Cylindrical wall for filtering solid particles in a fluid

Abstract

A cylindrical wall (100) for filtering solid particles in a fluid, through which this fluid is likely to circulate, this wall comprising: a perforated cylinder (30) being produced from at least one perforated plate, a grating assembly (110), of generally cylindrical form, intended to be in contact with the solid particles, the grating assembly and the perforated cylinder being concentric, the grating assembly comprising at least one grating element (113), said grating element comprising a plurality of wires (111), means for assembling said at least one grating element so as to form the grating assembly of generally cylindrical form, said assembly means being arranged to ensure a fixing of said at least one grating element on the perforated plate that can be dismantled.

Claims

1. A cylindrical wall for filtering solid particles in a fluid, through which this fluid is likely to circulate, this wall comprising: a perforated cylinder extending in a longitudinal direction, the cylinder being produced from at least one perforated plate, a grating assembly, of generally cylindrical form, intended to be in contact with the solid particles, the grating assembly and the perforated cylinder being concentric, the grating assembly comprising at least one grating element, the grating element comprising a plurality of wires each extending in the longitudinal direction, and means for assembling the at least one grating element so as to form the grating assembly of generally cylindrical form, the assembly means being arranged to ensure fixing of the at least one grating element on the perforated plate that can be dismantled.

2. The wall as claimed in claim 1, wherein the assembly means are arranged to be able to be themselves installed on the perforated cylinder so as to be able to be dismantled.

3. The wall as claimed in claim 2, wherein the assembly means comprise a rod intended to be introduced into or through a perforated plate of the perforated cylinder.

4. The wall as claimed in claim 1, wherein the assembly means being arranged to ensure a dismantlable fixing of at least one grating element on the perforated cylinder, the assembly means defining at least one cavity to receive at least a portion of at least one grating element end edge.

5. The wall as claimed in claim 4, wherein the assembly means comprise at least one retention portion intended to cover the end edge of the grating element received in the corresponding cavity, characterized in that the assembly means are arranged so that the retention portion exerts a pressure against the end edge in order to press the end edge against the perforated cylinder.

6. The wall as claimed in 3, wherein the assembly means comprises a flange element comprising the retention portion and defining an orifice for the passage of the rod.

7. The wall as claimed in claim 1, wherein the grating assembly comprises a plurality of grating elements, characterized in that each grating element extends tangentially so as to occupy an angular range strictly less than 360.

8. The wall as claimed in claim 1, further comprising an additional perforated cylinder comprising a perforated sheet, the additional perforated cylinder being arranged concentrically between the grating assembly and the perforated cylinder.

9. The wall as claimed in claim 1, further comprising sealing means arranged to block, on an end edge of at least one grating element, a flow passage between this grating element and the perforated plate.

10. The wall as claimed in claim 1, the wall being a radial flow catalyst bed wall.

11. A reactor comprising a radial flow catalyst bed wall as claimed in claim 10.

12. A catalytic reforming unit comprising a reactor as claimed in claim 11.

13. The catalytic reforming unit as claimed in claim 12, wherein the radial flow catalytic bed wall as claimed in claim 11 is a center pipe wall.

Description

(1) The invention will be better understood with reference to the figures, which illustrate embodiments given by way of example and in a nonlimiting manner.

(2) FIG. 1, already described, shows an example of catalytic reformer according to the prior art.

(3) FIG. 2 is a cross-sectional view of a section of a portion of a radial flow catalyst bed center pipe wall according to an embodiment known from the prior art,

(4) FIG. 3 is a cross-sectional view of a section of a portion of wall according to an embodiment of the invention,

(5) FIG. 4 is a perspective and highly schematic view of a center pipe wall according to the embodiment of FIG. 3,

(6) FIG. 5A is a perspective view of a portion of wall according to another embodiment of the invention,

(7) FIG. 5B is a cross-sectional view of a section of a portion of wall according to yet another embodiment of the invention,

(8) FIG. 6 is a cross-sectional view of a section of a portion of wall according to another embodiment of the invention.

(9) The proportions are not necessarily retained from one figure to another.

(10) On the other hand, references that are identical from one figure to another can be used to denote identical or similar elements.

(11) Referring to FIG. 2, a reforming reactor can comprise an outer basket and a center pipe of which a portion is represented here.

(12) This center pipe comprises a perforated cylinder 3 produced from a perforated sheet secured by its two opposite edges (not visible on the portion represented).

(13) The perforated cylinder 3 extends in a longitudinal direction corresponding to the vector {right arrow over (z)}.

(14) The center pipe further comprises a grating assembly 10 arranged concentrically relative to the perforated cylinder 3, this grating assembly is formed by the assembly of grating elements comprising flats 2 and wires 1.

(15) The wires 1 extend in the longitudinal direction {right arrow over (z)}, whereas the flats 2 extend tangentially so as to form circles spaced apart from one another along the longitudinal direction {right arrow over (z)}.

(16) A weld bead 5 makes it possible to secure the flats 2 to the perforated plate 3 and to secure the flats 2 to one another. This same weld bead 5 extends over all the height of the cylinder.

