GB2186209A

GB2186209A - A tubular reactor and process for supplying granular catalyst material and/or liquid into the tubes of the tubular reactor

Info

Publication number: GB2186209A
Application number: GB08700656A
Authority: GB
Inventors: Emil Supp
Original assignee: Metallgesellschaft AG
Current assignee: GEA Group AG
Priority date: 1986-01-18
Filing date: 1987-01-13
Publication date: 1987-08-12
Also published as: DE3601366C2; DE3601366A1; GB8700656D0; GB2186209B

Abstract

The reactor tubes 8 of a tubular reactor are mounted in an upper tube plate 6 and are surrounded by a liquid coolant during operation. A vertically movable distributor plate 15 is disposed over the upper tube plate and is provided with distributor tubes 18, which extend into the top portions of the reactor tubes. Granular catalyst material is first supplied onto the distributor plate, and then through the tubes into the reactor tubes. The catalyst material on the distributor plate is then removed and the plate is raised so that the distributor tubes are emptied. The reactor tubes are thus filled except for an upper volume, which remains free of catalyst. The distributor plate may also be used to distribute liquid into the reactor tubes. <IMAGE>

Description

SPECIFICATION A tubular reactor and process for supplying granular catalyst material and/or liquid into the tubes of the tubular reactor This invention relates to a tubular reactor of the kind which comprises a reactor housing, reactor tubes mounted in the housing with their upper ends mounted in an upper tube plate, at least one inlet for reactants to the housing, at least one outlet for reaction products from the housing, an inlet for supplying coolant to a space surrounding said reactor tubes and an outlet for removing heated coolant from said space, the reactor tubes being adapted to contain granular catalyst material so that when the reactor is in operation mixed gaseous reactants flow through the reactor tubes from top to bottom and the tubes are surrounded by liquid coolant. Such a tubular reactor will hereinafter be referred to as "a tubular reactor of the kind set forth".

This invention also relates to processes for supplying granular catalyst material and liquid into vertical reactor tubes of a tubular reactor of the kind set forth.

Tubular reactors are generally known and have been described in published German Application No. 30 28 646 and the corresponding United States Patent Specification No.

4,369,255. Highly exothermic reactions are generally carried out in tubular reactors and the heat which is generated is dissipated by a liquid coolant, such as water or a salt bath. If the coolant eyaporates at the prevailing temperatures, a vapour cushion will usually be formed directly under the upper tube plate even when the hot liquid coolant is continuously withdrawn. Measures for avoiding or at least reducing the formation of such a vapour cushion involve considerable expenditure. For instance, the vapour may be vented through the upper tube plate but such venting will give rise to considerable difficulties.

The reactor tubes which contain the catalyst material are very inadequately cooled adjacent to the vapour cushion so that hot spots may occur at the upper tube plate and in the catalyst material adjacent to the upper tube plate.

This can be avoided in a simple manner by not filling the reactor tubes with catalyst material as far as to their top ends so that a catalyst-free volume is left in that region.

It is an object of the invention to be able to fill the reactor tubes uniformly in a simple manner with catalyst material so that a catalyst-free volume is maintained adjacent to and directly below the upper tube plate.

According to one aspect of the present invention there is provided a tubular reactor of the kind set forth, wherein a vertically movable distributor plate is disposed over the upper tube plate and is provided with distributor tubes, which protrude into the upper portions of the reactor tubes.

By means of such a distributor plate the granular material can be supplied by first placing the catalyst on the distributor plate, supplying the catalyst material through the distributor tubes into the reactor tubes until the latter have been filled to a level which does not exceed approximately the level of the bottom ends of the distributor tubes, removing the catalyst material remaining on the distributor plate with the exception of the catalyst material in the filled distributor tubes, and raising the distributor plate so that the distributor tubes are emptied intow the reactor tubes. Because the volume of catalyst material in the distributor tubes is much smaller, a volume in each reactor tube adjacent to its top end remains free of catalyst when the distributor tubes have been emptied. All reactor tubes are filled substantially to the same level.

The distributor plate of the tubular reactor can desirably be used also for uniformly distributing liquid to the various reactor tubes.

Such a supply of liquid may be required, e.g.

in highly exothermic processes. In that case the reactor tubes are supplied from above with a liquid coolant, which may consist of a product of the completed exothermic reaction.

