CN107921388B

CN107921388B - Stabilizing device and mixing device

Info

Publication number: CN107921388B
Application number: CN201680047488.0A
Authority: CN
Inventors: J·S·唐尼; M·斯米特
Original assignee: Johnson Matthey Davy Technologies Ltd
Current assignee: Johnson Matthey Davy Technologies Ltd
Priority date: 2015-08-12
Filing date: 2016-06-16
Publication date: 2021-10-08
Anticipated expiration: 2036-06-16
Also published as: CN107921388A; GB201514334D0; GB201610528D0; GB2541283A; WO2017025706A1; GB2541283B; TW201707777A

Abstract

A stabilizing apparatus (28) for stabilizing an agitator shaft (24) in a mixing vessel having an outlet in the bottom thereof, the stabilizing apparatus comprising: a shaft receiving bearing (30) configured to receive an end of the stirring shaft (24); and a support arrangement (32) for supporting the shaft receiving bearing (30) and spacing the shaft receiving bearing (30) from the outlet of the mixing vessel; wherein the support arrangement comprises a vortex reducing structure.

Description

Stabilizing device and mixing device

Technical Field

The invention relates to a stabilizing device for stabilizing a stirring shaft. More particularly, the present invention relates to a stabilizing device for stabilizing a stirring shaft, which does not hinder the removal of material from the container in which the stabilizing device is located. Still more particularly, the present invention relates to a stabilizing device for stabilizing a stirring shaft, said stabilizing device comprising a vortex breaker. In other arrangements, the invention relates to a mixing vessel (such as a reactor) comprising a stabilising device for stabilising the agitator shaft.

Background

Various processes require mixing of components (such as components). In some arrangements, the components to be mixed are fluids or both fluids and solids. Typically, the ingredients are mixed in a mixing vessel to form the desired mixture. In a chemical process, the components to be mixed may be reactants and/or other components (such as catalysts) desired for the reaction. The ingredients may be mixed in a mixing vessel prior to transferring the ingredients to the reactor. Alternatively, mixing may be performed in the reactor such that mixing and reaction are performed simultaneously. In this arrangement, what is removed from the mixing vessel will be the reaction product, optionally together with unreacted components. In many reactions, it is desirable to mix the reactants to ensure adequate contact between them so that an effective or improved reaction can occur. In one arrangement, the reactants to be mixed are liquids. In another arrangement, at least one liquid reactant needs to be mixed with a gaseous reactant. Additionally, one or more solids may be present with the liquid reactant and/or the gaseous reactant.

Although a variety of mechanisms may be used to assist in mixing, mechanical mixers for agitating the ingredients are typically used to provide the desired level of mixing. These mechanical mixers may be powered by a drive unit, such as an electric motor. A drive unit is typically located outside the mixing vessel, which drives a rotating shaft attached to the impeller blades. Upon operation of the drive unit, the rotating shaft rotates, which in turn causes the impeller blades to rotate, thereby facilitating mixing of the ingredients in the mixing vessel.

In the simplest form, the end of the rotation shaft remote from the drive unit is not attached and is therefore a free end. This arrangement is simple and therefore inexpensive to manufacture. However, because the free end is not attached, the rotating shaft may oscillate and/or vibrate during use, which may result in incomplete mixing and may cause wear of the mixing device, especially if the rotating shaft is connected to a drive unit. This is particularly problematic in large mixing vessels where longer rotating shafts are required to achieve acceptable mixing.

In view of solving these problems, various designs for holding the free end of the rotating shaft have been proposed. One such arrangement is a so-called "stabilising bearing" assembly which is located in the mixing vessel such that it can receive the free end of the agitator shaft and so maintain it stable as it rotates, thereby preventing wobble and reducing or eliminating wobble.

Examples of stabilizing bearings are described in US3149888 and US 3489469. In this arrangement, the bearing is located outside the mixing vessel and the rotating shaft extends through the bottom of the mixing vessel before it is constrained into the stabilizing bearing. In other arrangements, for example, those described in US4660989, the stabilising bearing is located within the mixing vessel.

Typically, the axis of rotation will be located on the central axis of the mixing vessel to achieve optimal mixing. However, since the outlet of the mixing vessel is typically located at the bottom center of the vessel, it is difficult to find a suitable location for stabilizing the bearing. There is therefore a conflict between the need to locate the outlet at the centre of the bottom of the mixing vessel and the requirement to locate the stabilising bearing at the centre of the bottom of the vessel in order to ensure that the rotating shaft is coaxial with the central axis of the vessel.

