CN201454390U - SCR denitrifying device adopting ammonia injection grid with injection orifices of unequal diameters - Google Patents

SCR denitrifying device adopting ammonia injection grid with injection orifices of unequal diameters Download PDF

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Publication number
CN201454390U
CN201454390U CN2009201284698U CN200920128469U CN201454390U CN 201454390 U CN201454390 U CN 201454390U CN 2009201284698 U CN2009201284698 U CN 2009201284698U CN 200920128469 U CN200920128469 U CN 200920128469U CN 201454390 U CN201454390 U CN 201454390U
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China
Prior art keywords
ammonia
spray
spray ammonia
hole
scr
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Expired - Lifetime
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CN2009201284698U
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Chinese (zh)
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杜云贵
余宇
隋建才
邓佳佳
洪燕
丁小红
何凡
李紫龙
刘艳荣
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Chongqing University
CPI Yuanda Environmental Protection Engineering Co Ltd
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Chongqing University
CPI Yuanda Environmental Protection Engineering Co Ltd
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Abstract

The utility model discloses an SCR denitrifying device adopting an ammonia injection grid with injection orifices of unequal diameters, wherein by adopting the ammonia injection grid with the injection orifices of unequal diameters, the diameters of the ammonia injection orifices with unequal diameters of the ammonia injection grid shrink gradually along the flowing direction of ammonia, thereby ensuring that the ammonia quantities injected from all ammonia injection orifices remain the same during the ammonia injecting process, which produces no influence on the mixing length of ammonia and smoke, so as to ensure effectively the denitrifying effect.

