WO2024261494A1

WO2024261494A1 - Bearing arrangement for a rotating packed bed

Info

Publication number: WO2024261494A1
Application number: PCT/GB2024/051594
Authority: WO
Inventors: Nilesh PAYGUDE; Makarand DHEKANE; Ajay JAGTAP
Original assignee: Carbon Clean Solutions Ltd
Current assignee: Carbon Clean Solutions Ltd
Priority date: 2023-06-23
Filing date: 2024-06-21
Publication date: 2024-12-26
Anticipated expiration: 2025-12-23

Abstract

A bearing arrangement (23) for a rotating packed bed (1) which comprises a packing assembly (8) coupled to a shaft (11) that rotates within a housing (5), wherein the bearing arrangement (23) comprises: a bearing (28) comprising an aperture (31) configured to receive the shaft (11); and an elastically deformable support structure (25) configured to be carried by a part of the housing (5), wherein the bearing (28) is attached to the elastically deformable support structure (25) and the elastically deformable support structure (25) is configured to be deformed elastically by movement of the shaft (11) to dampen displacements of the shaft (11) as the shaft (11) and the packing assembly (8) rotate within the housing (5).

Description

BEARING ARRANGEMENT FOR A ROTATING PACKED BED

FIELD

The present invention relates to a bearing arrangement for a rotating packed bed (RPB). The present invention more particularly relates to a bearing arrangement for supporting a shaft and dampening displacements of the shaft while the RPB is in use.

BACKGROUND

Gas streams from power plants and other industrial activities include pollutants, for example greenhouse gases. One such greenhouse gas is CO2 which contributes to the greenhouse effect and global warming.

Static packed beds or columns are used for a variety of chemical processing applications such as absorption, distillation, stripping and liquid-liquid extraction. These static packed beds are filled with packing through which fluids can flow. The packing increases the contact between fluids, thereby increasing the rate of mass transfer.

Advantageously, RPBs provide significantly improved mass transfer performance compared to conventional static packed beds. RPBs can be used in at least distillation, absorption and stripping applications. In a RPB, liquid flows from the inner radius of the packing of the RPB (typically made of structured packing or mesh) to the outer radius, while gas or vapor typically flows counter-current from the outside to the inside, though some cases of co-flow and cross-flow liquid/gas flow regimes are also known to exist. Rotation of the packing results in improved mass transfer by virtue of creating small droplets and thinner liquid films than in conventional beds. Rotation also creates an acceleration potential field (i.e., a centrifugal force) that improves vapor/liquid de-entrainment.

A drive system, connected to a central shaft aligned with the packing of the RPB, drives the rotation of the packing. Typical RPB rotation speeds range from 100 RPM to 600 RPM however, the use of speeds outside of this range is also known. Bearings support the shaft of a RPB and allow the shaft to rotate.

In a conventional vertical RPB system, a pulley connects a drive system to a RPB shaft. An upper bearing and lower bearing support each end of the shaft and allow the shaft to rotate about its vertical axis. The RPB packing is attached to and rotates with the shaft.

During operation of a vertical RPB, the lower bearing of the RPB supports most of the load produced by the mass and rotation of the packing. Because of this, the packing and lower bearing can act as a vertical cantilever, with the support being the lower bearing. This can lead to excessive levels of vibration and deflection at the upper bearing, which increases friction between the upper shaft and upper bearing. This friction can raise the drive load and cause the drive system to trip.

There is a need for a bearing arrangement for a RPB that alleviates at least some of the problems outlined herein.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides a bearing arrangement for a rotating packed bed (RPB) as claimed in claim 1 and a rotating packed bed as claimed in claim 13. The present invention also provides preferred embodiments as claimed in the dependent claims.

BRIEF DESCRIPTION OF THE FIGURES

In order that the present disclosure may be more readily understood, preferable arrangements thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view of a RPB comprising a bearing arrangement of one example of this disclosure;

Figure 2 is an enlarged view of part of the RPB shown in Figure 1 ;

Figure 3 is a cross-sectional view of a bearing arrangement of one example of this disclosure;

Figure 4 is a diagrammatic perspective view of an elastically deformable support structure of the bearing arrangement of Figure 3;

Figure 5 is a cross-sectional view of an elastically deformable support structure of one example of this disclosure with the elastically deformable support structure shown in an undeformed state;

Figure 6 is a cross-sectional view of the elastically deformable support structure of Figure 5 with the elastically deformable support structure shown a deformed state; and