Solutions have been proposed for this by mounting the stabilising bearing at an elevated position within the mixing vessel so that both the outlet and the stabilising bearing can be aligned with the central axis. Examples of stable bearings of this type are described in US2516918, US2657912, US2865615, US3443794, US3489469, US4932787, US5088832, US5568985, US5618107, US7378431 and US 7402023.

A vortex is formed when the mixed component or product stream is withdrawn from the mixing vessel through an outlet located at the bottom of the mixing vessel in the case where the mixing vessel is a reactor.

In the case of a stabilizing bearing in a raised position above the outlet, the legs supporting the stabilizing bearing in the raised position and thus spaced from the bottom of the mixing vessel may themselves cause a vortex to form.

The formation of a vortex is disadvantageous because it can cause gas to be entrained in the liquid removed from the mixing vessel. Swirl can also lead to poor separation or excessive pressure drop in downstream processing. The presence of entrained gas can also cause cavitation in downstream pumps.

In order to minimize vapor entrainment in the liquid recovered from the bottom of the mixing vessel, a so-called "vortex breaker" can be mounted directly on top of the outlet inside the vessel. These vortex breakers act to reduce some of the angular velocity of the liquid as it exits the discharge.

One example of a vortex breaker is described in US 8439071. The vortex breaker comprises a basket with a cylindrical screening wall, which is fitted on the vessel outlet. A flow modifier with vanes is located in the basket to disrupt the radially directed flow. Other examples of vortex breakers are described in US4696741, EP1309393, US8397751 and WO 2013/096570.

Although prior art raised stabilized bearings can in principle be used in combination with vortex breakers, the resulting structure will suffer from various disadvantages and drawbacks. Their use is particularly aggravating for the gas entrainment problem, which the vortex breaker must try to minimize, because the support for the raised stabilizing bearing itself increases the swirl. This additional complication can mean that vortex breakers cannot effectively prevent the formation of vortices and therefore will not minimize or prevent the formation of entrained gas.

While stabilizing bearings and vortex breakers of the type described above have been, and may continue to be, satisfactory in some circumstances, it is desirable to provide an improved arrangement which allows both stabilizing bearings and vortex breakers to be provided, but which is less complicated than arrangements which might be envisaged using various combinations of known types of stabilizing bearings and known types of vortex breakers.

Disclosure of Invention

According to a first aspect of the present invention there is provided a stabilising device for stabilising a mixing shaft in a mixing vessel, the mixing vessel having an outlet in a base thereof, the stabilising device comprising:

a shaft receiving bearing configured to receive an end of the stirring shaft; and

support means for supporting the shaft receiving bearing and spacing the shaft receiving bearing from the outlet of the mixing vessel;

wherein the support arrangement comprises a vortex reducing structure.

Thus, the stabilizing apparatus of the present invention provides both a stabilizing bearing for the agitator shaft and a vortex reducing structure. Thus, the means for separating the bearing from the bottom portion of the mixing vessel provides a vortex reducing structure. Thus, rather than the support increasing the likelihood of vortex formation noted in the prior art, the support actually reduces and may even prevent vortex formation.

By providing the bearing and vortex reducing structure as a single device, the resulting apparatus is simple, compact, mechanically stable and inexpensive to construct.

Because the apparatus of the present invention will reduce or even eliminate vortex formation, the amount of entrained gas in the liquid exiting the vessel via the outlet will be reduced.

Any suitable vortex reducing structure may be used. In one arrangement, the vortex reducing structure is configured to reduce the angular velocity of the exiting liquid. This may be achieved by using at least one blade. Typically, multiple blades are used. The vanes may be arranged in any suitable configuration. In one arrangement, the blades may extend radially outwardly from a central axis of the apparatus to the tips of the blades. Two, three, four, five, six or more blades may be used. Where there are multiple blades, they may be evenly spaced or the spacing between adjacent blades may be different.

In one arrangement, there are four substantially equally spaced blades. In an alternative arrangement there are six equally spaced blades.

It should be understood that the outlet may simply be a hole in the bottom of the mixing vessel. However, in one arrangement, the bottom of the mixing container may be shaped to form a well-like outlet extending outwardly from the bottom. In such an arrangement, the vortex reducing structure may be configured to extend into the shaped outlet port.

