CN104069723A - Combined method for desulfurization, denitration and decarburization of exhaust gas - Google Patents
Combined method for desulfurization, denitration and decarburization of exhaust gas Download PDFInfo
- Publication number
- CN104069723A CN104069723A CN201410340249.7A CN201410340249A CN104069723A CN 104069723 A CN104069723 A CN 104069723A CN 201410340249 A CN201410340249 A CN 201410340249A CN 104069723 A CN104069723 A CN 104069723A
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- naocl
- flue gas
- stage
- oxidation
- complex liquid
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- 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
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Abstract
The invention discloses a combined method for desulfurization, denitration and decarburization of exhaust gas. The method comprises the following steps: (1) oxidization: leading the exhausted gas into an NaOCl/NaOCl2 complex liquid for oxidization; (2) absorption: leading the oxidized gas into an ammonia solution, and then discharging the gas. According to the method, SO2, NOx and CO2 in the exhausted gas of combustion can be removed simultaneously; (NH4)2SO4 and NH4NO3 particles obtained after reaction can be used as nitrogenous fertilizers; CO2 can be produced into high-concentration gas for recovery and use; part of the ammonia solution can be used in a circulating manner. Therefore, air pollutants can be utilized as resources effectively.
Description
Technical field
The present invention relates to a kind for the treatment of technology of coal-fired flue-gas.
Background technology
China is one of country taking coal as main energy sources, and this general layout can not change in the future for a long period of time.The generated energy of China is only second to the U.S., and within 2010, national capacity of installed generator reaches 580GW left and right, and wherein thermoelectricity 380GW, accounts for 65.5%; Within 2020, national capacity of installed generator reaches 900GW left and right, and wherein thermoelectricity 580GW, accounts for 64.4%; 2030, national thermoelectricity installed capacity occupation rate will remain on 58% left and right, although coal electricity proportion will decline year by year to some extent, its leading position in electric power energy structure can not change.In the fuel of fired power generating unit, coal has accounted for more than 95%.Coal in China consumption in 2010 has exceeded 3,000,000,000 tons, and approximately 70% for generating.Therefore, the main coal-fired rich and influential family of China is power industry, has accounted for 45% of whole atmosphere pollution by the atmosphere pollution of its generation.According to statistics, 70% of national smoke discharge amount, 90% of SO2 emissions, 67% of nitrogen oxide, 70% left and right of carbon dioxide all comes from fire coal, is the primary pollution source that affects atmospheric environment.
Coal-fired flue-gas pollutant mainly comprises dust, SO
2, NO
x, CO
2, heavy metal etc., wherein dust, SO
2, NO
xthere is the removal methods of comparative maturity, CO
2the technology that removes also just in flourish process.At present, in coal-fired flue-gas, the pollution control of sulfur dioxide and nitrogen oxide is the topmost task in Air Pollution Control field.Existing multinomial desulfur technology enters commercial Application; But low NO
xcombustion technology can not meet NO
xdischarge standard, certainly will adopt gas denitrifying technology.But multiple pollutants are controlled one by one, can cause variety of issue.The common feature of these techniques is: a technology, by a set of special equipment, only removes a kind of pollutant., there is the problems such as once investment is large, and operating cost is high, and land occupation is many in this man-to-man administration way.Along with progressively raising and the discharge standard of environmental requirement are constantly promoted to a higher rank, except desulphurization and denitration, will further administer trace heavy metals in flue gas, PM
2.5and greenhouse gases CO
2improvement, gas pollution control chain is more and more longer, energy enterprise cannot bear more and more higher expenses of environmental protection.Therefore, exploitation simultaneously combined desulfurization and denitration decarburization new technology, new equipment has become emerging research direction both at home and abroad, realizes industrialization desulfurization and denitrification integral technology extremely urgent.
Summary of the invention
To the object of the invention is the defect existing in prior art in order solving, to provide the one can be effectively to SO in combustion product gases
2, NO
x, CO
2combine the method removing.
In order to achieve the above object, the invention provides a kind of method of flue gas combined desulfurization and denitration decarburization, this process method step is as follows: (1) oxidation stage: flue gas is passed into NaOCl/NaOCl
2in complex liquid, be oxidized;
(2) absorption stage: the flue gas after oxidation is passed in ammoniacal liquor, and all the other tail gas are discharged.
