CN103272470B - A kind of additive for improving SNCR ammonia activity and application thereof - Google Patents
A kind of additive for improving SNCR ammonia activity and application thereof Download PDFInfo
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- CN103272470B CN103272470B CN201310156356.XA CN201310156356A CN103272470B CN 103272470 B CN103272470 B CN 103272470B CN 201310156356 A CN201310156356 A CN 201310156356A CN 103272470 B CN103272470 B CN 103272470B
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- additive
- denitration
- reducing agent
- enol
- flue gas
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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
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/10—Capture or disposal of greenhouse gases of nitrous oxide (N2O)
Abstract
The invention discloses a kind of additive for improving SNCR ammonia activity and application thereof, described additive is made up of enol, inorganic sodium and KOH, spray in flue gas after being mixed with denitrification reducing agent by described additive, the temperature range of described flue gas is 760 ~ 850 DEG C.The present invention spray in the temperature range of 760 ~ 850 DEG C in ammoniacal liquor or urea liquid be mixed into a small amount of enol, sodium salt, KOH compounding substances carry out denitration, the change of different oxygen concentration can be adapted to, reduce accessory substance N
2the generation of O, and denitration efficiency is reached between 40% ~ 80%.Compare existing SNCR denitration method, effective denitration humidity province expands, and the scope of the oxygen amount of permission also expands, and the escaping of ammonia reduces.
Description
Technical field
The present invention relates to flue gas SNCR denitration field, being specifically related to a kind of for improving active denitration additive and the application thereof with reducing the escaping of ammonia of low-temperature denitration in SNCR denitrating flue gas.
Background technology
Control NOx emission technology at present both at home and abroad and be roughly divided into two classes: a class is low NOx combusting technology, namely by the optimization of Boiler Operation or control combustion process, suppress the reaction of NOx in combustion process to generate, thus reduce the final concentration of emission of NOx.Another kind of is gas denitrifying technology, namely the NOx generated is reduced to N
2, thus remove NOx in flue gas, mainly contain SNCR technology SNCR and SCR technology SCR.
Selective non-catalytic reduction (SelectiveNon-CatalyticReduction, SNCR) is a kind of NOx control treatment technology of maturation, and cost is lower, and transformation is convenient, is one of denitration technology of applicable China's national situation.Reducing agent has ammoniacal liquor, liquefied ammonia and urea, and these reducing agents are used for, in gas denitrifying technology, can obtaining similar denitration effect.Urea is used easily to produce more N for reducing agent
2o, and reaction temperature comparatively ammoniacal liquor is high; Liquefied ammonia belongs to hazardous chemical, and the requirement store, use, managed is higher; Industrial 20% or the ammoniacal liquor of 25%, much less than liquefied ammonia of security requirement, store, conveying and process all simple than liquefied ammonia, thus main based on ammoniacal liquor and urea in engineering at present.
Mainly by ammonia or containing in the flue gas of amino reducing agent after the temperature province of 850 ~ 1050 DEG C is injected to burning, there is Chemoselective reduction, NO be reduced into N in SNCR technology
2.This technology has strict requirement to reaction temperature, and the temperature limiting of relative narrower is a difficult point of SNCR technology application.
US Patent No. 5443805 discloses and uses hydrocarbon fuel as atomizing medium delivering ammonia reducing agent, because the reaction of hydrocarbon fuel is fast, is run out of by the oxygen in flue gas, is partially formed reducing atmosphere, can improve the denitration effect of SNCR.Method disclosed in US Patent No. 3900554, US Patent No. 4208386 and USUS4325924, and the improvement nearest to SNCR method comprises and also proposes similar effect described in US6030204 and U.S. Patent Application Publication No. US2002/0025285A1.
Above-mentioned SNCR patent all industrially achieves the application of certain limit, but existing additive, the optimum activity of denitration is all more than 850 DEG C, China's boiler type is more, and operation stability is bad, and flue-gas temperature can lower than 800 DEG C often, even to less than 760 DEG C, causing closing down of SNCR denitration system, limit the application of SNCR technology, developing a kind of denitration activity for improving 760 ~ 850 DEG C for this reason, reduce the denitration additive of the escaping of ammonia there is wider application prospect.
Summary of the invention
The invention provides a kind of additive for improving SNCR ammonia activity and application thereof, this additive is used in SNCR reducing agent, improve flue gas 760 ~ 850 DEG C denitration activity, reduce the escaping of ammonia.