The shaft receiving bearing may have any suitable configuration. Similarly, the support means may have any suitable configuration. In one arrangement, the support device can be configured as a platform with three or four support legs.

The shaft receiving bearing may be a separate component of the apparatus or the shaft receiving bearing may be integrally formed with the support means.

The support device may further comprise a flange extending therefrom. The flange may define a circumferential rim extending laterally from the shaft receiving bearing and the support means. In use, the flange assists in directing material to be removed from the mixing container to the outlet port. Disturbances caused at the outlet port that interfere with the operation of the shaft receiving bearing may also be minimized.

It will be appreciated that the stabilising device of the first aspect of the invention may be made of any suitable material. The material selected will depend on the application to which the mixing vessel is to be put. For example, in the case where the mixing vessel is a reactor, the reaction conditions under which the stabilization device is placed will determine the material to be selected. In one arrangement, metal will be used.

According to a second aspect of the present invention, there is provided a mixing apparatus comprising:

a mixing vessel comprising an inlet port and an outlet port;

a rotatable stirring shaft extending into the mixing vessel;

an impeller attached to the rotatable stirring shaft; and

a stabilising arrangement for stabilising the agitator shaft according to the first aspect described above, the stabilising arrangement being located within the mixing vessel and secured to an inner surface of the mixing vessel such that the stabilising arrangement is located above the outlet and the rotatable agitator shaft is received in the shaft receiving bearing.

The mixing vessel may be a reactor.

The stabilizing device used to stabilize the stirring shaft may be of any suitable size. In one arrangement, the distance between the tip of the first vane and the tip of the second vane is from about 1.5 to about 3 times, optionally from about 2 to about 2.5 times the width of the outlet port. In the case of a circular cross-section of the outlet port, the distance is from about 1.5 to about 3 times, optionally from about 2 to about 2.5 times the diameter of the outlet port.

The device may have any suitable height. In one arrangement, the stabilizing device may be dimensioned such that the shaft receiving bearing is spaced from the outlet port by a distance of from about 1.5 to about 2.5 times, optionally about 2 times, the width of the outlet port. In the case of a circular cross-section of the outlet port, the distance is from about 1.5 to about 2.5 times, optionally about 2 times, the diameter of the outlet port.

In an alternative arrangement, the height of the stabilising device of the first aspect of the invention will be from about 1 to about 2 times the width of the outlet port, optionally about 1.5 times. In the case of a circular cross-section of the outlet port, the height will be about 1 to about 2 times, optionally about 1.5 times, the diameter of the outlet port.

Where the flange is provided in the stabilising device of the first aspect of the invention, it may be of any suitable size. In one arrangement, the flange extends beyond the tip of the vane by a distance of from about one quarter to about three quarters of the width of the outlet port, optionally about half. In the case where the outlet port is circular in cross-section, the distance will be from about one quarter to about three quarters, optionally about half, of the width of the outlet port. In one arrangement, the flange may be formed from a disc having a diameter substantially equivalent to three times the width of the outlet port. In the case where the outlet port is circular in cross-section, the diameter of the flange will be about two to about four times, optionally about three times, the diameter of the outlet port.

In one arrangement of the invention, the vortex reducing structure extends at least partially into the outlet port. In one arrangement, the vortex reducing formation extends into the outlet port a distance of from about one quarter to about three quarters of the width of the outlet port, optionally about half. In the case where the outlet port is circular in cross-section, the vortex reducing formation extends into the outlet port a distance of from about one quarter to about three quarters, optionally about half, of the diameter of the outlet port.

In an alternative arrangement, the portion of the vortex reducing formation above the outlet port terminates above the outlet port by a distance of from about one quarter to about three quarters of the width of the outlet port, optionally about half. In the case where the outlet port is circular in cross-section, it terminates above the outlet port a distance of from about one quarter to about three quarters, optionally about half, of the diameter of the outlet port.

However, it should be understood that the vortex reducing structure may terminate at any suitable location that allows the desired reduction and preferably eliminates vortex formation.

