Fixed-bed tubular reactor with multi-part insert

Abstract

The invention relates to a tubular reactor (1) which comprises a catalytic powder bed confined in an annular space (30), a hollow insert (20) comprising a distribution chamber (40) and a collection chamber (50), a second wall (21) comprising at least one distribution opening (42) and at least one collection opening, characterized in that the hollow insert (20) comprises an insert body obtained by assembling at least one first intermediate insert piece with a second intermediate insert piece, having, by observation in cross-section, one or more contact portions whose external surface conforms to the shape of the internal surface of the second hollow intermediate insert piece, the interior of said at least one first intermediate insert piece defining a distribution chamber (40) or a collection chamber (50),and the space(s) located between a recessed portion and the second intermediate insert piece defining the other chamber(s), respectively collection (50) or distribution (40). Figure for the abbreviation: Figure 1,

Description

Title of the invention: Fixed-bed tubular reactor with multi-part insert. TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the general field of heat exchanger reactors. In particular, the present invention relates to the field of catalytic heat exchanger reactors using a solid catalyst, and especially a solid catalyst in powder form.

[0002] More specifically, the invention relates to a catalytic reactor-exchanger capable of implementing exothermic organic synthesis processes. These organic compounds may notably include synthetic fuels and propellant. STATE OF THE TECHNOLOGY

[0003] Catalytic reactors using solid catalysts are widely used for the synthesis of organic compounds such as synthetic fuels or fuels, including natural gas substitutes, dimethyl ether or methanol.

[0004] These compounds are obtained in particular by reaction of hydrogen and carbon oxide in the presence of a suitable solid catalyst.

[0005] However, the chemical reactions involved in the synthesis of these compounds are highly exothermic and consequently release a quantity of heat that can degrade the solid catalyst. This degradation results in a reduction in the conversion rate of the chemical species present and a decrease in the selectivity of the reactions involved. In other words, the solid catalyst is deactivated by the heat.

[0006] Thus, in practice, these reactions can be implemented in a shell-and-tube reactor-exchanger comprising a reactive channel equipped with the solid catalyst and continuously cooled by a heat transfer fluid. In this type of reactor, the reactive gases flow axially through tubes containing a catalyst, for example in powder form.

[0007] Nevertheless, despite the implementation of cooling by the heat transfer fluid, this type of reactor remains sensitive to the heat released by the reactions occurring in said reactor.

[0008] In particular, a hot spot, generally observed near the inlet of the reactive gases, degrades the solid catalyst, and therefore reduces the performance of the reactor-exchanger.

[0009] In order to limit these effects, the following solutions have been proposed:

[0010] - a reduction in the volume density of the catalyst, in particular by depositing the latter on the walls of the tube or an insert or by diluting it in a non-reactive medium;

[0011] - a dilution of the reactive gases with a portion of the products generated to decrease the activity of the reaction;

[0012] - to perform several injection points of one or more reagents to distribute the hot spot area over a larger area;

[0013] - a reduction in the dimensions of the tubes or by placing conductive parts therein the heat in order to improve the cooling of the tubes.

[0014] These solutions are not satisfactory, however. Indeed, even though they reduce the effects of the hot spot, they are complex to implement.

[0015] Moreover, their implementation reduces the flexibility of use of the reactor-exchanger, and makes the latter not very compact.

[0016] To overcome these problems, an arrangement was proposed that distributes the reactants along the entire length of the tubes. This solution allows for better temperature homogeneity along the entire length of the reactor.

[0017] In this regard, US patents 3,758,279 A, ​​4,374,094 A, EP 0 560 157 A1, and 2,997,374 A propose reactor-exchangers implementing reactant distribution from an annular distribution space. Specifically, these reactor-exchangers, generally cylindrical in shape, comprise, arranged coaxially from outside the reactor, a tube, the annular distribution space, a catalyst charge, and a collection space.

[0018] This arrangement is not satisfactory, however. Indeed, the presence of the annular distribution space around the catalyst charge limits heat transfer from the catalyst to the tube, rendering the cooling systems generally used ineffective. It remains possible, however, to insert heat-conducting elements into the reactor. Such a solution, however, remains incompatible with reactors containing small-diameter tubes.

[0019] Conversely, document CN 103990420 A proposes to implement an insert provided with a distribution chamber and a collection chamber, arranged in the center of a tube and defining with the latter an annular space housing the solid catalyst.

[0020] However, the arrangement proposed in this document does not allow for homogeneous distribution within the annular space. More specifically, this The arrangement does not allow for an optimal temperature profile within the solid catalyst.

[0021] Furthermore, a principle for the staged distribution of gas in a reactor-exchanger is known from the Applicant's European patent application EP 3 827 895 A1. The reactor comprises a catalyst located in an annular space between a hollow tube and a hollow insert equipped with distribution and collection chambers. The hollow insert typically corresponds to a single-piece component obtained by specific manufacturing techniques that limit the possibilities in terms of materials, geometry, manufacturing time, and excess material used, among other things.

