops spray hydrogen peroxide solution；
When the flue-gas temperature of the second hydrogen peroxide solution spray site is in preset temperature range, sprayed in the second hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the second hydrogen peroxide solution spray site is outside preset temperature range, the
Two hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution；
When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is in preset temperature range, sprayed in the 3rd hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is less than preset temperature range, the
Three hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is higher than default temperature
When spending scope, all hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution；
Flue gas obtains aoxidizing flue gas after spraying hydrogen peroxide solution；
B), the scrubbed liquid washing of the oxidation flue gas, obtains denitration flue gas；H is added with the cleaning solution2O2, You Jiya
Sulfone or sulphite.
In the present invention, hydrogen peroxide solution spray site is set first on boiler flue.Wherein, the boiler flue is along cigarette
Flow of air direction is disposed with sectionalized superheater, and afterbody superheater downstream is additionally provided with economizer.There is provided in the present invention
One embodiment in, the boiler flue is provided with reversal chamber, and the afterbody superheater is located under the reversal chamber of flue
Side, that is, be arranged on vertical gas pass.In one embodiment provided by the invention, along flow of flue gas direction, afterbody overheat
Flue length corresponding to device section is 8~15m, concretely 10m, 11m, 12m, 13m or 14m.In the present invention, the first dioxygen
Aqueous solution spray site is located at flue and corresponded in the section between afterbody superheater and upper level superheater.There is provided in the present invention
One embodiment in, along flow of flue gas direction, the first hydrogen peroxide solution spray site and afterbody superheater top
Distance is 2~5m, concretely 2m, 2.5m, 3m, 3.5m, 4m, 4.5m or 5m.In the present invention, the second hydrogen peroxide solution sprays
Point is corresponded in the section of afterbody superheater positioned at flue.In one embodiment provided by the invention, second dioxygen
Aqueous solution spray site is arranged on the centre position that flue corresponds to the section of afterbody superheater.In the present invention, the 3rd dioxygen
Aqueous solution spray site is located at flue and corresponds to section between afterbody superheater and economizer.In a reality provided by the invention
Apply in example, along flow of flue gas direction, the distance of the 3rd hydrogen peroxide solution spray site and afterbody superheater end for 1~
12m, concretely 1m, 2m, 3m, 4m, 5m, 6m, 7m, 8m, 9m, 10m, 11m or 12m.In the present invention, each hydrogen peroxide solution
If spray site is provided with Heavenly Stems and Earthly Branches spray gun.In one embodiment provided by the invention, automatic telescopic is respectively provided with every spray gun
Device, can according to signal automatically into or exit working condition, also set up flow control valve on every group of spray gun, for adjust spray
The amount of penetrating.In the present invention, each hydrogen peroxide solution spray site is additionally provided with temperature measuring equipment, for monitoring flue-gas temperature.
In the present invention, flue gas is when flowing through above three hydrogen peroxide solution spray site, according to flue gas spray site temperature
Whether degree, regulation and control include to flue gas injection hydrogen peroxide solution, specific control strategy：
When the flue-gas temperature of the first hydrogen peroxide solution spray site is in preset temperature range, sprayed in the first hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the first hydrogen peroxide solution spray site is outside preset temperature range, the
One hydrogen peroxide solution spray site stops spray hydrogen peroxide solution.Wherein, the default temperature range is preferably 400~500 DEG C.
When the flue-gas temperature of the second hydrogen peroxide solution spray site is in preset temperature range, sprayed in the second hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the second hydrogen peroxide solution spray site is outside preset temperature range, the
Two hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution.Wherein, the default temperature range is preferably 400~500 DEG C.
When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is in preset temperature range, sprayed in the 3rd hydrogen peroxide solution
Exit point sprays hydrogen peroxide solution to flue gas；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is less than preset temperature range, the
Three hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is higher than default temperature
When spending scope, all hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution, and now flue-gas temperature is higher, fully meet SCR (choosings
Selecting property catalysis reduction) denitration temperature requirement, use SCR carry out denitration.Wherein, the default temperature range is preferably
400~500 DEG C.
