CN216630330U

CN216630330U - Static mixer

Info

Publication number: CN216630330U
Application number: CN202122426136.7U
Authority: CN
Inventors: 谢新华; 周健; 何金亮; 陈宝康; 卢承政; 韦振祖; 梁俊杰; 李明磊; 黄飞
Original assignee: Xian Thermal Power Research Institute Co Ltd; Suzhou Xire Energy Saving Environmental Protection Technology Co Ltd
Current assignee: Xian Thermal Power Research Institute Co Ltd; Suzhou Xire Energy Saving Environmental Protection Technology Co Ltd
Priority date: 2021-10-09
Filing date: 2021-10-09
Publication date: 2022-05-31
Anticipated expiration: 2031-10-09

Abstract

The utility model relates to a static mixer which comprises at least one mixing unit, wherein the mixing unit comprises a plurality of mixing elements, each mixing element comprises a first plate body and a second plate body, one sides of the first plate body and the second plate body are connected to form an included angle of 0-180 degrees, each mixing element comprises a first mixing element and a second mixing element which are positioned on one side, and a third mixing element and a fourth mixing element which are positioned on the other side, the first mixing element and the second mixing element are parallel to each other and form a first channel therebetween, the third mixing element and the fourth mixing element are parallel to each other and form a second channel therebetween, and the extending directions of the first channel and the second channel form an included angle of 0-180 degrees in space. The utility model can ensure NO at the inlet of the ammonia spraying grid_xThe concentration distribution is greatly reduced relative to the standard deviation, the weight is lighter under the condition of the same resistance, the resistance is smaller under the condition of the same weight, and the structure with the side opening and the slope surface prevents the serious dust deposition in the mixer from the root.

Description

Static mixer

Technical Field

The utility model relates to the field of flue gas denitration and chemical industry, in particular to a static mixer.

Background

To satisfy NO_xUltra low emission of NO from coal-fired power plants_xThe emission is reduced to 50mg/m³Hereinafter, the SCR denitration efficiency needs to be improved to about 90%. In order to control the ammonia escape concentration and ensure the safe operation of the unit, not only the catalyst with enough volume needs to be added,NH to top catalyst inlet of SCR reactor₃/NO_xThe uniformity of the molar ratio distribution also places higher demands. NO at SCR inlet_xConcentration and distribution are directly related to combustion conditions in the furnace, and the change of load and grinding combination of a unit and the change of the combustion conditions in the furnace brought by combustion adjustment can cause NO at an SCR inlet_xThe concentration distribution is obviously changed, and NH at the inlet of the catalyst₃/NO_xThe uniformity of the distribution of the molar ratio is poor, the escape of ammonia at the denitration outlet is increased,

for increasing NH inlet of SCR catalyst₃/NO_xUniformity of molar ratio distribution, AIG nozzles and static mixers are typically arranged in an array of SCR inlet cross sections to enhance mixing of the nozzle outlet reductant ammonia with the flue gas. The mixing range of the SCR static mixers is small (less than or equal to 3 m), and the SCR static mixers can only adapt to NO in upstream smoke by adjusting the flow of AIG branch pipes_xVariations in concentration and flow fields. AIG upstream NO when different loads of the unit and coal mills are combined_xWhen the concentration distribution changes greatly, the working condition of the conventional ammonia spraying mixing device cannot be self-adapted, and the NH at the catalyst inlet₃/NO_xThe mixing uniformity becomes worse.

For example, chinese patent document CN106731827A discloses an AIG upstream flue gas large-scale self-mixing device, in which a diamond-shaped partition part is arranged in the middle of the inlet, both sides of the device are guided by straight plates or folded plates, and the outlet is not provided with a flow-around element, because of the limitation of the inlet and outlet structures of the device, only NO at the inlet of an ammonia injection grid can be used_xThe concentration distribution is reduced by 20-40% relative to the standard deviation, and the performance needs to be further improved. Chinese patent document CN112717683A discloses a triangular multi-channel SCR static mixer, which makes NO at the inlet of ammonia injection grid_xThe reduction range of the concentration distribution relative to the standard deviation reaches more than 60 percent, but the size and the weight are large, and the device can only be used for an SCR denitration device with a part of vertical flues being long. Chinese patent document CN100339154C discloses a static mixer for low viscosity fluid, which is a cross channel static mixer composed of corrugated plates, and has small size and weight, flexible arrangement, but the risk of ash deposition in the channel when used in an SCR inlet horizontal flue.