In case the mixing vessel is a reactor for gas-liquid reactions, the mixing vessel will comprise introducing means for introducing gas into the reactor. In one arrangement, the mixing vessel will include a gas supply conduit. The gas supply conduit may be connected to a gas distribution distributor. In one arrangement, the sparger can comprise a gas distribution ring. The gas dispersion ring is typically arranged such that it surrounds the stabilising device of the first aspect of the invention. The gas dispersion ring may be spaced from the stabilising device of the first aspect described above by a distance of from about three to about five times, optionally about four times, the width of the outlet port. In the case of a circular cross-section of the outlet port, the distance is about three to about five times, optionally about four times, the diameter of the outlet port.

The mixing vessel of the present invention may further comprise a baffle plate located on a bottom surface of the mixing vessel, surrounding the outlet port. In one arrangement, the baffle may be of circular configuration. In use, the baffle minimizes gas circulating around from the gas dispersion to the outlet port.

The spacer may have any suitable dimensions. In one arrangement, the height of the baffle is between about one quarter and about three quarters, optionally about half, of the width of the outlet port. In the case where the outlet port is circular in cross-section, the height of the baffle is from about one quarter to about three quarters, optionally about half, of the width of the outlet port.

Where the baffles form a circle, the diameter of the circle will be about one quarter to about three quarters, optionally about half, of the width of the outlet port. In the case where the outlet port is circular in cross-section, the diameter of the circle will be about one quarter to about three quarters, optionally about half, of the width of the outlet port.

Drawings

The invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a mixing apparatus for mixing fluids, the mixing apparatus comprising an apparatus according to a first aspect of the present invention;

FIG. 2 is an enlarged side view of a lower region of the mixing apparatus shown in FIG. 1;

FIG. 3 is an enlarged perspective view of the apparatus of FIG. 2;

FIG. 4 is an enlarged schematic view of one arrangement of vortex reducing structures;

FIG. 5 is a schematic bottom view of an apparatus according to the present invention in an alternative arrangement;

FIG. 6 is a bottom schematic bottom plan view of an alternative vortex reducing structure;

FIG. 7 is an enlarged schematic side view of another alternative vortex reducing structure;

FIG. 8 is an enlarged schematic side view of yet another alternative vortex reducing structure;

fig. 9 is an enlarged schematic side view of an apparatus according to the invention additionally comprising a gas supply conduit and a bubble transfer directing means.

Detailed Description

In particular, the invention is described in an arrangement where the mixing vessel is a reactor. In particular, the invention is described with reference to a reactor for use in the hydroformylation of olefins to form acetaldehyde, wherein the olefin is contacted with carbon monoxide and hydrogen. A catalyst is typically present.

As shown in fig. 1, the reactor 10 includes a reactor housing 12 having a top wall 14, side walls 16, and a bottom wall 18. The top wall 14, side walls 16 and bottom wall 18 define a chamber 20 for containing a liquid, which is an olefin in a hydroformylation reaction. The reactor shell 12 may have any cross-sectional configuration, but is typically substantially cylindrical.

The reactor 10 includes an agitator that mixes the reactants when in operation. A drive unit 22 (e.g., an electric motor) mounted outside the reactor shell 12 is coupled to a stirring shaft 24, the stirring shaft 24 extending into the chamber 20. When in operation, the drive unit 22 causes the agitator shaft 24 to rotate, which in turn drives the impeller 26. The impeller 26 typically includes a plurality of blades.

The distal end of the stirring shaft 24 engages a stabilization device 28. The stabilization device 28 includes a shaft receiving bearing 30. Shaft-receiving bearing 30 allows agitator shaft 24 to rotate about its longitudinal axis 31 while at the same time preventing agitator shaft 24 from vibrating and/or wobbling. The shaft receiving bearing 30 may be of any suitable construction to accomplish this function.

The stabilization apparatus 28 also includes a support 32 that extends downwardly from the underside of the shaft receiving bearing 30. Support 32 may be separate from shaft receiving bearing 30 or may be integrally formed with the shaft receiving bearing. The support 32 supports the shaft-receiving bearing 30 and separates the shaft-receiving bearing 30 from an outlet port 34 of the reactor housing 12. The stabilizing device 28 is suitably secured to the bottom wall 18 of the reactor housing 12 via a support 32. The support 32 is configured such that it allows fluid to flow from the chamber 20 via the outlet port 34. Because the stabilization device 28 is secured to the bottom wall 18 of the reactor housing 12 by any suitable means, the support 32 provides a stable bottom for the shaft receiving bearing 30.

