CN113713649B - SCR denitration export flue gas blender - Google Patents

Abstract

The invention relates to an SCR denitration outlet flue gas mixer, which comprises a shell, a first plate body, a second plate body, a third plate body and a fourth plate body, wherein a flue gas channel is formed in the shell, a flue gas inlet and a flue gas outlet are formed at two ends of the shell respectively, the flue gas inlet and the flue gas outlet are square, two ends of the first plate body are connected with two opposite sides of the flue gas outlet respectively, one sides of the second plate body and the third plate body in the length direction are connected with two opposite sides of the flue gas inlet respectively, the other sides of the second plate body and the third plate body in the length direction are connected with the first plate body, the fourth plate body is arranged between the second plate body and the third plate body, and the extending direction of the fourth plate body is consistent with the extending direction of the flue gas channel. The invention realizes the large-range mixing of flue gas, solves the problems of distribution deviation of nitrogen oxides at the outlet of the SCR denitration device and high local ammonia escape concentration, overcomes the limitation of poor adaptability of variable working conditions of the SCR ammonia spraying optimization adjustment technology, and has simple structure.

Description

An SCR denitration outlet flue gas mixer

technical field

The invention belongs to the technical field of SCR denitration, and in particular relates to an SCR denitration outlet flue gas mixer.

Background technique

After the ultra-low emission transformation of the coal-fired power plant, due to the high overall or partial ammonia escape at the outlet of the SCR denitrification device, there will be a serious problem of ammonium hydrogen sulfate blockage in the air preheater, resulting in an increase in the power consumption of the fan and an increase in the exhaust gas temperature. In the mid-low temperature range of 235-147°C in the middle and lower layers of the air preheater, ammonia escape reacts with sulfur trioxide and water vapor in the flue gas to form highly viscous ammonium bisulfate droplets, and the liquid ammonium bisulfate adheres to the heating surface or After the fly ash surface, it will greatly increase its viscosity, promote the deposition of fly ash on the surface of the heat storage element, aggravate the blockage of the air preheater, the deposition rate of ammonium hydrogen sulfate in the air preheater and the ammonia and trioxide in the flue gas. proportional to the sulfur concentration.

In order to improve the quality of SCR denitration automatic control and reduce the instantaneous overall over-injection of ammonia, a multi-point sampling system has emerged in recent years to replace the earlier single-point sampling to eliminate the problem of uneven distribution of nitrogen oxides at the outlet of the SCR denitration reactor. point representative effect. The multi-point sampling system usually arranges 4 to 8 sampling branch pipes in the SCR outlet flue, and the representativeness of the measurement is better than that of the single-point sampling. representative.

In order to reduce the local ammonia escape peak at the SCR outlet, the SCR ammonia injection optimization adjustment test is mainly used to reduce the deviation of nitrogen oxide distribution at the denitrification outlet. The SCR ammonia injection optimization adjustment test is to use the grid method to measure the nitrogen oxide concentration distribution at the denitrification outlet under the stable working conditions of the high load or conventional operating load of the unit, and open the manual valve of the ammonia injection grille corresponding to the high concentration area. The opening of the ammonia injection grille corresponding to the low concentration area is closed and the opening of the manual valve of the ammonia injection grille corresponding to the low concentration area is reduced, so as to reduce the deviation of nitrogen oxide distribution at the denitration outlet. Generally, the local ammonia slip peak also decreases after the NOx distribution deviation at the denitrification outlet is reduced.

However, in terms of adaptability to variable operating conditions, there are still obvious limitations in the optimization and adjustment test of SCR ammonia injection. In the actual operation process, the change of the combustion conditions in the furnace caused by the change of unit load, mill combination and combustion adjustment will lead to a significant change in the concentration distribution of nitrogen oxides at the SCR inlet, and the uniformity of the NH ₃ /NO molar ratio distribution at the catalyst inlet will change. The deviation of nitrogen oxide distribution at the denitrification outlet increases, and the local ammonia escape increases. The large change in the concentration distribution of nitrogen oxides in the measurement section will affect the representativeness of the measurement points of the multi-point sampling system. Therefore, during the operation process, the deviation between the measured value of nitrogen oxides at the denitrification outlet and the emission value of the chimney is often large and small. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an SCR denitration outlet flue gas mixer, which is used to solve the problems of uneven mixing of flue gas in the prior art.