In order further to recycle resource, the inventive method also can be improved as follows:
(1) oxidation stage: flue gas is passed into NaOCl/NaOCl
2in complex liquid, be oxidized;
(2) absorption stage: the flue gas after oxidation is passed in ammoniacal liquor;
(3) the recycling stage: by the ammoniacal liquor heating absorbing after flue gas, obtain crystallization, carbon dioxide and ammonia; Described crystallization obtains (NH after dehydration
4)
2sO
4and NH
4nO
3particle; Described ammonia passes in water capable of circulation for step (2).
Wherein, NaOCl/NaOCl in step (1)
2the pH value of complex liquid is 5.5, adopts NaOCl and NaOCl
2mixed liquor, NaOCl concentration is 5mmol/L, NaOCl
2concentration is 3 mmol/L.The temperature of this oxidation stage is 60 DEG C, in spray column, carries out; NaOCl/NaOCl
2complex liquid sprays from spray column upper nozzle; Flue gas enters from spray column bottom; NaOCl/NaOCl
2the ratio that passes into of complex liquid and flue gas is 19L/m
3; The flow of flue gas is 0.5m
3/ h.In spray column, be provided with three layers, every layer four nozzle; Every layer of nozzle is square to be placed, one, each angle, and between the adjacent nozzle of diagonal, spacing is 0.1m; Spray column bottom is provided with sieve plate; On sieve plate, be uniformly distributed 69 pores.
In step (2), the concentration of ammoniacal liquor is 10%.This absorption stage adopts bubble absorption device, and absorption temperature is normal temperature, preferably 20 DEG C.
The present invention has the following advantages compared to existing technology: the present invention can remove the SO in combustion product gases simultaneously
2, NO
x, CO
2, and (the NH of reaction generation
4)
2sO
4and NH
4nO
3particle can be used as nitrogenous fertilizer, and carbon dioxide can be made into high concentrations of gas and recycles, and partial ammonia water can recycle, and has effectively realized the recycling of atmosphere pollution.
Brief description of the drawings
Fig. 1 is the flow chart of flue gas combined desulfurization and denitration decarbonization method of the present invention;
Fig. 2 is the structural representation of spray column in Fig. 1.
In figure, 1-spray column, 2-bubble absorption device, 3-reclaims reactor, and 4-is oxidized liquid pot compound, 5-ammonia water tank, 11-nozzle, 12-sieve plate.
Detailed description of the invention
Below in conjunction with accompanying drawing, the present invention is described in detail.
(1) oxidation stage
3 layers of nozzle of the interior layout of spray column 1, every layer is provided with four nozzles, be square setting, and the adjacent injector spacing of diagonal is 0.1m.Spray angle >60 °, can cover whole tower diameter cross section.In addition, spray column bottom is provided with sieve plate 12, and on sieve plate, 69 pores are uniformly distributed, and can further increase gas-liquid contact area.Flue gas is passed in spray column 1 by sieve plate 12 from spray column 1 bottom, and control flue gas flow is 0.5m
3/ h.In oxidation liquid pot compound 4, NaOCl/NaOCl is housed
2complex liquid, the NaOCl/NaOCl in oxidation liquid pot compound 4
2complex liquid passes in spray column 1, from nozzle 11 ejections on top, controls NaOCl/NaOCl
2the liquid-gas ratio of complex liquid and flue gas is 19L/m
3.Flue gas fully contacts with complex liquid, and oxidation reaction occurs:
(1) oxidation of sulphur:
sO
2hydrolysis
SO
2+H
2O=HSO
3 -+H
+
hSO
3 -oxidation
ClO
2 -?+?2HSO
3 -?=2SO
4 2-?+2H
+?+Cl
-
2ClO
2+5HSO
3 -?+H
2O?=5SO
4 2-?+7H
+?+2Cl
-
HClO+?HSO
3 -=?SO
4 2-?+2H
+?+Cl
-
Cl
2+HS
O 3 -?+H
2O=?SO
4 2-+3H
+?+2Cl
-
(2) oxidation of nitrogen
gas-phase reaction:
ClO
2+NO=NO
2+ClO
ClO+?NO=?NO
2+Cl
Cl+?Cl=Cl
2
NO
2+NO=N
2O
3
NO
2+NO
2=N
2O
4
liquid phase reactor:
The material existing in liquid phase has H
2o, ClO
2, Cl
2, ClO
-, ClO
2 -and ClO
3 -, Cl
-deng, when the product of above-mentioned gas-phase reaction diffuses into liquid phase, can there is following reaction:
2NO
2+H
2O=HNO
2+HNO
3
N
2O
4+H
2O=?HNO
2+HNO
3
N
2O
3+H
2O=2HNO
2
The ClO existing in liquid phase
2and Cl
2also can be oxidized NO, following reaction occurs:
ClO
2+NO=NO
2+ClO
ClO+?NO=?NO
2+Cl
HClO+2NO+H
2O=2NO
2 -?+3H
+?+Cl
-
ClO
2+?NO
2 -?=NO
3 -?+?ClO
ClO+?NO
2 -?=?NO
3 -?+?Cl
HClO+?NO
2 -?=?NO
3 -?+?Cl
-?+H
+
This stage adopts NaOCl and NaOCl
2mixed liquor, NaOCl/NaOCl
2the oxidisability of complex liquid will be apparently higher than their independent oxidability.NaOCl and NaOCl
2oxidisability can reduce along with the increase of absorption liquid pH, thereby reduced the oxidation absorption to sulfur dioxide.Nitric oxide is insoluble in water, there is no hydrolytic process in water, and the rising of absorption liquid pH is little on its solubility impact, and its absorption mainly depends on sodium chlorite and liquor natrii hypochloritis's oxidisability.Therefore, constant when other conditions, along with the rising of pH value, denitration efficiency obviously declines.So the lower flue gas removal effect of pH value is better, but consider that highly acid absorption liquid can cause strong corrosion to equipment, therefore oxidation reaction is chosen pH value in 5.5 left and right.And NaOCl
2proportion is larger, and the oxidisability of complex liquid is higher, but considers economy, and it is 5mmol/L that the present invention adopts NaOCl concentration, NaOCl
2concentration is 3 mmol/L.
Excess Temperature can make SO
2solubility reduce, say from mass transfer angle, high temperature is unfavorable for mass transfer.In the time that other parameters are all constant, reaction temperature is higher, and resistance to mass tranfer is larger, and desulfurization degree declines.Practical Project is in service, and the absorption liquid of spray column low temperature and the flue gas of high temperature carry out after heat exchange, and making slurry temperature is 40-70 DEG C.At smoke outlet, flue-gas temperature can be down to groove in the temperature of absorption liquid suitable.The above analysis, it is 60 DEG C that oxidation reaction is selected optimal reaction temperature.
(2) absorption stage
Ammoniacal liquor in ammonia water tank 5 passes in bubble absorption device 2, and the flue gas after oxidation stage enters bubble absorption device 2 by gas phase channel, carries out absorption reaction by ammoniacal liquor.
H
2SO
4+2NH
3=(NH
4)
2SO
4
HNO
3+NH
3=NH
4NO
3
CO
2+2NH
3+H
2O=(NH
4)
2CO
3
CO
2+NH
3+H
2O=NH
4HCO
3
In this absorption reaction, ammoniacal liquor is volatile, and temperature influence is larger.Adopt the ammoniacal liquor that concentration is 10%, pH is 7.5-8.5, carries out at normal temperatures absorption reaction the best.
(3) the recycling stage
The solution carrying out after absorption reaction finishes passes in recovery reactor 3, after condensing crystallizing dehydration, can obtain (NH
4)
2sO
4and NH
4nO
3particle, as chemical fertilizer or chemical fertilizer raw material; CO
2ammonium carbonate and carbonic hydroammonium with ammoniacal liquor generates, generate CO through adding thermal decomposition
2gas and ammonia.By CO
2the mist of gas and ammonia passes in water, ammonia because of solubility very big and soluble in water, the CO that solubility is less
2be discharged from.High concentration CO
2recycle as product, ammonia passes in water and recycles.
(NH
4)
2CO
3=2NH
3+CO
2+H
2O
NH
4HCO
3=NH
3+CO
2+H
2O
NH
3+H
2O=NH
3·H
2O
We have carried out following flue gas and have removed experiment in laboratory: SO
2initial concentration is 500mg/m
3, NO initial concentration is 125mg/m
3, CO
2initial concentration is 2000mg/m
3, buffer gas is pure nitrogen gas.This pending flue gas is passed into reaction unit, be oxidized absorption reaction, after tested, desulfurization degree mean value is 94.2%; Denitration rate is minimum is 86.8%, is up to 93.2%, and mean value is 90%; Carbon-drop rate is minimum is 87.5%, is up to 94.3%, average out to 90.9%.
