Method for realizing internal walls of catalytic reactors

Abstract

Reactor (1) for catalytic chemical reactions, comprising: a partially open outer vessel (2) comprising a manhole (6) for accessing to the interior, and at least one internal wall (5) comprising a plurality of panels (5.1, 5.2, . . . 5.n) assembled inside the vessel (2) so as to form said wall (5); the panels are flexible and deformable so that they may be inserted through said manhole (6), and the resulting wall (5) is not self-supporting and rests against a load-bearing wall (7) of the reactor.

Claims

1. A reactor for catalytic chemical reactions, comprising: a partially open outer vessel comprising a manhole for accessing to the interior, inlet and outlet openings for inlet and outlet, respectively, of reagents and reaction products, and at least one internal wall, the partially open vessel having no full-diameter openings, and the only openings and flanges of the vessel being significantly smaller than its diameter, wherein: the reactor comprises a catalyst cartridge which contains a catalyst bed with radial or axial-radial through-flow, and which comprises a load-bearing external wall; said at least one internal wall is a single-wall outer collector of the catalyst bed; said catalyst bed being delimited by an inner collector and said single-wall outer collector, which are perforated and gas-permeable; wherein said single-wall outer collector comprises a plurality of panels, which are assembled inside the vessel to form said outer collector, the panels being flexible and deformable so as to allow their insertion through said manhole and/or through at least one of said inlet and outlet openings, and the resulting outer collector being non self-supporting and resting on said load-bearing wall of the cartridge, and said panels have dimensions greater than said manhole and openings, and the panels are introduced in the reactor in elastically deformed condition and recover their original undeformed configuration after introduction into the reactor.

2. The reactor according to claim 1, wherein said panels are shaped with crests or ribs directed parallel to the reactor axis and defining lines of bearing contact of the outer collector against the load-bearing wall.

3. The reactor according to claim 2, wherein the crests or ribs of the panels define a distance between the outer collector and the load-bearing wall of the cartridge, thus defining an interspace for the passage of gas between said wall and said collector.

4. The reactor according to claim 2, the panels being made of fretted metal sheet or corrugated metal sheet.

5. The reactor according to claim 1, wherein each of said panels has at least a surface portion which is gas permeable and a surface portion which is non gas-permeable.

6. The reactor according to claim 1, wherein each panel comprises at least: a first surface zone with a first arrangement of gas passages, and a second surface zone with a second arrangement of gas passages, the first and second arrangements being different in terms of shape and/or size and/or mutual spacing of the gas passages.

7. The reactor according to claim 1, also comprising one or more section-breaker rings fixed to the panels.

8. The reactor according to claim 1, wherein the panels can be introduced into the vessel through said manhole by means of elastic or partially elastic reversible deformation thereof.

9. A method for realizing an internal wall and collector inside a partially open catalytic reactor, said reactor comprising an outer vessel and at least one manhole for accessing the inside of the vessel, the method being characterized in that: said internal wall is assembled inside the vessel by means of a plurality of panels, the panels are deformed elastically so that they can be introduced inside the reactor through said reactor manhole, wherein the panels are introduced in the reactor in elastically deformed condition and recover their original undeformed configuration after introduction into the reactor, after being introduced into the reactor, the panels are assembled so as to rest against a load-bearing wall of the reactor, forming a non self-supporting collector, wherein: said reactor comprises a catalyst cartridge containing a catalyst bed with radial or axial-radial through-flow and comprising a load-bearing external wall; said internal wall is formed by an outer collector of the catalyst bed, situated inside the cartridge, and said collector is assembled with the component panels resting against said load-bearing wall of said cartridge.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a schematic cross-sectional view of a reactor according to an embodiment of the invention.

(2) FIG. 2 shows the collector of the reactor according to FIG. 1, inside the vessel and resting against a wall of the catalyst cartridge of the reactor.

(3) FIG. 3 shows a detail of the joint between two panels of the collector according to FIG. 2.

(4) FIG. 4 shows a detail of FIG. 2 relating to the contact zone between collector and wall of the cartridge.

(5) FIG. 5 shows a preferred mode of forming a closing joint of the collector.

(6) FIG. 6 shows a cross-sectional view of a joint between two panels of the collector.

