CN202762311U - Spraying device for selective catalytic reduction (SCR) denitration reducing agent - Google Patents
Spraying device for selective catalytic reduction (SCR) denitration reducing agent Download PDFInfo
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- CN202762311U CN202762311U CN201220417809.0U CN201220417809U CN202762311U CN 202762311 U CN202762311 U CN 202762311U CN 201220417809 U CN201220417809 U CN 201220417809U CN 202762311 U CN202762311 U CN 202762311U
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Abstract
The utility model discloses a spraying device for an SCR denitration reducing agent and belongs to the field of SCR denitration of boilers. The spraying device comprises a denitration reducing agent channel, wherein one end of the denitration reducing agent channel is communicated with a 500 DEG C-900 DEG C temperature zone of the boiler, the other end of the denitration reducing agent channel is communicated with an inlet flue of an SCR reactor, the denitration reducing agent channel comprises a urea decomposition pipeline, an ammonia/smoke gas mixture pipeline and an ammonia injection pipeline which are communicated sequentially, and the urea decomposition pipeline is provided with a urea solution spraying gun. The spraying device for the SCR denitration reducing agent is low in investment, low in operation cost, low in energy consumption, high in safety and reliability and complete in urea decomposition.
Description
Technical field
The utility model belongs to boiler SCR denitration field.
Background technology
Selective catalytic reduction flue gas denitration technique (Selective Catalytic Reduction of NO
x, being called for short the SCR denitrating technique) and reducing agent mainly contains liquefied ammonia, ammoniacal liquor, three kinds of forms of urea.Liquefied ammonia is because process system is simple, and investment and operating cost are lower, in the SCR denitrating technique, use wider, but liquefied ammonia belongs to also original of high-risk, its transportation and storage request harshness and be subject to more and more the restriction of policy, rules, very inconvenient; Equally, ammoniacal liquor is also because its transportation, storage problem and investment operating cost occupy high and limitation that used; SCR denitrification reducing agent-the urea lower as security requirement has the denitration performance identical with liquefied ammonia, be green fertilizer, not dangerous policy, regulation limitations can betransported easily, store and use, at present, urea is adopted by power plant gradually as the SCR denitrification reducing agent.
Urea is as the SCR denitrification reducing agent, and present common technique is that independent ammonia preparation system from urea will be set, and urea is resolved into ammonia in advance, and then ammonia is sent into denitrification apparatus.Urea ammonia processed commonly used has two kinds of techniques: urea pyrolysis ammonia processed and hydrolysis of urea ammonia processed, pyrolysismethod is that urea liquid quick decomposes in 600 ℃ atmospheric pressure environment becomes gas ammonia, its thermal source adopts about 300 ℃ hot blast of boiler or air usually, then is heated to 600 ℃ through heater; Hydrolyze method is that hydrolysis generation gas ammonia occurs in the environment of 140-200 ℃ of temperature, pressure 0.4-2.0MPa urea liquid, and its thermal source generally is to introduce steam to hydrolyzer.No matter be urea pyrolysis or hydrolysis ammonia processed, all unavoidably introduce thermal source and need to consume a large amount of energy, and system complexity, investment and operating cost be too high.
Patent documentation: publication number CN 101734685 A, Chinese invention patent application discloses a kind of method of utilizing urea ammonia quantitative production and denitration, the urea solid particle to be heated to 132.7 ℃ in advance make it be molten state, the atomizing of the urea of molten state sprayed into it is decomposed into contain the ammonia gaseous mixture, contain the ammonia gaseous mixture and send into the denitrating catalyst surface and under catalyst action, continue to be decomposed into ammonia and participate in denitration reaction.The method defective is: the urea technology difficulty of transporting molten attitude is large, material requirements is high, be difficult to atomizing, security reliability is poor, contains the ammonia gaseous mixture and continues to be decomposed into ammonia and need catalyst, and investment and operating cost are large.
Patent documentation: publication number CN 102068904 A, Chinese invention patent application discloses a kind ofly introduces 280-410 ℃ flue gas as SCR method of denitration and the device of urea decomposition thermal source at conventional Benitration reactor downstream flue gas, see accompanying drawing Fig. 3.Be stored in and expect under the urea granules of urea warehouse 4 that grinder 5 grinds, the urea powder after the grinding is given through screw(-type) feeder 6 and is expected Urea device 2.The thermal source of Urea device 4 returns SCR reactor 1 downstream flue again after SCR reactor 1 downstream flue is extracted flue gas urea out, urea powder after the heating is regulated the urea amount of powder and is sent into urea-spray device 3 by vapours inlet adjusting valve 31 steam regulation by charging control valve 33, and the urea powder in the injector 3 is ejected into SCR reactor 1 upstream flue by nozzle 32.The method is not enough: adopt the urea powder, and draw SCR reactor downstream flue only 280-410 ℃ flue gas come the heating urea powder to make it to resolve into ammonia, urea decomposition is incomplete, the productive rate of ammonia is low, the intermediate by-products of association is high, and the utilization rate of urea is low, consumption is large; Extracting flue gas needs itself also to need energy consumption; Spray into reactor upstream flue with the pattern of urea powder and carry out denitration, also can bring new problem: urea powder-processed difficulty, emitted dose are wayward, and pipeline, nozzle easily stop up, security reliability is poor.Owing to also need to introduce the extra energy of steam consumption of heat, investment and operating cost are higher simultaneously, and the energy consumption of whole denitrification apparatus is also larger.