Need to develop a new type of SCR static mixer, reduce the load of the unit, grind the combination and adjust the combustion to the SCR inlet NO_xThe influence of concentration distribution fundamentally improves the working condition change adaptability of the SCR denitration device and reduces ammonia escape.

SCR: selective Catalytic Reduction, SCR for short. The SCR denitration technology means that a reducing agent (such as liquid ammonia, urea, ammonia water and the like) selectively reacts with NOx in flue gas under the action of a catalyst within the range of 280-420 ℃ to generate pollution-free N₂And H₂NO of O_xAnd (3) emission reduction technology.

And (3) AIG: an Ammonia Injection Grid (AIG for short) is a device for uniformly injecting a reducing agent into flue gas.

The information disclosed in this background section is only for enhancement of understanding of the general background of the utility model and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The utility model aims to provide a static mixer which can be used for mixing flue gas at an SCR denitration inlet, greatly improves the weight, resistance and mixing effect compared with the prior art, can eliminate the risk of ash deposition in a channel, and can also be used for mixing various fluids in the chemical field.

In order to achieve the purpose, the utility model adopts the technical scheme that:

a static mixer comprises at least one mixing unit, wherein one end of the mixing unit forms an inlet end, the other end forms an outlet end, the mixing unit comprises a plurality of mixing elements, each mixing element comprises a first plate body and a second plate body, one side of each first plate body and one side of each second plate body are connected, so that an included angle which is larger than 0 degree and smaller than 180 degrees is formed between the first plate body and the second plate body, each mixing element comprises a first mixing element and a second mixing element which are positioned on one side, a third mixing element and a fourth mixing element which are positioned on the other side, the first mixing elements and the second mixing elements are arranged in parallel, a first channel for media to flow is formed between the first mixing elements and the second mixing elements, a second channel for media to flow is formed between the third mixing elements and the fourth mixing elements in parallel, and an included angle which is larger than 0 degree and smaller than 180 degrees is formed in space in the extending direction of the first channel and the second channel, one end of the first channel and one end of the second channel are the inlet ends, and the other end of the first channel and the other end of the second channel are the outlet ends.

Preferably, among first mixing element, the second mixing element the opening orientation of the contained angle that forms between first plate body, the second plate body is the same, just among the second mixing element the opening orientation of the contained angle that forms between first plate body, the second plate body first mixing element, among the third mixing element, the fourth mixing element the opening orientation of the contained angle that forms between first plate body, the second plate body is the same, just among the third mixing element the opening orientation of the contained angle that forms between first plate body, the second plate body fourth mixing element.

Further preferably, in the first mixing element and the fourth mixing element, the openings of the included angle formed between the first plate body and the second plate body face opposite directions, and in the second mixing element and the third mixing element, the openings of the included angle formed between the first plate body and the second plate body face opposite directions.

Preferably, the projections of the first and second channels on the inlet end of the mixing unit are parallel to each other.

Preferably, an included angle formed between the first plate body and the second plate body ranges from 60 degrees to 120 degrees.

Preferably, the extending directions of the first channel and the second channel form an included angle of 60-150 degrees in space.

Preferably, the first mixing element, the second mixing element, the third mixing element and the fourth mixing element are the same in shape.

Preferably, the first plate body and the second plate body of the same mixing element are identical in shape and symmetrically arranged, and the first plate body and the second plate body are in a parallelogram shape or a trapezoid shape.

Preferably, in the same mixing unit, the first mixing element is connected to the third mixing element, and the second mixing element is connected to the fourth mixing element.

Further preferably, in the same mixing unit, one end of the first mixing element is connected to one end of the fourth mixing element.