[0022] An object of the present invention is to propose a fixed-bed tubular reactor allowing a more uniform distribution of reactants within the solid catalyst.

[0023] Another object of the present invention is also to propose a fixed-bed tubular reactor allowing a more homogeneous distribution of the heat flux generated within the solid catalyst.

[0024] Another objective of the present invention is also to propose a tubular reactor allowing for better cooling management.

[0025] Another object of the present invention is also to propose a tubular reactor for which the reliability and lifespan are improved compared to known reactors in the prior art.

[0026] Another object of the present invention is to propose a tubular reactor making it possible to optimize (increase) the time of passage of gases in the fixed bed of catalytic powder.

[0027] Another object of the present invention is to propose a tubular reactor comprising an insert of improved design, in particular through specific manufacturing techniques. Description of the invention

[0028] The invention aims to remedy at least partially the needs mentioned above and the disadvantages relating to the achievements of the prior art.

[0029] The invention thus relates, according to one of its aspects, to a fixed-bed tubular reactor which extends, along a longitudinal axis, between a first end and a second end,

[0030] said reactor comprising a bed of catalytic powder confined in an annular space delimited by a first wall of a hollow tube and a second wall of a hollow insert, disposed in the hollow tube and substantially coaxial to the latter,

[0031] the hollow insert comprising at least one distribution chamber and at least one collection chamber, separated from each other by a separating wall, and comprising, respectively, a gas inlet opening at the first end and a gas outlet opening at the second end,

[0032] the second wall comprising at least one distributing opening and at least one collecting opening, which extend over a length, the distributing opening allowing the distribution of a gas that can be admitted through the inlet opening of the distribution chamber to the annular space, and the collecting opening allowing the collection of the gas distributed in the annular space by the collecting chamber,

[0033] characterized in that the hollow insert comprises an insert body obtained by assembling at least one first intermediate hollow insert piece with a second distinct intermediate hollow insert piece, said at least one first intermediate insert piece being located inside the second intermediate insert piece,

[0034] said at least one first intermediate insert piece having, by observation in cross-section with respect to the longitudinal axis, one or more contact portions whose external surface follows the shape of the internal surface of the second hollow intermediate insert piece, and one or more recessed portions located at a distance from the second hollow intermediate insert piece, the interior of said at least one first intermediate insert piece defining a distribution chamber or a collection chamber, and the space or spaces located each between a recessed portion and the second intermediate insert piece defining the other chamber(s), respectively of collection or distribution.

[0035] The reactor according to the invention may further comprise one or more of the following characteristics taken individually or in any possible technical combinations.

[0036] The gas inlet opening may be located at the first end. The gas outlet opening may be located at the second end. Alternatively, the gas inlet opening and the gas outlet opening may be located at the same end, in particular at the first end.

[0037] The hollow tube and the hollow insert advantageously have a substantially cylindrical shape, but not necessarily a cylindrical shape of revolution.

[0038] Moreover, when the hollow insert is placed in the hollow tube and substantially coaxial with the latter, the annular space can exhibit rotational symmetry.

[0039] Thus, the reactor according to the present invention makes it possible to distribute the reactive gases, due to the extent of the distributing opening, in a relatively homogeneous manner in the annular space. These then react with the catalytic powder bed across the entire cross-section covered by the distributor opening. The products of the gas reaction, as well as the unreacted gases, are collected at the collector opening and discharged from the reactor through the discharge opening opposite the inlet opening.

[0040] This arrangement, in which the gases are admitted through one end and expelled through the other end, allows for a better distribution of the reactive species (the gases) in the annular space, and consequently a better distribution of the heat that may be released during the reaction of the reactive species in the annular space.

[0041] This better distribution of the heat released makes it possible to consider a less powerful cooling system and therefore smaller in size.

[0042] The arrangement according to the present invention therefore makes it possible to consider a more compact reactor, and one with improved reliability compared to the tubular reactors known in the prior art.

[0043] Advantageously, one or more of the recessed portions, in particular all of the recessed portions, may have an arc-shaped form, in particular concave or convex with respect to the longitudinal axis. However, other types of shape may be envisaged, for example a rectilinear, curved or open polygonal shape.

[0044] The use of circular arcs can help to maintain a certain elasticity and also to minimize the friction surface of the gas in the chambers.

[0045] The second intermediate insert piece may, by observation in cross-section with respect to the longitudinal axis, have a substantially circular shape.

[0046] Said at least one first intermediate insert piece may include at least two recessed portions, in particular at least three recessed portions, in particular distributed regularly around the longitudinal axis.

[0047] The second intermediate insert piece may include distributing openings or collecting openings, in particular in the form of longitudinal grooves.

