CN212283535U - A flue mixer structure for SNCR denitrification of pulverized coal boiler flue gas - Google Patents
A flue mixer structure for SNCR denitrification of pulverized coal boiler flue gas Download PDFInfo
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- CN212283535U CN212283535U CN202020696275.4U CN202020696275U CN212283535U CN 212283535 U CN212283535 U CN 212283535U CN 202020696275 U CN202020696275 U CN 202020696275U CN 212283535 U CN212283535 U CN 212283535U
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Abstract
The utility model provides a flue mixer structure for SNCR denitration of pulverized coal boiler flue gas, which uses a simple-structured and efficient flue gas/reducing agent mixer structure body in a proper area in the flue of the pulverized coal boiler, so that flue gas wrapped with a reducing agent can be fully mixed when flowing through the flue gas, thereby improving the SNCR denitration reaction efficiency; the device overall design is comparatively simple, and the region that internal devices such as the no screen heat exchanger exists in usable flue is directly arranged, and is very little to the change of flue structure, can gain better economic benefits and social.
Description
Technical Field
The utility model relates to a coal fired boiler environmental protection technology field, in particular to a flue mixer structure for pulverized coal fired boiler flue gas SNCR denitration.
Background
If most of NOx in the flue gas can be removed greatly before entering the SCR device, the denitration pressure of the downstream SCR device can be effectively relieved, the service life of the SCR catalyst can be prolonged, and good economic and social benefits can be generated.
China Huaneng group clean energy technology research institute Limited (hereinafter referred to as Qing energy institute for short) researches selective non-catalytic reduction reaction of flue gas (when SNCR discovers that good mixing of reducing agent and flue gas can be quickly realized, autoxidation share of amino reducing agent in high-temperature environment can be effectively reduced, so that NOx reduction share of the amino reducing agent is improved, even if the flue gas temperature is higher, SNCR denitration can still realize ideal denitration efficiency, for example, the Qingneng energy institute discovers that under the condition of proper ammonia nitrogen molar ratio and quick and uniform mixing of flue gas/reducing agent, even in high-temperature flue gas of 1000 ℃, SNCR denitration efficiency can generally reach 60% -70%, and the highest 80%, if a reasonable flue gas/reducing agent mixing and SNCR reaction device is designed at a proper position upstream of an SCR device of a pulverized coal boiler, NOx content in the flue gas before the SCR device can be effectively reduced, the expected purpose is achieved.
Disclosure of Invention
An object of the utility model is to provide a flue mixer structure for pulverized coal boiler flue gas SNCR denitration, solved current pulverized coal boiler and adopted selective catalytic reduction (the SCR method carries out the NOx desorption, the device construction cost who exists is high, the high defect of catalyst use cost.
In order to achieve the above purpose, the utility model discloses a technical scheme is:
the utility model provides a flue mixer structure for SNCR denitration of pulverized coal boiler flue gas, which comprises a mixer structure body, wherein the mixer structure body is arranged in a flue; the mixer structure body comprises two first drainage baffles, a mixer inner baffle, a mixer outer baffle and a second drainage baffle, wherein the two first drainage baffles are symmetrically arranged on the side wall of the flue, and an inclination angle is formed between the two first drainage baffles and the side wall of the flue;
the two mixer inner baffles are arranged in parallel in the flue; one end of each of the two mixer internal baffles is connected with the free end of each of the two first drainage baffles;
the two mixer outer baffles are arranged at the downstream of the mixer inner baffle; the baffle plates are arranged on the outer sides of the inner baffle plates of the mixer in a one-to-one correspondence manner, and S-shaped flow passages are formed between the baffle plates and the inner baffle plates of the mixer;
two second drainage baffles are arranged, and one ends of the two second drainage baffles are connected; the other ends of the two second drainage baffles are respectively connected with the two mixer outer baffles.
Preferably, a mixer rear baffle is arranged at the joint between the first drainage baffle and the mixer inner baffle, and the mixer rear baffle is vertically fixed on the side wall of the flue.
Preferably, the mixer rear baffle is of a heat-resistant steel plate structure, and both side surfaces of the heat-resistant steel plate structure are coated with a fireproof wear-resistant material layer.
Preferably, a mixer front baffle is arranged between the two mixer outer baffles, and the mixer front baffle is vertically arranged between the two mixer outer baffles and has a concave structure with the mixer outer baffles.
Preferably, a triangular structure is formed between the mixer front baffle and the two second flow guide baffles.
Preferably, the mixer front baffle is of a heat-resistant steel plate structure, and both side surfaces of the heat-resistant steel plate structure are coated with a fireproof wear-resistant material layer.