Description

Adopt the SCR denitrification apparatus of non-equal diameter spray orifice ammonia-spraying grid
Technical field
The utility model relates to the flue gases purification field, particularly a kind of SCR denitrification apparatus that adopts non-equal diameter spray orifice ammonia-spraying grid.
Background technology
China is the big country of production of energy and consumption, and disposable energy supply is based on coal, oil, natural gas resource shortage.According to statistics, China's total energy consumption in 2003 is 16.78 hundred million tons of standard coals, and wherein coal accounts for 67.1%, and crude oil accounts for 22.7%, and natural gas accounts for 2.8%, and regenerative resource accounts for 7.3%.
This primary energy production and consumption structure based on coal has been brought the serious environmental pollution problem, and has damaged the economy and the environmental basis of sustainable development.In the multiple pollutant of airborne release, the discharging of control sour gas is the emphasis of present stage control at coal burning.
The sour gas of coal burning discharging mainly is SOx and NOx, and China is to SO at present 2Discharging the pressure standard has been arranged, and standard is not also forced in the discharging of NOx.The proportion of SOx in atmospheric acid contact scar gas is descending, and the proportion of NOx in atmospheric acid contact scar gas is rising.According to the estimation of relevant research, in the near future, the total emission volumn of NOx will surpass SOx, becomes the first acid pollution gas of power industry discharging.
SCR (selective catalyst reactive) gas denitrifying technology is one of gas denitrifying technology that is most widely used at present, have advantages such as denitration efficiency height, selectivity are good, stable and reliable operation, from the seventies later stage since first SCR of power plant device installed by Japan, this technology obtains fast development, have above 170 commercial SCR devices in operation in Japan, installed capacity is near 100,000MW; Europe has also obtained popularizing rapidly since 1985 introduce the SCR technology, and installed capacity has at present reached 60,000MW.The SCR denitrification apparatus has become the indispensability of power plant of developed country.The operation principle of this technology is: under 280~420 ℃ of temperature, and the reducing agent NH that sprays in NOx in the flue gas and the upstream flue 3The reduction reaction takes place under catalyst action, generates N 2And H 2O etc.
Under the prerequisite of selected catalyst, the flue gas stream skewness causes NOx and NH easily 3Mixing and react insufficient, not only easily cause local spray ammonia excessive, cause the generation of side reaction, and influence denitration effect and economical operation.Therefore in the denitrification apparatus running,, require the even distribution of flue gas, NOx and NH in the flue for avoiding too high NOx discharging and too high amount of ammonia slip, raising system denitration rate 3Deng the full and uniform mixing of reducing agent.
The SCR gas denitrifying technology adopts ammonia (NH 3) make reducing agent, its explosion limit is 15%~28%.For guaranteeing that ammonia sprays into the safety of flue and mixes, introduce the concentration that air mixes ammonia with ammonia usually and be controlled at below 5%.NH 3Spraying into flue with the mist of diluent air by ammonia-spraying grid (AIG) mixes with flue gas from the boiler economizer outlet, for improving the mixed effect of ammonia/flue gas, usually be provided with static mixer in the flue behind the ammonia-spraying grid, accelerate NH by the effect of streaming that air flow stream is crossed behind the static mixer 3Mix with flue gas, after the abundant long distance, ammonia/flue gas has reached even, stable mixing requirement after ammonia/flue gas flows through static mixer, enters Benitration reactor and carries out the denitration catalyst reaction.From the ammonia-spraying grid to the ammonia/flue gas evenly, stable distance of mixing is commonly referred to mixing length.
Traditional ammonia-spraying grid is made up of many spray ammonia pipes side by side, several perforates of the same size are arranged as spout (as shown in Figure 1) on the every spray ammonia pipe. consider single spray ammonia pipe, can know according to Bernoulli equation, ejection along with mist in the pipe, the gas mean flow rate reduces in the spray ammonia pipe, gas dynamic pressure reduces, and the gas stagnation pressure is constant, therefore the static pressure of gas is rising. and the gas flow of each spout ejection depends on the size of spout, static pressure in the static pressure of mist and the spout rear pass space poor in the spray ammonia pipe before the spout. static pressure is consistent in the spout rear pass, under the identical situation of nozzle diameter, the gaseous mixture scale of construction of each spout ejection increases along the bearing of trend of spray ammonia pipeline. the ammonia (NH that this makes each spout ejection 3) amount is inhomogeneous, increased the mixing length of ammonia/flue gas, influenced denitration effect.
The utility model content
