CATALYST SUPPORT

Abstract

A support for a catalyst. The support is for use in a packed-bed reactor for the production of an alkylene oxide. The support includes ceramic material and the support has a substantially spherical or ellipsoidal macrostructure. The support further includes surface structures and has a porosity of 0.35 cm.sup.3/g. The catalyst may be included in an apparatus and used for the production of an alkylene oxide.

Claims

1. A support for a catalyst, wherein the support comprises ceramic material, and wherein the support has a substantially spherical or ellipsoidal macrostructure and comprises surface structures, and wherein the support has a porosity of 0.35 cm.sup.3/g.

2. A supported catalyst for use in a packed-bed reactor for the production of an alkylene oxide, wherein the supported catalyst comprises ceramic material, and wherein the supported catalyst has a substantially spherical or ellipsoidal macrostructure and comprises surface structures.

3. The support according to claim 1, wherein the macrostructure of the support is substantially in the form of a sphere.

4. The support according to claim 1, wherein the support does not comprise a fluid communication intra-particle channel extending through the support from a first aperture on a first side of the support to a second aperture on a substantially opposing second side of the support.

5. The support according to claim 1, wherein the support/supported catalyst comprises a plurality of repeating surface structures having substantially the same shape.

6. The support according to claim 1, wherein, the support/supported catalyst comprises at least 5 repeating surface structures.

7. The support according to claim 1, wherein the surface structure comprises a ridge, trough, mound and/or depression.

8. (canceled)

9. (canceled)

10. The support according to claim 1, wherein the support/supported catalyst, such as a support/supported catalyst having a diameter or largest dimension of 8 mm.

11. The support according to claim 1, wherein the support/supported catalyst has a geometric surface area per volume (GSA) of 0.7 cm.sup.2/cm.sup.3.

12. (canceled)

13. The support according to claim 1, wherein the support/supported catalyst has a side crush strength of 8 kgf.

14. (canceled)

15. (canceled)

16. (canceled)

17. (canceled)

18. The supported catalyst according to any of claim 2, wherein the supported catalyst has a porosity of 0.35 cm.sup.3/g.

19. (canceled)

20. The support according to claim 1, wherein the support is a cast support.

21. (canceled)

22. (canceled)

23. The support according claim 1, wherein the ceramic material has a D.sub.10 of from 0.1 to 20 m, a D.sub.50 of from 0.5 to 35 m, or a D.sub.90 of from 10 to 100 m.

24. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)

28. (canceled)

29. The supported catalyst according to claim 2, wherein the catalytic material comprises a metal.

30. (canceled)

31. The support according to claim 1, wherein the support/supported catalyst is for use in a packed-bed reactor for the production of ethylene oxide, 1,9-decadiene oxide, 1,3-butadiene oxide, 2-butene oxide, isobutylene oxide, 1-butene oxide or propylene oxide.

32. (canceled)

33. A method for producing a support or a supported catalyst comprising the steps of: a. contacting a composition for producing a support/supported catalyst, suitably a gel cast composition as defined in claim 20, with an initiator and optionally a polymerisation accelerator; b. arranging the resulting composition of step (a) in a mould; c. demoulding the composition to produce a green body; d. optionally, drying the green body at room temperature or baking the green body at elevated temperature; e. calcining the green body; f. optionally, contacting the support with catalytic material.

34. A reactor for the production of an alkylene oxide comprising a catalyst bed wherein the catalyst bed comprises a support according to claim 1.

35. (canceled)

36. A reactor tube or reaction medium for the production of an alkylene oxide comprising a catalyst bed wherein the catalyst bed comprises a support according to claim 1.

37. (canceled)

38. A method for the production of an alkylene oxide comprising the use of a reactor comprising a catalyst bed wherein the catalyst bed comprises a support according to claim 1 to produce an alkylene oxide.

39. (canceled)

40. The method for the production of an alkylene glycol comprising producing an alkylene oxide according to claim 38 and then using the produced alkylene oxide in the production of the alkylene glycol.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0128] FIG. 1 shows a perspective view of a first comparative supported catalyst.

