EP1166861B1 - Mixer for mixing at least two gas streams or other Newtonian liquids - Google Patents

Abstract

A separate flow channel (5) for a second gas stream extends into a main channel (1) and discharges at the rear (10) of a baffle (7) situated in the main gas stream. Preferred Features: Discharge occurs near the front half of the baffle (7). The flow channel for the second stream leads into chambers within it. Their outlet openings are on the rear of the baffle. The chamber has sidewalls at an angle to the baffle surface (7), which strengthen the it against bending loads. The separate flow channel is led to the front or the rear side of the baffle, which is supported by stays in the main flow channel. One stay is tubular and forms a separate flow channel. The angle ( alpha ) of the baffle with respect to the main flow direction can be adjusted. Outlet openings of separate chambers are arranged in series.

Description

The invention relates to a mixer for the mixture of at least two Gas streams or other Newtonian fluids, with one of the first Gas stream flowed through the main flow channel with a arranged therein, the Flow influencing mounting surface, the mounting surface is a vortex-generating Disc with free-flowing, directed against the flow leading edges whose course is both one in the main flow direction of the gas flow as well as a transverse thereto extending component.

Generic mixers are known, for example, from EP-A-0 956 897, EP-A-0 526 393 and DE 37 23 618 C previously known. All this mix is common, in that they have a mounting surface arranged in the main flow channel, wherein it is further known from EP-A-0 956 897 to mix in the second gas flow with respect to the flow direction on the back of the To introduce mounting surface.

For mixing gas or liquid flows in pipes or in channels With turbulent flow mixing lengths of 15 to 100 times are needed of the channel diameter. By means of suitable static mixers in the form of Einbaukörpem This mixing section can be significantly shortened. It must, however, at In particular, in most commonly used systems, high pressure loss occurs then be accepted if high demands on homogeneity the adjusting mixture are made. Many of the conventional ones Mixing systems are also limited to simple geometries, e.g. on cylindrical pipes or square channels and can not be used in large plants and complex mixing chamber systems.

From DE 29 11 873 C2 is for use in a cooling tower, a static mixer known, in which the internals of obliquely flowed, delta-shaped or circular disc-shaped sheets are made at the leading edges vortex. The thus formed stationary and stable vortex systems act in the Flow back into it, the components to be mixed are layered rolled up, resulting in a quick mixing at very low Pressure loss leads. These so-called "vertebral surfaces" are due to the achievable short mixing distances proven in practice.

The invention has for its object to provide a mixer for the mixing of at least two gas streams or other Newtonian liquids, which is characterized by a fast mixing at a short mixing distance even when a volume flow, a comparatively small proportion of another component is to be added.

To solve this problem, a mixer is proposed with the invention, which is characterized in that the mounting surface has a chamber into which a flow channel for a second gas flow leads, and that the chamber facing away from the inflow of the first gas flow back of the mounting surface is provided with outlet openings.

The advantages of such a mixer exist in particular in such cases, in which a relatively small volume flow of a first component Volume flow of a second component is admixed and nevertheless then homogenization is achieved on a short mixing section got to. The chamber into which the flow channel for the second gas stream leads allows adapted to the operation of the mixer distribution of Outlets for the second gas stream, d. H. the arrangement of these Outlets can be done with great freedom in design. That's the way it is Example possible, the outlet openings against the main flow direction or to install special deflection, which from the Outlet openings escaping gas flow particularly favorable in the field of steer themselves from the leading edges of the disc forming vertebrae.

Applications arise, for example, in Denox systems in the flue gas cleaning technology or in the conditioning of dust in electrostatic precipitators. In the flue gas cleaning, the flue gas flowing to the reactor chambers is to be admixed with NH ₃ or NH ₄ OH, the proportion of the ammonia compound being only about 2% by mass. In this case, a rapid mixing of the two components with a short mixing distance can be achieved with the mixer according to the invention. The mixing has the consequence that the profiles of the guided gas and / or liquid flow are uniformed, with performance losses are avoided. Despite the formation of extensive and stable vertebrae, the vortex mounting surface has a relatively low flow resistance, since it does not act with its entire surface as a guide surface, but generates vortex fields with their front edges, which expand automatically in the flow direction, without additional fittings or fins for this extension would be required.

Homogenization on the shortest mixing distance further contributes, if according to a preferred embodiment of the invention, the mouth of the second Gas stream is located in the area of the front half of the disc. In this way is the second, via the separate flow channel introduced gas flow already detected by those early onset vortex fields, those in the foremost edge region the disc will be generated.

A further advantage is that the chamber used for stiffening the installation surface can be. For this purpose, it is proposed that the chamber with side walls is provided, which are arranged at an angle to the disc and the Stiffen the disc against bending loads and any vibrations.

With respect to the arrangement of the flow channel for the second gas flow within the main flow channel is proposed that the separate Flow channel facing on the inflow of the first gas stream Front of the disc is guided to this. That's how it affects you Construction volume of the separate flow channel not the vortex formation and - reproduction at the back of the disc.