Still further preferably, the first and second mixing elements are at a distance L from one end of the first channel, the third and fourth mixing elements are at a distance L from one end of the second channel, and the shortest distance between the second mixing element at the other end of the first channel and the third mixing element at the other end of the second channel is d, d = 0.1-0.5L.

Preferably, when the static mixer is provided with a plurality of mixing units, the inlet ends of the plurality of mixing units are located on the same plane, one end of a first mixing element in one mixing unit is connected with one end of a fourth mixing unit in an adjacent mixing unit, the first mixing element in one mixing unit is connected with a third mixing unit in an adjacent mixing unit, one end of a second mixing element in one mixing unit is connected with one end of a third mixing unit in an adjacent mixing unit, and the second mixing element in one mixing unit is connected with the fourth mixing unit in an adjacent mixing unit.

Due to the application of the technical scheme, compared with the prior art, the utility model has the following advantages:

the utility model can make the NO at the inlet of the ammonia injection grid_xThe concentration distribution has the advantages of greatly reduced relative standard deviation, simple structure, easy production and manufacture, saved consumption of production materials, lighter weight under the condition of the same resistance, smaller resistance under the condition of the same weight, and capability of preventing serious dust deposition inside the mixer fundamentally due to the structure of the side opening and the slope surface when being arranged in a flue.

Drawings

FIG. 1 is a schematic structural diagram of a mixing unit in this embodiment;

FIG. 2 is a schematic view of the structure of the static mixer in this embodiment;

FIG. 3 is a front view of the static mixer disposed within the flue in this embodiment;

FIG. 4 is a top view of the static mixer in this embodiment disposed within the flue;

FIG. 5 is a schematic front view of a flue gas flow line with the static mixer disposed in the flue of this embodiment;

FIG. 6 is a schematic top view of a flue gas flow line with the static mixer disposed in the flue in this embodiment;

FIG. 7 shows NO when the static mixer is disposed in the flue in this embodiment_xCFD simulation results of the mixing effect are shown schematically.

In the above drawings: 1. a first mixing element; 2. a second mixing element; 3. a third mixing element; 4. a fourth mixing element; 5. a first plate body; 6. a second plate body.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, 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. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in figures 1 and 2, the static mixer comprises a mixing unit, wherein the flue gas can be mixed by one mixing unit, the flue gas can also be mixed by mutually matching and connecting a plurality of mixing units, one end of each mixing unit forms an inlet end, the other end forms an outlet end, and the inlet end and the outlet end of each mixing unit are arranged along the flowing direction of the flue gas.

As shown in fig. 1, the mixing unit includes a plurality of mixing elements, the shape of the plurality of mixing elements is the same, each mixing element includes a first plate 5 and a second plate 6, the shape of the first plate 5 and the second plate 6 is also the same and adopts a parallelogram or a trapezoid, one side of the first plate 5 and one side of the second plate 6 are connected, so that an included angle α of more than 0 ° and less than 180 ° is formed between the first plate 5 and the second plate 6, as shown in fig. 1, that is, the first plate 5 and the second plate 6 are integrally arranged and spliced into a folded plate. The sharp-angled structure and the inside of the corner of the mixing element are provided with the folded structure, so that the boundary layer of the flue gas falls off on two sharp angles and sharp edges at the tail end of the mixing element to generate vortex on a microscopic layer, and the mixing effect of the flue gas is improved. In same mixing element, first plate body 5, the symmetry setting of second plate body 6, the contained angle that forms between first plate body 5, the second plate body 6 is 60~120 when, under the mixing element's of equidimension condition, the flue gas mixing effect is better.

The mixing elements comprise a first mixing element 1 and a second mixing element 2 which are positioned on one side of the mixing unit, and a third mixing element 3 and a fourth mixing element 4 which are positioned on the other side of the mixing unit, wherein the first mixing element 1 and the second mixing element 2 are arranged in parallel (namely, the first plate body 5 and the second plate body 6 are respectively parallel), and a first channel for flue gas flowing is formed between the first mixing element 1 and the second mixing element 2, the third mixing element 3 and the fourth mixing element 4 are arranged in parallel (namely, the first plate body 5 and the second plate body 6 are respectively parallel), and a second channel for flue gas flowing is formed between the third mixing element 3 and the fourth mixing element 4, one end of the first channel and one end of the second channel are inlet ends of the mixing unit, and the other end of the first channel and the other end of the second channel are outlet ends of the mixing unit.