In view of this, the utility model provides a kind of SCR denitrification apparatus that adopts non-equal diameter spray orifice ammonia-spraying grid, but take into full account in the ammonia-spraying grid gas-static to the influence of mixing length, improve by structure existing ammonia-spraying grid, make the ammonia amount of spout ejection roughly even, thereby reduced the mixing length of ammonia and flue gas, guaranteed denitration effect.
The purpose of this utility model provides a kind of SCR denitrification apparatus that adopts non-equal diameter spray orifice ammonia-spraying grid, described SCR denitrification apparatus comprises gas mixer and SCR reactor, the flue that is connected behind the inlet of described gas mixer and the boiler economizer links to each other, the outlet of described gas mixer is connected with the inlet of SCR reactor, in the described gas mixer, be disposed with ammonia-spraying grid and static mixer along the flue gas approach axis, described ammonia-spraying grid is made of many spray ammonia pipes arranged side by side, be provided with a plurality of spray ammonia hole on the described spray ammonia pipe vertically, flow direction according to ammonia, extremely terminal from the inlet end of spray ammonia pipe, the diameter in described spray ammonia hole dwindles successively gradually;
Further, described spray ammonia hole axially evenly arranging along spray ammonia pipe;
Further, described spray ammonia hole is a circular port, and extremely terminal from the inlet end of spray ammonia pipe, the diameter in described spray ammonia hole dwindles successively gradually;
Further, the spray ammonia hole that is in least significant end on the spray ammonia pipe is set to circular spray ammonia hole, all the other spray ammonia holes on the spray ammonia pipe are set to oblate spray ammonia hole, the two ends in described oblate spray ammonia hole are set to the arc of symmetry, the radius of described arc is identical with the radius in circular spray ammonia hole, extremely terminal from the inlet end of spray ammonia pipe, the length in described oblate spray ammonia hole is dwindled successively gradually;
Further, described SCR reactor is disposed with rectifier, first catalyst layer, second catalyst layer and preparing catalyst layer along the flow of flue gas direction.
The beneficial effects of the utility model are:
1. traditional ammonia-spraying grid structure static pressure unanimity in the spout rear pass, under the identical situation of nozzle diameter, the gaseous mixture scale of construction of each spout ejection increases along the bearing of trend of spray ammonia pipeline, make that the ammonia amount of each spout ejection is inhomogeneous, increased the mixing length of ammonia/flue gas, influenced denitration effect, and the utility model is by adopting the ammonia-spraying grid of non-equal diameter spray orifice, each size of spraying the ammonia hole is dwindled gradually with the flow direction of ammonia, thereby guarantee in spray ammonia process, it is roughly the same that each sprays the ammonia amount of ammonia hole ejection, thereby can not have influence on the mixing length of ammonia and flue gas, the reduction denitration effect;
2. circular port can be adopted as required in the spray ammonia hole of ammonia-spraying grid of the present utility model, also can adopt the mode in circular port+flat hole, thereby satisfies the use needs under the multiple situation, its compact conformation, and easy to process, implementation result is good, is fit to promote the use of.
Other advantages of the present utility model, target and feature will be set forth to a certain extent in the following description, and to a certain extent, based on being conspicuous to those skilled in the art, perhaps can from practice of the present utility model, obtain instruction to investigating hereinafter.Target of the present utility model and other advantages can realize and obtain by following specification and claims.
Description of drawings
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with accompanying drawing the utility model is described in further detail, wherein:
Fig. 1 is injection grid schematic diagram commonly used;
Fig. 2 is a SCR denitrification apparatus structural representation of the present utility model;
Fig. 3 is a circular spray ammonia hole spray ammonia tubular construction schematic diagram of the present utility model;
Fig. 4 is a mixed type spray ammonia hole spray ammonia tubular construction schematic diagram of the present utility model;
Fig. 5 is the enlarged diagram of Fig. 4 at the I place;
Fig. 6 is the enlarged diagram of Fig. 4 at the II place.
The specific embodiment
Hereinafter with reference to accompanying drawing, preferred embodiment of the present utility model is described in detail.Should be appreciated that preferred embodiment only for the utility model is described, rather than in order to limit protection domain of the present utility model.
The 1-ammonia-spraying grid; The 2-static mixer; The 3-deflector; The 4-rectifier; 5-first catalyst layer; 6-second catalyst layer; 7-preparing catalyst layer.