The utility model content
The purpose of this utility model is: propose a kind of investment and operating cost is low, energy consumption is low, security reliability is high, urea decomposition SCR denitrification reducing agent injection apparatus completely.
The utility model purpose realizes by following technical proposals:
A kind of SCR denitrification reducing agent injection apparatus, comprise that an end is communicated to 500 ℃ of-900 ℃ of temperature provinces of boiler (further optimum temperature range is 600 ℃-700 ℃), the other end is communicated to the denitrification reducing agent passage of SCR reactor inlet flue, described denitrification reducing agent passage comprises urea decomposition pipeline, ammonia/flue gas mist pipeline and the ammonia injection pipeline that is communicated with successively, and described urea decomposition pipeline is provided with the urea liquid spray gun.
As preferably, described ammonia/flue gas mist pipeline length satisfies ammonia/5 seconds flue gas mist time of staying at least, and preferred 5-30 second is to guarantee the urea liquid evaporation and to decompose fully.
As preferably, in the described urea decomposition passage, urea liquid spray gun provided upstream has gas proportioning damper.
As further preferred, in the described urea decomposition passage, the gas proportioning damper upstream is provided with smoke filter.
As preferably, described urea liquid spray gun entrance is communicated with respectively compressed air line and urea liquid pipeline, described urea liquid pipeline is provided with the urea liquid flowmeter, and the urea liquid control valve of regulating the urea liquid flow according to urea liquid flow meter signal feedback, described compressed air line is provided with the compressed air require meter, and the compressed air regulating valve of regulating air supply according to compressed air require meter signal feedback.
As preferably, also be provided with blender between described ammonia injection pipeline and the SCR Benitration reactor.
As preferably, in the described urea decomposition passage, the gas proportioning damper upstream also is provided with blower fan.
The course of work is: ammonia is the final reducing agent of SCR denitration generation reduction reaction, and the urea decomposes can produce ammonia.In the time of 450 ℃, urea effectively decomposes, the gas ammonia productive rate reaches 75%, and in the time of 600 ℃, urea effectively decomposes, the gas ammonia productive rate reaches 100%, and is maintained to 900 ℃.The utility model is according to urea decomposition and gas ammonia productive rate relation, according to layout of boiler characteristics and flue gas characteristic, the poor gravity flow of flue gas depended on pressure of 500 ℃-900 ℃ in boiler (further optimum temperature range is 600 ℃-700 ℃) temperature province is drawn a small amount of flue gas (usually about 0.5-1%) as thermal source, and spraying urea liquid is mapped in this flue gas, urea liquid is heated, evaporation, resolve into gas ammonia fully, gas ammonia and flue gas are mixed, ammonia/flue gas mist is returned to the SCR denitration reactor inlet and mixes the rear SCR of inflow Benitration reactor with the flue gas of economizer exit, and ammonia and nitrogen oxide generation reduction reaction generate water and nitrogen under catalyst action, reach the purpose of denitration.
The beneficial effects of the utility model: the utility model need not extra heat source, utilize layout of boiler characteristics and flue gas characteristic, the dependence flue gas pressures is poor, gravity flow is drawn a small amount of flue gas as ureaclastic thermal source, need not to arrange independent urea pyrolysis or hydrolysis system, operation energy consumption can greatly be reduced, reduce investment outlay cost and operating cost.
System controllability and measurability is strong, and security reliability is high, and urea decomposition flue gas and the amount and the atomizing particle size that are ejected into the urea liquid in the denitrification apparatus can be regulated, and can adapt to the denitration working conditions change and guarantee fast decomposes of urea.
Passing through denitrification reducing agent passage process, the denitrfying agent and the flue gas that atomize in ammonia/flue gas mist mix, and enter fully reaction in the SCR Benitration reactor after being conducive to, the raising denitration efficiency.
High as ureaclastic thermal source flue-gas temperature, urea can realize that 100% decomposes fully, and gas ammonia productive rate and urea utilization rate are high, have farthest reduced reducing agent urea consumption.
A small amount of boiler tail flue gas that 0.5-1% is drawn in gravity flow does not affect boiler performance as the urea decomposition thermal source.
