GB2173122A

GB2173122A - A method of, and apparatus for, emptying pipes

Info

Publication number: GB2173122A
Application number: GB08605407A
Authority: GB
Inventors: Hans Joachim Rockstuhl
Original assignee: Richard Buchen GmbH
Current assignee: Richard Buchen GmbH
Priority date: 1985-03-06
Filing date: 1986-03-05
Publication date: 1986-10-08
Also published as: GB2173122B; DE3507868C2; IT1189980B; IT8619516A0; DE3507868A1; FR2578446B1; IT8619516A1; FR2578446A1; GB8605407D0

Abstract

A method of emptying pipes, in particular catalyst-filled thin-walled vertical pipes 20, by means of a conveying fluid utilizes a probe, which discharges the conveying fluid, and is introduced from above into the catalyst pipes, the probe being moved continuously downwards to loosen the filling and to convey it away by suction through a coaxial connector 3. <IMAGE>

Description

SPECIFICATION A method of, and apparatus for, emptying pipes This invention relates to a method of, and apparatus for, emptying filled pipes, and is particularly concerned with emptying pipe group reactors filled with solid catalyst material.

In orderto empty filled pipes, in particular small bore pipes of the type frequently used in the catalyst field, spent catalyst is removed to exchange the filling by introducing a probe into the catalyst, the probe extending to the base of the pipe, and by discharging through this probe a conveying fluid, by means of which the bulk material is expelled at the top. Liquids and gases may be used as conveying fluid, but preference is generally given to compressed air.

This method has not proved suitable for particularly narrow and long pipes. This is because the conveying fluid has to flow through the entire catalyst bed from the bottom, so that the pressure drops considerably towards the outlet. Blockages, which can only be loosened with difficulty, frequently occur.

Catalysts of this type often have spherical lumps at the top and bottom, the diameter of these spherical lumps being about twice as great as that of the catalyst itself. This additionally complicates discharge.

Moreover, a considerable quantity of dust is raised at the top of the pipe group with the known method.

As catalyst beds of this type frequently comprise several thousand pipes, each having a length far exceeding 10 m, exchange of catalyst is very expensive and time-consuming, owing to the problems mentioned above.

The aim of the invention, therefore, is to provide a method of, and apparatus for, simplifying and accelerating the emptying of catalyst pipes, whilst avoiding the raising of dust and associated environmental pollution.

The present invention provides a method of emptying pipes, in particular of catalyst-filled thinwalled vertical pipes, by means of a conveying fluid, the method comprising the steps of introducing a probe into each of the pipes from above, the probe discharging the conveying fluid, and moving the probe continuously downwards so that the filling is simultaneously loosened, conveyed and sucked from the tops of the pipes.

These features give rise to the following advantages: Expulsion of the catalyst occurs as the probe is being introduced, with simultaneous discharge of conveying fluid. In addition to the considerable saving of time, this means that only a relatively small quantity is stripped from the top, and the bed is not all moved at once, thus avoiding blockages. The discharge is also simplified by the simultaneous application of a vacuum, so that all the dust formed passes into the vacuum system and can, therefore, conveniently be collected.

The conveying fluid, preferably compressed air, can be discharged via a probe, to which there is connected a flexible tube which is sufficiently rigid to push it into the pipe and into the catalyst filling.

However, it is proposed that the forwards (downwards) movement of the probe, and at the same time the discharge of the catalyst material, is assisted by the thrust resulting from rearwardly-directed nozzles provided in the probe.

The catalyst material can advantageously be fed to a separator, which is connected to a vacuum system and from which it is sluiced in timed manner.

The dust-laden air then passes into a suction unit where it can be purified, for example by means of fiiters.

The invention also provides apparatus for emptying pipes, in particular catalyst-filled thinwalled vertical pipes, the apparatus comprising a pressure generator and a probe which can be connected to the pressure generator by a pressure line, the pressure line being guided in a sealed manner in a pipe connection which is connected to a vacuum sleeve, the vacuum sleeve being connected, via a suction line to a separator and a suction unit.

The pipe connection is preferably formed coaxially with the vacuum sleeve, and this simplifies introduction of the probe into the system. The vacuum sleeve can have, at its base, a guide connection which is inserted into the catalyst pipe. The probe is then also pushed through this guide connection, and subsequently passes into the catalyst bed, the guide connection simultaneously acting as a seal.