For improving an additive for SNCR ammonia activity, the quality mol ratio of described additive consists of:
Enol 0 ~ 6g
Inorganic sodium 0.01 ~ 0.1mol
KOH0.01～0.1mol。
As preferably, the quality mol ratio of described additive consists of:
Enol 0 ~ 4g
Inorganic sodium 0.01 ~ 0.05mol
KOH0.01～0.05mol。
More preferably, the quality mol ratio of described additive consists of:
Enol 0.5 ~ 4g
Inorganic sodium 0.01 ~ 0.05mol
KOH0.01～0.05mol。
As preferably, described enol to be carbon atom quantity be 5 ~ 12 enol.
Further preferably, described enol is at least one in 3-Methyl-1-pentene-4-alkynes-3-alcohol, 3,7-dimethyl-6-octene-1s-alkynes-3-alcohol, 2-M3BOL and Pherocon CM.
As preferably, described inorganic sodium is NaHCO
3, Na
2cO
3with at least one in NaCl.
Present invention also offers a kind of method utilizing described additive to carry out denitrating flue gas, spray in flue gas after being mixed by described additive with denitrification reducing agent, the temperature range of described flue gas is 760 ~ 850 DEG C.
As preferably, described denitrification reducing agent is ammoniacal liquor, urea or both mixtures.
As preferably, NH in enol and denitrification reducing agent in described additive
3quality mol ratio be 0 ~ 6g/mol; NH in inorganic sodium and denitrification reducing agent in described additive
3mol ratio be 0.01 ~ 0.1mol/mol; NH in KOH and denitrification reducing agent in described additive
3mol ratio be 0.01 ~ 0.1mol/mol.
Further preferably, NH in enol and denitrification reducing agent in described additive
3quality mol ratio be 0.5 ~ 4g/mol; NH in inorganic sodium and denitrification reducing agent in described additive
3mol ratio be 0.01 ~ 0.05mol/mol; NH in KOH and denitrification reducing agent in described additive
3mol ratio be 0.01 ~ 0.05mol/mol.
Mixed with reducing agent by additive in the present invention and spray in flue gas after being atomized by spray gun fully, reaction principle is as follows:
It is denitrification reducing agent that the present invention adopts containing ammonia reducing agent, and total chemical equation of reducing NOx mainly contains:
In microcosmic elementary reaction, NH
3to NH
2conversion reaction, only have and following reaction occur:
The reduction reaction of NOx below could be there is:
Appropriate OH, O, H primitive is the necessary condition of NOx reduction reaction, and active primitive only has and could produce at sufficiently high temperature, and this is the reason that SNCR denitration technique is difficult to carry out at low temperatures.Active primitive in flue gas is not enough lower than generation during temperature window 850 DEG C in temperature, reaction rate can be caused too slow, can not get higher NOx clearance within the shorter time of staying.
Appropriate enol in the flue gas entering high temperature, with CH, CO, H
2separate out etc. form, react with the oxygen in surrounding environment while precipitation, consume the oxygen that major part is even whole, cause local in flue gas to set up reducing atmosphere rapidly.Enol generates O, H, OH isoreactivity primitive in flue gas, and the deficiency of active primitive under supplementing low temperature, excites NO reduction reaction, the reaction temperature window of SNCR is expanded to low-temperature end, improves the denitration efficiency under low temperature.
In addition, the additive that the present invention selects can for improving crucial OH, NH in denitration reaction
2isoreactivity root, under low temperature, the restriction of the too low reaction rate of script has been broken in the increase of these important active radicals concentration, and NO reduction reaction is by activated in advance, and within certain time of staying, denitration efficiency increases.
Further preferably, NH in enol and denitrification reducing agent in described additive
3quality mol ratio be 0.5 ~ 4g/mol.As NH in enol and denitrification reducing agent
3quality mol ratio produce too much higher than the primitive such as OH, O during preferred proportion, below reaction can occupy main status gradually
a large amount of generations of above-mentioned reaction can cause the clearance of NOx to reduce, and even make the NOx content in flue gas not fall anti-increasing, denitration efficiency is reduced.