To achieve the above object, the technical scheme adopted in the present invention is:

An SCR denitration outlet flue gas mixer, comprising a casing extending in a single direction, a flue gas channel is formed inside the casing, and a flue gas inlet and a flue gas outlet are formed at both ends of the casing, respectively. The flue gas inlet and the flue gas outlet are all square; the mixer also includes a first plate body, and the two ends of the first plate body are respectively connected with the opposite sides of the flue gas outlet; the The mixer also includes a second plate body and a third plate body, and one side of the second plate body and the third plate body in the longitudinal direction is respectively connected with the opposite sides of the flue gas inlet, and the second plate body and the third plate body are respectively connected with the opposite sides of the flue gas inlet. The other side of the plate body and the third plate body in the length direction is connected with the first plate body, and the second plate body and the third plate body are along the width direction of the first plate body. extending from one end to the other end; the mixer further includes a fourth plate body, the fourth plate body is arranged between the second plate body and the third plate body, and the fourth plate body is The extension direction of the plate body is consistent with the extension direction of the flue gas channel.

Preferably, the size of the opening of the flue gas inlet is larger than the size of the opening of the flue gas outlet.

Further preferably, the cross section from the flue gas inlet to the flue gas outlet gradually decreases.

Preferably, the first plate body includes a first left plate body and a first right plate body, the first left plate body and the first right plate body are arranged in parallel, and the first left plate body, A gap is formed between the first right plate bodies.

Preferably, the second plate body includes a second left plate body and a second right plate body, and one side of the second left plate body and the second right plate body in the longitudinal direction is respectively connected with the smoke The opposite sides of the inlet are connected, the other side of the second left plate body in the length direction is connected with the first right plate body, and the other side of the second right plate body in the length direction is connected with the said first right plate body. The first left board body connection.

Preferably, the third plate body includes a third left plate body and a third right plate body, and one side of the third left plate body and the third right plate body in the longitudinal direction is respectively connected with the flue gas. The opposite sides of the inlet are connected, the other side of the third left plate body in the length direction is connected with the first left plate body, and the other side of the third right plate body in the length direction is connected with the said first left plate body. the first right board body connection.

Preferably, the fourth plate body includes a fourth front plate body and a fourth rear plate body, and the fourth front plate body is disposed between the second right plate body and the third left plate body, The fourth rear plate body is arranged between the second left plate body and the third front plate body.

Preferably, the fourth front plate body and the fourth rear plate body are both trapezoidal, and the two end points of the upper bottom edges of the fourth front plate body and the fourth rear plate body are respectively connected with the first The left plate body and the first right plate body are connected, and the two end points of the lower bottom edges of the fourth front plate body and the fourth rear plate body are respectively connected with the opposite sides of the flue gas inlet.

Preferably, one side of the second right plate body in the width direction is connected to the inner wall of the casing, and the other side of the second right plate body in the width direction is connected to the fourth front plate body connected to form a first chimney between the second right plate body, the fourth front plate body and the casing; one side of the second left plate body in the width direction is connected to the inner wall of the casing connection, the other side of the second left plate body in the width direction is connected with the fourth rear plate body, so that the second left plate body, the fourth rear plate body and the shell form a first Two chimneys.

Preferably, both sides of the third left plate body and the third right plate body in the width direction are respectively connected with the fourth front plate body and the fourth rear plate body, so that the third left plate body is , A third flue is formed between the third right plate body, the fourth front plate body and the fourth rear plate body.

Due to the application of the above-mentioned technical solutions, the present invention has the following advantages compared with the prior art:

The flue gas mixer proposed by the invention can realize the large-scale mixing of flue gas, solve the problems of deviation of nitrogen oxide distribution at the outlet of the SCR denitration device and high local ammonia escape concentration, and overcome the need for the SCR ammonia injection optimization adjustment test technology to change the work. It has the limitation of poor adaptability in the aspect of adaptability, and has simple structure, convenient use and good stability.