However, a design has proved particularly advantageous in which the vacuum sleeve rests on a base plate whose underside is provided with a seal, the base plate having a central opening whose diameter is at least equal to the internal diameter of the pipes to be emptied.

This embodiment is used in cases where the catalyst pipes are held in a common head plate. The base plate is placed on the head plate in such a way that the opening leaves the pipe orifice free. The suction apparatus is then switched on, causing the base plate to be fixed by the vacuum. The probe can then be lowered, and the supply of compressed air can commence.

To simplify the positioning procedure, guides may be arranged on the base plate, the guides being introducable into the adjacent pipes to be emptied.

This can easily be achieved, because the pipes have equal diameters, and they are grouped in a symmetrical arrangement with constant intervals between axes.

The pressure generator and the suction unit are preferably adapted to one another in terms of output so as to produce a total pressure somewhat lower than atmospheric pressure, so that pressure is applied to the base plate. However, it is also possible for the tightness to be produced by the operator, the load produced by his body weight being sufficient.

To simplify handling, a valve may be arranged on the vacuum sleeve, the valve controlling the flow of conveying fluid, and the pressure line may be connected to the valve. The person operating the apparatus can then regulate the supply of compressed air himself, without the risk of pressure surges.

If the probe is adapted to the diameter of the tube, a rigidly-mounted, cylindrical seal which closely surrounds the pressure tube is adequate.

To simplify introduction of the tube and the probe into the seal, however, the pipe connection may be provided with a sliding sealing element for sealing against the pressure line, the sealing element being of divided construction. The sealing element can, therefore, be removed, and the probe introduced through the vacuum sleeve into a given pipe.

The seal halves are placed round the pressure line, are introduced into the pipe connection, and are connected thereto. This method of assembly has the advantage, among other things, that the introduction of the probe into the pipe to be emptied can be observed from above, if the pipe connection and the external diameter of the seal are suitably dimensioned.

Advantageously, the suction and pressure lines each have distributors to which several emptying units can be connected. This allows work to take place at several positions simultaneously.

Preferably, the probe has a central nozzle oriented in the advance direction, and lateral nozzles which are arranged at an angle to the advance direction.

The lateral nozzles run obliquely, and have diameters corresponding to that of the central nozzle, typically about 3 mm.

Advantageously, the probe has a widened top over which the pressure tube can be slid, the external diameter of the probe being about one third of the internal diameter of the pipe to be emptied.

This is accompanied by a constriction in crosssection, which has a positive effect owing to the associated acceleration of the flowing fluid. The concentration of catalyst material is apparently diluted suddenly by the acceleration, and this also counteracts blockages. The free remaining crosssection should represent about two-thirds of the pipe.

Pipe emptying apparatus constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure lisa side elevation of the apparatus in use on a catalyst pipe group; Figure 2 shows the emptying unit of the apparatus with the various connections; and Figure 3 shows the probe of the apparatus.

Referring to the drawings, Figure 1 shows a typical catalyst pipe group 20 in which 4,750 catalyst-filled pipes, each having a length of 12.8 m, are combined in a group. Figure 1 also shows an emptying unit comprising a vacuum sleeve 3, a pipe connection 2 and a valve (check member) 12, the unit being positioned on the pipe group top in alignment with one of the pipes to be emptied.

The vacuum sleeve 3 rests on a base plate 8, below which a seal 9 (see Figure 2) is located. A pressure line 14 having a distributor 16; and a suction line 15 having a distributor 17 project into the space above the pipe group top. The pressure line 14 leads to a pressure generator 5; and the suction line 15 leads, via a separator, to a suction unit 7.

Four emptying units can be connected to the distributors 16 and 17, and the following parameters for the pressure generator 5 and the suction unit 7 (with the interposition of the separator 6) have proved beneficial: The compressor 5 is designed for 11,000 litres per minute at pressure of from 8 to 10 bar, whereas the suction unit produces 2,100 cubic metres per hour at a vacuum of 5,500 millimeters water column. The free cross-section of the catalyst pipes is 3.8 cm, and the greatest width of the probe (or of the connected tube) is from 1 to 1.2 cm.