Sodium salt has good regulating action to serve as active primitive buffer medium to very important active radicals concentration OH, H etc. in SNCR reaction: at low temperatures, generates OH isoreactivity root, cause the chain reaction of SNCR when active radicals concentration is low by catalytic reaction; At high temperature, when active radicals concentration is high, by catalytic reaction, OH, H active radicals is aggregated into H
2o, reduces ammonia root and is oxidized to NO; Na+N
2o=NaO+N
2.Because NaO can regenerate Na by chain reaction, a Na atom can reduce multiple N
2o molecule, therefore another important function can suppress the generation of denitration accessory substance, improves ammonia utilization rate.
KOH can produce O, H, OH isoreactivity primitive in flue gas, can promote the removal of NOx.There is neutralization reaction in the HNCO that KOH generates as basic species mass-energy and urea decomposition simultaneously, consumes HNCO, avoids it to participate in follow-up generation N
2o reacts
reduce N
2the generation of O.Enol, sodium salt, KOH are carried out mixing and are suitable for, in raising SNCR reaction temperature to while low temperature skew, improve ammonia to low temperature NO reduce selective, decrease N
2the secondary pollutions such as O, improve the utilization rate of ammonia.
Further preferably, NH in inorganic sodium and denitrification reducing agent in described additive
3mol ratio be 0.01 ~ 0.05mol/mol.NH in KOH and denitrification reducing agent in described additive
3mol ratio be 0.01 ~ 0.05mol/mol.As NH in inorganic sodium or KOH and denitrification reducing agent
3mol ratio higher than preferred proportion time, accessory substance N
2the reduction of O diminishes even constant, thus too much sprays into denitration efficiency without increase, and the quality of flyash also can be made to reduce.
Compared with existing denitrating catalyst, beneficial effect of the present invention:
Spray in the temperature range of 760-850 DEG C in ammoniacal liquor or urea liquid be mixed into a small amount of enol, sodium salt, KOH compounding substances carry out denitration, the change of different oxygen concentration can be adapted to, reduce accessory substance N
2the generation of O, and denitration efficiency is reached between 40% ~ 80%.Compare existing SNCR denitration method, effective denitration humidity province expands, and the scope of the oxygen amount of permission also expands, and the escaping of ammonia reduces.
Detailed description of the invention
Following examples are all at 200Nm
3on/hSNCR denitration experimental system for simulating.Produce flue gas by burning diesel oil in the burner, the quantity combusted controlling diesel oil regulates the temperature of flue gas, and this device can make flue-gas temperature adjustable controlled within the scope of 700 ~ 1200 DEG C; Pass into NO in a device to modulate the concentration level of NOx in flue gas; With Lange peristaltic pump the reducing agent of pre-configured a certain proportion of enol, sodium salt, KOH be delivered to the fluid path of spray gun and control ammonia nitrogen than NSR, utilizing compressed air be atomized by reducing agent and spray in flue gas, by detecting NOx concentration and the NH of tail end
3concentration calculates denitration activity and the escaping of ammonia rate, and the reaction time of the experimental data adopted in this example is 0.2s, and inlet NOx concentration controls at 200mg/Nm
3.
Embodiment 1
Flue-gas temperature is 760 DEG C, and reducing agent is ammoniacal liquor (5% mass concentration), and NSR is 1.2, and additive level and measurement result are in table 1
The ratio of table 1 additive and denitration situation
Wherein, enol is 3-Methyl-1-pentene-4-alkynes-3-alcohol, and inorganic sodium is NaHCO
3.
Embodiment 2
Flue-gas temperature is 800 DEG C, and reducing agent is ammoniacal liquor (5% mass concentration), and NSR is 1.2, and additive level and measurement result are in table 2
The ratio of table 2 additive and denitration situation
Wherein, enol is 3,7-dimethyl-6-octene-1-alkynes-3-alcohol, and inorganic sodium is Na
2cO
3.
Embodiment 3
Flue-gas temperature is 850 DEG C, and reducing agent is ammoniacal liquor (5% mass concentration), and NSR is 1.2, and additive level and measurement result are in table 3
The ratio of table 3 additive and denitration situation
Wherein, enol is 2-M3BOL, and inorganic sodium is NaCl.
Embodiment 4
Flue-gas temperature is 760 DEG C, and reducing agent is urea liquid (10% mass concentration), and NSR is 1.2,
Additive level and measurement result are in table 4
The ratio of table 4 additive and denitration situation
Wherein, enol is Pherocon CM, and inorganic sodium is NaHCO
3.