As shown in fig. 1 and 2, the openings of the included angle formed between the first plate body 5 and the second plate body 6 in the first mixing element 1 and the second mixing element 2 are oriented in the same direction, the openings of the included angle formed between the first plate body 5 and the second plate body 6 in the second mixing element 2 are oriented in the first mixing element 1, and the first mixing element 1 and the second mixing element 2 are arranged along the direction of the opening orientation. The openings of the included angle formed between the first plate body 5 and the second plate body 6 in the third mixing element 3 and the fourth mixing element 4 are in the same direction, the openings of the included angle formed between the first plate body 5 and the second plate body 6 in the third mixing element 3 are in the direction of the fourth mixing element 4, and the third mixing element 3 and the fourth mixing element 4 are arranged along the direction of the opening directions. In the same mixing unit, the openings of the included angles formed between the first plate body 5 and the second plate body 6 in the first mixing element 1 and the fourth mixing element 4 face opposite directions, and the openings of the included angles formed between the first plate body 5 and the second plate body 6 in the second mixing element 2 and the third mixing element 3 face opposite directions.

In the flue, the first mixing element 1 and the second mixing element 2 and the third mixing element 3 and the fourth mixing element 4 are arranged along the length direction of the flue, but the first mixing element 1 and the second mixing element 2 are opposite to the openings of the third mixing element 3 and the fourth mixing element 4, the first mixing element 1 and the fourth mixing element 4 are arranged diagonally, and the second mixing element 2 and the third mixing element 3 are arranged diagonally. In the same mixing unit, the first mixing element 1 is connected with the third mixing element 3, the second mixing element 2 is connected with the fourth mixing element 4, so as to form a structure for supporting and stabilizing the static mixer, and one end of the first mixing element 1 is connected with one end of the fourth mixing element 4 (namely, connected at the inlet end of the mixing unit), so that the static mixer is convenient to install and position. Through forming the modular matrix structure, help the stable even flow of flue gas, be convenient for mix.

The extending directions of the first channel and the second channel form an included angle beta which is larger than 0 degrees and smaller than 180 degrees in space, as shown in figure 3, but the projections of the first channel and the second channel on the inlet end of the mixing unit are parallel to each other. Equivalently, the first channel and the second channel are arranged in a crossed manner, and are not completely parallel in space, but at the same time, the space where the extension range of the first channel is located and the space where the extension range of the second channel is located are parallel to each other, and the first channel and the second channel are not overlapped in a crossed manner, as shown in fig. 1. The structure of the mixing unit enables the mixing element to be provided with openings on the side surface, and meanwhile, the structural design of the mixing element with the slope surface in the smoke flowing direction fundamentally prevents the interior of the mixer from being seriously accumulated with dust. When the extending direction of first passageway, second passageway contained angle in the space was 60~150, under the mixing element's of equidimension condition, the flue gas mixing effect was better, can both have the vortex mixing effect, avoids too big resistance simultaneously.

The distance between the first mixing element 1 and the second mixing element 2 at one end of the first channel is L, the distance between the third mixing element 3 and the fourth mixing element 4 at one end of the second channel is L, as shown in fig. 2, 3 and 4, i.e. the opening width of the first channel and the second channel at the inlet end of the mixing unit is L, the shortest distance between the second mixing element 2 at the other end of the first channel and the third mixing element 3 at the other end of the second channel is d, as shown in fig. 2, 3 and 4, and d =0.1 to 0.5L, the inlet end of the mixing unit can be observed from the outlet end of the mixing unit in the flue gas flowing direction of the flue gas without being blocked by the mixing elements, as shown in fig. 4, a certain distance d is reserved at the other end point of the second mixing element 2 and the third mixing element 3, the resistance when the flue gas flows out can be reduced, by defining the length ratio of d to L, to avoid excessive resistance due to the too long length of the mixing element.

