CN100540116C - Method for reducing flue gas acidity in furnace - Google Patents
Method for reducing flue gas acidity in furnace Download PDFInfo
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- CN100540116C CN100540116C CNB2005800113259A CN200580011325A CN100540116C CN 100540116 C CN100540116 C CN 100540116C CN B2005800113259 A CNB2005800113259 A CN B2005800113259A CN 200580011325 A CN200580011325 A CN 200580011325A CN 100540116 C CN100540116 C CN 100540116C
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- flue gas
- classification
- fuel
- microcosmic
- combustion
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- 239000003546 flue gas Substances 0.000 title claims abstract description 86
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 85
- 238000000034 method Methods 0.000 title claims abstract description 67
- 239000002253 acid Substances 0.000 claims abstract description 70
- 239000000446 fuel Substances 0.000 claims abstract description 53
- 238000002485 combustion reaction Methods 0.000 claims abstract description 48
- 238000007254 oxidation reaction Methods 0.000 claims description 17
- 239000003245 coal Substances 0.000 claims description 16
- 230000003647 oxidation Effects 0.000 claims description 15
- 238000005259 measurement Methods 0.000 claims description 4
- 150000007513 acids Chemical class 0.000 abstract 1
- 239000000543 intermediate Substances 0.000 abstract 1
- 230000001590 oxidative effect Effects 0.000 abstract 1
- 238000006722 reduction reaction Methods 0.000 description 25
- 230000009467 reduction Effects 0.000 description 22
- 238000006243 chemical reaction Methods 0.000 description 10
- 229910052760 oxygen Inorganic materials 0.000 description 10
- 238000002156 mixing Methods 0.000 description 9
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 7
- 239000003054 catalyst Substances 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 238000003916 acid precipitation Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 239000012717 electrostatic precipitator Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000005864 Sulphur Substances 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 125000004430 oxygen atom Chemical group O* 0.000 description 2
- 239000013618 particulate matter Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000036632 reaction speed Effects 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
- 101100494265 Caenorhabditis elegans best-15 gene Proteins 0.000 description 1
- 208000035126 Facies Diseases 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 230000036651 mood Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 230000001932 seasonal effect Effects 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Abstract
A method for reducing acidity and lowering the acid dew point of flue gas, the method steps comprising: partially combusting the fuel in a first stage to create a reducing environment; maintaining the reducing environment for a sufficient period of time to reduce reducible acids to a desired acid concentration in the flue gas; and combusting the remainder of the fuel and combustion intermediates in a second stage with an oxidizing environment; thereby reducing the acidity and lowering the acid dew point of the flue gas by reducing the acid concentration of the flue gas.
Description
Technical field
The present invention relates to a kind of method that is used to reduce from the byproduct emission of combustion reaction in general, and more specifically relates to a kind of method that lowers burning inner flue gas of the stove acidity.
Background technology
Acidity reduces
People think that always the flue gas in power plant is a kind of source of atmospheric pollution for a long time.In the burning of fossil fuel, the oxidized formation of some naturally occurring element (for example) SO
3, NOx, HCl, HF and like that.(the SO especially if these acid
3) concentration surpassed some critical value then it may have problems.For example, work as SO
3When concentration raise, the acid dew-point temperature of flue gas can raise.If the temperature of flue gas is lower than the acid dew-point temperature of flue gas, the then SO in the gas
3Form H with condensing and reacting with water
2SO
4, cause stove internal corrosion problem.And, from the flue gas that burner hearth leaves can cool off rapidly and described gas in SO
3And other sour condensing, (it is SO to form local acid rain
3And other sour coagulation and landing thing) fall on every side on the ground, have subsequent corrosion.Too much SO
3Can condense into droplet, and form visible plume when leaving burner hearth, this can cause aesthetic problem and local political issue.If have the NH of being similar in the described flue gas
3Compound, then these compounds may with SO
3React and form ammonium hydrogen sulfate (NH
3HSO
4), it subsequently can the contaminated air heater.
Therefore, there are following needs: reduce the flue gas acid dew point temperature so that acid dew-point temperature is lower than the flue-gas temperature in the coldest part of burner hearth (for example carrier pipe and chimney).Also there are another needs: reduce the acid content of flue gas so that minimize local acid rain and the other problem relevant with the peracidity flue gas.