In other cases, it can also be an advantage if this is due to the separate Flow channel conditional volume not the even front Influence of the vortex installation surface disturbs. With a second embodiment is therefore proposed that the separate flow channel on the back of the Disc is guided to this.

Finally, in the sense of a structural union and thus simplification suggested that the disc supported by struts in the main flow channel is, one of which is tubular and the separate flow channel forms. In this case, the flow channel also assumes a static Function in the arrangement of the vortex mounting surface within the main flow channel.

Figur 1

einen Schnitt durch eine Denox-Anlage einer Rauchgas-Reinigungsanlage mit einer in dem Hauptströmungskanal vor dem Reaktor angeordneten Wirbeleinbaufläche in Gestalt einer Scheibe;

Figur 2

eine Draufsicht auf die Rückseite der Scheibe nach Figur 1;

Figur 3

eine Draufsicht auf die Rückseite einer Scheibe bei einer gegenüber Figur 2 abgewandelten Ausführungsform;

Figur 4

eine Draufsicht auf die Rückseite einer Scheibe bei einer gegenüber den Figuren 2 und 3 nochmals abgewandelten Ausführungsform;

Figur 5

eine Draufsicht bei einer weiteren Ausführungsform;

Figur 6

in Schnittdarstellung eine weitere Ausführungsform einer Wirbeleinbaufläche in Gestalt einer Scheibe;

Figur 7

in Schnittdarstellung einschließlich des Hauptströmungskanals eine weitere Ausführungsform einer Wirbeleinbaufläche in Gestalt einer Scheibe;

Figur 8

eine Draufsicht auf die Rückseite der Scheibe nach Figur 7;

Figur 9

eine Draufsicht auf die Rückseite einer Wirbeleinbaufläche in Form einer deltaförmig gestalteten Scheibe und

Figur 10

in Schnittdarstellung eine weitere Ausführungsform einer scheibenförmigen Wirbeleinbaufläche.

In the drawing, an embodiment of a mixer according to the invention is shown, in which:

FIG. 1

a section through a Denox system of a flue gas cleaning system with a arranged in the main flow channel in front of the reactor vortex mounting surface in the form of a disc;

FIG. 2

a plan view of the back of the disc of Figure 1;

FIG. 3

a plan view of the back of a disc in a modified from Figure 2 embodiment;

FIG. 4

a plan view of the back of a disc in a comparison with Figures 2 and 3 again modified embodiment;

FIG. 5

a plan view in a further embodiment;

FIG. 6

a sectional view of another embodiment of a vortex mounting surface in the form of a disc;

FIG. 7

in section, including the main flow channel another embodiment of a vortex mounting surface in the form of a disc;

FIG. 8

a plan view of the back of the disc of Figure 7;

FIG. 9

a plan view of the back of a vortex mounting surface in the form of a delta-shaped disk and

FIG. 10

in a sectional view another embodiment of a disk-shaped vortex mounting surface.

Figure 1 shows a section through a portion of a flue gas denitrification with a main flow channel 1 in an upwardly rising arm and a reactor 2 in a downwardly pointing flow arm of the plant. The reactor 2 is usually equipped with catalysts 3. To operate the system, the flue gas passing through 4 in the main flow channel 1 NH ₃ or NH ₄ OH is to be added. This is done via a separate flow channel 5, which is guided through the wall 6 of the main flow channel 1 therethrough. Then it comes in a manner described in more detail below to a very rapid distribution and thus homogenizing the ammonia compound in the flue gas, so that in the subsequent inflow into the reactor 2, the ammonia compound is distributed completely uniformly in the flue gas stream.

The mixture of media is carried out using at least one in the Main flow channel 1 arranged mounting surface 7. In the installation surface. 7 it is a so-called "swirling area" for the production of Leading edge vortices. The free flow around, against the flow in the Main flow channel 1 directed leading edges 8 of the e.g. a circular disk designed mounting surface 7 have both in the main flow direction 9, as also a transverse to this component. Furthermore, since each installation surface 7 at an acute angle α to the main flow direction 9 in the Flow channel 1 is arranged, arise at each leading edge of the Installation area Vortex fields, which spread downstream in a circular cone shape. The individual vortices roll inwards on the back 10 of the Installation surface 7 from. The vortex formed at the individual leading edges 4, of which a vortex is shown simplified in Figure 1, behave largely stationary, therefore do not change their situation. Each vortex field forms through its Rotation a flow component transverse to the main flow direction 9 of the Gas, by the associated pulse exchange transversely to the flow direction results in a good mixing of the gas mixture.

The vortex-generating properties of the mounting surface 7 are in Achieved connection with all so-called "Newtonian fluids", i. at Gases as well as in such fluids, resulting in their fluidic properties behaving comparably to the gases.

The preferably designed as a pipe separate flow channel 5 for the second Gas flow extends into the main flow channel 1 and opens there in the chamber 13 of the mounting surface 7. About several struts 11 is the Installation surface 7 relative to the wall 6a of the main flow channel 1 so supported, that the angle α with respect to the main flow direction 9 between 40 ° and 80 ° and preferably about 60 °.