Preferably, a plurality of SNCR spray guns are arranged on the first flow guide baffle along the height direction of the first flow guide baffle, and a reducing agent storage tank is connected with the SNCR spray guns.
Preferably, first drainage baffle, baffle in the blender, blender outer baffle and second drainage baffle all include heat-resisting steel sheet structure, the both sides face of heat-resisting steel sheet structure all coats and has fire-resistant wear-resisting material layer.
Compared with the prior art, the beneficial effects of the utility model are that:
the utility model provides a flue mixer structure for SNCR denitration of pulverized coal boiler flue gas, which uses a simple-structured and efficient flue gas/reducing agent mixer structure body in a proper area in the flue of the pulverized coal boiler, so that flue gas wrapped with a reducing agent can be fully mixed when flowing through the flue gas, thereby improving the SNCR denitration reaction efficiency; the device overall design is comparatively simple, and the region that internal devices such as the no screen heat exchanger exists in usable flue is directly arranged, and is very little to the change of flue structure, can gain better economic benefits and social.
Drawings
FIG. 1 is a front view and a top view of a mixer structure disposed in a flue of a pulverized coal fired boiler in accordance with the present invention;
FIG. 2 is a block diagram of the structural body of the mixer;
FIG. 3 is a block diagram of a baffle;
FIG. 4 is a graph of the relative size of the mixer based on the flue width.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1, the utility model provides a pair of flue mixer structure for pulverized coal fired boiler flue gas SNCR denitration, baffle 7, second drainage baffle 8 and SNCR spray gun 9 before baffle 6, the blender before pulverized coal fired boiler 1, flue 2, first drainage baffle 3, blender backplate 4, the blender, wherein, pulverized coal fired boiler 1's exhanst gas outlet connection flue 2's flue gas entry, flue 2's the external SCR device of exhanst gas outlet connection.
The upper reaches of external SCR device are provided with the blender structure body that is used for flue gas SNCR denitration, the blender structure body is arranged in flue 2.
The mixer structure body comprises two first drainage baffles 3, two mixer inner baffles 5 and two mixer outer baffles 6, wherein the two first drainage baffles 3 are symmetrically arranged on the side wall of the flue 2, and an inclination angle is formed between the two first drainage baffles and the side wall of the flue 2; so that the inner cavity of the flue 2 forms a reducing flow passage.
The two mixer inner baffles 5 are arranged in parallel in the flue 2; and one end thereof is connected with the free end of the first flow-directing baffle 3.
Due to the narrow area caused by the existence of the inclined first flow guide baffle 3, in order to avoid pressure loss caused by backflow of a large amount of smoke flowing into the area, a mixer rear baffle 4 perpendicular to the wall surface of the flue is arranged at the joint of the first flow guide baffle 3 and the mixer inner baffle 5, so that the smoke flows through the square flow channel which is formed by the mixer outer baffle 6 and the wall surface of the flue and flows back to the mixer outer baffle 6.
A mixer rear baffle 4 is arranged at the joint between the first drainage baffle 3 and the mixer inner baffle 5, and the mixer rear baffle 4 is fixed on the side wall of the flue 2.
The two mixer outer baffles 6 are arranged in parallel in the flue 2; and are correspondingly arranged below the baffles 5 in the mixer one by one, and S-shaped flow channels are formed between the baffles 5 in the mixer.
Two second drainage baffles 8 are further arranged at the downstream of the flue 2, and the two second drainage baffles 8 are arranged in a triangular structure.
The free ends of the two second flow guide baffles 8 are respectively connected with the two mixer outer baffles 6.
The free ends of the two second flow-guiding baffles 8 are connected through a mixer front baffle 7.
The mixer front baffle 7 and the mixer outer baffle 6 are perpendicular to each other.
The flue gas flows through the flow channel formed by the inner baffle 5 of the mixer, and flows back to the S-shaped flow channel between the inner baffle 5 of the mixer and the outer baffle 6 of the mixer due to the blocking effect of the front baffle 7 of the mixer.
A concave structure is formed between the mixer front baffle 7 and the mixer outer baffle 6; a triangular structure is formed between the mixer front baffle 7 and the two second drainage baffles 8; so that the two second flow-directing baffles 8 form a divergent flow channel.
The smoke flowing out from the square flow passages on the two sides finally converges and flows to the downstream of the flue, and the pressure loss of the smoke flowing in the suddenly increased through-flow area is avoided due to the gradually expanding flue.
A certain number of SNCR spray guns 9 are arranged on the wall surface of the first drainage baffle plate 3 along the height direction, and reducing agents such as ammonia water or urea solution are sprayed into the flue in the form of tiny droplets after being crushed by the SNCR spray guns 9.