SO
3
Increase
The particulate matter that is loaded with in the flue gas can be removed by electrostatic precipitator, electrostatic precipitator can make described individual particle accept an electric charge and utilize this electric charge that they are attracted to collecting board subsequently and implement the cleaning.The efficient of these electrostatic precipitator depends on that described individual particle obtains the ability of electric charge, that is, and and the resistivity of described particle.Have been found that and have SO in the flue gas
3Can effectively reduce the resistivity of described particle, it is charged that it is easier to electrostatic means.
In coal combustion, some naturally occurring sulphur is converted into SO
3On the other hand, SO
3The validity that reduces described particulate matter resistivity depends on SO
3Concentration, wherein about 15 to 2,000 ten thousand umbers (ppm) can obtain optimum.Therefore, dust collector efficiency is regulated SO in the flue gas
3The quantity sulfur content of institute's coal combustion (no matter how) is Zong so that SO
3Concentration is in the influence of the ability in the optimum range.
SO
3Also be in SCR (catalyst) device, to pass through SO
2Oxidation produce, and surpass the optium concentration of best 15 to 20 ppm through regular meeting.In SCR, be generally used for NOx is reduced to N
2The catalyst admixture of (in the presence of ammonia) also can be with SO
2Be oxidized to SO
3The speed of this reaction has strong temperature dependency, and under higher temperature, can be with 1% SO
2Change into SO
3High sulfur-bearing U.S. coal any position in boiler all can produce from 2,000 to 3 the SO of 000ppm
2, and therefore can produce 20 to 30ppm SO in the SCR outside
3The SO that problem is, similar 50% (or 10 to 15ppm) comes out from described SCR
3Can discharge chimney by cleaner.About 8 to 10ppm the time (depending on granule density), SO
3Become a visible blue plume.
And, SO
3Can also catalytic way in other boiler surfaces via interacting with element/chemicals (for example vanadium) and producing.
Therefore, because all SO that before SCR, form
3Can be added into the SO of discharge
3In, so reduce the SO that before SCR, forms
3For reducing the SO that discharges
3Be important and allow and use SCR to reduce the NOx of gas and can not produce excessive SO
3
SO
3
Control
If SO
3Concentration is too low, and then deduster will be to be lower than best efficient work.On the other hand, if SO
3Concentration is too high, and then flue gas can become peracidity, produces " blue smoke " and promotes to form acid rain.In addition, acidic flue gas can promote the corrosion to the transmission flue, and works as and NH
3The type chemicals in conjunction with the time can block air heater.
And SCR common every year, only desire was used six months (in summer ozone control season), then had been left in the basket in winter.This situation in deduster, in pipeline, and can cause SO in exhaust chimney outside
3The seasonal variations of concentration.
Therefore people expect whether dependence uses SCR to control SO in the flue gas
3Concentration.SO near 40ppm
3Concentration can cause the sour problem in serious disadvantageous part, though not necessarily adjusted, can cause the local political issue of facility.U.S.EPA points out that expectation is in the future to SO
3Discharging manage.
Therefore, people expectation has and a kind ofly can regulate SO in the flue gas under the situation of using or do not use SCR
3The SO of concentration
3Flue gas system is with SO
3Thereby concentration maintains optimum level reaches high ESP usefulness, and does not increase local SO
3Discharging.
Classification
The burning classification is with two or the process of more a plurality of stage calcinating fuel (being coal).The rich fuel stage (or briefly, enrichment stage) is available air inadequate stage for the described fuel of completing combustion wherein.The poor fuel stage is one wherein to have for the described fuel of completing combustion fully or stage of excess air.Classification is used to pass through a) to reduce peak temperature (heating power type NOx) in the prior art and b) provides a reducing environment to come reducing NOx (NOx reduction).Macroscopical classification is that each section of burner hearth is divided into the enrichment stage with the poor stage and by using these for example after-flame wind technology such as (OFA) realizations.The microcosmic classification promptly produces and has the different functionalities feature the nearly micro of (for example reduction potential, temperature, and like that).For example, the microcosmic classification in the burner hearth can be in the phase I of described burner hearth by using low-NOx combustor and regulating the rotary blade setting value and air register is reached.The classification that increases can be increased in the time of staying in the reducing atmosphere and can strengthen the effect of described reducing atmosphere.