Figure 7 is a cross-sectional view of the elastically deformable support structure of Figure 5 with the elastically deformable support structure shown a deformed state.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring initially to Figure 1 of the accompanying drawings, a rotating packed bed (RPB) system of one example of this disclosure comprises a RPB 1 rotatably coupled to a drive system 2 by a pulley 3. In this example, the RPB 1 is a ten metric tonne per day RPB, but in other examples the RPB 1 may be configured to capture CO2 at a different rate. The RPB 1 comprises a central axis indicated by line 4. The RPB 1 of this example comprises a housing 5 having a gas inlet 6 and a liquid inlet 7. The RPB 1 further comprises a gas outlet and a liquid outlet (not shown). The housing 5 encloses a rotatably mounted packing assembly 8 which comprises a substantially cylindrical packing body 9. The cylindrical packing body 9 has a central axis which is aligned with the central axis 4. The packing body 9 comprises an elongate central cylindrical chamber 10 which extends in line with the central axis 4 along the length of the packing body 9.

Referring now to Figure 2 of the accompanying drawings, the RPB 1 comprises a shaft 11 incorporating a cylindrical shaft body 12 having a central axis which is substantially aligned with the central axis 4 of the RPB 1. In this example, the shaft 11 is positioned at an upper end of the RPB

1.

The shaft 11 comprises a flange 13 extending radially outwardly at one end of the cylindrical shaft body 12. The flange 13 is attached to a top rotor plate 15 which is provided at the top of the packing assembly 8. The top rotor plate 15 is coupled to a top surface of the packing body 9 and is configured to rotate together with the packing body 9. In this example the flange 13 is attached to the top rotor plate 15 by a plurality of bolts 14 that are screwed into respective apertures in the top rotor plate 15. In other examples, the flange 13 may be attached to the top rotor plate 15 by another attachment arrangement, such as a weld.

In this example of the disclosure, the cylindrical shaft body 12 comprises a further aperture 16 which extends in line with the central axis 4 along the length of the cylindrical shaft body 12. The further aperture 16 is configured to receive the liquid inlet 7. The liquid inlet 7 comprises an elongate tubular body 17 having a longitudinal axis aligned with the central axis 4. The liquid inlet 7 extends in line with the central axis 4 along the length of the further aperture 16 and at least partially into the chamber 10. In this example, the liquid inlet 7 comprises a plurality of fluid apertures 18 configured to permit the flow of fluid from the interior of the tubular body 17 to the interior wall of the chamber 10.

In this example of the disclosure, the RPB 1 comprises a further shaft 19 having a further cylindrical shaft body 20 having a central axis which is aligned with the central axis 4 of the RPB 1. In this example, the further shaft 19 is positioned at a lower end of the RPB 1 and supports the majority of the weight of the packing assembly 8. The pulley 3 connects the further shaft 19 to the drive system

2.

The further shaft 19 comprises a further flange 21 extending radially outwardly at one end of the further cylindrical shaft body 20. The further flange 21 is attached to a bottom rotor plate 22 of the packing assembly 8. The bottom rotor plate 22 is coupled to a bottom surface the packing body 9 and is configured to rotate together with the packing body 9. In this example the further flange 21 is attached to the bottom rotor plate 22 by a plurality of bolts that are screwed into respective apertures in the bottom rotor plate 22. In other examples, the further flange 21 may be attached to the bottom rotor plate 22 by another attachment arrangement, such as a weld.

The shaft 1 1 is rotatably mounted to an upper part of the RPB housing 5 by a bearing arrangement 23. The further shaft 19 is rotatably mounted to a lower part of the RPB housing 5 by a further bearing arrangement 24.

Referring now to Figures 3 and 4 of the of the accompanying drawings, the bearing arrangement 23 comprises an elastically deformable support structure 25 comprising an elastically deformable portion 26. A free end of the elastically deformable support structure 25 is attached to the RPB housing 5. In this example, the elastically deformable support structure 25 is attached to the RPB housing 5 by a plate 27.

In this example, the elastically deformable portion 26 is of metal, preferably stainless steel or carbon steel or a spring metal. However, in other examples, the elastically deformable portion 26 is at least partly or wholly of plastic, such as polytetrafluoroethylene (PTFE), or polypropylene (PP) or polyethylene.

The elastically deformable support structure 25 supports a bearing 28. The bearing 28 may be external to the elastically deformable support structure 25. For example, the bearing may sit atop the elastically deformable support structure 25. The bearing 28 may alternatively be internal of the elastically deformable support structure 25.

The bearing 28 is affixed to the elastically deformable support structure 25 in a manner which does not hamper the deformability of the elastically deformable portion 26. The bearing 28 may be affixed directly to the elastically deformable support structure 25, or alternatively be indirectly affixed to the elastically deformable support structure 25.

