CN218222402U

CN218222402U - Reactor device

Info

Publication number: CN218222402U
Application number: CN202220908965.0U
Authority: CN
Inventors: M·拉特瓦-科科; V·斯特勒默; 夏吉良
Original assignee: Metso Outotec Finland Oy
Current assignee: Metso Finland Oy
Priority date: 2021-04-19
Filing date: 2022-04-19
Publication date: 2023-01-06
Anticipated expiration: 2032-04-19
Also published as: WO2022223868A1; EP4326427A1; CN115212828A

Abstract

A reactor apparatus (100). The apparatus (100) comprises a reactor tank (10), a draft tube (1) disposed in the reactor tank (10), and an impeller (8) disposed proximate a lower end (6) of the draft tube (1). The wall (2) of the draft tube comprises openings (3) through the wall such that the total surface area of the openings (3) is at most 4% of the total outer surface area of the draft tube (1).

Description

Reactor device

Technical Field

The utility model relates to a reactor device.

Background

In leaching (leaching) concentrates and minerals from a slurry, such as a metal concentrate, the participating oxygen required in the leaching process is introduced in the form of oxygen or an oxygen-containing gas and dissolved into the solids-containing slurry so that the oxygen can participate in the leaching reaction of the solid matter. A high reactor provided with a draft tube (draft tube) is used to dissolve oxygen, thus creating a high hydrostatic pressure at the bottom of the reactor, such as 1.5 to 3.0 atmospheres, i.e. 0.15 to 0.30MPa. The high hydrostatic pressure promotes dissolution of oxygen in the slurry.

A problem arises if the free surface of the slurry falls below the upper end of the draft tube. Then the slurry may not flow into the draft tube. This may cause mechanical stresses and vibrations in the draft tube and may jeopardize the safe operation of the reactor.

SUMMERY OF THE UTILITY MODEL

Viewed from a first aspect, there may be provided a reactor apparatus comprising: a reactor tank; a draft tube disposed in the reactor tank; and an impeller disposed proximate a lower end of the draft tube, wherein a wall of the draft tube includes a plurality of openings therethrough, wherein a total surface area of the plurality of openings is at most 4% of a total outer surface area of the draft tube.

Hereby, a reactor arrangement can be achieved which makes safe operation possible also during situations where the slurry level is at a lower level than the upper end of the draft tube, without sacrificing reactor performance during normal operation.

The present apparatus and methods are characterized as described herein. Some other embodiments feature what is described herein. Embodiments of the invention are also disclosed in the description and drawings of the present patent application. The inventive content of the patent application can also be defined in other ways than is done in the text. The inventive content may also consist of several separate inventions, especially if the invention is viewed in the light of explicit or implicit sub-tasks or in view of advantages or sets of advantages achieved. In view of the independent utility concepts, some of the definitions contained herein may not be necessary. The features of the different embodiments of the invention can be applied to other embodiments within the scope of the basic inventive concept.

In one embodiment, the total surface area of the openings is in the range of 0.5% to 4% of the total external surface area of the draft tube. In one embodiment, the total surface area of the plurality of openings is in a range of 0.5% to 2%.

The advantage is that the reactor performance during situations where the slurry level is lower than the draft tube height can be optimized without sacrificing reactor performance during normal operation.

In one embodiment, at least one of the openings is circular.

The advantage is that the flow capacity relationship of the opening is maximized with respect to its circumference.

In one embodiment, the width of the opening is in the range of 5% to 30%, preferably in the range of 10% to 20%, of the outer diameter of the draft tube.

The advantage is that a proper flow in the draft tube can be achieved without compromising the mechanical strength of the draft tube.

In one embodiment, the openings are arranged in a plurality of opening groups, the opening groups comprising at least two openings and being arranged consecutively in the longitudinal direction of the draft tube, wherein the distance between adjacent opening groups in the longitudinal direction of the draft tube is larger than the distance between openings arranged in the same opening group.

It is an advantage that the flow in the draft tube can be enhanced on those parts of the draft tube that contain the set of openings.

In one embodiment, the openings are evenly spaced between the opening closest to the upper end of the draft tube and the opening closest to the lower end of the draft tube.

The advantage is that a stable flow in the draft tube is achieved irrespective of the height of the free surface.

In one embodiment, the number and location of the openings are designed to enable fluid to flow through the openings in the draft tube along substantially the entire length of the draft tube between the opening closest to the upper end of the draft tube and the opening closest to the lower end of the draft tube.