Prior art has adopted the microcosmic classification to reduce the discharging of NOx in the combustion furnace.Low-NOx combustor (LNB) is delivered in the burner hearth by a wind with high fuel content and mixes to come classification with the secondary wind facies that flows through one or more secondary air register.LNB mainly uses the microcosmic classification.Flow by a LNB is designed to make the volatile components of coal to mix with available near zone air with the stoichiometric proportion near (1.0).Near the clean burning in the central core of burner be generally enriched fuel and can not produce a large amount of hot NOx because temperature is very low.When increasing air was mixed in described central core lentamente, coal finally exhausted through furnace depth.Most of NOx of this region generating is NO from fuel-bound nitrogen and via intermediate HCN reaction.The speed that outside secondary wind is mixed in the core air-flow is set by the rotary blade in damper and rotary blade and the coal pipeline.Have a combustion product that enriches and the continuous mixing of secondary wind owing to spread all over the combustion zone, the LNB system reduces NOx by classification.Blending ratio increases between abundant core air-flow and the outside secondary general mood stream by reducing in classification.
Prior art has adopted macroscopical classification to reduce discharging in the combustion furnace.The macroscopic view classification is made up of the fuel and the air that highly mix in the low burner hearth, is mixed to one and is lower than one stoichiometric proportion for most of air-flow.Final still need excessive oxygen to guarantee that all fuel have burnt and reduce the danger of exploding.In the burner hearth of macroscopical classification, excess air is introduced the downstream of burner.The classification that increases is reached by the quality that increases the time of staying, temperature or reduce combustion product under the situation that lacks oxygen.
The NOx that prior art uses microcosmic classification (LNB) and macroscopical classification (OFA) dual mode to reduce in the combustion furnace discharges.Under microcosmic classification and both situations of macroscopical classification, use each above-mentioned combination and adjusted to reach the reduction of NOx emission.
Never teaching is crossed the SO that classification is used for the reduction of flue gas acidity, acid dew-point temperature control or burning gases in the prior art
3Concentration control.
Summary of the invention
The present invention relates to a kind of method that is used at combustion system and method reduction flue gas acidity.
The invention further relates to a kind of being used in combustion system and method attenuating flue gas acid dew point method of temperature.
Therefore one aspect of the present invention provides a kind of method that is used at combustion system and method reduction flue gas acidity, said method comprising the steps of:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) make described reducing environment keep a grace time section, thereby so that reducible acid reduction is reached the acid concentration of expectation in described flue gas;
C) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
Reduce the acidity of described flue gas thus by the acid concentration that reduces described flue gas.
Another aspect of the present invention provides a kind of being used for and lowers the flue gas acid dew point method of temperature in combustion system and method with classification.
Another aspect of the present invention provides a kind of reduction flue gas acid dew point method of temperature, said method comprising the steps of:
A) in a phase I the described fuel of partial combustion to produce a reducing environment;
B) in a second stage, use oxidation environment combustion fuel residue and burning intermediate;
C) acid dew point of measurement flue gas;
D) regulate that reducing environment keeps an adequate time section so that with the acid of flue gas
Further aspect of the present invention provides a combustion furnace that uses a method that reduces flue gas acidity to operate, and these method steps comprise:
A) in a phase I the described fuel of partial combustion to produce a reducing environment;
B) make described reducing environment keep a grace time section, thereby so that reducible acid reduction is reached the acid concentration of expectation in described flue gas;
C) in a second stage, use oxidation environment combustion fuel residue and burning intermediate;
Reduce the acidity of described flue gas thus by the acid concentration that reduces described flue gas.
Another aspect of the present invention provides a kind of method that reduces flue gas acidity, said method comprising the steps of:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) make described reducing environment keep a grace time section, thereby so that reducible acid is reduced to predeterminated level reaches expectation in described flue gas acid concentration;
C) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
Reduce the acidity of described flue gas thus by the acid concentration that reduces described flue gas.
