Device for dispensing a fluid, which device can be arranged in a reactor comprising a fixed catalytic bed

Abstract

The invention relates to a device (D) for distributing a fluid, which is able to be arranged in a fixed catalytic bed (C.sub.1, C.sub.2) of a reactor (R), said device comprising conveying means for conveying said fluid, comprising a plurality of pipes each directly receiving a distinct share of said fluid, distribution means for distributing said fluid, means for generating a local pressure drop in said fluid, such that: the device comprises manifold means (2a) for collecting said fluid together, and providing the fluidic connection between the pipes of said fluid conveying means and said fluid distribution means, said means for generating a local pressure drop are added on to said conveying or distribution or manifold (2a) means.

Claims

1. A device (D) for distributing a fluid, wherein the device feeds a fixed catalytic bed (C.sub.1, C.sub.2; C′.sub.1, C′.sub.2) of a reactor (R) with a reactant, said device comprising: an upstream fluid conveyer comprising a plurality of pipes (1) each directly receiving a distinct share of said fluid, a downstream fluid distributer (3), a pressure reducing member, wherein the device comprises a manifold (2a; 2b) for collecting said fluid together, and providing a direct fluidic connection between the pipes of said fluid conveyer (1) and said fluid distributer (3), wherein said pressure reducing member is added on to said fluid conveyer (1) or fluid distributer (3) or manifold (2a; 2b).

2. The device of claim 1, additionally comprising a plurality of fluid distributers (3), a plurality of manifolds (2a; 2b), and a fluid connector (10); wherein said manifolds (2a; 2b) are arranged one below the other, wherein said fluid connector (10) provide a fluidic connection between the plurality of the manifolds (2a; 2b).

3. The device of claim 1, wherein the manifold for collecting said fluid comprise at least one tube or an array of tubes (2b), to which the pipes of the fluid conveyer (1) are connected, said tube or tubes (2b) being closed at their ends.

4. The device of claim 1, wherein said array of tubes (2b) is arranged in the form of a cross, a network, a grid or a star.

5. The device of claim 1, wherein the manifold for collecting said fluid comprise at least one ring (2a), to which the pipes (1) of the fluid conveyer are connected.

6. The device of claim 1, wherein said fluid conveyer (1) and/or a fluid connector (10) extend along an axis (z) and each of said fluid-collecting manifolds (2a; 2b) extend in a plane (P), such that the axis (z) and the plane (P) form an angle (α) comprised between 60 and 120 degrees.

7. The device of claim 1, wherein said pressure reducing member comprises a restriction in the cross section for passage of the fluid of the restriction orifice (5), local narrowing or bellows type.

8. The device of claim 1, wherein said fluid distributer comprises a plurality of nozzles (3), connected to said manifold (2a; 2b).

9. The device of claim 1, wherein the angle of connection (β) of the body of said nozzles with respect to the manifold is comprised between 60 and 120 degrees.

10. The device of claim 1, wherein the pressure reducing member (5) is added on to the fluid distributer in the vicinity of the region of connection to said manifold (2a; 2b).

11. A reactor (R), comprising: a fixed catalytic bed (C.sub.1, C.sub.2; C′.sub.1, C′.sub.2) a distribution device (D) as claimed in claim 1, arranged in said bed in such a way that the inlet or at least one of the inlets of the pipes (1) of the fluid conveyer of said device are upstream of or flush with said bed, and the manifold (2a; 2b), fluid distributer (3) and optionally fluid connector (10) of said device are in said bed.

12. The reactor (R) of claim 11, wherein said manifold of said device extend in a plane (P) orthogonal to the axis (z) of said reactor (R).

13. The reactor of claim 11, wherein said fixed catalytic bed supports the device.

14. The reactor of claim 11, wherein the catalytic bed contains catalytic elements and wherein the dimensions of the outlets of each of said fluid distributers are strictly smaller than the smallest dimension of said elements at the level of which the fluid is distributed.

15. A process wherein the device (D) of claim 1 is/are implemented, wherein a feedstock comprising naphtha, is hydrotreated, or wherein a cracked petroleum feedstock is selectively hydrogenated, or wherein a gas is cleaned of its impurities by adsorption.

16. The device of claim 2 wherein the plurality of manifolds comprise at least two superposed rings.

17. The device of claim 16 wherein the at least two superposed rings comprise an upper and lower ring wherein the upper ring extends in a plane (P.sub.1) orthogonal to the axis (z), and the lower ring extends in a plane (P.sub.2) which is parallel to (P.sub.1).

18. The device of claim 17 wherein the upper and lower rings are connected by the fluid connector, wherein said fluid connector comprises cylindrical pipes extending along the axis (z).