In one embodiment, there is a longitudinal section (length section) in the draft tube extending from the opening closest to the upper end to the opening closest to the lower end, and wherein the total area of the openings disposed in the upper half of the longitudinal section closest to the upper end accounts for at least 50% of the total area of all the openings disposed in the longitudinal section.

The advantage is that the flow capacity of the openings is concentrated in the upper part of the draft tube where the hydrostatic pressure is low, so that a satisfactory flow in these parts of the draft tube can be ensured.

In one embodiment, the total area of the openings provided in the upper half of the longitudinal portion is at least 60%.

An advantage is that a satisfactory flow in the upper part of the draft tube can be further ensured.

In one embodiment, at the upper end of the draft tube there is provided an upper conical extension into which the slurry flows, the diameter of the upper conical extension tapering towards the draft tube.

The advantage is that the inflow of slurry can be enhanced.

In one embodiment, there is a first clearance without openings between the openings closest to the upper end and the upper end, the first clearance being no greater than the draft tube diameter D. In one embodiment, the first pitch is in a range of 0.5 × D to 1 × D.

An advantage is that an undisturbed inflow of slurry at the upper end of the draft tube can be ensured.

In one embodiment, a lower conical extension for receiving the impeller is provided at the lower end of the draft tube, the lower conical extension tapering in diameter towards the draft tube.

The advantage is that the diameter of the impeller can be larger than the diameter of the draft tube, so that more efficient pumping can be achieved.

In one embodiment, the inner surface of the draft tube is provided with one or more blocking elements, such as baffles, which are arranged to extend in the longitudinal direction.

The advantage is that the downward flow in the draft tube can be controlled.

In one embodiment, the draft tube is disposed concentrically with the reactor tank.

An advantage is that a radially symmetrical and homogeneous mixing in the reactor tank can be achieved.

In one embodiment, there is a bottom spacing between the mid-height of the impeller and the bottom of the reactor tank, the bottom spacing being in the range of 0.8D to 1.5D.

An advantage is that an optimized space between the impeller and the bottom of the reactor tank for generating an optimized slurry flow, thereby enhancing the dissolution of gas into the slurry, can be achieved.

In one embodiment, the distance between the middle height of the impeller and the lower end of the draft tube is at most 0.5 × D. In one embodiment, the distance between the middle height of the impeller and the lower end of the draft tube is at most 0.25 × D.

An advantage is that the dissolution of gas into the slurry can be enhanced.

In one embodiment, the impeller is partially disposed inside the draft tube.

The advantage is that the flow capacity of the draft tube can be increased.

In one embodiment, the impeller is disposed entirely outside of the draft tube.

An advantage is that the dissolution of gas into the slurry can be enhanced.

In one embodiment, the apparatus comprises only one impeller.

The advantage is that a higher local mixing power intensity is obtained at the bottom of the reactor provided with the gas feed, so that a gas-to-liquid mass transfer can be enhanced.

In one embodiment, there is a top spacing between the upper end of the draft tube and the overflow, the top spacing being at most 1.0D.

The advantage is that the length of the draft tube can be optimised without compromising the proper operation of the device.

In one embodiment, the inner wall of the reactor tank is cylindrical with an inner diameter, and the ratio of the inner diameter to the outer diameter of the draft tube (i.e., R/D) is selected in the range of 2 to 4.

The advantage is that the flow capacity of the draft tube can be optimized with respect to the volume of the reactor tank.

In one embodiment, the internal height of the reactor tank is at least 10m.

An advantage is that a high hydrostatic pressure may be achieved which promotes dissolution of oxygen into the slurry.

In one embodiment, at least one blocking element (such as a baffle) is provided to the inner wall of the reactor tank.

An advantage is that an efficient structure for running flow patterns in the reactor tank can be achieved.

In one embodiment, an impeller is provided for generating a downwardly directed suction (kick) in the draft tube.

The advantage is that the flow capacity of the draft tube can be increased.

In one embodiment, the impeller is at least partially disposed outside of the draft tube.

An advantage is that the flow pattern in the reactor tank and outside the draft tube may be effectively influenced by the impeller.

In one embodiment, the impeller is arranged for generating a radially directed flow in the reactor tank.

The advantage is that an efficient dispersion of the gas in the slurry can be achieved.

In one embodiment, there is a second spacing between the opening closest to the lower end and the lower end, the second spacing being 1 to 2 times the draft tube diameter.

The advantage is that the damage of the opening to the pumping efficiency of the impeller can be mitigated.