In the present invention, flue gas is after spraying hydrogen peroxide solution, hydrogen peroxide solution cracking, and with the NO in flue gasxCarry out anti-
Should, obtain containing the soluble NO of high pricexOxidation flue gas.Wherein, hydrogen peroxide solution cracking reaction formula is H2O2→ 2OH, H2O2+OH→
HO2+H2NO in O, with flue gasxReacted, reaction equation NO+HO2→NO2+ OH, NO+H2O2→NO2+H2O, 2NO+3H2O2→
2HNO3+2H2O.In the present invention, to the NO in flow and flue gas of the flue gas in fluexConcentration is not particularly limited,
In one embodiment provided by the invention, flue gas flow is 50~300Nm3/ s, concretely 95.7Nm3/s、202.3Nm3/ s or
269.8Nm3/s.In one embodiment provided by the invention, NO in flue gasxConcentration is 200~500mg/Nm3, concretely
280Nm3、400Nm3Or 480Nm3.In the present invention, H in the hydrogen peroxide solution2O2Concentration be preferably 20~30wt%, tool
Body can be 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 27.5wt%,
28wt%, 29wt% or 30wt%；The H of each hydrogen peroxide solution spray site2O2Flue gas when emitted dose flows through the spray site with flue gas
Middle NOxThe mol ratio of content is preferably 2~3.In the present invention, the mol ratio of selection 2~3 can ensure NO in flue gasxOxygenation efficiency
More than 80%.
In the present invention, the injection situation of hydrogen peroxide solution is controlled by controller, power industry main flow import can be selected
PLC (programmable logic controller (PLC))；The controller obtains flue gas flow, NO by communication or hardwirexConcentration, temperature etc..
Wherein, most measuring points need to establish and are connected with power station DCS (dcs) both-way communication, and the connection is based on serial ports
MODUBUS or TCPMODBUS agreements.In some embodiments of the invention, single controller can complete the reduction of a unit
The subregion of agent spraying system controls in real time.In some embodiments of the invention, necessary automatic and hand is set inside DCS system
Dynamic switch logic, when communication or PLC failures, changeable is manual state of a control；And the primary control logic of the present invention is in PLC
Interior realization.
After flue gas is oxidized, containing the soluble NO of high pricexThe washing of oxidation flue gas scrubbed liquid, obtain denitration flue gas.Wherein,
H is added with the cleaning solution2O2, organic sulfoxide or sulphite；Organic sulfoxide preferably includes thionyl chloride, dimethyl
One or more in sulfoxide and diphenyl sulfoxide；The sulphite preferably includes sodium sulfite and/or potassium sulfite；It is described
H2O2, the addition of organic sulfoxide or sulphite in cleaning solution preferably >=0.06mol/L, more preferably 0.06~
0.12mol/L, most preferably 0.1mol/L.In the present invention, the pH value of the cleaning solution is preferably 3~6, concretely 3,
3.5th, 4,4.5,5,5.5 or 6.In the present invention, it is preferred to pass through Ca (OH)2Or the pH value of NaOH regulation and control cleaning solutions.In the present invention
In, the mode of the washing is preferably to spray, more preferably countercurrent spray.In the present invention, the cleaning solution and oxygen during washing
The liquid-gas ratio for changing flue gas is preferably 3~8L/m3, more preferably 5~6.5L/m3.In the present invention, flue gas is aoxidized in scrubbing tower
Washed, the tower temperature of scrubbing tower is preferably controlled in 40~55 DEG C；Aoxidize residence time of the flue gas in scrubbing tower be preferably 4~
8s, concretely 5.2s, 5.5s or 6s.
The present invention is water-soluble according to dioxygen during boiler startup process or underrun based on temperature data
Liquid is in flue gas to the NO in flue gasxThe optimum temperature section aoxidized, subregion control penetrating hydrogen peroxide solution in real time, utilize
Fume high-temperature excites the H in hydrogen peroxide solution2O2Produce OH and HO2Etc. strong oxidizing property group, make the NO in flue gasxRapidly
The soluble NOx of oxidation generation high-valence state；Washed afterwards by cleaning solution, will the soluble NO of high pricexAbsorbed with cleaning solution,
And by adding organic sulfoxide, sulphite or H in cleaning solution2O2, suppress the soluble NO of high pricexNO is then reduced into, so that
Method provided by the invention keeps higher denitration efficiency.
For the sake of becoming apparent from, it is described in detail below by following examples.
Embodiment 1
Mode shown in reference picture 1 sets hydrogen peroxide solution spray site, and Fig. 1 is hydrogen peroxide solution provided in an embodiment of the present invention
Spray site set location schematic diagram.In Fig. 1,1 is the first hydrogen peroxide solution spray site, and 2 be the second hydrogen peroxide solution spray site, 3
It is afterbody superheater for the 3rd hydrogen peroxide solution spray site, 4,5 be economizer, and 6 be reversal chamber, and 7 be that SCR denitration is reacted
Device.