The apparatus operates as follows. Compressed air passes via the compressor 5 and the pressure line 14 to the distributor 16. A line (not shown) leads from the distributor 16 to the valve 12. A pressure tube 14' (see Figure 3) of sufficient length for introduction into a catalyst pipe and suitably dimensioned is, in turn, connected to the valve 12, a probe 1 being located at the free end of the pressure tube 14'.After opening the valve 12, compressed air passes, via the probe 1, into the catalyst bed of a given pipe, and displaces the catalyst bed via the vacuum sleeve 3. The vacuum system (comprising the separator 6 and the suction unit 7) is connected, via the distributor 17, to the vacuum sleeve 3. The catalyst is sucked with all impurities, via the line 15, into the separator 6, and is separated from it via a sluice 21. Air and entrained dust pass into the suction unit 7.

An emptying process, which is perfectly harmless for the operator, is achieved with the apparatus illustrated. Dust and reaction products or unreacted reactants do not issue, as the system is subjected to a vacuum. Moreover, the emptying process is considerably accelerated.

Figure 2 shows, in more detail, the emptying unit comprising the vacuum sleeve 3 and the pipe connection 2 attached to the top. At sealing element 13, against which the pressure line (not shown) from the distributor 16 rests, is located in the pipe connection 2. The vacuum system can be connected via a suction port 4. Moreover, the valve 12, by means of which the supply of conveying fluid can be regulated, is arranged on the vacuum sleeve 3. The valve 12 is connected to the compressor 5 and to the probe 1.

An opening 10 in the base plate 8 is dimensioned such that its diameter is at least equal to the internal diameter of the pipes, that is to say it may also be slightly larger. Guide elements 11, which penetrate into the adjacent pipes and fix the emptying unit, are arranged laterally on the base plate 8.

The probe 1 (see Figure 3) has a central duct 22 and a coaxial nozzle 18. Nozzles 19, which run obliquely at an angle of about 45, are also arranged above the nozzle 18. The pressure tube 14' is inserted into an upper part 23 of the probe 1.

Alternatively, the pressure tube 14' could surround the upper part 23 if it were fixed in a suitable manner.

Claims

1. A method of emptying pipes, in particular of catalyst-filled thin-walled vertical pipes, by means of a conveying fluid, the method comprising the steps of introducing a probe into each of the pipes from above, the probe discharging the conveying fluid, and moving the probe continuously downwards so that the filling is simultaneously loosened, conveyed and sucked from the tops of the pipes.

2. A method as claimed in claim 1,wherein the conveying fluid is discharged simultaneously in the advance direction and laterally thereto in the opposite direction.

3. A method as claimed in claim 1 or claim 2, wherein the sucked-out filling is fed to a separator which is subjected to a vacuum, and is delivered from the separator by means of a timed sluice.

4. A method of emptying pipes substantially as hereinbefore described with reference to the accompanying drawings.

5. Apparatus for emptying pipes, in particular catalyst-filled thin-walled vertical pipes, the apparatus comprising a pressure generator and a probe which can be connected to the pressure generator by a pressure line, the pressure line being guided in a sealed manner in a pipe connection which is connected to a vacuum sleeve, the vacuum sleeve being connected, via a suction line to a separator and a suction unit.

6. Apparatus as claimed in claim 5, wherein the vacuum sleeve rests on a base plate whose underside is provided with a seal, the base plate having a central opening whose diameter is at least equal to the internal diameter of the pipes to be emptied.

7. Apparatus as claimed in claim 6, wherein the suction unit is such as to generate a vacuum which presses the seal on to the top of the pipe group.

8. Apparatus as claimed in any one of claims 5 to 7, wherein guides are arranged on the base plate, the guides being introducable into the adjacent pipes to be emptied.

9. Apparatus as claimed in any one of claims 5 to 8, wherein a valve is arranged on the vacuum sleeve, the valve controlling the flow of conveying fluid, and wherein the pressure line is connected to the valve.

10. Apparatus as claimed in any one of claims 5 to 9, wherein the pipe connection is provided with a sliding sealing element for sealing against the pressure line.

11. Apparatus as claimed in claim 10, wherein the sealing element is of divided construction.

12. Apparatus as claimed in any one of claims 5 to 11, wherein the suction and pressure lines each have distributors to which several emptying units can be connected.

13. Apparatus as claimed in any one of claims 5 to 12, wherein the probe has a central nozzle oriented in the advance direction, and lateral nozzles which are arranged at an angle to the advance direction.

14. Apparatus as claimed in any one of claims 5 to 13, wherein the probe has a widened top over which the pressure tube can be slid, the external diameter of the probe being about one third of the internal diameter of the pipe to be emptied.

15. Apparatus for emptying pipes substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.