Drawings

Some embodiments illustrating the disclosure are described in more detail in the accompanying drawings, wherein:

figure 1 shows a schematic side view of a reactor device in partial cross-section,

figure 2 is a schematic side view of a draft tube,

figure 3 is a schematic side view of another draft tube,

FIG. 4 shows some embodiments of a plurality of openings, an

Fig. 5 is a schematic view of a detail of the draft tube.

In the drawings, some embodiments are shown simplified for clarity. Similar parts are marked with the same reference numerals in the figures.

Reference mark

1: draught tube (draft tube)

2: wall(s)

3: opening of the container

4: upper end of draught tube

5: upper conical extension

6: lower end of draft tube

7: lower conical extension

8: impeller

9: barrier element

10: reactor tank

11: opening group

12: longitudinal section

12. b: half part

13: pipe support

14: overflow part

100: device for measuring the position of a moving object

C1: first pitch

C2: second pitch

BC: bottom space

D: outside diameter of draft tube

FS: free surface

H: height position

L: longitudinal direction of draught tube

ML: mid-height of impeller

R: inner diameter of reactor

TC: top space

w: width of

Detailed Description

Fig. 1 shows a schematic side view of a reactor device in partial cross-section. The reactor apparatus 100 comprises a reactor tank 10, a draft tube 1 disposed in the reactor tank 10, and an impeller 8 disposed proximate a lower end 6 of the draft tube 1. According to one aspect, said close proximity of the impeller may ensure that the slurry is drawn down in the draft tube.

The reactor apparatus may be used to mix a gas, such as oxygen or an oxygen-containing gas mixture, in a slurry, for example for leaching sulphidic material containing iron, nickel, cobalt, zinc and/or copper.

The wall 2 of the tube has a generally circular cross-section. The wall 2 comprises a plurality of openings 3 (i.e. through holes) extending through the wall. The total surface area of said openings 3 is at most 4% of the total outer surface area of the draft tube 1. In one embodiment, the percentage is in the range of 0.5% to 4%. In one embodiment, the percentage is in the range of 0.5% to 2%. Said total area of said openings ensures a satisfactory inflow in the draft tube 1 when the pulp falls below the upper end 4 of the draft tube, but on the other hand prevents an excessive outflow from the draft tube 1 under normal operating conditions when an inflow of pulp through the upper end 4 occurs.

According to one concept, the mass flow rate through the opening 3 during normal operation of the apparatus 100 does not exceed 30% of the pumping mass flow rate of the impeller 8 when the slurry level is higher than the upper end 4 of the draft tube 1. In one embodiment, the percentage does not exceed 10%.

In one embodiment, all openings 3 are circular, as shown in fig. 1. In other embodiments, not all openings are circular, but at least one of the openings is circular. In one embodiment, at least half of the openings 3 are circular.

In one embodiment, the inner wall of the reactor tank 10 is cylindrical with an inner diameter R. However, the reactor tank 10 may also have another shape.

In the embodiment shown in fig. 1, the lower end of the reactor tank 10 is in the shape of a half ellipse. However, the lower end may also be shaped, for example, flat or conical.

In one embodiment, draft tube 1 is disposed concentrically with reactor tank 10. However, this is not always necessary.

In one embodiment, the reactor tank 10 is cylindrical and has a ratio of its inner diameter R to the outer diameter D of the draft tube (i.e., R/D) selected in the range of 2 to 4. In one embodiment, the ratio is in the range of 2.5 to 3.5.

In one embodiment, the internal height of the reactor tank 10 is at least 10m. This height is sized to enable a higher hydrostatic pressure in the lower part of the reactor tank and to accelerate the dissolution of oxygen in the slurry.

In one embodiment, the draft tube 1 is attached to the reactor tank 10 by at least one tube support 13. The tube support may comprise, for example, a rod-like or plate-like structure.

There is a bottom space BC between the mid-height ML of the impeller 8 and the bottom of the reactor tank 10. The intermediate height ML is determined by the uppermost and lowermost edges of the blades of the impeller in the longitudinal direction L of the draft tube. In one embodiment, the impeller 8 and draft tube 1 are located in the reactor tank 10 such that the bottom spacing BC is in the range of 0.8D to 1.5D, where D is the outer diameter of the draft tube.

In one embodiment the impeller 8 is positioned such that the distance between the middle height ML of the impeller 8 and the lower end 6 of the draft tube is at most 0.5 x D, when measured in the longitudinal direction L of the draft tube. In one embodiment, the distance is at most 0.25 × D. The intermediate height ML is determined by the uppermost and lowermost edges of the blades of the impeller in the longitudinal direction L of the draft tube.