As shown in fig. 3 and 4, when the static mixer is provided with a plurality of mixing units, the inlet ends of the plurality of mixing units are positioned on the same plane to jointly form the inlet of the static mixer, the outlet ends of the plurality of mixing units are positioned on the same plane to jointly form the outlet of the static mixer, one end of the first mixing element 1 in one mixing unit is connected with one end of the fourth mixing element 4 in the adjacent mixing unit (i.e. at the inlet of the mixing unit), the first mixing element 1 in one mixing unit is connected with the third mixing element 3 in the adjacent mixing unit (i.e. at the side edge of the respective plate body), one end of the second mixing element 2 in one mixing unit is connected with one end of the third mixing element 3 in the adjacent mixing unit (i.e. at the inlet of the mixing unit), the second mixing element 2 in one mixing unit is connected with the fourth mixing element 4 in the adjacent mixing unit (i.e. at the side edge of the respective plate body), forming a matrix structure. In the length direction of the flue, the mixing units are arranged in parallel at equal intervals (L), and are also arranged in parallel at equal intervals (L) of the mixing elements, and in the width direction of the flue, the mixing units are connected in parallel, namely, the projections of the adjacent first channel and the second channel between the adjacent mixing units on the inlet end of the static mixer are parallel to each other. The larger the number of mixing units provided, the poorer the mixing effect in the width direction of the flue.

Specific applications of this example and comparison with the prior art are given below:

in a section of SCR inlet flue with the cross-sectional dimension of 15m 3m, a static mixer as shown in FIG. 2 is arranged to form a structure as shown in FIGS. 3 and 4. In the length direction of the flue, 5 sets of mixing units were provided, and in the width direction of the flue, 2 sets of mixing units were provided. The first mixing element 1 and the third mixing element 3 are perpendicularly crossed at 90 degrees, the second mixing element 2 and the fourth mixing element 4 are perpendicularly crossed at 90 degrees, the first plate body 5 and the second plate body 6 of the mixing elements are parallelogram, the included angle between the first plate body and the second plate body is 90 degrees, L =1.5m, d =0.7m, and the height of the static mixer is 1.1m along the flowing direction of smoke. The average flow velocity of the flue gas is 15m/s, and NO is introduced into an SCR inlet_xThe distribution is in a severe distribution with one side higher and the other side lower.

After adding the static mixer of this example, NO_xThe relative standard deviation (CV value) of the concentration distribution decreased from 50% to 21% after a mixing distance of 10m and from 50% to 18% after a mixing distance of 15m, as shown in fig. 7. Chinese patent literatureCN112717683A discloses a triangular multi-channel SCR static mixer, NO_xThe relative standard deviation (CV value) of the concentration distribution was reduced from 50% to 24% over a mixing distance of 10m and from 50% to 18% over a mixing distance of 10 m. Chinese patent document CN100339154C discloses a static mixer for low viscosity fluids, which uses a corrugated plate static mixer, NO_xThe relative standard deviation (CV value) of the concentration distribution was reduced from 50% to 23% over a mixing distance of 10m and from 50% to 21% over a mixing distance of 15 m.

The three mixer sizes and performance index comparisons are detailed in table 1. Compared with the triangular multi-channel SCR static mixer disclosed in Chinese patent document CN112717683A, the static mixer of the embodiment has absolute advantages in weight and size, and the short-distance mixing effect is better. Compared with the static mixer for low-viscosity fluid disclosed in chinese patent document CN100339154C, which uses a corrugated plate static mixer, the static mixer of the present embodiment has better effects of weight, mixing effect and resistance. In addition, the structural design of the side openings and the slope surfaces of the mixing elements in the embodiment fundamentally prevents the static mixer from being seriously accumulated with dust.