19. A process wherein the reactor (R) of claim 11 is/are implemented, wherein a feedstock comprising naphtha, is hydrotreated, or wherein a cracked petroleum feedstock is selectively hydrogenated, or wherein a gas is cleaned of its impurities by adsorption.

Description

DETAILED DESCRIPTION

(1) The other features and advantages of the invention will become apparent from reading the nonlimiting examples and referring to the figures hereinbelow:

(2) FIG. 1a depicts a transverse view and FIG. 1b a view from above of one example of the distribution device, according to a first variant of the invention in “simple mode”.

(3) FIG. 2 depicts the view in cross section of the detail of the same distribution device as FIG. 1.

(4) FIGS. 3a, 3b and 3c each depict, in section, one type of nozzle that can be used as distribution means in the device according to the invention.

(5) FIGS. 4 and 5 depict views from above of two other examples of the distribution device according to two other variants of the invention.

(6) FIG. 6 depicts the distribution device D of FIG. 1 arranged inside a reactor R according to a first variant of the invention, in “simple mode”.

(7) FIG. 7 depicts the distribution device D arranged inside a reactor R according to a second variant of the invention, in “tiered mode”.

(8) The figures are highly schematic and depict the various components as they are positioned in operating mode.

(9) FIG. 1a depicts a view from above of one example of the distribution device D according to a first variant of the invention, in “simple mode”. The device D is made of stainless steel. The pipes 1 of the conveying means consist of vertical cylindrical tubes. The manifold means consist of a ring 2a, of cylindrical cross section and of toric shape, to which the pipes 1 are connected. The distribution means consist of nozzles 3 uniformly distributed around the ring 2a. The pipes 1, the ring 2a and the nozzles 3 are mechanically connected to one another to transport the fluid that is to be distributed from the pipes 1 toward the ring 2a and then from the ring 2a toward the nozzles 3. In the variant depicted, the nozzles 3 extend in the horizontal plane, in which the ring 2a extends.

(10) Optionally, means for preventing the ingress of solid particles into the pipes 1 consist of cowls 4a arranged above the inlet of each pipe. Alternatively, the inlets of the pipes 1 may be blocked off by a solid circular plate and openings may be formed on the exterior envelope of the pipes 4b: these may either be round openings, rectangular openings or slots, or regions with a wide-pitch Johnson™ screen for example.

(11) FIG. 1b depicts a view from above of the distribution device D according to the same variant of the invention as FIG. 1a. The nozzles are distributed on either side of the ring 2a: the outlet of one series of nozzles 3a is oriented toward the outside of the ring 2a and the outlet of one series of nozzles 3b is oriented toward the inside of the ring 2a.

(12) FIG. 2 depicts the view in section of the region of connection between the distribution means and the manifold means in the same variant as FIGS. 1a and 1b. A nozzle 3, consisting of a hollow cylinder, is welded to the ring 2a. A restriction orifice 5 is welded to the inlet of the nozzle 3. Once inside the reactor (see FIG. 5), the outlet 6 of the nozzle opens freely into the catalytic bed and its nominal diameter is less than or equal to the smallest dimension of the elements of the bed and fixed at this level.

(13) FIG. 3a depicts a first variant of nozzle that can be used as distribution means in the device according to the invention, in a view from above and in transverse section. The passage cross section of the nozzle 3 is rectangular. Three restriction orifices 5 are arranged at the inlet of the nozzle.

(14) FIG. 3b depicts a second variant of nozzle that can be used as distribution means in the device according to the invention, in a view from above and in transverse section. The nozzle 3 is formed of two concentric cylinders 7. At the center of the central cylinder, there is a restriction orifice 5. Six restriction orifices 5 are distributed in the annular region situated between the two cylinders.

(15) FIG. 3c depicts a third variant of nozzle that can be used as distribution means in the device according to the invention, in a view from above and in transverse section. The nozzle 3 is formed of a cylinder 7 at the center of which a rod 8 is positioned. Three restriction orifices 5 are inscribed on a median circle.

(16) FIG. 4 depicts a view from above of a second example of the distribution device D according to a second variant of the invention. The device according to the invention comprises manifold means consisting of a straight cylindrical pipe 2b and of the cylindrical conveying pipes 1. Nozzles 3 are distributed along the two sides of the straight cylindrical pipe 2b. In this configuration, the length of the nozzles contributes to the stability of the device D.

(17) FIG. 5 depicts a view from above of another example of the distribution device D according to another variant of the invention. The device according to the invention comprises manifold means consisting of two straight cylindrical pipes 2b, assembled in the form of a cross, and of five cylindrical conveying pipes 1. Nozzles 3 are distributed along the two straight cylindrical pipes.