Another aspect of the present invention provides a kind of method that reduces the acid dew-point temperature of flue gas, said method comprising the steps of:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) regulate that reducing environment keeps a grace time section so that make the acid dew point of described flue gas be reduced to aspiration level by reducing reducible acid;
C) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
Reduce the acid dew-point temperature of described flue gas thus by the acid concentration that lowers described flue gas.
One side more of the present invention provides a kind of method that reduces the acid dew-point temperature of flue gas, said method comprising the steps of:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
C) acid dew point of the described flue gas of measurement;
D) regulate reducing environment and keep a grace time section so that the acid dew point of described flue gas is reduced to aspiration level;
Reduce the acid dew-point temperature of described flue gas thus by the reducible acid concentration that lowers described flue gas.
Those skilled in the art are aspect hereinafter will understand that the present invention these and other after the description about preferred embodiment in conjunction with graphic reading in the industry.
The specific embodiment
In the explanation, identical conventional letter is all represented identical or corresponding part in some views hereinafter.Equally, in the explanation, should be appreciated that term " forward ", " backward ", " preceding ", " back ", " right side ", " left side ", " making progress ", " downwards " and like that hereinafter all for ease of describing used vocabulary and it should not being interpreted as restricted term.In the present invention, " reducible acid " refer to wherein and can reduce or eliminate acid acid by described acid being carried out electrochemical reduction.
The present invention relates to one uses the burning classification to reduce and control the method for acid dew-point temperature in stove.The invention further relates to one uses the burning classification at furnace reduction and control SO
3Method.The classification that increases is advantageously used in reducing simultaneously acidity, reduces acid dew-point temperature and reduces SO in the flue gas
3Level.
Reduce acidity, acid dew-point temperature and SO via the microcosmic classification
3
With in rich " reduction " environment, NOx is reverted back N
2Method similar, in reducing environment with SO
3Revert back SO
2For macroscopical classification, the burner hearth center that is lower than the OFA mouth is enriched with a large amount of fuel.The environment of this classification can be adjusted into even still less mix to produce the classification of reproducibility microcosmic in the phase I at described burner hearth.Thereby rotary blade speed setting value that can be by reducing wind and coal stream or reduce secondary wind rotary blade and air register in addition or otherwise and set value to reduce to mix and produce the reproducibility microcosmic stage; Can be in addition or otherwise change wind and coal stream and secondary be distinguished and admirable between relative muzzle velocity.
During the fuel-bound combustion of sulfur, though most of fuel-bound sulphur forms SO
2The time, but some directly form SO
3SO
2Can form more SO via following oxidation reaction
3
SO
2+O(+M)→SO
3(+M)
Yet this trisome reaction speed is very slow.In an oxidation environment, produce SO
3Another source be by the reaction:
SO
2+O
2→SO
3+O。
This reaction does not need three main bodys to collide simultaneously; Yet it is very responsive to temperature, need high temperature, and it is easy to take place back reaction:
SO
3+O→SO
2+O
2。
In a reducing environment, owing to lack O and O
2Material, above-mentioned three kinds of reactions are neither to be taken place with any remarkable quantity.In a reducing environment, SO
3To SO
2Directly transform by following general " reduction " reaction and take place:
SO
3+R→SO
2+RO，
Wherein R is any reduction group class.In fossil-fuel-fired, main group is the H group.
SO
3+H→SO
2+OH
In a reducing environment, many groups and molecule can be functional; For example H, OH, C, CO, CH, CH
2C
2H, CH
3, C
nH
m, N, NHi, and many other groups and molecule.
When the reduction group of valid density (" R "), above-mentioned SO
3Reduction reaction speed is exceedingly fast.In stage, sufficient concentration mainly appears in the reducing environment at first (rich fuel) of described burner hearth.
In a rich fuel staging reducing environment, (for example OH, O, O because the oxidisability combustible substance
2, HO
2, H
2O
2, and other this type of material) concentration reduce greatly, so the oxidation chemistry process stops.In this environment, for all can utilize oxygen species, each material was that very tool is emulative.With the molecule that relatively exists than small concentration with oxygen atom by the aerobic material consumption that exists with high concentration; For example, the oxygen among the NO is by such as C, CO, H, and other material consumption of CH.Molecule with a plurality of oxygen atoms is especially dangerous; That is SO,
3To change into SO rapidly via any group around almost (the most remarkable be H atom) removal oxygen
2
Therefore, in a reducing environment, when keeping described reducing environment, SO
3Reduction reaction is very fast and in fact irreversible.