[0129] FIG. 2 shows a perspective view of a second comparative supported catalyst

[0130] FIG. 3 shows a perspective view of a first embodiment of a supported catalyst according to the present invention.

[0131] FIG. 4 shows a perspective view of a second embodiment of a supported catalyst according to the present invention.

[0132] FIG. 5 shows the flow results for the first comparative supported catalyst with a cross-section of the side of the column along the lateral X axis.

[0133] FIG. 6 shows the flow results for the first comparative supported catalyst with a cross-section from the top of the column along the longitudinal Z axis.

[0134] FIG. 7 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is aligned with the direction of flow with a cross-section from the side of the column along the lateral X axis.

[0135] FIG. 8 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is aligned with the direction of flow with a cross-section from the side of the column along the lateral Y axis.

[0136] FIG. 9 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is aligned with the direction of flow with a cross-section from the top of the column along the longitudinal Z axis.

[0137] FIG. 10 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is at 90 to the direction of flow with a cross-section from the side of the column along the lateral X axis.

[0138] FIG. 11 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is at 90 to the direction of flow with a cross-section from the side of the column along the lateral Y axis of.

[0139] FIG. 12 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is at 90 to the direction of flow with a cross-section from the top of the column along the longitudinal Z axis.

[0140] FIG. 13 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is at 45 to the direction of flow with a cross-section from the side of the column along the lateral X axis.

[0141] FIG. 14 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is at 45 to the direction of flow with a cross-section from the side of the column along the lateral Y axis.

[0142] FIG. 15 shows the flow results for the second comparative supported catalyst when the intra-particle flow channel is at 45 to the direction of flow with a cross-section from the top of the column along the longitudinal Z axis.

[0143] FIG. 16 shows the flow results for the first embodiment of a supported catalyst according to the present invention with a cross-section from the side of the column along lateral axis X.

[0144] FIG. 17 shows the flow results for the first embodiment of a supported catalyst according to the present invention with a cross-section from the top of the column along longitudinal axis Z.

[0145] FIG. 18 shows the flow results for the second embodiment of a supported catalyst according to the present invention with a cross-section from the side of the column along lateral axis X.

[0146] FIG. 19 shows the flow results for the second embodiment of a supported catalyst according to the present invention with a cross-section from the top of the column along longitudinal axis Z.

DESCRIPTION OF EMBODIMENTS

[0147] Computational fluid dynamics (CFD) compared the performance of two comparative supported catalysts to a supported catalyst according to the present invention.

[0148] The first comparative supported catalyst 100, shown in FIG. 1, has a 16 mm diameter grooved spherical macrostructure with four equally spaced parallel fluid communication intra-particle channels in the form of bores 102 extending between apertures on opposite sides of the outer surface of the supported catalyst. The grooves 104 of supported catalyst 100 are in the form of four equally spaced parallel linear grooves with curved lateral cross-sections on the outer surface of the supported catalyst. The outer surface of the supported catalyst 100 has the expected smooth continuous curvature of a spherical macrostructure.

[0149] The second comparative supported catalyst 200, shown in FIG. 2, is known as a Rashig ring and is in the form of an 8 mm by 8 mm cylinder having a central linear intra-particle fluid channel extending from an aperture in the upper face to and aperture in the lower face. The outer surface of the supported catalyst 200 has the expected smooth continuous curvature of a cylinder macrostructure.

[0150] The first embodiment of a supported catalyst 300 according to the present invention, shown in FIG. 3, is the same as the first comparative supported catalyst, with bores 302 and grooves 304, but in addition the outer surface of supported catalyst 300 comprises surface structures in the form of a plurality of interconnected hexagon-shaped annular ridged surface structures 306 extending over substantially the whole of the outer surface apart from the apertures of bores 302 and the surface of grooves 304. The portion of the outer surface that extends between the inner edges of the annular ridges is formed of an open ended inverted hexagonal pyramid.