Furthermore, Figure 1 shows that multiple existing Outlet openings 12 at the level of the front half of the disc or mounting surface 7 are located. The separate flow channel 5 is on the front of the Installation surface 7 led to this. Here, the pipe takes over the separate Flow channel 5 at the same time the static function of one of the struts 11. This Struts 11 are located on the front of the mounting surface 7 to the Do not cause the vortex on the back to influence.

It is possible to adapt to the respective operating conditions An attack angle α of the disc 7 relative to the main flow direction 9 to change, for example, by changing the effective length of the struts 11. This change or adjustment may also occur during operation of the mixer respectively.

Figure 1 also shows that the separate flow channel 5 is not immediate merges into the outlet openings 12, but rather via the flow channel. 5 supplied second gas stream first passes into a chamber 13, which on the Rear of the mounting surface 7 is arranged. In the outside of the chamber 13 then are the outlet openings 12th

FIGS. 2 and 3 show two possible embodiments of the chambers 13, wherein in the case of Figure 3, the outlet openings 12 about the center line 14th the disc 7 are arranged around, while in the embodiment according to Figure 3, the outlet openings 12 on two groups on both sides of the center line 14 so as to escape only in those areas that are from the left or be swept over by the right leading edge vertebrae.

The embodiment of Figure 4 differs from the embodiment according to Figure 3 by two separate flow channels 5, on the two separate Gas flows in turn get two separate chambers 13 a, 13 b. To this For example, it is possible to have two different gas flows in the Main flow channel guided gas stream to mix. The separate chambers 13a, 13b can also be behind each other. This is shown in Fig. 5a.

In Figure 6 it is shown that the outlet opening 12 of the chamber with a Deflection plate 15 can be provided in order to achieve the best possible inflow of the second gas flow in the region of the leading edge vortex formed achieve.

Figures 7 and 8 show that the outlet openings 12 in the Area of the front end face 16 of the chamber 13 can be located. To this The result is an outflow, the almost opposite to the the leading edges 8 forming vertebral fields, which makes it a very early Mixing comes.

In the context of the above-described embodiments of the invention the installation surfaces 7 were designed substantially circular or elliptical. Figures 9 and 10 show that the mounting surface and the shape a delta-shaped triangle directed counter to the flow direction Tip may have. For the exit of the second gas stream can also, as Figure 10 reveals an additional hood 16 with over its entire circumference distributed outlet openings 12 are used. The hood 16 is on the up the back of the disc 7 arranged chamber 13 placed, however, can also be the chamber 13 itself hood-shaped.

Finally, FIGS. 1 to 10 show that the walls of the chamber 13, since these are arranged perpendicularly, but at least at an angle to the mounting surface 7 are that can reinforce the mounting surface 7 with respect to bending loads. Out For this reason, close to serve as the distributor for the second gas stream Kammem 13 more Kammem 17 on, but no distribution function or fluidic function, but only the stiffening serve the mounting surface 7.

LIST OF REFERENCE NUMBERS

1

Main flow channel

2

reactor

3

catalysts

4

entry

5

separate flow channel

6

wall

6a

wall

7

Installation surface, disc

8th

leading edge

9

Main flow direction

10

back

11

strut

12

outlet opening

13

chamber

13a

chamber

13b

chamber

14

center line

15

baffle

16

Hood

17

chamber

α

angle

Claims (7)

1. Mixer for mixing at least two gas streams or other Newtonian fluids, with a main flow duct (1), through which the first gas stream flows, with a built-in surface (7) disposed therein and influencing the flow, wherein the built-in surface (7) is a vortex-generating disc with front edges (8) around which the fluids freely flow, are directed against the flow and the path of which comprises both a component extending in the main flow direction (9) of the gas stream and one extending transversely thereto,
   characterised in that the built-in surface (7) comprises a chamber (13, 13a, 13b) into which a flow duct (5) for a second gas stream leads, and that the chamber (13, 13a, 13b) is provided with outlet openings (12) at the back (10), which is remote from the inflow of the first gas stream, of the built-in surface (7).
2. Mixer according to Claim 1, characterised in that the second gas stream flows into the first gas stream in the region of the front half of the built-in surface (7).
3. Mixer according to Claim 1 or 2, characterised in that the chamber (13, 13a, 13b) is provided with side walls which are disposed at an angle to the built-in surface (7) and reinforce the built-in surface (7) with respect to bending loads.
4. Mixer according to any one of Claims 1 to 3, characterised in that the separate flow duct (5) leads to the built-in surface (7) at the front, which faces the inflow of the first gas stream, of this surface (7).
5. Mixer according to any one of Claims 1 to 4, characterised in that the built-in surface (7) is supported via struts (11) in the main flow duct (1), one of which struts is tubular and forms the separate flow duct (5).
6. Mixer according to any one of the preceding Claims, characterised by a device for adjusting the angle of incidence (α) of the built-in surface (7) in relation to the main flow direction (9).
7. Mixer according to any one of the preceding Claims, characterised in that the outflow openings (12) of separate chambers (13a, 13b) are disposed one behind the other.

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