Wonderful and importantly, for the inventive method and system, the SO of net effect in the phase I, during burning, forming
3Be reduced to SO rapidly
2, and by being oxidized to SO
2And can not regenerate SO
3, because in burner hearth, do not have the sufficient time of staying in the stage under the sufficiently high temperature at poor fuel afterwards.Therefore, the present invention can utilize reaction rate difference to reduce easily and keep SO in the flue gas
3Level.
The reduction potential that the classification that increases can be increased in the time of staying in the reducing atmosphere or increase described atmosphere is to reduce SO
3Concentration also reduces dew-point temperature thus.Therefore, for promoting SO
3Reduction, can increase the time of staying maybe can increase reduction potential in the flue gas.
For increasing the time of staying, can utilize several different methods.
1) can prolong distance between between the stage
2) can increase mixing for macroscopical hierarchical application
3) can reduce mixing for the microcosmic hierarchical application
4) can reduce mass flow (deep layer classification)
5) can increase volume utilization (for example vortex) between the stage
6) can increase pressure
7) can increase density
For increasing the reduction potential in the flue gas, can utilize several different methods.
1) can increase temperature
2) can reduce stoichiometric proportion (that is the ratio of air and fuel).
3) can increase local burnup's stream (for fixing air stream)
4) can reduce local air stream (for fixing fuel stream)
Mixing in the stage also can influence reduction process.One has complete mix stages the best of stoichiometric proportion mixture, and this is because these reaction conditions can reach maximum temperature, still keeps described reducing environment simultaneously; That is, minimize such as oxide groups such as O groups.But, be unpractical owing to mix fully, therefore, in fact use one less than 1 stoichiometric proportion, it can make the appearance that has greater than the position of 1 stoichiometric proportion minimize.Yet, when mixing minimizing, need the longer time of staying and/or higher temperature reach total acidity, acid dew-point temperature and/or SO
3The similar attenuating of concentration.Yet the temperature of burning gases depends on the level of mixing on a certain degree, reduces its reduction if mix.Therefore, if the mixing of a given degree needs a temperature that raises, then must be by the alternate manner temperature that raises, for example air is carried out preheating, changes the heat transfer characteristic, and like that of burner hearth.Perhaps or in addition, can introduce (for example OFA sprays) and increase the time of staying in the described reducing environment by postponing poor stage air.
Note SO
3By in a catalyst to SO
2A catalyst carries out oxidation and forms, because can make SO
2By following reaction oxidation:
SO
2+
1/
2O
2→SO
3
Only depend on SO owing to described through catalytic reaction
2And O
2Concentration, SO in the catalyst
3Generation be not subjected to SO in the gas
3The restriction of concentration.Therefore, the whole SO that reduce by the present invention
3Can reduce outlet SO independently
3And be not subjected to SO in the catalyst
3The influence of generation and can not influence SO in the catalyst
3Generation.
Therefore, the invention provides just like following method: control also reduces flue gas acidity, flue gas SO especially
3Concentration influences the efficient of electrostatic precipitator to help (1), reaches more preferably, and (2) reduce SO in the flue gas
3And the concentration of other reducible acid to be to reduce flue gas acidity and acid dew point, reduces thus that air heater stops up, air channel burn into and be disposed to SO in the environment
3Emission (it may be the source of visible plume and local acid rain).
In a preferred embodiment of the present invention, adjust acidity and SO in the burner hearth
3Macroscopical classification of level is reached by using OFA.In another preferred embodiment, regulate acidity and SO in the burner hearth
3The microcosmic classification of level is reached by using low-NOx combustor.In another preferred embodiment, will be used to regulate acidity and SO in the burner hearth by being used in combination macroscopical classification and the microcosmic classification that OFA and low-NOx combustor reach
3Level.Use the burner hearth of SCR for being in operation, preferable acidity is regulated to reduce total flue gas acidity.For the burner hearth that does not use SCR or use bypass SCR, preferable to SO
3Regulate so that to the SO of ESP
3Level increases or helps sinking.For current ESP, the SO in waste gas between about 10 to about 15ppm (by volume)
3Level is suitable for best ESP efficient.