[0151] The second embodiment of a supported catalyst according to the present invention 400, shown in FIG. 4, is the same as the second comparative supported catalyst, with grooves 402 and surface structures 404, except that supported catalyst 400 does not have fluid communication intra-particle channels extending through the body of the supported catalyst.

[0152] The supports of the first and second embodiments were produced from a moulding composition formed by mixing the components provided below using the following method.

[0153] An aqueous monomer solution containing the chain forming monomer, the chain linking monomer and the water was formed. To this dispersant was added. The pore former was then introduced and mixed until fully dispersed. The alumina powders were then mixed to form an aqueous slurry. The catalyst and initiator were then added to the aqueous slurry. The amounts of each component in the resulting slurry were:

TABLE-US-00001 % Alumina powder* 58.0 Pore former 1.8 Dispersant 2.0 Polymerisable monomer 3.7 Crosslinking member 1.8 Catalyst 0.3 Initiator 1.1 Water 31.3 *D.sub.10 of 1.32 m, D.sub.50 of 18.7 m, D.sub.90 of 44.2 m

[0154] The resulting aqueous slurry was then cast into a mould having the negative impressions operable to form surface structures on the moulded support. Once the slurry had gelled into a solid green body after 4-5 mins it was then demoulded. At this point the green body support had a rubbery, jelly-like consistency. The green body was then dried at 110 C. for 24 hours. The dried green body was then fired to 1450 C., at which point the binder, dispersant and pore former were burnt off to leave a solid, porous, supported catalyst.

[0155] The supports had a porosity/total intruded volume of 0.45 cm.sup.3/g and a side crush strength of 15 kg. The support of the first embodiment had a GSA of 493.8 mm.sup.2.

[0156] CFD was used to test the flow around the above-mentioned supported catalysts.

[0157] The test conditions were as follows: [0158] Large tube diameter selected so as to not interfere with flow around pellet (50 mm ID) [0159] Simulation resolution 0.125 mm per pixel [0160] Flow rate: 0.4 m.sup.3/min [0161] Orientation of the holes/side-channels in the same direction of flow

[0162] The result of the flow tests were:

TABLE-US-00002 Measured stagnant velocity zone below pellet (truncated cone) Comp. 2 Comp. 1 With flow At 90 At 45 Ex. 1 Ex. 2 Height of dead 7.5 3.4 7.3 9.8 7.4 7.25 zone below pellet (mm) Volume of dead 246.39 160.6 191.5 210.5 147.55 167.65 zone (mm.sup.3) Domain avg 0.05082 0.05015 0.05011 0.05010 0.05088 0.05095 velocity Re 1414.8 1382.6 1382.6 1382.6 1416.5 1330.3 Dead zone ht 46.88 42.50 91.25 122.5 46.09 45.31 relative to pellet diameter, % Dead zone vol 13.14 56.39 67.24 73.91 8.55 8.79 relative to pellet vol, %

[0163] As shown by the results of the above table and in FIGS. 5 to 19, compared to the comparative supported catalysts, the supported catalysts according to the invention provides a higher gas velocity in contact with the supported catalyst. In FIGS. 5 to 19, darker areas such as A in FIG. 5 indicate a lower/static gas velocity and lighter areas such as B in FIG. 5 indicate a higher gas velocity. In addition, the supported catalysts according to the invention provides a higher amount of gas turbulence above the supported catalyst, and also provides a smaller velocity static zone below supported catalyst.

[0164] Furthermore, for the second comparative example, it can be seen that the pellet orientation has a significant effect on the size of the dead zone (see the darkest shading below the pellet). When the pellet is orientated at 45 to the direction of flow, the dead zone volume increases from 50 of total pellet volume (when flow aligned) to 75% of pellet volume. The dead zone height is even more significantly affected, going from 43% of pellet diameter (when flow aligned) to 123% (45). This would have significant effect in a packed bed on the pellets directly below those at such an angle, reducing the catalyst-gas contact.

[0165] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0166] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0167] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0168] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.