In the present embodiment, afterbody superheater 4 is arranged on the lower section of boiler reversal chamber 6.Superheater flue is in vertical cigarette
The sectional dimension in flow of air direction is 10 × 20m, the first hydrogen peroxide solution spray site 2.5m before afterbody superheater top,
Second hydrogen peroxide solution spray site is among afterbody superheater, and the 3rd hydrogen peroxide solution spray site is in afterbody superheater
12m (2m behind superheater end) behind top.
Specific denitrification process：
Boiler is during lighting a fire with underrun, and the flue-gas temperature at the first hydrogen peroxide solution spray site 1 is to 400 DEG C
When, put into the first hydrogen peroxide solution spray site 1 at spray gun, spray hydrogen peroxide solution；At second hydrogen peroxide solution spray site 2
When flue-gas temperature is to 400 DEG C, the spray gun put at the second hydrogen peroxide solution spray site 2 sprays, and penetrates hydrogen peroxide solution；If first pair
When flue-gas temperature at oxygen aqueous solution spray site 1 is more than 500 DEG C, the spray gun that exits at the first hydrogen peroxide solution spray site 1, if
When flue-gas temperature at first hydrogen peroxide solution spray site 1 is not above 500 DEG C, continue to put into the first hydrogen peroxide solution spray site
Spray gun at 1；When flue-gas temperature at the 3rd hydrogen peroxide solution spray site 3 is to 400 DEG C, input the 3rd hydrogen peroxide solution injection
Spray gun at point 3, spray hydrogen peroxide solution；If the flue-gas temperature at the second hydrogen peroxide solution spray site 2 is more than 500 DEG C,
The spray gun exited at the second hydrogen peroxide solution spray site 2, if the flue-gas temperature at the second hydrogen peroxide solution spray site 2 is not super
When crossing 500 DEG C, continue the spray gun put at the second hydrogen peroxide solution spray site 2；Cigarette at the 3rd hydrogen peroxide solution spray site 3
When temperature degree is to 500 DEG C, all spray guns are exited, stop injection hydrogen peroxide solution, now steam generator system temperature is higher, completely
Meet the requirement that SCR is used, system carries out denitration using SCR.Exhaust gas volumn during oxidation and denitration is 269.8Nm3/ s, NOxConcentration
400mg/Nm3, H in hydrogen peroxide solution2O2Concentration be 27.5wt%, the hydrogen peroxide injection of each hydrogen peroxide solution spray site
Amount and flue gas when flowing through the spray site in flue gas the mol ratio of NOx content between 2~3.
Flue gas carries out cleaning solution washing after spray site spray hydrogen peroxide solution oxidation in countercurrent spray tower.Spray column tower
Footpath 13.7m, exhaust gas volumn 269.8Nm3/ s, for tower temperature between 40~55 DEG C, cleaning solution is calcium hydroxide slurry, and pH is controlled 3
Between~6, sodium sulfite is added in cleaning solution, addition about 0.1mol/L, flue gas is in dwell time in the tower about 6s, cleaning solution spray
Leaching amount about 1350L/s, denitration flue gas is obtained in spray column overhead gas outlet.To the NO of denitration flue gasxContent is monitored, as a result
For：NOxConcentration about 90mg/Nm3。
It can be seen that the method for denitration that the present embodiment provides can ensure that kind of boiler has preferably during lighting a fire with underrun
Denitration effect.
Embodiment 2
Mode shown in reference picture 1 sets hydrogen peroxide solution spray site, and in the present embodiment, afterbody superheater 4 is set
Below boiler reversal chamber 6.Sectional dimension of the superheater flue in vertical flow of flue gas direction is 5.8 × 12.6m, the first dioxygen
Aqueous solution spray site 2m before afterbody superheater top, the second hydrogen peroxide solution spray site is in afterbody superheater
Between, the 3rd hydrogen peroxide solution spray site 11m (1m behind superheater end) behind afterbody superheater top.