(17) Referring to FIG. 3, a catalyst bed wall 100 of a center pipe comprises a grating assembly 110 and a perforated cylinder 30 arranged concentrically and extending in a longitudinal direction {right arrow over (z)}.

(18) The grating assembly 110 is intended to be in contact with a catalyst that is not represented.

(19) Fluid that is not represented is intended to pass through this wall 100 by a substantially radial flow.

(20) The perforated cylinder defines orifices 31 for allowing the fluid to pass. These orifices 31 can have dimensions of the order of a few millimeters (for example between 3 mm and 30 mm).

(21) The catalyst grains can for example have dimensions of the order of a millimeter, for example an average particle diameter between 1.0 and 3.0 millimeters.

(22) The grating assembly 110 makes it possible to ensure the retention of the catalyst in the annular space. This grating is produced from several grating elements 113, each grating element 113 comprising flats 20 extending tangentially and spaced apart from one another in the longitudinal direction {right arrow over (z)}.

(23) Each grating element 113 further comprises wires 111, here of triangular section, secured to the flats 20.

(24) Since the space between two adjacent wires is relatively restricted (less than the average diameter of the particles of the catalyst), the grating assembly 110 participates in the retention of the catalyst and does so despite the passage of the fluid through the wall 100.

(25) Assembly means ensure a dismantlable fixing of the grating elements 113 on the perforated cylinder 30.

(26) As can be seen in FIG. 4, several grating elements 113 are provided for one and the same given cylinder height, each grating element corresponding to a given angular range, for example between 60 and 90. Furthermore, each grating element occupies only a portion of the height of the cylinder. The grating elements 113 can thus be of relatively small dimensions, and in particular pass through a manhole.

(27) The assembly means comprise assembly elements, each assembly element comprising a flange element 120, threaded rods 101 and nuts 102, 104. The assembly elements have an elongate form, so as to cover all of a grating element end edge, here two edges per assembly element. The assembly elements thus form a support framework for the grating elements.

(28) Each flange element defines orifices for the passage of threaded rods 101, and retention portions 103, 103 covering corresponding grating element 113 end edges.

(29) In this example, the retention portions extend tangentially or longitudinally, so as to cover at least a part, and advantageously all, of the corresponding end edges.

(30) The flange element 120 comprises two retention portions 103, 103, for two end edges of two respective adjacent grating elements.

(31) These retention portions covering the end edges and the space between these end edges, the flange element 120 incorporates sealing means blocking, on the corresponding end edges, flow passages between the corresponding grating elements and the perforated cylinder.

(32) The threaded rods 101 pass through the orifices 31 of the perforated plate 30.

(33) Nuts 102, 104 make it possible to rigidly and dismantlably fix the flange element to the perforated plate 30.

(34) In this example, the flange element 120 defines recesses 105 on its upper part, in order to receive one 104 of these nuts. The nuts 104 can thus, when screwed, be flush with the surface of the flange elements 120.

(35) When the nuts 102, 104 are sufficiently tightened, the retention portions 103, 103 exert a pressure on the end edges of the corresponding grating elements, thus pressing these end edges of the grating 113 against the perforated cylinder.

(36) As emerges from FIG. 3, the flange element defines, with the perforated plate 30 (or, if appropriate, the containing cylinder), two cavities for receiving the two end edges of the two corresponding grating elements. The grating elements 113 can thus be assembled to form a grating cylinder without modification of the grating elements themselves.

(37) As emerges from FIG. 4, the assembly means for these grating elements 113 thus form a kind of support framework, allowing a rigid but dismantlable assembly of the different grating elements 113.

(38) In the embodiments of FIGS. 5A and 5B, elements are also provided that are dedicated to sealing, here plates 50 and, in the variant of FIG. 5B, 50 and 50, extending longitudinally over all the length of the grating cylinder.

(39) Referring to FIG. 5A, these plates 50 are arranged in proximity to the ends of the flats 20, on the edge of the grating element.

(40) These plates 50 define recesses for receiving ends of the flats 20.

(41) Referring to FIG. 5B, additional plates 50 are provided, in addition to the plates 50 at the edges of the grating elements.

(42) The additional plate 50 is parallel or substantially parallel to the plate 50, and is separated from this plate 50 by a length slightly greater than the width of a wire 111.

(43) The sealing means thus have a structure with a double thickness, thus ensuring a reinforced sealing.

(44) In the embodiment of FIG. 6, the wall 100 further comprises an additional perforated sheet 140 forming an additional perforated cylinder.

(45) This additional perforated cylinder is interposed between the perforated cylinder 30 and the grating assembly 110. The additional perforated sheet defines orifices 61 of much smaller sections than the orifices 31 of the perforated cylinder 30, thus allowing the retention of the catalyst in the case of a mechanical failure of the grating cylinder.

(46) This additional perforated sheet 140 is kept in place by the flange element 120, thus ensuring an independent fixing of the perforated cylinder and of the grating 110, thus making it possible to limit the sensitivity to changes of temperature.