The support device 32 includes a flow modifying structure shown in detail in fig. 2-8 that modifies the flow of fluid before it exits the mixing vessel 12 via the outlet port 34. Thus, the flow modifying structure is a vortex breaker.

A fluid outlet path 36, indicated by arrows, from the mixing chamber 20 to the outlet port 34 is defined by the space of the flow modifying structure located below the support means 32 and surrounding the support means 32. The flow modifying structure of the support device 32 is configured to affect the fluid in these fluid outlet paths 36 to reduce the angular velocity of the fluid in the fluid outlet paths 36. As this reduces or inhibits vortex formation, entrainment of gas in the fluid outlet path 36 will be reduced or inhibited.

In operation, liquid olefin 38 is introduced into the mixing chamber 20 via a supply conduit 40.

The stirring axle 24 is driven in rotation about its longitudinal axis 31 by the drive unit 22, as indicated by arrow 42. Rotation of the stirring shaft 24 causes the impeller 26 to rotate within the mixing chamber 20 so that mixing occurs.

The reaction products are recovered from the mixing chamber 20 via the outlet port 34. As the fluid travels toward the bottom of the mixing chamber 20, the fluid retains an angular velocity component due to the influence of the impeller 26. The product stream continues with this angular velocity component down and around shaft-receiving bearing 30 and then to fluid outflow path 36. The product stream then encounters the flow modifying features of the support apparatus 32. This serves to disrupt the fluid flow and reduce the angular velocity component of the fluid mixture. Because the angular velocity component of the product stream decreases, the main component of flow is a downward velocity component, such that other streams of the product stream, which arrive from the outlet port 34 to downstream processing or storage vessels as appropriate, are directed in a downward direction toward the outlet port 34.

An enlarged side view of the lower region of the mixing device provided with the stabilizing device 28 is shown in more detail in fig. 2. The flow modifying structure of the support device 32 comprises a plurality of blades. In the embodiment shown in fig. 2, the support means comprises four vanes, only three of which are visible and extend radially from the central axis of the support means 32. The first blade 44 extends from the central axis in a first direction and terminates in a first blade tip 46 at a location remote from the central axis. A second blade 48 extends from the central axis in a second direction opposite the first direction and terminates in a second blade end 50 at a location remote from the central axis. A third blade 52 extends from the central axis in a third direction transverse to the first and second directions and terminates in a third blade end 54 at a location remote from the central axis. The fourth vane is not shown in fig. 2 but is visible in fig. 6. A fourth blade 56 extends from the central axis in a fourth direction opposite the third direction and transverse to the first and second directions and terminates in a fourth blade tip 58.

Portions of the lower edge of each of the vanes, generally indicated by reference numeral 60 in fig. 2, terminate at a level below the lowest level of the bottom wall 18 of the mixing vessel 12. That is, portions of each

vane

44, 48, 52, and 56 each extend downwardly into the outlet port 34.

The flange 62 extends from the stabilization device 28 around the circumference of the stabilization device 28. The flange 62 extends from a location between the shaft receiving bearing 30 and the support device 32. The flange 62 assists in directing the outward flow of product flow to the outlet.

Fig. 3 is a perspective view of the features described above in relation to fig. 2. The same features shown in fig. 3 as those shown in fig. 1 and 2 are denoted by the same reference numerals. For clarity, some reference numerals have been omitted in fig. 3.

Fig. 4 shows an enlarged schematic side view of the support device 32, wherein the individual dimensions are indicated with reference numerals D, H, S, T and W, wherein:

d is the diameter of the outlet port 34 with a circular cross-section;

h is the distance between a point located in the same horizontal plane as the lowermost level of the bottom wall 18 of the mixing vessel 12 and the top of the support means 32;

s is the distance that the flange 62 extends beyond the end of the plate of the support device 32;

t is the distance between a point in the same horizontal plane as the lowermost level of the bottom wall 18 of the mixing vessel 12 and the lower edge 60 of each of the plates. Thus, it describes the distance that the lower edge 60 is above or below the mouth of the outlet port 34; and

w is the distance between the ends of the oppositely extending plates of the support device 32.

The dimensions may have the following relationship:

W＝2D；

H＝D；

T＝D/2；

S＝D/2。

however, these dimensions are merely indicative and are considered to be changeable as appropriate to achieve the required flow and provide sufficient mechanical strength in the support arrangement 32 to enable the shaft receiving bearing 30 to be mounted thereon.