In the flow channel, the flow velocity of the flue gas is gradually increased due to the reduction of the sectional area, and the high-flow-velocity flue gas flows forwards with the reducing agent fog drops; due to the U-shaped flow channel formed by the front baffle 7 of the mixer, the outer baffle 6 of the mixer, the rear baffle 4 of the mixer and the wall surface of the flue, the flue gas/reducing agent starts to flow along a U-shaped route in the mixer, the mixing of the flue gas and the reducing agent is promoted in the advancing and turning process of the flue gas, meanwhile, a strong backflow area can be formed in the local right-angle area of the U-shaped flow channel in the high-speed flowing process, and the mixing effect of the flue gas and the reducing agent in local internal driving can be further improved.
The flue gas and the reducing agent experience U-shaped deflection in two flowing directions in the mixer, and the shrinkage of the flow channel effectively improves tassel, and effective mixing can be expected, so that the ideal SNCR denitration efficiency is obtained, if the SNCR denitration efficiency exceeds 60%, and the concentration of the NOx in the flue gas before the SCR device can be greatly reduced.
As shown in fig. 3, the first flow-guiding baffle 3, the mixer rear baffle 4, the mixer inner baffle 5, the mixer outer baffle 6, the mixer front baffle 7 and the second flow-guiding baffle 8 have the same structure, wherein the first flow-guiding baffle 3 is a heat-resistant steel plate structure 10, such as a 310S stainless steel plate-like structure, and both side surfaces of the plate-like structure are coated with a refractory wear-resistant material layer 11.
The thicknesses D1, D2, and D3 of the heat-resistant steel material 10 and the refractory wear-resistant material layer 11 may be comprehensively designed in combination with the case of the pulverized coal boiler 1 and the mixer.
As shown in fig. 4, having determined the thickness D of the first flow-directing baffle 3, the mixer backplate 4, the mixer inner baffle 5, the mixer outer baffle 6, the mixer front baffle 7 and the second flow-directing baffle 8, i.e. D-1 + D2+ D3, the specific dimensions of the mixer are designed in combination with the flue width 12 of the flue region in the flue 2 suitable for arranging the mixer:
1. inclination angle alpha of first flow-guiding baffle 31And the angle of inclination alpha of the second baffle 82The specific length of the mixer layout area can be specifically designed, and the smaller the value of the specific length, the smaller the pressure loss caused by the reduction or gradual expansion of the flow;
2. in principle, changes in the flow area in the mixer should be avoided in order to reduce the pressure loss of the flow, i.e. the flow width 16 between the mixer inner baffle 5 and the mixer outer baffle 6 is equal to the flow width 15 between the mixer outer baffle 6 and the side wall of the flue 2, and the flow width 13 between two mixer inner baffles 5 is equal to 2 times the flow width 16 between the mixer inner baffle 5 and the mixer outer baffle 6;
3. the baffle length 14 of the mixer tailgate 4 and the baffle length 20 of the mixer tailgate 7 are determined in conjunction with the throughflow widths 13, 15 and 16 and the baffle thickness d;
4. the length 18 of the baffle plate of the inner baffle plate 5 of the mixer and the length 17 of the baffle plate of the outer baffle plate 6 of the mixer need to be determined in consideration of the space of a flue region for arranging the mixer, and can be properly increased when conditions allow, so that the mixing effect and the retention time of flue gas in the mixer are improved, and the SNCR denitration efficiency is favorably improved;
5. since the mixer inner baffle 5 needs to be partially inserted into the concave space formed by the mixer outer baffle 6 and the mixer front baffle 7 to form the U-shaped flow passage, the flow width 19 is equal to the flow width 21 and is equal to the flow width 16 in view of reducing the pressure loss.
Claims (8)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020696275.4U CN212283535U (en) | 2020-04-29 | 2020-04-29 | A flue mixer structure for SNCR denitrification of pulverized coal boiler flue gas |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020696275.4U CN212283535U (en) | 2020-04-29 | 2020-04-29 | A flue mixer structure for SNCR denitrification of pulverized coal boiler flue gas |
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| CN212283535U true CN212283535U (en) | 2021-01-05 |
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| CN202020696275.4U Active CN212283535U (en) | 2020-04-29 | 2020-04-29 | A flue mixer structure for SNCR denitrification of pulverized coal boiler flue gas |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111420542A (en) * | 2020-04-29 | 2020-07-17 | 华能国际电力股份有限公司 | A flue mixer structure for SNCR denitrification of pulverized coal boiler flue gas |
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- 2020-04-29 CN CN202020696275.4U patent/CN212283535U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111420542A (en) * | 2020-04-29 | 2020-07-17 | 华能国际电力股份有限公司 | A flue mixer structure for SNCR denitrification of pulverized coal boiler flue gas |
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