In one embodiment, the impeller 8 or its blades are located completely outside the draft tube 1.

In one embodiment, there is an overhead spacing TC between the upper end 4 of the draft tube and the overflow 14 (such as a launder, chute, channel or pipe). The overflow 14 may define the free surface FS of the slurry during normal operation of the apparatus 100. In one embodiment, the tip spacing TC is at most 1.0D, where D is the outer diameter of the draft tube.

In one embodiment, at least one blocking element 9 is arranged at the inner wall of the reactor tank 10. For example, the blocking element 9 may be or comprise a baffle. The blocking element 9 may be arranged to extend in the direction of the longitudinal direction L. The blocking element 9 may be arranged parallel to L or at a position offset (parallel) from the longitudinal direction L. In one embodiment there is at least one blocking element 9 in the upper half of the reactor tank 10. In one embodiment there is at least one blocking element 9 in the lower half of the reactor tank 10. In one embodiment, as shown in fig. 1, there are blocking elements 9 in both the upper and lower halves of the reactor tank 10.

In one embodiment the inner surface of the wall 2 of the draft tube is provided with one or more blocking elements 9. The blocking element 9 may be or comprise a baffle arranged to extend in the direction of the longitudinal direction L. The blocking element 9 may be arranged parallel to L or at a position (parallel) offset from the longitudinal direction L.

In one embodiment, as shown in fig. 1, the device comprises only one impeller 8.

The impeller 8 is arranged to create a downwardly directed suction in the draft tube 1, i.e. to move the pulp inside the draft tube 1 towards the lower end 6. Such suction may be provided by, for example, suitably shaped curved impeller blades (not shown) that produce an axially downwardly directed flow.

In one embodiment, as shown in fig. 1, the impeller 8 is partially disposed outside the draft tube 1 and partially disposed inside the draft tube 1. In one embodiment, the impeller 8 is arranged to generate a flow in the reactor tank 10 that is at least partially directed radially (i.e. horizontally). The radially directed flow may be generated, for example, by straight blades of an impeller or turbine blades (not shown). The radially directed flow effectively disperses the gas fed below the impeller into the slurry.

In one embodiment the impeller 8 comprises a first set of blades arranged in its upper part for generating an axially downwardly directed flow, and a second set of blades in its lower part for generating an at least partly radially directed flow.

In one embodiment, the impeller 8 is arranged completely outside the draft tube 1.

Fig. 2 is a schematic side view of a draft tube. In one embodiment, as shown in fig. 2, the plurality of openings 3 are arranged in groups of openings 11. The opening group 11 may include two or more openings. The groups of openings 11 are arranged consecutively in the longitudinal direction L of the draft tube 1 such that the distance between adjacent groups of openings 11 is larger than the distance between openings arranged in the same group of openings 11.

In one embodiment, the number of groups of openings 11 is 4 to 10. In one embodiment, the number of openings 3 in one opening group 11 is selected in the range of 2 to 6. It is to be noted that the number of openings may be the same in all the opening groups 11; however, this is not essential. Furthermore, in each group of openings 11, the shape, size, position and total area of the openings may be the same, or, alternatively, there may be variations in the variables.

In one embodiment, the openings 3 are evenly spaced between the opening closest to the upper end 4 of the draft tube 1 and the opening closest to the lower end 6 of the draft tube 1.

In one embodiment, as shown in fig. 5, the number and location of the openings 3 are designed such that slurry or liquid can flow through the openings in the draft tube 1 along substantially the entire length of the longitudinal portion 12 between the opening closest to the upper end 4 and the opening closest to the lower end 6 of the draft tube. Thus, the lower edge of an opening located higher can be positioned at the same height position H as the upper edge of another opening located lower or lower than the upper edge of said other opening located lower. In fig. 5, the lower edge and the upper edge are located at the same height position H.

In one embodiment, as shown in fig. 2, the upper end 4 of the draft tube 1 is provided with an upper conical extension 5. The diameter of the upper conical extension 5 tapers towards the draft tube 1. The upper conical extension 5 may facilitate the flow of slurry into the draft tube 1.

There is a first distance C1 in the draft tube between the opening 3 closest to the upper end 4 and said upper end 4. In other words, the first pitch C1 has no opening. In one embodiment, the first spacing C1 is not greater than the draft tube diameter D. In one embodiment, the first pitch C1 is in a range of 0.5 × D to 1 × D.