Claims (9)
1. a method for flue gas combined desulfurization and denitration decarburization, is characterized in that: comprise the following steps:
(1) oxidation stage: flue gas is passed into NaOCl/NaOCl
2in complex liquid, be oxidized;
(2) absorption stage: the flue gas after oxidation is passed in ammoniacal liquor, and all the other tail gas are discharged.
2. method according to claim 1, is characterized in that: said method comprising the steps of:
(1) oxidation stage: flue gas is passed into NaOCl/NaOCl
2in complex liquid, be oxidized;
(2) absorption stage: the flue gas after oxidation is passed in ammoniacal liquor;
(3) the recycling stage: by the ammoniacal liquor heating absorbing after flue gas, obtain crystallization, carbon dioxide and ammonia; Described crystallization obtains (NH after dehydration
4)
2sO
4and NH
4nO
3particle; Described ammonia passes in water capable of circulation for step (2).
3. method according to claim 1 and 2, is characterized in that: NaOCl/NaOCl in described step (1)
2the pH value of complex liquid is 5.5.
4. method according to claim 1 and 2, is characterized in that: described step (1) NaOCl/NaOCl
2in complex liquid, NaOCl concentration is 5mmol/L, NaOCl
2concentration is 3 mmol/L.
5. method according to claim 1 and 2, is characterized in that: in described step (2), the concentration of ammoniacal liquor is 10%.
6. method according to claim 1 and 2, is characterized in that: the temperature of described step (1) oxidation stage is 60 DEG C; The temperature of described step (2) absorption stage is 20 DEG C.
7. method according to claim 1 and 2, is characterized in that: described step (1) oxidation stage carries out in spray column; Described NaOCl/NaOCl
2complex liquid sprays from spray column upper nozzle; Described flue gas enters from spray column bottom; Described NaOCl/NaOCl
2the ratio that passes into of complex liquid and flue gas is 19L/m
3; The flow of described flue gas is 0.5m
3/ h.
8. method according to claim 7, is characterized in that: in described spray column, be provided with three layers, every layer four nozzle; Described every layer of nozzle is square to be placed, and between the adjacent nozzle of diagonal, spacing is 0.1m; Described spray column bottom is provided with sieve plate; On described sieve plate, be uniformly distributed 69 pores.
9. method according to claim 1 and 2, is characterized in that: described step (2) absorption stage adopts bubble absorption device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410340249.7A CN104069723A (en) | 2014-07-17 | 2014-07-17 | Combined method for desulfurization, denitration and decarburization of exhaust gas |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410340249.7A CN104069723A (en) | 2014-07-17 | 2014-07-17 | Combined method for desulfurization, denitration and decarburization of exhaust gas |
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|---|---|
| CN104069723A true CN104069723A (en) | 2014-10-01 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410340249.7A Pending CN104069723A (en) | 2014-07-17 | 2014-07-17 | Combined method for desulfurization, denitration and decarburization of exhaust gas |
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Cited By (3)
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|---|---|---|---|---|
| CN104307337A (en) * | 2014-10-27 | 2015-01-28 | 李元杰 | Method and system for catching and separating carbon dioxide in flue gas of hot blast stove |
| CN106178899A (en) * | 2016-08-30 | 2016-12-07 | 山东格润内泽姆环保科技有限公司 | Compound dioxygen oxidation and denitration process and device |
| CN107497273A (en) * | 2017-09-25 | 2017-12-22 | 济南大学 | A kind of preparation method and application of environment protection, low cost smoke denitrifier |
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| CN102068893A (en) * | 2009-11-20 | 2011-05-25 | 四川帝澳环保节能工程有限公司 | Process for simultaneously desulfurizing and denitrating coal combustion flue gas by wet method |
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2014
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Patent Citations (3)
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| CN1843574A (en) * | 2006-03-29 | 2006-10-11 | 华北电力大学 | Liquid phase flue gas desulfurizing and denitrifying purification method and apparatus |
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|---|
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104307337A (en) * | 2014-10-27 | 2015-01-28 | 李元杰 | Method and system for catching and separating carbon dioxide in flue gas of hot blast stove |
| CN106178899A (en) * | 2016-08-30 | 2016-12-07 | 山东格润内泽姆环保科技有限公司 | Compound dioxygen oxidation and denitration process and device |
| CN107497273A (en) * | 2017-09-25 | 2017-12-22 | 济南大学 | A kind of preparation method and application of environment protection, low cost smoke denitrifier |
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Application publication date: 20141001 |