As shown in Figure 2, the SCR denitrification apparatus of the non-equal diameter spray orifice of employing of the present utility model ammonia-spraying grid, comprise gas mixer and SCR reactor, the flue that is connected behind the inlet of gas mixer and the boiler economizer links to each other, the outlet of gas mixer is connected with the inlet of SCR reactor, in the gas mixer, be disposed with ammonia-spraying grid 1 and static mixer 2 along the flue gas approach axis, ammonia-spraying grid 1 is made of many spray ammonia pipes arranged side by side, evenly be provided with a plurality of spray ammonia hole vertically on the spray ammonia pipe, according to the flow direction of ammonia, extremely terminal from the inlet end of spray ammonia pipe, the diameter in spray ammonia hole dwindles successively gradually.Be provided with deflector 3 in the inlet duct of SCR reactor, its inside is disposed with rectifier 4, first catalyst layer 5, second catalyst layer 6 and preparing catalyst layer 7 along the flow of flue gas direction.
As shown in Figure 3, spray ammonia hole is a circular port, and is extremely terminal from the inlet end of spray ammonia pipe, and the diameter in spray ammonia hole dwindles successively gradually, and this kind set-up mode is applicable to the less demanding occasion of ammonia spray volume control accuracy.
Extremely shown in Figure 6 as Fig. 4, the spray ammonia hole E that is in least significant end on the spray ammonia pipe is set to circular spray ammonia hole, all the other spray ammonia hole A on the spray ammonia pipe, B, C, D all are set to oblate spray ammonia hole, the two ends in oblate spray ammonia hole are set to the arc of symmetry, the radius of arc is identical with the radius in circular spray ammonia hole, extremely terminal from the inlet end of spray ammonia pipe, the length in oblate spray ammonia hole is dwindled successively gradually, and this kind set-up mode is applicable to the occasion that the ammonia spraying amount control accuracy in each spray ammonia hole is had relatively high expectations.
SCR denitrification apparatus of the present utility model in use, ammonia is injected ammonia-spraying grid after pressurizeing, ammonia sprays from the spray ammonia hole on the grid, carry the master of ammonia, control valve is housed on the branch pipe(tube), to regulate the input quantity of ammonia, select best nitrogen ammonia mol ratio, static mixer can guarantee that ammonia and the nitrogen oxide in the flue gas realize full and uniform mixing of nitrogen oxide composition in ammonia and the flue gas under the acting in conjunction of turbulent flow and flow mixing device, deflector evenly imports ammonia that mixes and the flue gas that contains oxynitrides in the top air chamber of SCR reactor, generation mixes, the air-flow that flow velocity is mild, through catalytic reduction reaction, realize denitration again.
Spray ammonia pipe design example:
The spray ammonia pipe of internal diameter 100mm, its inlet flow velocity is 19.2m/s, 5 spout perforates of design on the spray ammonia pipe design by following dual mode respectively:
Scheme one: according to traditional design, spray ammonia hole is by the equal diameter design, and the diameter in spray ammonia hole is 40mm.
Scheme two: spray the ammonia hole and use circular spray ammonia hole, extremely terminal from the inlet end of spray ammonia pipe, the diameter in spray ammonia hole reduces successively gradually, is respectively 43.7mm, 42.5mm, 41.3mm, 40.6mm, 40mm.
Scheme three: the mixing spray ammonia hole design in circular spray ammonia hole+oblateness spray ammonia hole is used in spray ammonia hole, the radius of circular spray ammonia hole and arc is 20mm (length in oblate spray ammonia hole can be regarded the length of the radius * 2+ mid portion of arc as), the length in each oblate spray ammonia hole is along the ammonia flow direction, be respectively (40+6) mm, (40+4) mm, (40+2) mm, (40+1) mm, the diameter in circular spray ammonia hole is 40mm.
In order to compare the result of this patent, by computer simulation software above-mentioned two kinds of schemes have been set up simulation model respectively, by identical spray ammonia condition is set, inlet flow rate is 0.1845kg/s, the outlet relative pressure is 0Pa, and according to analog result, it is as shown in the table with each spout flow for the import of spray ammonia pipe:
Inlet flow rate (kg/s) Spout 1 flow (kg/s) Spout 2 flows (kg/s) Spout 3 flows (kg/s) Spout 4 flows (kg/s) Spout 5 flows (kg/s) Minimax spout difference in flow (kg/s)
Scheme 1 0.1845 0.03341 0.03522 0.03721 0.03882 0.03979 0.00638
Scheme 2 0.1845 0.03655 0.03688 0.03692 0.03723 0.03692 0.00068
Scheme 3 0.1845 0.03676 0.03684 0.03682 0.03722 0.03682 0.00046
As seen adopt the non-equal diameter spray ammonia hole mode of second kind of scheme and the third scheme, the difference in flow in maximum and minimum spray ammonia hole reduces greatly, and the ammonia of ejection is more even, more helps the mixing of ammonia/flue gas.
Explanation is at last, above embodiment is only unrestricted in order to the explanation the technical solution of the utility model, although the utility model is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement the technical solution of the utility model, and not breaking away from the aim and the scope of the technical program, it all should be encompassed in the middle of the claim scope of the present utility model.