Table 1 shows the results of comparing the mixing effect of the present example with chinese patent documents CN112717683A and CN 100339154C:

the mixing principle of the static mixer in this embodiment is:

in the length direction of the flue, a plurality of mixing units are arranged at equal intervals (L), a flue gas channel is formed between every two adjacent mixing elements, and the streamline of the flue gas after mixing is shown in figures 5 and 6. In the width direction of the flue, the first mixing element 1 and the third mixing element 3 are crossed and paired with each other, the second mixing element 2 and the fourth mixing element 4 are crossed and paired with each other, the arrangement divides the flowing flue gas into even layers in the width direction of the flue, the left layer flows to the right layer by layer, under the action of the mixing elements, the flue gas is divided and transferred, after the flue gas is transferred to the left by a certain channel, the air pressure at the right side of the channel is reduced, after the flue gas is transferred to the right by a certain channel, the air pressure at the left side of the channel is reduced, therefore, a vortex is formed in a mixing unit, but at the same time, the flow directions of the flue gas are uniform in each layer, the integral transfer of the flue gas is caused, and therefore, the large-range transfer and cross mixing of the air flow are realized, as shown in fig. 5. The cross-flow downstream of the static mixer flows forward while swirling, presenting a set of swirling vortices, forming a large vortex mixing, as shown in fig. 6. On a microscopic level, the boundary layer of the airflow falls off on two sharp corners and sharp edges at the tail end of the mixing element to generate vortex, and the mixing effect is further improved.

The static mixer in this embodiment is not limited to be used in the field of SCR denitration, and may also be used for mixing fluids in the chemical field, and the mixing principle is the same as that described above, and the mixed flow state of the fluids is the same as that of the flue gas described above.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A static mixer, characterized by: including at least one mixing unit, mixing unit's one end forms the entry end, the other end forms the exit end, mixing unit includes a plurality of mixing element, mixing element includes first plate body, second plate body, one side of first plate body, second plate body is connected, makes form between first plate body, the second plate body and is greater than 0 and is less than 180 contained angle, mixing element is including the first mixing element and the second mixing element that are located one side, the third mixing element and the fourth mixing element that are located the opposite side, first mixing element, second mixing element parallel arrangement and form the first passageway that supplies the medium flow between the two, third mixing element, fourth mixing element parallel arrangement and form the second passageway that supplies the medium flow between the two, the extending direction of first passageway, second passageway forms the contained angle that is greater than 0 and is less than 180 on the space, one end of the first channel and one end of the second channel are the inlet ends, and the other end of the first channel and the other end of the second channel are the outlet ends.

2. The static mixer of claim 1, wherein: in first mixing element, the second mixing element the opening orientation of the contained angle that forms between first plate body, the second plate body is the same, just in the second mixing element the opening orientation of the contained angle that forms between first plate body, the second plate body first mixing element, in third mixing element, the fourth mixing element the opening orientation of the contained angle that forms between first plate body, the second plate body is the same, just in the third mixing element the opening orientation of the contained angle that forms between first plate body, the second plate body the fourth mixing element.

3. The static mixer of claim 2, wherein: the opening directions of the included angle formed between the first plate body and the second plate body in the first mixing element and the fourth mixing element are opposite, and the opening directions of the included angle formed between the first plate body and the second plate body in the second mixing element and the third mixing element are opposite.

4. The static mixer of claim 1, wherein: the included angle that forms between first plate body, the second plate body is 60~ 120.

5. The static mixer of claim 1, wherein: the extension directions of the first channel and the second channel form an included angle of 60-150 degrees in space.

6. The static mixer of claim 1, wherein: the first mixing element, the second mixing element, the third mixing element and the fourth mixing element are the same in shape.

7. The static mixer of claim 1, wherein: the first plate body and the second plate body of the same mixing element are identical in shape and are symmetrically arranged, and the first plate body and the second plate body are parallelogram or trapezoid.

8. The static mixer of claim 1, wherein: in the same mixing unit, the first mixing element is connected to the third mixing element, and the second mixing element is connected to the fourth mixing element.

9. The static mixer of claim 8, wherein: in the same mixing unit, one end of the first mixing element is connected to one end of the fourth mixing element.

10. The static mixer of claim 9, wherein: the distance between the first mixing element and the second mixing element at one end of the first channel is L, the distance between the third mixing element and the fourth mixing element at one end of the second channel is L, the shortest distance between the second mixing element at the other end of the first channel and the third mixing element at the other end of the second channel is d, and d = 0.1-0.5L.