WO2018184036A1

WO2018184036A1 - Dispersion trays

Info

Publication number: WO2018184036A1
Application number: PCT/ZA2018/050015
Authority: WO
Inventors: Ruan KUKARD; Abraham Barend SMIT; Barend Jacobus BEYLEFELD; Charl Jan DU PREEZ
Original assignee: Kukard Ruan; Smit Abraham Barend; Beylefeld Barend Jacobus; Du Preez Charl Jan
Priority date: 2017-03-27
Filing date: 2018-03-27
Publication date: 2018-10-04

Abstract

A dispersion tray (10) comprising upper and lower parts (12, 14) each comprising parallel transverse half pipes, wherein the half pipes (16, 30) of the lower part ("the lower pipes") (30) face upwards and the pipes of the upper part ("the upper pipes") (16) face downwards, wherein the ends of the lower pipes (30) terminate at a first plane and the ends of the upper pipes (16) terminate at a second plane which is parallel to the first plane, and wherein the half pipes (16, 30) are arranged in spaced pairs with the adjacent ends of the pipes of each pair being at least close to each other and the outer ends of each pair in the one part terminating midway along the width of the pipes in the other part on either side of a space between the pairs of pipes of the said other part.

Description

DISPERSION TRAYS

[0001] This invention relates to fluidising solids in a vessel and in particular to dispersion trays which are used in such vessels and through which the feed must pass before entering a bed of solids particles. [0002] A known and widely used dispersion tray for this purpose comprises a bubble cap plate consisting of a cross plate carrying a number of bubble caps through which the feed passes. This has the disadvantage that in use the bubble caps have serious maintenance problems. Furthermore there is excessive pressure drop across the dispersion tray because of limited open area.

[0003] According to one aspect of the invention there is provided a dispersion tray comprising upper and lower parts each comprising parallel transverse half pipes,

wherein the half pipes of the lower part ("the lower pipes") face upwards and the pipes of the upper part ("the upper pipes") face downwards, wherein the ends of the lower pipes terminate at a first plane and the ends of the upper pipes terminate at a second plane which is parallel to the first plane, and

wherein the half pipes are arranged in spaced pairs

with the adjacent ends of the pipes of each pair being at least close to each other and

the outer ends of each pair in the one part terminating midway along the width of the pipes in the other part on either side of a space between the pairs of pipes of the said other part. [0004] The half pipes are preferably all of the same wall thickness and the same internal radius. The spaces between the pairs of pipes of each part are preferably the same and preferably the same as the pairs of pipes as the other part. The distance apart of the planes is reduced to a minimum.

[0005] According to another aspect of the invention there is provided a fluidised vessel having a main part in which the solids may be provided and a feed chamber therebelow, the feed chamber being separated from the main part of the column by a dispersion plate as set out above.

[0006] An embodiment of the invention will now be described with reference to the accompanying drawings.

[0007] In the drawings:

Figure 1 is a perspective view of the dispersion plate of the invention, Figure 2 is a section on line 2 - 2 of Figure 1,

Figure 3 is an enlarged detail of the dispersion plate of Figure 2,

Figure 4 is an exploded perspective view of the dispersion plate, and Figure 5 is a diagrammatic view of a fluidised carbon column

incorporating a dispersion plate of the invention.

[0008] Referring now to Figures 1 to 4 there is shown a dispersion plate 10 of the invention. The dispersion plate 10 comprises upper and lower horizontal parts 12 and 14. [0009] The upper part 12 comprises a number of half pipes 16 all being of identical cross section and being formed by pipes which are divided along horizontal diameters. The half pipes 16 ("the upper half pipes") are arranged facing downwards. The sides 18 of the upper half pipes 16 terminate at a plane (the "upper plane") 20 which in use is horizontal. The upper half pipes 16 are arranged in spaced pairs. The space 22 between the pairs of upper half pipe 16 is slightly greater than the outside diameter of a half pipes 16. The adjacent side edges 24 of the half pipes 16a and 16b of each pair are closely spaced as possible i.e. by a few millimetres.

[0010] The half pipes 16 cover a circular area and the ends of the upper half pipes butt against and are secured internally to a cylindrical ring 26 of low height being welded or bolted thereto.

[0011] The lower part 14 is similarly formed by a number of identical half pipes 30 (the "lower half pipes")(which are identical to the upper half pipes 16) similarly formed and located but being arranged facing upwards with the pairs of the half pipes 30 located apart from one another by space 32. The sides 34 of the lower half pipes 30 all terminate in a lower plane 36 which is parallel to and spaced from the upper plane 20 by a small distance as will be described.