In accordance with a further aspect of the invention, there is provided a process for supplying liquid into vertical tubes of a tubular reactor of the kind set forth, wherein a distributor plate provided with upstanding distributor tubes which extend into the reactor tubes is provided over the top ends of the reactor tubes and the liquid is supplied on to the distributor plate and caused to flow through the distributor tubes into the reactor tubes. In such an arrangement the liquid is supplied to the distributor plate and is caused to flow through the distributor tubes into the reactor tubes. As the liquid level rises, the liquid enters the distributor tubes at their top ends or through openings provided in all distributor tubes on the same level.

By means of the distributor plate, even reactors comprising 10,000 to 20,000 or more reactor tubes can be uniformly supplied with catalyst material and/or with liquid. Because the distributor plate is movable, the reactor parts disposed under the distributor plate can be inspected without difficulty; such inspection is required at regular intervals.

In order to enable the invention to be more readily understood, reference will now be made to the accompanying drawings, which illustrate diagrammatically and by way of example, some embodiments thereof, and in which Figure 1 is a diagrammatic longitudinal sectional view through a tubular reactor, Figures 2 and 3 illustrate the cooperation of a reactor tube and a distributor tube as the reactor tube is supplied with catalyst material, and Figures 4 to 6 each show modified distributor tubes for supplying catalyst material and liquid.

The tubular reactor shown in Figure 1 comprises a pressure-resisting housing 1, which has a supply line 2 for a reactant material consisting e.g., of mixed gases, and which has a line 3 for withdrawing the product. The housing is provided with at least one detachable cover 4 and has a liquid supply line 5.

The housing 1 contains an upper tube plate 6, a lower tube plate 7 and numerous reactor tubes 8, which extend between the tube plates and are substantially filled with granular catalyst material. The catalyst is supported in each reactor tube 8 on a grate 9. A liquid coolant supplied through a line 10 and withdrawn through a line 11 flows through the region between the tube plates 6 and 7 and around the reactor tubes 8.

During operation of the reactor, an exothermic reaction is carried out in the catalyst, surplus heat is dissipated by the liquid coolant and a vapour cushion is usually formed directly below the upper tube plate 6 so that the cooling in that region is substantially restricted. For this reason a distributor plate 15 is used to ensure that the catalyst material will be supplied into the reactor tubes 8 to fill them only to a level which is slightly below their top ends.

The distributor plate 15 has approximately the shape of a shallow bowl, with a flat bottom and a rising side wall 15a, and is provided with short distributor tubes 18, which are associated with respective reactor tubes 8. In order to permit vertical adjustment of the distributor plate 15, the latter is provided with a plurality of screw-threaded rods 19 and 20, which are screwed through the distributor plate and rest on top of the tube plate 6. The rods 19 and 20 can be screwed to raise or lower the distributor plate 15. Alternatively the plate 15 can be moved by a different lifting mechanism.

It will now be explained with reference to Figures 2 and 3 how the granular catalyst material is charged into each reactor tube 8 before the operation proper begins. For that purpose the cover 4 is removed to expose a hole, through which the catalyst material is supplied onto the distributor plate 15. The catalyst is permitted to trickle through the distributor tubes 18 into the respective reactor tubes 8 until the catalyst in each reactor tube 8 has reached the level of the bottom end of the associated distributor tube 18 (see Figure 2). The catalyst will automatically cease to flow when that state has been reached. Any surplus catalyst material on the distributor plate 15 is then removed, whereas the distributor tubes 18 remain filled with catalyst material as far as to their top ends.The catalyst material can be removed from the plate 15, e.g., by suction or mechanically by an operator. The distributor plate 15 is subsequently raised as shown in Figure 3 so that all catalyst in the distributor tubes can flow out and the level of the catalyst in each reactor tube 8 will rise above the catalyst level shown in Figure 2, but a region 22 in the top end portion of the reactor tube 8 will remain free of catalyst (Figure 3). In a given apparatus, the height of the region 22 can be controlled within certain limits by a selection of the depth to which the distributor tube 18 is immersed into the reactor tube 8, provided that the reactor tube 8 is filled to the level of the bottom end of the distributor tube 18 (see Figure 2).Such control can easily be performed by a person skilled in the art in practice because he is aware of the catalyst volume that is contained in the distributor tube 18 and of the height to which said relatively small volume corresponds in the reactor tube 8.

In practice it is recommendable to use distributor tubes which are 5 to 30 mm, in outside diameter and reactor tubes which are 20 to 60 mm, in inside diameter.