Specific denitrification process：
Boiler is during lighting a fire with underrun, and the flue-gas temperature at the first hydrogen peroxide solution spray site 1 is to 400 DEG C
When, put into the first hydrogen peroxide solution spray site 1 at spray gun, spray hydrogen peroxide solution；At second hydrogen peroxide solution spray site 2
When flue-gas temperature is to 400 DEG C, the spray gun put at the second hydrogen peroxide solution spray site 2 sprays, and penetrates hydrogen peroxide solution；If first pair
When flue-gas temperature at oxygen aqueous solution spray site 1 is more than 500 DEG C, the spray gun that exits at the first hydrogen peroxide solution spray site 1, if
When flue-gas temperature at first hydrogen peroxide solution spray site 1 is not above 500 DEG C, continue to put into the first hydrogen peroxide solution spray site
Spray gun at 1；When flue-gas temperature at the 3rd hydrogen peroxide solution spray site 3 is to 400 DEG C, input the 3rd hydrogen peroxide solution injection
Spray gun at point 3, spray hydrogen peroxide solution；If the flue-gas temperature at the second hydrogen peroxide solution spray site 2 is more than 500 DEG C,
The spray gun exited at the second hydrogen peroxide solution spray site 2, if the flue-gas temperature at the second hydrogen peroxide solution spray site 2 is not super
When crossing 500 DEG C, continue the spray gun put at the second hydrogen peroxide solution spray site 2；Cigarette at the 3rd hydrogen peroxide solution spray site 3
When temperature degree is to 500 DEG C, all spray guns are exited, stop injection hydrogen peroxide solution, now steam generator system temperature is higher, completely
Meet the requirement that SCR is used, system carries out denitration using SCR.Exhaust gas volumn during oxidation and denitration is 95.7Nm3/ s, NOxConcentration
280mg/Nm3, H in hydrogen peroxide solution2O2Concentration be 27.5wt%, the hydrogen peroxide injection of each hydrogen peroxide solution spray site
Amount and flue gas when flowing through the spray site in flue gas the mol ratio of NOx content between 2~3.
Flue gas carries out cleaning solution washing after spray site spray hydrogen peroxide solution oxidation in countercurrent spray tower.Spray column tower
Footpath 8.8m, exhaust gas volumn 95.7Nm3/ s, for tower temperature between 40~55 DEG C, cleaning solution is calcium hydroxide slurry, and pH is controlled 3~6
Between, sodium sulfite is added in cleaning solution, addition is about 0.1mol/L, and flue gas is in dwell time in the tower about 5.2s, cleaning solution
Spray flux about 620L/s, denitration flue gas is obtained in spray column overhead gas outlet.To the NO of denitration flue gasxContent is monitored, knot
Fruit is：NOxConcentration about 78mg/Nm3。
Embodiment 3
Mode shown in reference picture 1 sets hydrogen peroxide solution spray site, and in the present embodiment, afterbody superheater 4 is set
Below boiler reversal chamber 6.Sectional dimension of the superheater flue in vertical flow of flue gas direction is 10 × 14m, the first hydrogen peroxide
Solution spray site 3.5m before afterbody superheater top, the second hydrogen peroxide solution spray site is in afterbody superheater
Between, the 3rd hydrogen peroxide solution spray site 12m (1m behind superheater end) behind afterbody superheater top.
Specific denitrification process：
Boiler is during lighting a fire with underrun, and the flue-gas temperature at the first hydrogen peroxide solution spray site 1 is to 400 DEG C
When, put into the first hydrogen peroxide solution spray site 1 at spray gun, spray hydrogen peroxide solution；At second hydrogen peroxide solution spray site 2
When flue-gas temperature is to 400 DEG C, the spray gun put at the second hydrogen peroxide solution spray site 2 sprays, and penetrates hydrogen peroxide solution；If first pair
When flue-gas temperature at oxygen aqueous solution spray site 1 is more than 500 DEG C, the spray gun that exits at the first hydrogen peroxide solution spray site 1, if
When flue-gas temperature at first hydrogen peroxide solution spray site 1 is not above 500 DEG C, continue to put into the first hydrogen peroxide solution spray site
Spray gun at 1；When flue-gas temperature at the 3rd hydrogen peroxide solution spray site 3 is to 400 DEG C, input the 3rd hydrogen peroxide solution injection
Spray gun at point 3, spray hydrogen peroxide solution；If the flue-gas temperature at the second hydrogen peroxide solution spray site 2 is more than 500 DEG C,
The spray gun exited at the second hydrogen peroxide solution spray site 2, if the flue-gas temperature at the second hydrogen peroxide solution spray site 2 is not super
When crossing 500 DEG C, continue the spray gun put at the second hydrogen peroxide solution spray site 2；Cigarette at the 3rd hydrogen peroxide solution spray site 3
When temperature degree is to 500 DEG C, all spray guns are exited, stop injection hydrogen peroxide solution, now steam generator system temperature is higher, completely
Meet the requirement that SCR is used, system carries out denitration using SCR.Exhaust gas volumn during oxidation and denitration is 202.3Nm3/ s, NOxConcentration
480mg/Nm3, H in hydrogen peroxide solution2O2Concentration be 27.5wt%, the hydrogen peroxide injection of each hydrogen peroxide solution spray site
Amount and flue gas when flowing through the spray site in flue gas the mol ratio of NOx content between 2~3.