[0012] The lower half pipes 30 cover a circular area and the ends of the lower half pipes 30 butt against and are secured internally to a narrow cylindrical collar 38 being welded or bolted thereto. [0013] The upper and lower half pipes 16 and 30 are all parallel and are off-set from one another so that the outer sides 16a of each pair of upper half pipes 16 are located substantially midway above the mid-point of the lower half pipes 30a and 30b on each side of the spaces 42 (as is best shown in Figure 3).

[0014] The half pipes have suitable dimensions conveniently having an inside diameter of 80mm. [0015] Between the upper and lower parts there is an annular ring plate 50. The ring plate 50 has a central opening 52 the diameter of which is slightly smaller than the diameter of the ring and collar which parts butt against the ring plate 50. Spanning the opening 52 are three parallel narrow support plates 54. These support the upper half plates 16 and may be spot welded to the lower half pipes to support the lower half pipes 30.

[0016] The part of the annulus of the ring plate 50 extending beyond the collar and ring has bolt holes formed therein to enable the dispersion plate to be secured in position in an appropriate vessel.

[0017] Reference will now be made to Figure 5 which shows a fluidised carbon column 60 in which a dispersion plate of the invention is used. The carbon column 60 has a funnel shaped main body 62 leading at its lower end to a smaller cylindrical part 64 and at its upper end to a larger cylindrical part 66. Spanning the smaller cylindrical part 64 about midway of its height is dispersion plate 10 and the space therebelow constitutes a feed chamber 68. A vertical static head pipe 70 leads via a horizontal feed pipe 72 at its lower end to the feed chamber 68. A carbon bed is placed on the dispersion plate. The carbon bed is fluidised by the transfer solution and the liquid overflows the upper part of the column 60 for further use.

[0018] In use, the fluid in the feed chamber 68 will move upwards through the large spaces 42 between the lower half pipes 40. The fluid will then enter the upper half pipes 30 where its flow direction will reverse and it will be guided into the lower half pipes 40. The direction of the flow will then be reversed again by the lower half pipes 40 and the fluid will pass through the spaces 36 between the pairs of upper half pipes 30 and thence into the main body of the column 10 fluidising the carbon.

[0019] We have found that the fluid flow through the dispersion plate 18 causes the fluid to move with an even spread through the carbon to fluidise the carbon bed so that the transfer solution will pass evenly through the carbon providing a good mixture between the solution and the carbon. [0020] It will be seen that the dispersion plate will support the carbon bed preventing it from falling into the feed chamber.

[0021] We have further found that the construction of the dispersion plate is such that this can easily be withdrawn from the column for maintenance and repair. Normally a spare dispersion plate will be provided so that this will replace the dispersion plate that was used and that can be worked on at a remote location separately with the down time being limited to a minimum of down time. [0022] The invention is not limited to the precise constructional details hereinbefore described and illustrated. Dimensions may differ. The shape of the collar may differ depending upon the cross section of the column into which the dispersion plate is to be inserted.

Claims

1 A dispersion tray comprising upper and lower parts each comprising parallel transverse half pipes,

wherein the half pipes are arranged in spaced pairs

the outer ends of each pair in the one part terminating midway along the width of the pipes in the other part on either side of a space between the pairs of pipes of the said other part.

2 A dispersion tray as claimed in claim 1 wherein the planes are horizontal.

3 A dispersion tray as claimed in claim 1 or 2 wherein the half pipes are all of the same wall thickness and the same internal radius.

4 A dispersion tray as claimed in claims 1, 2 or 3 wherein the spaces between the pairs of pipes of each part are the same.

5 A dispersion tray as claimed in any one of the preceding claims wherein the ends of the half pipes of the upper part are surrounded by a ring to which the ends are connected. 6 A dispersion tray as claimed in any one of the preceding claims wherein the ends of the half pipes are the lower part are surrounded by a collar to which the said ends are connected. 7 A dispersion tray as claimed in any one of the preceding claims further comprising a support member having a through opening the size of the upper and/ or lower parts is provided between the upper and lower plates and wherein narrow supporting plates span the said opening and support the half plates.

8 A dispersion tray as claimed in claim 5, 6 and 7 wherein the support member comprises an annular plate the outside diameter of which is greater than the ring and collar. 9 A dispersion tray as claimed in claim 8 wherein the outside part of the annulus lying outside the ring and collar has openings through which can pass bolts which secure the dispersion plate to the vessel.

10 A dispersion tray as claimed in claim 4 wherein the spaces between the pairs of pipes of each part are the same and the same as the spaces between the pairs of pipes of the other part.

11 A fluidised vessel having a main part in which the solids may be provided and a feed chamber therebelow, the feed chamber being separated from the main part of the column by a dispersion plate characterised in that the dispersion plate is as claimed in any one of the preceding claims. 12 A dispersion plate having parts arranged and operating substantially as hereinbefore described and as illustrated in the drawings.

Not Furnished Upon Filing