Fig. 5 shows a bottom plan view of the support device 32. First plate 44, second plate 48, third plate 52, and fourth plate 56 extend radially outward from central axis 31 and are arranged in a cross-configuration. That is, the first blade 44 extends in an opposite direction from the second blade 48 such that the first blade tip 46 is located on an opposite side of the central axis from the second blade tip 50. The third and

fourth vanes

52, 56 extend in a direction transverse to the direction of the first and

second vanes

44, 48. Further, the third vane 52 extends in an opposite direction from the fourth vane 56 such that the third vane tip 54 is located on an opposite side of the central axis from the fourth vane tip 58. Thus, the blades are equally spaced and the angle between adjacent blades is substantially 90 °.

An alternative configuration is shown in figure 6. In this arrangement, the support device 32 comprises six blades arranged in a star configuration. The first, second, third, fourth, fifth, and

sixth vanes

64, 66, 68, 70, 72, 74 extend radially outward from the central axis 31.

The first vane 64 extends in a direction opposite the second vane 66. The third vane 68 and the fourth vane 70 extend in a direction different from the direction of the first vane 64 and the second vane 66. Further, the third blade 68 extends in a direction opposite to that of the fourth blade 70. Still further, the fifth and sixth vanes 72, 74 extend in a direction different from the direction of the first, second, third and

fourth vanes

64, 66, 68, 70. The fifth blade 72 extends in a direction opposite to that of the sixth blade 74. Thus, the blades are equally spaced and the angle between adjacent blades is substantially 60 °.

An alternative arrangement of the support means is shown in fig. 7, showing an alternative arrangement of the support means 32 of the stabilizing device 28. In this alternative arrangement, the lower edge 60 of the plate terminates at a level higher than the lowermost level of the bottom wall 18 of the mixing vessel 12. This corresponds to a location above the mouth of the outlet port 34.

Fig. 8 shows a further arrangement of the support device 32 of the stabilization device 28. In this alternative arrangement, the level at which the lower edge 60 of the plate terminates is at a point in the same horizontal plane as the lowermost level of the bottom wall 18 of the mixing vessel 12. This corresponds to an entry into the outlet port 34.

Where the reactor is used to react a gas with a liquid (such as in a hydroformylation reaction), the reactor 10 includes an introduction means for introducing the gas. The introduction means may be located in any suitable location. One arrangement is shown in fig. 9. In this arrangement, gas supply conduit 76 allows gas to be supplied to gas distribution ring 78. Thus, in the hydroformylation reaction, hydrogen and carbon monoxide are supplied through the gas dispersion ring and can thus be bubbled through the alkane. Gas dispersion ring 78 comprises a generally toroidal tube positioned such that it surrounds agitator shaft 24. Typically, the center of the protuberance will coincide with a point on the longitudinal axis of the agitator shaft 24. Gas dispersion ring 78 includes apertures or perforations in the wall of the conduit to allow gas to be introduced from gas supply conduit 76 into the mixing chamber.

In one arrangement, as shown in fig. 9, the reactor may additionally include a plate 80, the plate 80 extending upwardly from the bottom wall 18 of the reactor shell 12. In one arrangement, plate 80 comprises a cylindrical plate positioned such that its axis is coaxial with the longitudinal axis of the mixing shaft and such that it surrounds the stabilizing apparatus.

The plate 80 serves to reduce and preferably prevent gas bubbles in the fluid mixture from reaching the flow modifying structure of the support device 32, thereby also reducing entrained gas in the product stream recovered from the reactor 10.

In fig. 9, a plurality of dimensions are indicated by reference numerals A, F and G, wherein:

a is the height of the plate 80, i.e., the distance the plate 80 extends upwardly from the bottom wall 18;

f is the diameter of the cylinder forming the plate 80; and

g is the height of gas distribution ring 78 above the location that lies in the same horizontal plane as the top of support device 32.

The dimensions may have the following relationship:

g ═ 4D to 6D;

f ═ 0.5D to 3D;

a ═ 0.5D to 1.5D.

The cross-sectional diameter of the gas dispersion ring 78 is typically the same as the diameter of the gas supply conduit 76.

However, these dimensions are merely indicative and can be varied to suit achieving the desired flow, varied for different mixing processes and/or varied for different fluids to be mixed.

