Method for completely emptying a catalytic reactor

Abstract

The present invention provides a method for emptying a reactor containing at least one bed of spent catalyst particles, wherein the reactor comprises at least one dump tube that opens into the reactor. The method comprising the steps of: (a) causing a portion of the bed of spent catalyst particles to flow out of the reactor via the dump tube; and (b) extracting the remainder of the spent catalyst particles from the reactor by driving the remainder of the spent catalyst particles toward the opening of the dump tube using a removable device comprising at least one flexible extraction sleeve introduced into the reactor via the said dump tube and connected to an extraction system situated outside the reactor, the sleeve being provided on its external surface with protuberances and being able to move, inside the reactor, translationally and rotationally with respect to the dump tube.

Claims

1. A method for emptying a vertical reactor containing at least one bed of spent catalyst particles, wherein the vertical reactor comprises at least one dump tube that opens into the reactor at the bottom of the bed of particles or underneath the latter, the method comprising the steps of: (a) causing a portion of the bed of spent catalyst particles to flow out of the reactor via the dump tube; and (b) extracting, without human manual intervention on the inside of the vertical reactor, the remainder of the spent catalyst particles from the reactor by sucking up the remainder of the spent catalyst particles with at least one flexible extraction sleeve introduced into the vertical reactor via the dump tube and connected to an extraction system situated outside the vertical reactor, the sleeve being provided on its external surface with protuberances and being able to move, inside the vertical reactor, translationally and rotationally with respect to the dump tube.

2. The method of claim 1, wherein step (a) is performed under gravity by causing a proportion of the bed of spent catalyst particles to flow out of the reactor under gravity via the dump tube.

3. The method of claim 1, wherein during the course of step (a), the proportion of the bed of spent catalyst particles extracted from the reactor is greater than 50 wt % of the initial bed.

4. The method of claim 3, wherein the portion of the bed of spent catalyst particles extracted from the reactor ranges from 60 to 95 wt % of the initial bed of catalyst particles.

5. The method of claim 3, wherein the portion of the bed of spent catalyst particles extracted from the reactor ranges from 70 to 90 wt % of the initial bed of catalyst particles.

6. The method of claim 1, wherein during the course of step (b), the sleeve is moved by guide means located outside the reactor.

7. The method of claim 6, wherein means of detecting the position of the sleeve are present inside the reactor.

8. The method of claim 7, wherein the detection means comprise one or more cameras positioned on an internal wall of the reactor and/or on the sleeve.

9. The method of claim 1, wherein the protuberances at the surface of the sleeve are selected from the group consisting of splines, teeth of varying degrees of roundedness or pointedness, brushes, elongated cylindrical protuberances, studs, pins, spikes and nails.

10. The method of claim 9, wherein the protuberances are present over the entire length of the extraction sleeve.

11. The method of claim 1, wherein the end of the sleeve introduced into the reactor is curved.

12. The method of claim 1, wherein the dump tube is horizontal or inclined downwards.

13. The method of claim 12, wherein the dump tube is inclined downwards, with an angle of inclination with respect to the vertical from 0 to 75 degrees.

14. The method claim 12, wherein the dump tube is inclined downwards, with an angle of inclination with respect to the vertical from 10 to 60 degrees.

15. The method of claim 1, further comprising, prior to step (a), deagglomerating the catalyst by injecting a pressurized inert gas into the bed of spent catalyst particles.

16. The method of claim 15, wherein the inert gas is carbon dioxide or nitrogen.

Description

(1) The present invention will now be illustrated in greater detail and nonlimitingly using the attached figures in which:

(2) FIG. 1 illustrates implementation of the first step of the method according to the invention in an industrial reactor containing a bed of spent catalyst,

(3) FIG. 2 shows the same reactor at the end of the first step,

(4) FIG. 3 illustrates implementation of the second step of the method according to the invention, in the same reactor,

(5) FIGS. 4 to 7 illustrate examples of structures of protuberances liable to be present at the surface of the extraction sleeve.

(6) FIG. 1 shows an industrial reactor 1 of the columns type, containing a bed 3 of spent catalyst particles. The reactor 1 comprises a downwardly inclined dump tube 2, with an angle of inclination with respect to the vertical of around 45 degrees. The tube 2 opens into the reactor 1 at the bottom of the bed 3 of particles.

(7) In order to allow the first step of the method according to the invention to be implemented, the dump tube 2 has been opened by opening the dump valve 7, so that the particles of catalyst flow out of the reactor 1 under gravity flow, via the tube 2.

(8) The dotted lines 4 show the initial upper level of the bed of catalyst 3 before the gravity flow was initiated, and the arrows in FIG. 1 show the direction in which the catalyst flows.

(9) FIG. 2 illustrates the same reactor 1 at the end of the first gravity flow emptying step, and shows that at the end of this step the reactor 1 still contains the remainder 3 of the spent catalyst which here represents approximately 15 wt % of the initial bed of catalyst, and which corresponds to the angle of repose of the mass of particles of catalyst. The remainder 3 of the catalyst corresponds to the dig out which cannot be removed simply under gravity flow emptying.

(10) As illustrated in FIG. 3, according to the second step in the method according to the invention, the remainder of the catalyst 3 is then sucked out of the reactor 1 using a flexible extraction sleeve 5 introduced into the reactor 1 via the dump tube 2. The end of the sleeve 5 introduced into the reactor, namely the suction head of the sleeve, is curved. The protuberances present at the surface of the sleeve 5 are not visible on the scale of FIG. 3, but may in particular be as described in FIGS. 4 to 7 below.

(11) The sleeve 5 is connected to an extraction system 6 situated outside the reactor. In addition, the sleeve 5 is able to move translationally with respect to the axis of symmetry of the dump tube 2, and able to move rotationally with respect to this same axis. For that, a system 8 for the translational and rotational drive of the sleeve (for example a pair of motors) is fixed to the flange at the outlet of the dump tube 2.

(12) FIGS. 4 to 7 illustrate nonlimiting examples of structures of protuberances that may be present at the surface of the extraction sleeve 5.

(13) FIG. 4a shows an embodiment in which the sleeve 5 is provided on its external surface with splines 9. FIG. 4b shows a cross section of the sleeve 5.

(14) FIG. 5 shows an embodiment in which the sleeve 5 is provided on its external surface with a collection of knob-like lumps 10, for example uniformly arranged over the surface of the sleeve.

(15) FIG. 6 shows a cross section through the sleeve 5 and illustrates one embodiment in which the sleeve 5 is provided on its external surface with teeth 11 of rounded shape, but which could also be pointed, or even hook-shaped.

(16) FIG. 7 shows an embodiment in which the sleeve 5 is provided on its external surface with a collection of protuberances 12 in the form of studs or pins uniformly arranged over the surface of the sleeve.