(7) FIG. 7 illustrates another embodiment of the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

(8) FIG. 1 shows a schematic illustration of a chemical reactor 1 with radial or axial-radial flow and centripetal (inward) flow, which essentially comprises: a partially open vessel 2, a catalyst cartridge 3 containing a catalyst bed 4 with the radial or axial-radial through-flow; an outer collector 5 arranged around the catalyst bed 4.

(9) The partially open vessel 2 comprises a manhole 6 with a diameter smaller than the diameter of the vessel 2, a top inlet opening 30 and a bottom outlet opening 31 with a diameter smaller than the manhole 6.

(10) The axial-radial through-flow of the bed 4 is achieved by means of the outer collector 5 and an inner collector 20.

(11) The outer collector 5 rests against the cartridge 3 and has a modular design, being formed substantially by a plurality of panels which can be inserted through the manhole 6 and/or through the top opening 30.

(12) It should be noted that the collector 5 is flexible along its transverse extension, but is rigid longitudinally. Consequently, should the axis of the manhole 6 not be vertical, it does not allow the insertion of long elements beyond the internal diameter of the apparatus, but smaller elements, which are as long as the apparatus, may be inserted through the top inlet opening 30.

(13) A preferred embodiment is shown in FIG. 2, which partially show two panels 5.1 and 5.2 forming part of the outer collector 5, resting against a load-bearing wall 7 of the catalyst cartridge 3. The panels forming the collector 5 in the example are made from a small-thickness, elastically flexible, fretted metal sheet and are joined together by longitudinal joints using bolts 8.

(14) A preferred embodiment of the connection is shown in FIG. 3. There is a covering zone 9 between the panel 5.1 and the panel 5.2, and the end flange 10 of the panel 5.1 is bolted to the underlying flat portion 11 of the panel 5.2.

(15) The panels comprise ribs 12 which rest and make contact against the wall 7 and space the collector 5 from said wall 7, defining a gas flow interspace 13, as also shown in the detail of FIG. 4.

(16) The panels comprise gas passages, for example holes, which are distributed in a uniform or varied manner. For example, the panels comprise a first arrangement of gas passages on the flat surfaces 14 and a second arrangement of gas passages on the sides 15, the first and second arrangements being different in terms of shape and/or size and/or pitch of the gas passages. For example, the gas passages consist of holes or slots and the different arrangements of passages correspond to different holed arrangements. In the example shown in the figures, each panel has a flange 10 which is used for fixing (FIG. 2) and which has a continuous surface area without passages for the gas.

(17) The figure also shows a section-breaker ring 16. Advantageously the section-breaker ring 16 comprises protuberances 17 matching with grooves 18 defined by the ribs 12. A plurality of section-breaker rings may be arranged at a suitable distance from each other, depending on the stressed state of the collector 5. Typically said distance is comprised between one and two meters.

(18) FIG. 5 shows a preferred embodiment of a final closing joint of the collector. Two end panels 5.1 and 5.n are joined together by a terminal panel 5.c suitably shaped with two flanges 10 on opposite sides so that it may be bolted to both the end panels, in particular along a section 19 without holes.

(19) The cross-section of a typical bolted joint between panels of the collector 5 is shown in FIG. 6.

(20) FIG. 7 show an embodiment where the panels 5.1, 5.2, . . . comprises arc-shaped portions 21. Preferably said portions 21 are circular arcs. Said portions 21 are interconnected by joints 22, made for example on V-shaped terminations 23 which partially overlap. An advantage of this embodiment is an even distribution of stress thanks to the circular shape of portions 21. As in the previous embodiments, the collector 5 has no solution of continuity and the vessel 7 is not exposed to the catalyst.

(21) Advantageously, the panels 5.1, 5.2, . . . 5.n have a small thickness, for example of not more than 1 mm, which makes them easily deformable. Owing to their deformability, the panels may be folded or rolled up in order to be introduced into the manhole 6 of the reactor 1. Consequently the dimensions of a single panel may be increased, compared to the conventional art, with a reduction in the number of panels needed to form the collector 5, for the same surface area. Assembly is also made easier since the connections between the panels are not load-bearing and it is no longer required to perform high-quality long welds as in the prior art. The invention therefore achieves the objects which have been illustrated above.