The utility model need not to arrange independent urea pyrolysis/hydrolysis system and consumes extra energy consumption, can significantly reduce denitration operating cost and cost of investment.Take the 300MW unit as example: the SCR denitrating system energy consumption of traditional urea pyrolysis technique is 600kW/h, adopts energy consumption of the present utility model to be lower than 60kW/h, and operation energy consumption is saved up to more than 90%; Owing to reduced system configuration, the cost of investment of the utility model urea decomposition system can save 20% simultaneously.The utility model especially is particularly suitable for the SCR denitration of the low coal-burning boiler of large electric power plant station fuel-oil or fuel-gas boiler and dust content concentration.
Description of drawings
Fig. 1 is the device schematic flow sheet of the utility model embodiment;
Fig. 2 is the structural representation of the urea liquid spray gun of the utility model embodiment;
Fig. 3 is the device schematic flow sheet of prior art.
The specific embodiment
Following non-limiting examples is used for explanation the utility model.
As shown in Figure 1, by Open valve 12, the urea in the urea granules silo 11 falls into urea dissolving tank 13.In urea dissolving tank 13, urea mixes with the water 14 of adding and dissolves.The urea liquid that generates after the urea granules dissolving is sent in the urea liquid storage tank 16 by urea liquid circulating pump 15 and is stored.Present embodiment is only listed is that urea liquid prepares a kind of in the scheme, and this patent does not limit it and how to prepare urea liquid, and what need only is urea liquid.
Urea liquid in the urea liquid storage tank 16 is sent in the urea liquid spray gun 2 that is installed in the urea decomposition pipeline 40 by urea liquid feed pump 17.Compressed air 19 enters urea liquid spray gun 2, with urea liquid atomizing and be ejected in the urea decomposition flue gas 41.Regulate urea liquid flow (urea liquid flowmeter 18-2 signal feedback) by urea liquid control valve 18-1 and control the urea liquid amount that is ejected in the urea decomposition flue gas 41, to adapt to flue gas operating mode load variations; Regulate the size that air supply (compressed air require meter 19-2 signal feedback) control is ejected into urea liquid atomizing particle in the urea decomposition flue gas 41 by compressed air regulating valve 19-1, it is preferably dimensioned to be 1-100 μ m.
As shown in Figure 2, urea liquid spray gun 2 adopts two medium spray guns, is comprised of nozzle 21, outer tube 22, inner sleeve 23.Urea liquid spray gun 2 entrances are communicated with respectively compressed air line and urea liquid pipeline.The outer tube medium is urea liquid, connects urea liquid pipe joint 24.The inner sleeve medium is compressed air, connects compressed air hose pipeline joint 25.Spray gun also can inner sleeve medium urea liquid, outer tube medium compressed air.This patent does not limit the spray gun that adopts other types.
Denitrification reducing agent passage one end is communicated to 500 ℃ of-900 ℃ of temperature provinces of boiler (further optimum temperature range is 600 ℃-700 ℃), the other end is communicated to SCR reactor inlet flue, and this denitrification reducing agent passage comprises urea decomposition pipeline, ammonia/flue gas mist pipeline and the ammonia injection pipeline that is communicated with successively.According to the boiler smoke pressure differential, the a small amount of flue gas of drawing 0.5-1% that flows automatically from 500 ℃-900 ℃ in boiler (further optimum temperature range is 600 ℃-700 ℃) temperature province (such as heated surface at the end of boiler 33 such as tail vertical well 32, low temperature superheater, low-temperature reheater sections) flue gas 31 enters in the urea decomposition pipeline 40 as urea decomposition flue gas 41, the heat of urea decomposition flue gas 41 makes urea 100% be decomposed into gas ammonia fully the heating of urea liquid particle, evaporation that 2 atomizings of urea liquid spray gun spray into.Urea decomposition flue gas 41 can be removed flue dust through smoke filter 45 in advance, regulates required urea decomposition exhaust gas volumn size by gas proportioning damper 42.For combustion gas or oil burning boiler, smoke filter 45 can not arrange.
According to the layout of boiler characteristics, if flue gas pressures is poor not, can the upstream flue before gas proportioning damper 42 installs blower fan additional and make 41 superchargings of urea decomposition flue gas overcome the pyrolysis smoke drag losses.
A small amount of flue gas that gravity flow is drawn can not affect boiler performance or very little on the impact of boiler performance.
Ureaclastic ammonia and urea decomposition flue gas 41 are mixed into ammonia/flue gas mist 43, flow into the ammonia injection pipeline 5 that is arranged in the SCR reactor inlet flue 7 by ammonia/flue gas mist pipeline 44.Ammonia/flue gas mist pipeline 44 length satisfy ammonia/5 seconds flue gas mist time of staying at least, and preferred 5-30 second is to guarantee the urea liquid evaporation and to decompose fully.