Claims (5)

1. adopt the SCR denitrification apparatus of non-equal diameter spray orifice ammonia-spraying grid, it is characterized in that: described SCR denitrification apparatus comprises gas mixer and SCR reactor, the flue that is connected behind the inlet of described gas mixer and the boiler economizer links to each other, the outlet of described gas mixer is connected with the inlet of SCR reactor, in the described gas mixer, be disposed with ammonia-spraying grid and static mixer along the flue gas approach axis, described ammonia-spraying grid is made of many spray ammonia pipes arranged side by side, be provided with a plurality of spray ammonia hole on the described spray ammonia pipe vertically, flow direction according to ammonia, extremely terminal from the inlet end of spray ammonia pipe, the diameter in described spray ammonia hole dwindles successively gradually.
2. the SCR denitrification apparatus of the non-equal diameter spray orifice of employing according to claim 1 ammonia-spraying grid is characterized in that: described spray ammonia hole is axially evenly arranged along spray ammonia pipe.
3. the SCR denitrification apparatus of the non-equal diameter spray orifice of employing according to claim 2 ammonia-spraying grid is characterized in that: described spray ammonia hole is a circular port, and extremely terminal from the inlet end of spray ammonia pipe, the diameter in described spray ammonia hole dwindles successively gradually.
4. the SCR denitrification apparatus of the non-equal diameter spray orifice of employing according to claim 2 ammonia-spraying grid, it is characterized in that: the spray ammonia hole that is in least significant end on the spray ammonia pipe is set to circular spray ammonia hole, all the other spray ammonia holes on the spray ammonia pipe are set to oblate spray ammonia hole, the two ends in described oblate spray ammonia hole are set to the arc of symmetry, the radius of described arc is identical with the radius in circular spray ammonia hole, extremely terminal from the inlet end of spray ammonia pipe, the length in described oblate spray ammonia hole is dwindled successively gradually.
5. the SCR denitrification apparatus of the non-equal diameter spray orifice of employing according to claim 1 ammonia-spraying grid, it is characterized in that: in the described SCR reactor, be disposed with deflector, rectifier, first catalyst layer, second catalyst layer and preparing catalyst layer along the flow of flue gas direction.
CN2009201284698U 2009-08-14 2009-08-14 SCR denitrifying device adopting ammonia injection grid with injection orifices of unequal diameters Expired - Lifetime CN201454390U (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102228794A (en) * 2011-05-25 2011-11-02 上海龙净环保科技工程有限公司 Two stage rotary mixing equipment for ammonia gas and flue gas in SCR (selective catalytic reduction) denitrification system
CN101637700B (en) * 2009-08-14 2012-10-03 中电投远达环保工程有限公司 SCR denitrification process and denitrification device of ammonia injection grid adopting non-unidiameter injection orifices
CN106178949A (en) * 2016-08-25 2016-12-07 华电电力科学研究院 A kind of efficient SCR denitration device of stepped mixing

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101637700B (en) * 2009-08-14 2012-10-03 中电投远达环保工程有限公司 SCR denitrification process and denitrification device of ammonia injection grid adopting non-unidiameter injection orifices
CN102228794A (en) * 2011-05-25 2011-11-02 上海龙净环保科技工程有限公司 Two stage rotary mixing equipment for ammonia gas and flue gas in SCR (selective catalytic reduction) denitrification system
CN102228794B (en) * 2011-05-25 2012-10-17 上海龙净环保科技工程有限公司 Two stage rotary mixing equipment for ammonia gas and flue gas in SCR (selective catalytic reduction) denitrification system
CN106178949A (en) * 2016-08-25 2016-12-07 华电电力科学研究院 A kind of efficient SCR denitration device of stepped mixing

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Granted publication date: 20100512

Effective date of abandoning: 20090814