Embodiment 5
Flue-gas temperature is 800 DEG C, and reducing agent is urea liquid (10% mass concentration), and NSR is 1.2, and additive level and measurement result are in table 5
The ratio of table 5 additive and denitration situation
Wherein, enol is 3,7-dimethyl-6-octene-1-alkynes-3-alcohol, and inorganic sodium is NaCl.
Embodiment 6
Flue-gas temperature is 850 DEG C, and reducing agent is urea liquid (10% mass concentration), and NSR is 1.2, and additive level and measurement result are in table 6
The ratio of table 6 additive and denitration situation
Wherein, enol is 2-M3BOL, and inorganic sodium is Na
2cO
3.
Comparative example 1
Reducing agent is ammoniacal liquor (5% mass concentration), and NSR is 1.2, and flue-gas temperature and measurement result are in table 7
The non-additive denitration situation of table 7
Comparative example 2
Reducing agent is urea liquid (10% mass concentration), and NSR is 1.2, and flue-gas temperature and measurement result are in table 8
The non-additive denitration situation of table 8
From above Comparative result, in the temperature range of 760-850 DEG C, the ammoniacal liquor or urea liquid that are mixed with additive are sprayed in flue gas in the present invention and carry out denitration, different oxygen concentration changes can be adapted to, reduce accessory substance N
2the generation of O, and make denitration efficiency reach between 40% ~ 80%, the escaping of ammonia controls at 6mg/Nm
3within; And when not using additive, in the temperature range of 760-850 DEG C, the denitration efficiency of flue gas is generally lower than 40%, the escaping of ammonia is up to more than 20%.
Claims (4)
1. for improving an additive for SNCR ammonia activity, it is characterized in that, the quality mol ratio of described additive consists of:
Enol 0.5 ~ 4g
Inorganic sodium 0.01 ~ 0.05mol
KOH0.01～0.05mol
Described enol is at least one in 3-Methyl-1-pentene-4-alkynes-3-alcohol, 3,7-dimethyl-6-octene-1s-alkynes-3-alcohol, 2-M3BOL and Pherocon CM.
2. additive according to claim 1, it is characterized in that, described inorganic sodium is NaHCO
3, Na
2cO
3with at least one in NaCl.
3. utilize the additive described in claim 1 or 2 to carry out a method for denitrating flue gas, it is characterized in that, spray in flue gas after being mixed by described additive with denitrification reducing agent, the temperature range of described flue gas is 760 ~ 850 DEG C.
4. method according to claim 3, is characterized in that, NH in enol and denitrification reducing agent in described additive
3quality mol ratio be 0.5 ~ 4g/mol; NH in inorganic sodium and denitrification reducing agent in described additive
3mol ratio be 0.01 ~ 0.05mol/mol; NH in KOH and denitrification reducing agent in described additive
3mol ratio be 0.01 ~ 00.05mol/mol.
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| CN104074577B (en) * | 2014-06-25 | 2016-04-06 | 同济大学 | A kind of method improving SCR system of diesel engine urea pyrolysis hydrolysis efficiency |
| CN104645794A (en) * | 2015-01-13 | 2015-05-27 | 广州特种承压设备检测研究院 | Method for optimizing SNCR (selective non-catalytic reduction) denitrification system of garbage incinerator by adding anionic surfactant |
| CN111715050B (en) * | 2019-03-20 | 2021-10-15 | 中国科学院大连化学物理研究所 | Method for improving urea denitration efficiency by adopting alkaline alcohol solution |
| CN111715052B (en) * | 2019-03-20 | 2021-09-03 | 中国科学院大连化学物理研究所 | Method for synergistically and efficiently reducing emission of dioxin substances and NOx in household garbage incineration process |
| CN113877391B (en) * | 2020-07-01 | 2023-12-29 | 中冶长天国际工程有限责任公司 | Composite additive for selective non-catalytic reduction denitration of flue gas, preparation method and application thereof |
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| CN102806002A (en) * | 2012-08-22 | 2012-12-05 | 清华大学 | SNCR (selective non-catalytic reduction) denitration device and method for rotary cement kiln nitrogen oxide control |
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| CN102806002A (en) * | 2012-08-22 | 2012-12-05 | 清华大学 | SNCR (selective non-catalytic reduction) denitration device and method for rotary cement kiln nitrogen oxide control |
Non-Patent Citations (1)
| Title |
|---|
| NaOH作添加剂对NOxOUT工艺的试验影响;梁秀进 等;《锅炉技术》;20120331;第43卷(第2期);63-68 * |
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