Although the plate 80 is typically present where a gas distribution ring 76 is used, the plate 80 may be omitted. Similarly, the plate 80 may be present in an arrangement that does not use a gas dispersion ring.

It is to be understood that the reactor described may be used to carry out other reactions.

To describe the relative spatial arrangement of features of the device, reference is made to directions (e.g., top, bottom, above, below, etc.), and no limitation is intended in any sense.

Claims

1. A stabilizing apparatus for stabilizing a stirring shaft in a mixing vessel having an outlet in a bottom thereof, the stabilizing apparatus comprising:

support means for supporting the shaft-receiving bearing and spacing the shaft-receiving bearing from the outlet of the mixing vessel;

wherein the support arrangement comprises a vortex reducing structure.

2. The stabilizing apparatus of claim 1, wherein the vortex reducing structure comprises one or more blades.

3. A stabilising apparatus according to claim 2, wherein the or each vane extends radially outwardly from a central axis.

4. A stabilising arrangement according to claim 2 or 3, wherein two, three, four, five, six or more blades are used.

5. A stabilising apparatus according to claim 2 or 3, wherein the vortex reducing formations comprise four or six equally spaced blades.

6. A stabilising arrangement according to any one of claims 1 to 3, wherein the shaft receiving bearing is integrally formed with the support means.

7. A stabilising arrangement according to any one of claims 1 to 3, wherein the support means further comprises a flange extending therefrom.

8. The stabilizing apparatus of claim 7, wherein the flange defines a circumferential rim extending laterally from the support device.

9. A mixing apparatus, comprising:

a mixing vessel comprising an inlet port and an outlet port;

a rotatable stirring shaft extending into the mixing vessel;

an impeller attached to the rotatable stirring shaft; and

the stabilizing device of any one of claims 1 to 8 for stabilizing a rotatable agitator shaft, the stabilizing device being located within the mixing vessel and secured to an inner surface of the mixing vessel such that the stabilizing device is located above the outlet port and the rotatable agitator shaft is received in the shaft-receiving bearing.

10. The mixing apparatus of claim 9, wherein the vortex reducing structure comprises at least two blades, wherein a distance between a tip of a first blade and a tip of a second blade is 2 times a width of the outlet port.

11. The mixing apparatus of claim 9 or 10, wherein the shaft-receiving bearing is spaced from the outlet port by a distance of 2 times an outlet port width.

12. The mixing apparatus according to claim 9 or 10, wherein the height of the stabilizing apparatus for stabilizing the rotatable stirring shaft is 1.5 times the width of the outlet port.

13. The mixing apparatus of claim 10, wherein said stabilizing apparatus for stabilizing the rotatable agitator shaft comprises a flange, and said flange extends beyond said blades a distance of one-half the width of the outlet port.

14. The mixing apparatus according to claim 9 or 10, wherein the vortex reducing structure extends at least partially into the outlet port.

15. The mixing apparatus of claim 14, wherein the vortex reducing structure extends into the outlet port a distance that is half of an outlet port width.

16. The mixing apparatus of claim 9 or 10, wherein at least a portion of the vortex reducing structure terminates above the outlet port.

17. The mixing apparatus of claim 16, wherein the vortex reducing structure terminates above the outlet port a distance that is half of an outlet port width.

18. The mixing apparatus according to claim 9 or 10, wherein the mixing vessel is a reactor.

19. The mixing apparatus of claim 18, wherein the reactor is used in a gas-liquid reaction.

20. The mixing apparatus of claim 19, wherein the reactor further comprises a gas dispersion ring.

21. The mixing apparatus of claim 20, wherein the gas dispersion ring is arranged to surround the stabilizing apparatus for stabilizing the agitator shaft.

22. The mixing apparatus of claim 21, wherein the gas dispersion ring is spaced from the stabilizing apparatus for stabilizing the agitator shaft by a distance of 4 times the width of the outlet port.

23. The mixing apparatus of claim 9 or 10, the mixing vessel further comprising a baffle located on a bottom surface of the mixing vessel surrounding the outlet port.

24. The mixing apparatus of claim 23, wherein the height of the baffle is half the width of the outlet port.

25. The mixing apparatus of claim 23, wherein the baffle has a circular configuration and the diameter of the baffle is half the width of the outlet port.