Dew-point temperature is to be used to estimate and/or to regulate the reducing environment variable with the acidity that obtains fully to lower and/or the SO of expectation
3The suitable parameter of level.In order to reach the SO of an expectation
3Level and work relative humidity can be measured dew point and corresponding adjusting reducing environment variable to reach the expectation dew point.Measure acidity and/or SO
3Other method of level can be used for identical purpose and does not deviate from scope of the present invention.
In a preferred embodiment of the present invention, a power plant is controlled so that a microcosmic stage or a macroscopic view stage reducing environment along degree of depth classification to be provided in low burner hearth.OFA in higher burner hearth can provide essential oxygen to reach acceptable level with the after-flame of guaranteeing remaining uncombusted fuel, burning intermediate and/or CO.In addition, available SCR comes reducing NOx.Therefore, one embodiment of the invention comprises that one has the combustion furnace of OFA and low-NOx combustor, and it is applied to sulfurous fuels to reduce dew-point temperature and to lower SO
3Concentration.In addition, can provide SCR to come reducing NOx.Described low-NOx combustor is preferably just like following grade: it can provide abundant mixing to reduce and SO so that sufficient acid dew-point temperature to be provided in the starting stage
3Concentration lowers, and therefore, (if needs) allows use SCR.Therefore, one embodiment of the invention comprises that one has the combustion furnace of high-grade low-NOx combustor, and it is used to lower flue gas acidity, reduces acid dew-point temperature and flue gas SO
3The purpose of concentration.This embodiment can further comprise SCR.
Abundant reducing environment of the present invention be can less than about 2 seconds, better less than about 0.5 second in SO
3Be reduced to SO
2Reducing environment.In the present invention, this reducing environment can be in the phase I flue-gas temperature more than or equal to 900Kelvin (1160), better greater than about 1255K (1800) even goodly realize during greater than about 1650K (2500).One reducing environment for wherein reduce the concentration ratio of group and oxide group greater than concentration ratio about 1, more specifically H group and O group greater than about 1 environment.Better reducing environment for wherein reduce the concentration ratio of group and oxide group greater than concentration ratio about 10, more specifically H group and O group greater than about 10 environment.
Therefore, a kind of method of operating burner of the present invention may further comprise the steps:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) make described reducing environment keep a grace time section, so that with SO
3Be reduced to SO
2And reach the SO of expectation
3Level;
C) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
Control SO in the flue gas thus
3Level.
Perhaps, in another embodiment of the present invention, a kind of reduction flue gas acid dew point method of temperature may further comprise the steps:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
C) acid dew point of measurement flue gas;
D) regulate described reducing environment and keep the time period of an abundance so that make described flue gas acid dew point be reduced to aspiration level;
Reduce the acid dew-point temperature of described flue gas thus by the reducible acid concentration that lowers described flue gas.
Example
The result that following Examples set can use the inventive method to reach.In 3 different power plants, use the inventive method reduction flue gas acidity and reduce acid dew point.Because SO
3Be the main acid in the coal stove emission, so to SO
3The indicant of acidity and dew point is measured and be used as to emission.Experimental data shown in the table 1 and 2 is by using high speed after-flame wind and being measured by third company.
Table 1. hierarchy depth in 2 different power plant to SO
3The influence of level.
The N/A-data can not obtain;
*-98.5% sulphur is converted into SO in the hypothesis coal
2And 1.5% sulphur is converted into SO in the coal
3The basis on estimate to obtain.
For the situation of " shallow " classification, the after-flame air port is nearly closed, but still comprises cool stream (about 10% total air).For the situation of " medium " classification, total air stream of similar 20% is formed in the after-flame air port.For the situation of " deeply " classification, total air stream of similar 30% is formed in the after-flame air port.Three groups of equipment is all corner firing equipment and the OFA system is positioned at the burner region top just.The influence (power plant 3, with table 1 different) of the classification of three kinds of levels of table 2. in a single power plant.
Therefore, described experimental data is showed use the inventive method adjusting SO
3Ability, SO
3For the main acid in the coal stove emission and be the indicant of flue gas acidity and acid dew point.