Description of drawings

1 is a schematic perspective view of the flue gas mixer of the present embodiment;

2 is a schematic front view of the flue gas mixer of the present embodiment;

3 is a schematic side view of the flue gas mixer of the present embodiment;

4 is a schematic top view of the flue gas mixer of the present embodiment;

FIG. 5 is a three-dimensional schematic diagram of the housing and the first plate body of the present embodiment;

FIG. 6 is a schematic perspective view of the housing, the first plate body, the second plate body and the third plate body in this embodiment;

Accompanying drawing 7 is the flue gas flow diagram in the flue gas mixer of the present embodiment;

Accompanying drawing 8 is the ammonia and nitric oxide concentration distribution diagram that does not adopt flue gas mixer;

Accompanying drawing 9 is the ammonia and nitric oxide concentration distribution diagram adopting Sulzer corrugated mixer;

FIG. 10 is a diagram showing the concentration distribution of ammonia and nitric oxide using the flue gas mixer of this embodiment.

In the above drawings: 1, the shell; 2, the first plate body; 21, the first left plate body; 22, the first right plate body; 3, the second plate body; 31, the second left plate body; 32, The second right plate body; 4, the third plate body; 41, the third left plate body; 42, the third right plate body; 5, the fourth plate body; 51, the fourth front plate body; 52, the fourth rear plate body.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

An SCR denitration outlet flue gas mixer, as shown in Figures 1 to 4, includes a casing 1, a first plate body 2, a second plate body 3, a third plate body 4 and a fourth plate body 5. The first plate body 5 The plate body 2, the second plate body 3, the third plate body 4 and the fourth plate body 5 are all arranged inside the casing 1, wherein:

The casing 1 extends in a single direction, and a flue gas channel is formed inside the casing 1. The two ends of the casing 1 respectively form a flue gas inlet and a flue gas outlet. The flue gas inlet and the flue gas outlet are both square; Larger than the opening size of the flue gas outlet, as shown in Figure 3, the section from the flue gas inlet to the flue gas outlet gradually decreases.

Both ends of the first plate body 2 are respectively connected with the opposite sides of the flue gas outlet of the casing 1 in the width direction. As shown in FIG. 5 , the first plate body 2 includes a first left plate body 21 and a first right plate body. 22. The first left plate body 21 and the first right plate body 22 are arranged in parallel, and a gap is formed between the first left plate body 21 and the first right plate body 22 .

One side of the second plate body 3 and the third plate body 4 in the longitudinal direction are respectively connected with the opposite sides of the flue gas inlet of the casing 1 in the longitudinal direction. The second plate body 3 and the third plate body 4 are in the longitudinal direction. The other side is connected with the first plate body 2, and the second plate body 3 and the third plate body 4 extend along the direction from one end to the other end of the first plate body 2 in the width direction, as shown in FIG. Word:

The second plate body 3 includes a second left plate body 31 and a second right plate body 32 . One side of the second left plate body 31 and the second right plate body 32 in the length direction is respectively the length of the flue gas inlet of the casing 1 . The opposite sides in the direction are connected, the other side of the second left plate body 31 in the longitudinal direction is connected with the first right plate body 22, and the other side of the second right plate body 32 in the longitudinal direction is connected with the first left plate body 21 .

The third plate body 4 includes a third left plate body 41 and a third right plate body 42 , and one side of the third left plate body 41 and the third right plate body 42 in the longitudinal direction is respectively the length of the flue gas inlet of the casing 1 . The opposite sides in the direction are connected, the other side of the third left plate body 41 in the length direction is connected with the first left plate body 21, and the other side of the third right plate body 42 is connected with the first right plate body 22 in the length direction. .

The fourth plate body 5 is disposed between the second plate body 3 and the third plate body 4 , and the extending direction of the fourth plate body 5 is consistent with the extending direction of the flue gas channel of the casing 1 . The fourth plate body 5 includes a fourth front plate body 51 and a fourth rear plate body 52. The fourth front plate body 51 is disposed between the second right plate body 32 and the third left plate body 41. The fourth rear plate body 52 It is arranged between the second left plate body 31 and the third plate body 42, specifically:

Both the fourth front plate body 51 and the fourth rear plate body 52 are trapezoidal, and the two end points of the upper bottom edges of the fourth front plate body 51 and the fourth rear plate body 52 are The plate bodies 22 are connected, and the two end points of the lower bottom edges of the fourth front plate body 51 and the fourth rear plate body 52 are respectively connected to the opposite sides of the flue gas inlet of the casing 1 in the longitudinal direction.