In one embodiment, there is a second spacing C2 between the opening 3 closest to the lower end 6 and the lower end, no openings, the second spacing C2 being 1-2 times the draft tube diameter D, i.e., 1 × D to 2 × D.

In one embodiment, at the lower end 6 of the draft tube, an upwardly tapering lower conical extension 7 is provided. In one embodiment, the impeller 8 is partially disposed within the lower conical extension 7. In another embodiment, the impeller 8 is arranged below the lower conical extension 7 in close proximity to the lower conical extension 7.

Fig. 3 is a schematic side view of another draft tube. In one embodiment, the openings 3 are arranged in a longitudinal portion 12 in the draft tube such that the total area of the openings 3 in the upper half 12a of said longitudinal portion 12 (i.e. the half of the length of the longitudinal portion 12 closest to the upper end 4) is at least 50% of the total area of all the openings 3 arranged in the longitudinal portion 12. In other words, a large part of the total area of the openings is located in the upper half 12 a. In one embodiment, at least 60% of said total area of said opening 3 is provided in the upper half 12 a.

Fig. 4 shows some embodiments of the openings. As shown in fig. 1-3, the opening 3 may be circular.

In one embodiment, the at least one opening 3 is polygonal, such as triangular, quadrangular, etc.

In one embodiment, the at least one opening 3 is oblong, such as elliptical, oval or rectangular. In one embodiment, the longitudinal direction of the oblong opening is arranged at least substantially parallel to the longitudinal direction L of the draft tube. In one embodiment said longitudinal direction of the oblong opening is arranged at least substantially arranged in a perpendicular direction to the longitudinal direction L. In one embodiment, the longitudinal direction is set at an angle between the longitudinal direction and the vertical direction.

In one embodiment, the width w (i.e. the dimension perpendicular to the longitudinal direction L) of the opening 3 is defined as a percentage of the outer diameter D of the draft tube in the range of 5% to 30%. In one embodiment, the percentage is between 10% and 20%. In one embodiment, the width w is selected in the range of 5cm to 100 cm. In one embodiment, the width w is selected in the range of 10cm to 60 cm. In one embodiment, the width w is selected in the range of 15cm to 20 cm.

In one embodiment, the height of the opening 3 (i.e. its dimension perpendicular to the width w) is selected in the range of 5cm to 75 cm. In one embodiment, the height of the opening is selected in the range of 10cm to 60 cm. In one embodiment, the height of the opening is selected in the range of 15cm to 20 cm.

The invention is not limited to the embodiments described above, but may be varied within the scope of the inventive concept defined in the claims below. The features of different embodiments and applications may be used in combination with or instead of the features of another embodiment or application within the scope of the inventive concept.

The drawings and the related description are only intended to illustrate the inventive concept. The invention may vary in detail within the scope of the inventive concept defined in the claims below.

Claims

1. A reactor device, comprising:

a reactor tank (10) for the reaction of a gas,

a draft tube (1) disposed in the reactor tank (10), and

an impeller (8) arranged in close proximity to the lower end (6) of the draft tube (1),

wherein the wall (2) of the draft tube comprises:

a plurality of openings (3) through the wall, and wherein

The total surface area of the plurality of openings (3) is at most 4% of the total outer surface area of the draft tube (1).

2. The reactor device of claim 1,

the total surface area of the openings (3) is in the range of 0.5 to 4% of the total outer surface area of the draft tube (1).

3. The reactor device of claim 1,

the total surface area of the openings (3) is in the range of 0.5% to 2% of the total outer surface area of the draft tube (1).

4. The reactor device according to any one of claims 1 to 3,

at least one of the openings (3) is circular.

5. The reactor device according to any one of claims 1 to 3,

the width (w) of the opening (3) is in the range of 5% to 30% of the outer diameter (D) of the draft tube.

6. The reactor device according to any one of claims 1 to 3,

the width (w) of the opening (3) as a percentage of the outer diameter (D) of the draft tube is in the range of 10% to 20%.

7. The reactor device according to any one of claims 1 to 3,

the openings (3) are arranged in a plurality of opening groups (11) comprising at least two openings and being arranged consecutively in the longitudinal direction (L) of the draft tube (1) and wherein,

in the longitudinal direction (L) of the draft tube (1), the distance between adjacent groups of openings (11) is greater than the distance between openings arranged in the same group of openings (11).