In this example, the elastically deformable support structure 25 further comprises a substantially tubular insert 29 configured to support the bearing 28. The tubular insert 29 is not attached to the elastically deformable portion 26. In this example, the tubular insert 29 comprises an annular projection to support the bearing 28. The bearing 28 may also be supported by non-contiguous projections. In this example, the tubular insert 29 also comprises a substantially tubular top body 30 positioned above the bearing 28. The bearing 28 comprises a bearing aperture 31 configured to receive the shaft 11. In this example, the bearing 28 forms a substantially fluid tight seal with the shaft 11 , such that the bearing aperture 31 is sealed to minimise or prevent the flow of fluid between the bearing 28 and the shaft 11 .

The bearing 28 is attached to the elastically deformable support structure 25. As will be described below, the elastically deformable support structure 25 is configured to be deformed elastically by movement of the shaft 11 to dampen displacements of the shaft 11 when the RPB 1 is operating.

The elastically deformable portion 26 is a flexible element. The elastically deformable portion 26 may be an annularly corrugated element or expansion joint. In this example, the elastically deformable portion 26 is a bellows arrangement which is elastically deformable. In this example, the bellows arrangement comprises a side wall with a non-linear cross-section which is elastically deformable. In this example, the non-linear cross-section comprises at least one C-shaped or S- shaped or W-shaped portion of the side wall (when viewed in cross-section) which is elastically deformable. In other examples, the bellows arrangement comprises a side wall with a varying thickness or varying diameter which is elastically deformable.

In other examples, the elastically deformable support structure 25 comprises at least one elastically deformable spring in place of or in addition to the elastically deformable portion 26 of the example described above.

The function of the bearing arrangement 23 in damping displacements of the shaft 11 will now be described with reference to Figures 5-7 of the accompanying drawings. For clarity, Figures 6 and 7 show exaggerated deformation.

When the RPB 1 is operating, the drive system 2 drives the pulley 3 to rotate the further shaft 19 which in turn rotates the packing assembly 8. Since the packing assembly 8 is attached to the shaft 11 , the packing assembly 8 causes the shaft 11 to rotate. The weight of the packing assembly 8 inevitably produces vibrations in the shaft 11 as the packing assembly 8 rotates. The vibrations cause the shaft 11 to exert combinations of axial, angular, lateral, and torsional forces on the bearing 28. As the rotation speed increases, these forces exerted by the shaft 11 on the bearing 28 increase. When the forces exceed a predetermined level, the forces cause the elastically deformable support structure 25 to deform. As the elastically deformable support structure 25 deforms, the elastically deformable support structure 25 absorbs energy and dampens the displacements of the shaft 11 , thereby reducing or eliminating the vibrations.

Figure 5 shows the elastically deformable support structure 25 in an undeformed state when subject to no load. Figure 6 shows the elastically deformable support structure 25 experiencing deformation when subject to a load aligned with central axis 4. Specifically, the elastically deformable support structure 25 deforms at the elastically deformable portion 26. Figure 7 shows the elastically deformable support structure 25 experiencing deformation when subject to a load perpendicular with central axis 4.

The bearing arrangement 23 of some examples of this disclosure therefore enables the RPB 1 to operate without experiencing undesirable shaft 11 displacements because the bearing arrangement 23 absorbs energy and dampens the displacement of the shaft 11. Consequently, the bearing arrangement 23 helps to minimise friction between the shaft 11 and the bearing 28 and thereby minimises the risk of the drive system 2 being overloaded and tripping.

A further benefit of the bearing arrangement 23 of some examples of this disclosure is that the elastically deformable support structure 25 may be configured to provide damping characteristics to match a particular RPB 1 implementation. Different bearing arrangements 23 may be used interchangeably with an RPB 1 so that an RPB 1 can be customised according to the operating parameters of the RPB 1 . For example, bellows with different number of corrugated elements can be used. This makes the RPB 1 installation process more flexible since bearing arrangements 23 having different damping characteristics can be tested with an RPB 1 once the RPB 1 is operating. The bearing arrangement with optimum damping characteristics for the RPB 1 can thus be identified and installed for use with the RPB 1 .

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The invention may also broadly consist in the parts, elements, steps, examples and/or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and/or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure.

Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and/or to encompass equivalents.

REPRESENTATIVE FEATURES Representative features are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the text and/or drawings of the specification.

Clause 1 : A bearing arrangement for a rotating packed bed which comprises a packing assembly coupled to a shaft that rotates within a housing, wherein the bearing arrangement comprises: a bearing comprising an aperture configured to receive the shaft; and an elastically deformable support structure configured to be carried by a part of the housing, wherein the bearing is attached to the elastically deformable support structure and the elastically deformable support structure is configured to be deformed elastically by movement of the shaft to dampen displacements of the shaft as the shaft and the packing assembly rotate within the housing.