The second left plate body 31 , the second right plate body 32 , the third left plate body 41 , the third right plate body 42 , the fourth front plate body 51 , and the fourth rear plate body 52 connect the flue gas passages in the casing 1 Divided into multiple chimneys, specifically:

One side of the second right plate body 32 in the width direction is connected to the inner wall of the housing 1, and the other side of the second right plate body 32 is connected to the fourth front plate body 51 in the width direction, so that the second right plate body 32, A first flue is formed between the fourth front plate 51 and the casing 1; one side of the second left plate 31 in the width direction is connected to the inner wall of the casing 1, and the second left plate 31 in the width direction is connected to the inner wall of the casing 1. The other side is connected with the fourth rear plate body 52, so that a second chimney is formed between the second left plate body 31, the fourth rear plate body 52 and the casing 1; the third left plate body 41 and the third right plate body 42 are respectively connected with the fourth front plate body 51 and the fourth rear plate body 52 on both sides in the width direction, so that the third left plate body 41 , the third right plate body 42 , the fourth front plate body 51 and the fourth rear plate body A third flue is formed between the bodies 52 .

When the flue gas passes through the first flue, since the second right plate body 32 is inclined, that is, the second right plate body 32 forms an angle with the extending direction of the flue gas passage, the second right plate body 32 can flow to the first The flue gas in one flue is diverted from right to left; when the flue gas passes through the second flue, the second left plate body 31 is slanted, that is, the second left plate body 31 is formed with the extending direction of the flue gas passage. Therefore, the second left plate body 31 can guide the flue gas flowing into the first flue from left to right; when the flue gas passes through the third flue, because the third left plate body 41, the third right The plate body 42 is arranged obliquely, that is, the third left plate body 41 and the third right plate body 42 form an angle with the extending direction of the flue gas channel, so the third left plate body 41 and the third right plate body 42 can flow to the third The flue gas in the branch flue is guided from both sides to the middle, which promotes the flue gas to form a large-scale rotating vortex on the cross-section of the flue gas outlet, as shown in Figure 7, so as to realize a wide range of flue gas mixing.

In addition, by adjusting the distance between the first left plate body 21 and the first right plate body 22, the second left plate body 31, the second right plate body 32, the third left plate body 41, and the third right plate body can be made The angle of the included angle formed by 42 and the extending direction of the flue gas channel changes, so as to control the rotation intensity of the airflow, achieve different mixing effects and resistances, and meet the needs of different mixing uniformity. In this embodiment, the included angle between the second left plate body 31, the second right plate body 32 and the extending direction of the flue gas channel is 70°, and the third left plate body 41, the third right plate body 42 and the flue gas channel are at an angle of 70°. The included angle of the extension direction is 55°.

In the case of not using the flue gas mixer, using the Sulzer corrugated mixer, and using the flue gas mixer of this embodiment, simulation tests were performed on the concentration distribution deviations of ammonia and nitric oxide in the flue of the SCR denitration outlet. When the flue gas mixer is not used, the SCR denitration outlet flue includes a constriction section and an outlet section. The flue gas flows from the constriction section to the outlet section, and the size of the opening from the inlet to the outlet of the constriction section gradually decreases; when using Sur When the Sulzer corrugated mixer is used, the SCR denitration outlet flue includes a constriction section and an outlet section. The flue gas flows from the constriction section to the outlet section, and the size of the opening from the inlet to the outlet of the constriction section gradually decreases. The Sulzer corrugated mixer is set In the outlet section; when the flue gas mixer of this embodiment is used, the SCR denitration outlet flue includes the flue gas mixer of this embodiment and the outlet section, and the flue gas flows from the flue gas outlet of the flue gas mixer of this embodiment. flow to the exit section.