After reading above-mentioned explanation, those in the industry those skilled in the art also can carry out some modification or improvement.For simple and clear and be easy to read, this paper has left out all modifications and improvement, but these contents all suitably are covered by in the aforesaid right claimed range.
Claims (24)
1, a kind of method that reduces flue gas acidity said method comprising the steps of:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) make described reducing environment keep a grace time section, thereby so that reducible acid is reduced to predeterminated level reaches expectation in described flue gas acid concentration;
C) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
Reduce the acidity of described flue gas thus by the acid concentration that reduces described flue gas.
2, the method for claim 1, it further comprises the step of the described phase I fuel combustion of microcosmic classification.
3, method as claimed in claim 2, wherein said microcosmic classification provides by using low-NOx combustor.
4, the method for claim 1, it further comprises macroscopical classification step of described fuel combustion phase I.
5, method as claimed in claim 4, wherein said macroscopical classification provides by using after-flame wind.
6, the method for claim 1, it further comprises combining of microcosmic classification and macroscopical classification.
7, method as claimed in claim 6, wherein said microcosmic classification provides by low-NOx combustor and macroscopical classification provides by after-flame wind.
8, the method for claim 1, wherein said fuel are coal.
9, a kind of method that reduces the acid dew-point temperature of flue gas said method comprising the steps of:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) regulate that reducing environment keeps a grace time section so that make the acid dew point of described flue gas be reduced to aspiration level by reducing reducible acid;
C) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
Reduce the acid dew-point temperature of described flue gas thus by the acid concentration that lowers described flue gas.
10, method as claimed in claim 9, it further comprises the step of the described phase I fuel combustion of microcosmic classification.
11, method as claimed in claim 10, wherein said microcosmic classification provides by using low-NOx combustor.
12, method as claimed in claim 9, it further comprises macroscopical classification step of described fuel combustion phase I.
13, method as claimed in claim 12, wherein said macroscopical classification provides by using after-flame wind.
14, method as claimed in claim 9, it further comprises combining of microcosmic classification and macroscopical classification.
15, method as claimed in claim 14, wherein said microcosmic classification provides by low-NOx combustor and macroscopical classification provides by after-flame wind.
16, method as claimed in claim 9, wherein said fuel are coal.
17, a kind of method that reduces the acid dew-point temperature of flue gas said method comprising the steps of:
A) in the phase I the described fuel of partial combustion to produce reducing environment;
B) in second stage, use oxidation environment combustion fuel residue and burning intermediate;
C) acid dew point of the described flue gas of measurement;
D) regulate reducing environment and keep a grace time section so that the acid dew point of described flue gas is reduced to aspiration level;
Reduce the acid dew-point temperature of described flue gas thus by the reducible acid concentration that lowers described flue gas.
18, method as claimed in claim 17, it further comprises the step of the described phase I fuel combustion of microcosmic classification.
19, method as claimed in claim 18, wherein said microcosmic classification provides by using low-NOx combustor.
20, method as claimed in claim 17, it further comprises macroscopical classification step of described fuel combustion phase I.
21, method as claimed in claim 20, wherein said macroscopical classification provides by using after-flame wind.
22, method as claimed in claim 17, it further comprises combining of microcosmic classification and macroscopical classification.
23, method as claimed in claim 22, wherein said microcosmic classification provides by low-NOx combustor and macroscopical classification provides by after-flame wind.