Clause 2: The bearing arrangement of clause 1 , wherein the elastically deformable support structure comprises a tubular body, the tubular body comprising an elastically deformable portion which is configured to deform elastically to dampen displacements of the shaft.

Clause 3: The bearing arrangement of clause 2, wherein the elastically deformable portion comprises a side wall with a non-linear cross-section.

Clause 4: The bearing arrangement of clause 3, wherein the non-linear cross-section comprises at least one substantially C-shaped, S-shaped or W-shaped portion of the side wall.

Clause 5: The bearing arrangement of clause 1 or clause 2, wherein the elastically deformable portion comprises a side wall with a varying thickness or varying diameter.

Clause 6: The bearing arrangement of any one of clauses 3 to 5, wherein the elastically deformable portion is a bellows arrangement.

Clause 7: The bearing arrangement of any one of the preceding clauses, wherein the elastically deformable support structure comprises a spring which is configured to deform elastically to dampen displacements of the shaft.

Clause 8: The bearing arrangement of any one of the preceding clauses, wherein the bearing is configured to form a substantially fluid tight seal with the shaft, such that the aperture is sealed to minimise or prevent the flow of fluid between the bearing and the shaft. Clause 9: The bearing arrangement of any one of the preceding clauses, wherein the elastically deformable support structure is at least partly of metal.

Clause 10: The bearing arrangement of clause 9, wherein the metal comprises a metal selected from a group including at least one of stainless steel, carbon steel and a spring metal.

Clause 11 : The bearing arrangement of any one of clauses 1 to 8, wherein the elastically deformable support structure is at least partly of plastic.

Clause 12: The bearing arrangement of clause 11 , wherein the plastic comprises a plastic selected from a group including at least one of polytetrafluoroethylene (PTFE), polypropylene (PP) and polyethylene.

Clause 13: A rotating packed bed comprising: a housing carrying the bearing arrangement of any one of the preceding clauses; a shaft configured to rotate about an axis which extends along the length of the shaft; and a packing assembly attached to the shaft.

Various features of the disclosure are set forth in the following claims.

Claims

1. A bearing arrangement for a rotating packed bed which comprises a packing assembly coupled to a shaft that rotates within a housing, wherein the bearing arrangement comprises: a bearing comprising an aperture configured to receive the shaft; and an elastically deformable support structure configured to be carried by a part of the housing, wherein the bearing is attached to the elastically deformable support structure and the elastically deformable support structure is configured to be deformed elastically by movement of the shaft to dampen displacements of the shaft as the shaft and the packing assembly rotate within the housing.

2. The bearing arrangement of claim 1 , wherein the elastically deformable support structure comprises a tubular body, the tubular body comprising an elastically deformable portion which is configured to deform elastically to dampen displacements of the shaft.

3. The bearing arrangement of claim 2, wherein the elastically deformable portion comprises a side wall with a non-linear cross-section.

4. The bearing arrangement of claim 3, wherein the non-linear cross-section comprises at least one substantially C-shaped, S-shaped or W-shaped portion of the side wall.

5. The bearing arrangement of claim 1 or claim 2, wherein the elastically deformable portion comprises a side wall with a varying thickness or varying diameter.

6. The bearing arrangement of any one of claims 3 to 5, wherein the elastically deformable portion is a bellows arrangement.

7. The bearing arrangement of any one of the preceding claims, wherein the elastically deformable support structure comprises a spring which is configured to deform elastically to dampen displacements of the shaft.

8. The bearing arrangement of any one of the preceding claims, wherein the bearing is configured to form a substantially fluid tight seal with the shaft, such that the aperture is sealed to minimise or prevent the flow of fluid between the bearing and the shaft.

9. The bearing arrangement of any one of the preceding claims, wherein the elastically deformable support structure is at least partly of metal.

10. The bearing arrangement of claim 9, wherein the metal comprises a metal selected from a group including at least one of stainless steel, carbon steel and a spring metal.

11 . The bearing arrangement of any one of claims 1 to 8, wherein the elastically deformable support structure is at least partly of plastic.

12. The bearing arrangement of claim 11 , wherein the plastic comprises a plastic selected from a group including at least one of polytetrafluoroethylene (PTFE), polypropylene (PP) and polyethylene.

13. A rotating packed bed comprising: a housing carrying the bearing arrangement of any one of the preceding claims; a shaft configured to rotate about an axis which extends along the length of the shaft; and a packing assembly attached to the shaft.