The simulation test results are shown in Figures 8 to 10. The deviations of ammonia concentration distribution and nitric oxide concentration distribution at different locations under different conditions are obtained. As shown in Table 1 and Table 2, 15 downstream of the Sulzer ripple mixer Compared with the flue gas mixer without the use of the flue gas mixer, the concentration distribution deviations of ammonia and nitric oxide are both reduced by about 76% after using the flue gas mixer of this embodiment, compared with the use of the Sulzer corrugated mixer. , after using the flue gas mixer of this embodiment, the concentration distribution deviation of ammonia and nitric oxide is reduced by about 57%, the distribution uniformity is greatly improved, and the nitrogen oxide distribution deviation and local ammonia escape peak are effectively eliminated.

Table 1 Deviation of ammonia concentration distribution at different locations

Table 2 Deviation of nitric oxide concentration distribution at different locations

The above-mentioned embodiments are only intended to illustrate the technical concept and characteristics of the present invention, and the purpose thereof is to enable those who are familiar with the art to understand the content of the present invention and implement them accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included within the protection scope of the present invention.

Claims (3)

1. The utility model provides a SCR denitration export flue gas blender which characterized in that: the smoke-free air conditioner comprises a shell extending along a single direction, wherein a smoke channel is formed in the shell, a smoke inlet and a smoke outlet are formed at two ends of the shell respectively, and the smoke inlet and the smoke outlet are square; the mixer also comprises a first plate body, and two ends of the first plate body are respectively connected with two opposite sides of the smoke outlet; the mixer also comprises a second plate body and a third plate body, wherein one side of the second plate body and one side of the third plate body in the length direction are respectively connected with two opposite sides of the flue gas inlet, the other sides of the second plate body and the third plate body in the length direction are both connected with the first plate body, and the second plate body and the third plate body extend along the direction from one end of the first plate body to the other end in the width direction; the mixer also comprises a fourth plate body which is arranged between the second plate body and the third plate body, the extending direction of the fourth plate body is consistent with the extending direction of the smoke channel,

the first plate body comprises a first left plate body and a first right plate body which are arranged in parallel, and a gap is formed between the first left plate body and the first right plate body;

the second plate body comprises a second left plate body and a second right plate body, one side of the second left plate body and one side of the second right plate body in the length direction are respectively connected with two opposite sides of the flue gas inlet, the other side of the second left plate body in the length direction is connected with the first right plate body, and the other side of the second right plate body in the length direction is connected with the first left plate body;

the third plate body comprises a third left plate body and a third right plate body, one side of the third left plate body and one side of the third right plate body in the length direction are respectively connected with two opposite sides of the flue gas inlet, the other side of the third left plate body in the length direction is connected with the first left plate body, and the other side of the third right plate body in the length direction is connected with the first right plate body;

the fourth plate body comprises a fourth front plate body and a fourth rear plate body, the fourth front plate body is arranged between the second right plate body and the third left plate body, the fourth rear plate body is arranged between the second left plate body and the third left plate body,

the fourth front plate body and the fourth rear plate body are both trapezoidal, two end points of the upper bottom edge of the fourth front plate body and the fourth rear plate body are respectively connected with the first left plate body and the first right plate body, two end points of the lower bottom edge of the fourth front plate body and the fourth rear plate body are respectively connected with two opposite sides of the flue gas inlet, one side of the second right plate body in the width direction is connected with the inner wall of the shell, and the other side of the second right plate body in the width direction is connected with the fourth front plate body, so that a first branch flue is formed among the second right plate body, the fourth front plate body and the shell; the second left plate body on one side on width direction with shells inner wall connect, the second left plate body on the another side on width direction with fourth back plate body connect, make the second left plate body, fourth back plate body, casing between form second branch flue, the third left plate body, the third right plate body on width direction both sides respectively with fourth preceding plate body, fourth back plate body connect, make the third left plate body, the third right plate body, fourth preceding plate body, fourth back plate body between form third branch flue.

2. The SCR denitration outlet flue gas mixer of claim 1, wherein: the opening size of the smoke inlet is larger than that of the smoke outlet.

3. The SCR denitration outlet flue gas mixer of claim 2, wherein: the section from the flue gas inlet to the flue gas outlet is gradually reduced.

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