The flue gas 31 of 500 ℃ of-900 ℃ of denitration temperature provinces of boiler is through heated surface at the end of boiler 33 and economizer 34, mix by blender 6 from economizer 280 ℃-420 ℃ economizer exit flue gas 35 out and the ammonia of ammonia injection pipeline 5 injections/flue gas mist, flow into the SCR reactor 8 in downstream, the reduction reaction occurs under catalyst 8-1 effect reach the denitration purpose.
The above only is preferred embodiment of the present utility model; not in order to limit the utility model; all any modifications of within spirit of the present utility model and principle, doing, be equal to and replace and improvement etc., all should be included within the protection domain of the present utility model.
Claims (7)
1. SCR denitrification reducing agent injection apparatus, it is characterized in that: comprise that an end is communicated to 500 ℃ of-900 ℃ of temperature provinces of boiler, the other end is communicated to the denitrification reducing agent passage of SCR reactor inlet flue, described denitrification reducing agent passage comprises urea decomposition pipeline, ammonia/flue gas mist pipeline and the ammonia injection pipeline that is communicated with successively, and described urea decomposition pipeline is provided with the urea liquid spray gun.
2. SCR denitrification reducing agent injection apparatus as claimed in claim 1, it is characterized in that: in the described urea decomposition passage, urea liquid spray gun provided upstream has gas proportioning damper.
3. SCR denitrification reducing agent injection apparatus as claimed in claim 2, it is characterized in that: in the described urea decomposition passage, the gas proportioning damper upstream is provided with smoke filter.
4. SCR denitrification reducing agent injection apparatus as claimed in claim 1, it is characterized in that: described urea liquid spray gun entrance is communicated with respectively compressed air line and urea liquid pipeline, described urea liquid pipeline is provided with the urea liquid flowmeter, and the urea liquid control valve of regulating the urea liquid flow according to urea liquid flow meter signal feedback, described compressed air line is provided with the compressed air require meter, and the compressed air regulating valve of regulating air supply according to compressed air require meter signal feedback.
5. SCR denitrification reducing agent injection apparatus as claimed in claim 1 is characterized in that: also be provided with blender between described ammonia injection pipeline and the SCR Benitration reactor.
6. SCR denitrification reducing agent injection apparatus as claimed in claim 2, it is characterized in that: in the described urea decomposition passage, the gas proportioning damper upstream also is provided with blower fan.
7. SCR denitrification reducing agent injection apparatus as claimed in claim 1, it is characterized in that: described ammonia/flue gas mist pipeline length satisfies ammonia/5 seconds flue gas mist time of staying at least.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201220417809.0U CN202762311U (en) | 2012-08-22 | 2012-08-22 | Spraying device for selective catalytic reduction (SCR) denitration reducing agent |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201220417809.0U CN202762311U (en) | 2012-08-22 | 2012-08-22 | Spraying device for selective catalytic reduction (SCR) denitration reducing agent |
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| CN201220417809.0U Expired - Lifetime CN202762311U (en) | 2012-08-22 | 2012-08-22 | Spraying device for selective catalytic reduction (SCR) denitration reducing agent |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103551034A (en) * | 2013-11-05 | 2014-02-05 | 国家电网公司 | Urea-pyrolysis ammonia preparation device |
| CN104324612A (en) * | 2014-11-13 | 2015-02-04 | 安徽同兴环保工程股份有限公司 | Special single-bin heating regeneration denitration system for low-temperature flue gas, and denitration method |
| CN104587830A (en) * | 2015-01-09 | 2015-05-06 | 西安西热锅炉环保工程有限公司 | Urea solution intra-flue direct injection pyrolysis device and method with SCR (Selective Catalytic Reduction) system |
| CN109173639A (en) * | 2018-11-07 | 2019-01-11 | 四川金象赛瑞化工股份有限公司 | A kind of nitric acid tail gas denitrating technique |
-
2012
- 2012-08-22 CN CN201220417809.0U patent/CN202762311U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103551034A (en) * | 2013-11-05 | 2014-02-05 | 国家电网公司 | Urea-pyrolysis ammonia preparation device |
| CN104324612A (en) * | 2014-11-13 | 2015-02-04 | 安徽同兴环保工程股份有限公司 | Special single-bin heating regeneration denitration system for low-temperature flue gas, and denitration method |
| CN104587830A (en) * | 2015-01-09 | 2015-05-06 | 西安西热锅炉环保工程有限公司 | Urea solution intra-flue direct injection pyrolysis device and method with SCR (Selective Catalytic Reduction) system |
| CN109173639A (en) * | 2018-11-07 | 2019-01-11 | 四川金象赛瑞化工股份有限公司 | A kind of nitric acid tail gas denitrating technique |
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