8. The reactor device according to any one of claims 1 to 3,

the openings (3) are evenly spaced between the opening closest to the upper end (4) of the draft tube (1) and the opening closest to the lower end (6) of the draft tube (1).

9. The reactor device of claim 8,

the number and location of the openings (3) are designed such that fluid can flow through the openings (3) in the draft tube (1) along substantially the entire length of the draft tube between the opening closest to the upper end (4) of the draft tube (1) and the opening closest to the lower end (6) of the draft tube (1).

10. The reactor device according to any one of claims 1 to 3,

in the draft tube (1) there is a longitudinal portion (12) extending from an opening closest to the upper end (4) of the draft tube (1) to an opening closest to the lower end (6), and wherein,

the total area of the openings (3) arranged in the upper half (12 a) of the longitudinal portion (12) closest to the upper end (4) accounts for at least 50% of the total area of all the openings (3) arranged in the longitudinal portion (12).

11. The reactor device of claim 10,

the total area of the openings (3) provided in the upper half (12 a) of the longitudinal portion (12) accounts for at least 60% of the total area of all openings (3) provided in the longitudinal portion (12).

12. The reactor device according to any one of claims 1 to 3,

an upper conical extension (5) for the inflow of slurry is provided at the upper end (4) of the draft tube (1), the diameter of the upper conical extension (5) tapering towards the draft tube (1).

13. The reactor device according to any one of claims 1 to 3,

there is a first spacing (C1) between the opening (3) closest to the upper end (4) of the draft tube (1) and the upper end (4) that is free of openings, the first spacing being no greater than the outer diameter (D) of the draft tube.

14. The reactor device of claim 13,

the first pitch (C1) is in a range of 0.5 × D to 1 × D.

15. The reactor device according to any one of claims 1 to 3,

a lower conical extension (7) for accommodating an impeller (8) is provided at the lower end (6) of the draft tube (1), the diameter of the lower conical extension (7) tapering towards the draft tube (1).

16. The reactor device according to any one of claims 1 to 3,

the inner surface of the draft tube (1) is provided with one or more blocking elements (9) arranged to extend in the direction of the longitudinal direction (L).

17. The reactor device according to any one of claims 1 to 3,

the draft tube (1) is arranged concentrically with the reactor tank (10).

18. A reactor device according to any one of claims 1 to 3, comprising:

a bottom spacing (BC) between a mid-height (ML) of the impeller (8) and a bottom of the reactor tank (10), the bottom spacing (BC) being in a range of 0.8D to 1.5D.

19. A reactor device according to any one of claims 1 to 3, comprising:

a top spacing (TC) between the upper end (4) of the draft tube and the overflow (14), the top spacing (TC) being at most 1.0D.

20. The reactor device according to any one of claims 1 to 3,

the inner wall of the reactor tank is cylindrical with an inner diameter (R), and

the ratio R/D of the inner diameter (R) to the outer diameter (D) of the draft tube is selected in the range of 2 to 4.

21. The reactor device according to any one of claims 1 to 3,

the reactor tank (10) has an internal height of at least 10m.

22. The reactor device according to any one of claims 1 to 3,

at least one blocking element (9) is arranged on the inner wall of the reactor tank (10).

23. The reactor device of claim 16,

the blocking element (9) comprises a baffle.

24. The reactor device of claim 22,

the blocking element (9) comprises a baffle.

25. The reactor device according to any one of claims 1 to 3,

the impeller (8) is provided for generating a downwardly directed suction in the draft tube (1).

26. The reactor device according to any one of claims 1 to 3,

the impeller (8) is arranged at least partially outside the draft tube (1).

27. The reactor device of claim 26,

the impeller (8) is arranged partially inside the draft tube (1).

28. The reactor device according to any one of claims 1 to 3,

the impeller (8) is arranged completely outside the draft tube (1).

29. A reactor device according to any one of claims 1 to 3, comprising:

only one impeller (8).

30. The reactor device according to any one of claims 1 to 3,

the distance between the middle height (ML) of the impeller and the lower end of the draft tube is at most 0.5 XD.

31. The reactor device of claim 30,

the distance between the middle height (ML) of the impeller and the lower end of the draft tube is at most 0.25 XD.

32. The reactor device according to any one of claims 1 to 3,

the impeller (8) is arranged for generating a radially directed flow in the reactor tank (10).

33. A reactor device according to any one of claims 1 to 3, comprising a second spacing (C2) between the opening (3) closest to the lower end (6) and the lower end (6), the second spacing (C2) being 1 to 2 times the outer diameter (D) of the draft tube.