24, method as claimed in claim 17, wherein said fuel are coal.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US54472404P | 2004-02-14 | 2004-02-14 | |
| US60/544,724 | 2004-02-14 | ||
| US10/797,513 | 2004-03-10 |
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| CN1942707A CN1942707A (en) | 2007-04-04 |
| CN100540116C true CN100540116C (en) | 2009-09-16 |
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| CNB2005800113259A Expired - Fee Related CN100540116C (en) | 2004-02-14 | 2005-02-14 | Method for reducing flue gas acidity in furnace |
| CNB2005800112222A Expired - Fee Related CN100560187C (en) | 2004-02-14 | 2005-02-14 | For in-furnace reduction of SO in catalytic systems3Method (2) |
| CNB2005800113244A Expired - Fee Related CN100540118C (en) | 2004-02-14 | 2005-02-14 | Process for in-furnace reduction and control of sulfur trioxide |
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| CNB2005800112222A Expired - Fee Related CN100560187C (en) | 2004-02-14 | 2005-02-14 | For in-furnace reduction of SO in catalytic systems3Method (2) |
| CNB2005800113244A Expired - Fee Related CN100540118C (en) | 2004-02-14 | 2005-02-14 | Process for in-furnace reduction and control of sulfur trioxide |
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| CN102878550B (en) * | 2012-10-12 | 2015-04-15 | 浙江大学 | Method for water-coal-slurry burning slag tapping cyclone furnace classification air distribution and low NOx reburning |
| CN109364723B (en) * | 2018-11-07 | 2021-05-11 | 江西理工大学 | Method for reducing sulfur trioxide in non-ferrous smelting flue gas into sulfur dioxide |
| CN111167274B (en) * | 2020-01-19 | 2021-11-12 | 中南大学 | Method for removing sulfur trioxide from smelting flue gas and removing device thereof |
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|---|---|---|---|---|
| US4381718A (en) * | 1980-11-17 | 1983-05-03 | Carver George P | Low emissions process and burner |
| US4504211A (en) * | 1982-08-02 | 1985-03-12 | Phillips Petroleum Company | Combination of fuels |
| US4824441A (en) * | 1987-11-30 | 1989-04-25 | Genesis Research Corporation | Method and composition for decreasing emissions of sulfur oxides and nitrogen oxides |
| US5105747A (en) * | 1990-02-28 | 1992-04-21 | Institute Of Gas Technology | Process and apparatus for reducing pollutant emissions in flue gases |
| CN1079039A (en) * | 1992-01-10 | 1993-12-01 | 巴布考克及威尔克斯公司 | In stove, spray into ammonia and lime and dry-clean to improve the rate of removing of sulphur and oxynitride simultaneously |
| US5585081A (en) * | 1988-07-25 | 1996-12-17 | The Babcock & Wilcox Company | SOx, NOx and particulate removal system |
| CN1185778A (en) * | 1995-03-16 | 1998-06-24 | 纳可环技公司 | Simplified efficient process for reducing NOx, SOx and particulates |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5525317A (en) * | 1994-11-04 | 1996-06-11 | The Babcock & Wilcox Company | Ammonia reagent application for NOX SOX and particulate emission control |
| US5853684A (en) * | 1995-11-14 | 1998-12-29 | The Hong Kong University Of Science & Technology | Catalytic removal of sulfur dioxide from flue gas |
-
2005
- 2005-02-14 CN CNB2005800113259A patent/CN100540116C/en not_active Expired - Fee Related
- 2005-02-14 CN CNB2005800112222A patent/CN100560187C/en not_active Expired - Fee Related
- 2005-02-14 CN CNB2005800113244A patent/CN100540118C/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4381718A (en) * | 1980-11-17 | 1983-05-03 | Carver George P | Low emissions process and burner |
| US4504211A (en) * | 1982-08-02 | 1985-03-12 | Phillips Petroleum Company | Combination of fuels |
| US4824441A (en) * | 1987-11-30 | 1989-04-25 | Genesis Research Corporation | Method and composition for decreasing emissions of sulfur oxides and nitrogen oxides |
| US5585081A (en) * | 1988-07-25 | 1996-12-17 | The Babcock & Wilcox Company | SOx, NOx and particulate removal system |
| US5105747A (en) * | 1990-02-28 | 1992-04-21 | Institute Of Gas Technology | Process and apparatus for reducing pollutant emissions in flue gases |
| CN1079039A (en) * | 1992-01-10 | 1993-12-01 | 巴布考克及威尔克斯公司 | In stove, spray into ammonia and lime and dry-clean to improve the rate of removing of sulphur and oxynitride simultaneously |
| CN1185778A (en) * | 1995-03-16 | 1998-06-24 | 纳可环技公司 | Simplified efficient process for reducing NOx, SOx and particulates |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100560187C (en) | 2009-11-18 |
| CN1942706A (en) | 2007-04-04 |
| CN1942233A (en) | 2007-04-04 |
| CN1942707A (en) | 2007-04-04 |
| CN100540118C (en) | 2009-09-16 |
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