Figures 4 to 6 show different distributor tubes attached to the distributor plate 15 shown in Figure 1. The distributor tubes serve to supply the associated reactor tubes 8 with granular catalyst material and to ensure that liquid which has been placed on the distributor plate 15 from the line 5 will be uniformly supplied through all the distributor tubes into the associated reactor tubes. For this purpose the distributor tube 1 8a shown in Figure 4 comprises a tubular portion 28, which extends above the distributor plate 15. These tubular portions 28 serve mainly to ensure that the reactor tubes 8 will be uniformly supplied with liquid which flows from the line 5 initially onto the distributor plate 15.The liquid level then rises progressively until the liquid enters the distributor tube 1 8a across the top rim 28a of the tubular portion 28. Because a uniform rise of the level of the liquid on the distributor plate 15 can easily be ensured, the liquid will also flow uniformly or at least approximately uniformly in a downward direction through all tubular portions 28, which have the same height. The distributor tube 1 8a shown in Figure 4 can readily be used to charge catalyst because the catalyst is now supplied onto the distributor plate 15 up to a level above the top rim 28a of each tubular portion 28 and each reactor tube 8 is then filled to the level shown in Figure 2. All surplus catalyst material on the distributor plate 1 5 is then removed, whereas each tube 18a remains filled with catalyst up to its top rim 28a. Thereafter the distributor plate 1 5 is raised to the position shown in Figure 3 so that the reactor tube 8 is filled to the desired level and remains free of catalyst in a region near its topmost end.

The distributor tube 1 8b shown in Figure 5 is formed in its tubular upper portion 28 with a bore 30, which is smaller in diameter than the inside diameter of the distributor tube 1 8b and may be 1 to 10 mm, in diameter. The bore 30 serves to supply liquid from the distributor plate 15 through the bore 30 into the distributor tube 1 8b and from the latter into the associated reactor tube 8. As the bore 30 is disposed approximately at one-half of the height of the tubular portion 28, the liquid level can be maintained above the bore but below the rim 28a so that the liquid will be still more uniformly supplied through all distributor tubes 18b than is usually the case in the embodiment shown in Figure 4.The distributor tube 28b shown in Figure 5 comprises a protective sheath 31, which is used when the distributor plate 15 is used to supply catalyst material. In that case the sheath 31 ensures that the bore 30 will not be clogged by catalyst material. The sheath 31 is removed before the distributor plate 15 is used for the supply of liquid.

In the modification shown in Figure 6, a detachable tubular member 28c formed with a bore 30 is screwed into the distributor tube 18c at its top. The distributor tube 18c is joined by means of a threaded sleeve 32 to the distributor plate 1 5. The tubular member 28c will be mounted as shown in Figure 6 when the distributor plate 1 5 is used for the distribution of liquid. When catalyst is to be supplied into the reactor tubes 8 through the distributor plate 1 5 in the manner described hereinbefore before the reactor is operated, the tubular member 28c is removed. When liquid is to be supplied continuously or from time to time through the distributor plate 1 5 into the reactor tubes 8 during the operation of the reactor, the tubular member 28c is screwed into the sleeve 32.

Claims

1. A tubular reactor of the kind set forth, wherein a vertically movable distributor plate is disposed over the upper tube plate and is provided with distributor tubes, which protrude into the upper portions of the reactor tubes.

2. A reactor as claimed in Claim 1, wherein the distributor tubes in the distributor plate comprise upstanding tubular portions extending above the plate.

3. A reactor as claimed in Claim 2, wherein the upstanding tubular portions have bores disposed on the same level.

4. A reactor as claimed in Claim 2 or 3, characterized in that the upstanding tubular portions are detachable.

5. A tubular reactor of the kind set forth substantially as hereinbefore described with reference to Figures 1 to 3 alone or as modified by any one of Figures 4 to 6 of the accompanying drawings.

6. A process for supplying granular catalyst material into vertical reactor tubes of a tubular reactor of the kind set forth, comprising placing catalyst material on a vertically movable distributor plate comprising distributor tubes which protrude into the top ends of the reactor tubes, supplying catalyst material through the distributor tubes into the reactor tubes until they have been filled to a level which does not exceed approximately the level of the bottom ends of the distributor tubes, removing the catalyst material remaining on the distributor plate with the exception of the catalyst material in the filled distributor tubes, and raising the distributor plate to empty the distributor tubes so that the reactor tubes are substantially filled while leaving an upper volume of the reactor tubes free of catalyst.

7. A process for supplying liquid into vertical tubes of a tubular reactor of the kind set forth, wherein a distributor plate provided with upstanding distributor tubes which extend into the reactor tubes is provided over the top ends of the reactor tubes and the liquid is supplied onto the distributor plate and caused to flow through the distributor tubes into the reactor tubes.