(18) FIG. 6 depicts the distribution device D, of the example of FIGS. 1a and 1b, arranged inside a reactor R, along a vertical axis z, according to a first variant of the invention, in “simple mode”. The reactor R is operated in downflow gas mode with a fixed bed, liable to fouling, in which the device D according to the invention is embedded. The fluid that is to be distributed (the feedstock) enters via the pipe I in gaseous form and leaves via the pipe O. The upper layer C.sub.1 of the catalytic bed is made up, in this example, of packing elements. The fixed catalytic bed comprises a second layer C.sub.2. The distribution device D comprises conveying means, consisting of the pipes 1, which extend along the axis z, and manifold means, consisting of a ring 2a, which extend in the plane P. The axis z is coincident with the axis of the reactor R, and the plane P is parallel to the transverse section of the reactor.

(19) The ring 2a is provided with nozzles, not depicted, suitably distributed about its circumference.

(20) The ring 2a rests horizontally on the elements of the layer C.sub.1. Thus, the distribution device D is set down on the catalyst, preferably at a horizontal level situated between 20% and 80% of the height of said layer, and more preferentially between 40% and 60%. The inlets of the conveying pipes 1 are situated above the level of the layer C.sub.1.

(21) When the catalytic bed becomes fouled, the device D allows the layer of catalytic bed to be bypassed by a height h corresponding to the height of the device.

(22) FIG. 7 depicts the distribution device D′ arranged inside a reactor R′ according to a second variant of the invention, in “tiered mode”. The reactor R′ is very similar to the reactor R of FIG. 6. The distribution device D′ is in part identical to the distribution device D. The difference is that it comprises two manifold means, consisting of two superposed rings 2a. The upper ring extends in a plane P.sub.1 orthogonal to the axis z, and the lower ring extends in a plane P.sub.2 which is parallel to P.sub.1. The two rings 2a are connected by transfer means, consisting of cylindrical pipes 10 extending along the axis z. The two rings 2a are provided with nozzles, not depicted.

(23) The second ring 2a rests horizontally on elements constituting the layer C.sub.1′. Thus, the distribution device D′ is set down on the catalyst such that: the first ring is situated preferably at a horizontal level situated between 20% and 50% of the height of said layer, and more preferentially between 25% and 40%. the second ring is situated preferably at a horizontal level situated between 50% and 80% of the height of said layer, and more preferentially between 60% and 75%.

(24) The inlets of the conveying pipes 1 are situated above the level of the layer C.sub.1′.

(25) When the catalytic bed becomes fouled, the device D′ allows the layer of catalytic bed C.sub.1′ to be bypassed by a height h.sub.1 and then by a height h.sub.2.

Example 1

(26) A reactor R of diameter 1.4 m is provided with a device D according to the invention in simple mode, as in FIG. 5, in a variant of the device analogous to that depicted in FIGS. 1a and 1b. A feedstock of cracked naphtha in gaseous form is processed at 500 m3/h. The device is installed in a layer of catalytic bed which layer is made up of packing elements having a diameter of 51 mm.

(27) A ring 2a with a torus diameter of 1 m is installed in the reactor. The ring, having a cross section of a nominal diameter of 50 mm, receives the fluid from 6 conveying pipes consisting of hollow cylinders with a nominal diameter of 50 mm.

(28) 24 nozzles with an internal diameter of 48 mm and a length of 125 mm are distributed on the ring. Each nozzle is equipped at its inlet with a restriction orifice of a diameter of 19 mm.

(29) The time taken to mount the device in the reactor is estimated at 20 minutes, whereas the devices of the prior art with several adjacent devices require several hours.

Example 2

(30) A reactor of diameter 3.8 m is provided with three devices in simple mode according to the invention, these being arranged concentrically, in order to process a feedstock of naphtha in gaseous form at 4400 m3/h. The devices are installed in a layer of catalytic bed which layer is made up of packing elements having a diameter of 51 mm.

(31) The manifold means of each of the three devices consist of a ring of toric shape and of cylindrical cross section. The three rings are arranged concentrically, in the one same plane, and their respective torus diameters are 1 m, 2 m and 3 m. The rings have a nominal diameter of 75 mm, and respectively receive the fluid from 4, 8 and 12 conveying pipes. These have a nominal diameter of 75 mm.

(32) 128 nozzles with an internal diameter of 48 mm and a length of 125 mm are distributed on the 3 toruses which comprise 22 nozzles, 42 nozzles and 64 nozzles, respectively. Each nozzle is equipped at its inlet with a restriction orifice of a diameter of 19 mm.

(33) The time taken to mount the device in the reactor is estimated at 50 minutes, whereas the devices of the prior art with several adjacent devices require a day.