Flue gas carries out cleaning solution washing after spray site spray hydrogen peroxide solution oxidation in countercurrent spray tower.Spray column tower
Footpath 13m, exhaust gas volumn 202.3Nm3/ s, for tower temperature between 40~55 DEG C, cleaning solution is calcium hydroxide slurry, and pH is controlled 3~6
Between, sodium sulfite is added in cleaning solution, addition is about 0.1mol/L, and flue gas is in dwell time in the tower about 5.5s, cleaning solution
Spray flux about 1012L/s, denitration flue gas is obtained in spray column overhead gas outlet.To the NO of denitration flue gasxContent is monitored, knot
Fruit is：NOxConcentration about 88mg/Nm3。
Described above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, under the premise without departing from the principles of the invention, some improvements and modifications can also be made, these improvements and modifications also should
It is considered as protection scope of the present invention.
Claims (9)
1. a kind of SCR denitration method, comprises the following steps：
A), flue gas flows through boiler flue；Wherein, the section in flue between afterbody superheater and upper level superheater
The first hydrogen peroxide solution spray site is inside provided with, is corresponded in flue and the second hydrogen peroxide is provided with the section of afterbody superheater
Solution spray site, section of the flue between afterbody superheater and economizer is provided with the injection of the 3rd hydrogen peroxide solution
Point；
When the flue-gas temperature of the first hydrogen peroxide solution spray site is in preset temperature range, in the first hydrogen peroxide solution spray site
Hydrogen peroxide solution is sprayed to flue gas；When the flue-gas temperature of the first hydrogen peroxide solution spray site is outside preset temperature range, first pair
Oxygen aqueous solution spray site stops spray hydrogen peroxide solution；
When the flue-gas temperature of the second hydrogen peroxide solution spray site is in preset temperature range, in the second hydrogen peroxide solution spray site
Hydrogen peroxide solution is sprayed to flue gas；When the flue-gas temperature of the second hydrogen peroxide solution spray site is outside preset temperature range, second pair
Oxygen aqueous solution spray site stops spray hydrogen peroxide solution；
When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is in preset temperature range, in the 3rd hydrogen peroxide solution spray site
Hydrogen peroxide solution is sprayed to flue gas；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is less than preset temperature range, the 3rd pair
Oxygen aqueous solution spray site stops spray hydrogen peroxide solution；When the flue-gas temperature of the 3rd hydrogen peroxide solution spray site is higher than preset temperature model
When enclosing, all hydrogen peroxide solution spray sites stop spray hydrogen peroxide solution；
Flue gas obtains aoxidizing flue gas after spraying hydrogen peroxide solution；
B), the scrubbed liquid washing of the oxidation flue gas, obtains denitration flue gas；H is added with the cleaning solution2O2, organic sulfoxide or
Sulphite.
2. according to the method for claim 1, it is characterised in that the first hydrogen peroxide solution spray site, the second hydrogen peroxide solution
The preset temperature range of spray site and the 3rd hydrogen peroxide solution spray site is 400~500 DEG C.
3. according to the method for claim 1, it is characterised in that the second hydrogen peroxide solution spray site is arranged on flue pair
Answer the centre position of the section of afterbody superheater.
4. according to the method for claim 1, it is characterised in that along flow of flue gas direction, the first hydrogen peroxide solution spray
The distance at exit point and afterbody superheater top is 2~5m, and the 3rd hydrogen peroxide solution spray site overheats with afterbody
The distance of device end is 1~12m.
5. according to the method for claim 1, it is characterised in that the afterbody superheater is located under the reversal chamber of flue
Side.
6. according to the method for claim 1, it is characterised in that H in the hydrogen peroxide solution2O2Concentration for 20~
30wt%；The H of each hydrogen peroxide solution spray site2O2NO in flue gas when emitted dose flows through the spray site with flue gasxMole of content
Than for 2~3.
7. according to the method for claim 1, it is characterised in that the H2O2, organic sulfoxide or sulphite be in cleaning solution
Addition >=0.06mol/L.
8. according to the method for claim 1, it is characterised in that the pH value of the cleaning solution is 3~6.
9. according to the method for claim 1, it is characterised in that the mode of the washing is spray；Washing during washing
The liquid-gas ratio of liquid and oxidation flue gas is 3~8L/m3。
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