[0048] In addition, said at least one first intermediate insert piece may have passage openings, in particular in the form of longitudinal grooves, opposite the distributing openings or collecting openings of the second intermediate insert piece.

[0049] Alternatively, said at least one first intermediate insert piece may comprise, opposite the distributing or collecting openings of the second intermediate insert piece, intermediate chambers, in particular in the form of longitudinal channels, comprising a plurality of passage openings, in particular in circular form and / or in the form of a longitudinal groove, in particular of a dimension smaller than a longitudinal groove of a distributing opening or collector, opening into the interior of said at least a first intermediate insert piece.

[0050] In addition, said at least one first intermediate insert piece can be fixed to the second intermediate insert piece, in particular in the contact portion or portions, at the level of fixing areas, in particular by transparent welding.

[0051] Said at least a first intermediate insert piece can advantageously be obtained from a first profiled tube by rolling and welding or by drawing.

[0052] In addition, the second intermediate insert piece can be in the form of a second profiled tube of substantially cylindrical shape.

[0053] The assembly of said at least one first intermediate insert piece with the second intermediate insert piece can be obtained by co-stretching, resulting in particular in a reduction in diameter of the second intermediate insert piece in contact with said at least one first intermediate insert piece.

[0054] Advantageously, the insert body can be made of iron, nickel, iron alloy and / or nickel alloy, among others.

[0055] In addition, the external diameter of the insert body may be less than 5 cm, in particular less than 3 cm.

[0056] At least one distribution chamber can be sealed at the second end, and at least one collection chamber can be sealed at the first end.

[0057] The reactor may include at the first end and at the second end, respectively, a distributor space and a collector space between which the insert is disposed.

[0058] The catalytic powder can be retained in the annular space by a fibrous material seal at each end of the annular space.

[0059] The fibrous material seal can be held in compression against the catalytic powder by a spring, the spring being against a retaining plate mechanically linked to the tube.

[0060] The fibrous material seal in combination with the spring(s) can allow for better compaction of the catalytic powder and prevent attrition of the latter during handling or transport of the reactor.

[0061] The outer wall may be without an opening on a first section and a second section extending from, respectively, the first end and the second end, the first section and the second section being in overlap with the powder bed over a height H, the height H being between 0.5 times and 10 times, advantageously between 1 time and 2 times, the distance separating a distributing opening from an immediately adjacent collecting opening, and measured along the outer surface of the outer wall.

[0062] Thus, such an arrangement can make it possible to impose a passage time on reactive gases that may penetrate the annular space through the fibrous joint.

[0063] The hollow insert can be provided with centering means maintaining the latter in a substantially coaxial position with the hollow tube; advantageously, the centering means can include bosses formed on the second wall.

[0064] These centering means can allow for easier assembly of the reactor.

[0065] The surface area of ​​a section of the distribution chamber along a cross-sectional plane to the longitudinal axis can decrease from the first end to the second end; advantageously, said surface area can be zero at the second end.

[0066] The surface area of ​​a section of the collection chamber along a cross-section plane to the longitudinal axis can increase from the first end to the second end; advantageously, said surface area can be zero at the first end.

[0067] The collecting opening and the distributing opening may have a width between 1 / 400 and 1 / 2, advantageously between 1 / 20 and 1 / 100, of the diameter of the hollow tube.

[0068] The collecting and distributing openings may each include a filter preventing the passage of catalytic powder into either of the collecting or distributing chambers. The filter may include a plurality of inclined fiber planes.

[0069] Furthermore, the invention also relates, according to another of its aspects, to a method of manufacturing an insert body of a hollow insert of a tubular reactor as defined above, in which the plurality of intermediate insert pieces is obtained by a drawing and / or rolling and welding process.

[0070] In particular, the process may include the step of obtaining said at least one first intermediate insert piece by rolling and welding, in particular of a sheet, and / or by drawing, in particular through a die.

[0071] The process may further include the step of assembling said at least one first intermediate insert piece and the second intermediate insert piece by co-stretching.

[0072] The assembly of the intermediate insert parts can be achieved by fitting, welding, brazing and / or joining intermediate insert parts in the form of collars with a substantially circular cross-section. BRIEF DESCRIPTION OF THE FIGURES

[0073] Other advantages, purposes and special features of the invention will become apparent from the following non-limiting description of at least one embodiment of the present invention, with reference to the accompanying figures, in which: • Fig. 1 is a schematic representation of a fixed-bed tubular reactor, along a longitudinal section plane passing through a longitudinal axis of the reactor. • [Fig.2] is a schematic representation of the reactor of [Fig.1] according to a transverse section plane perpendicular to the longitudinal axis, • [Fig.3] is a representation of a filter, and in particular of a filter formed of four fiber planes, which can be implemented in the tubular reactor of [Fig.1], • [Fig.4] is a representation of a fixed-bed tubular reactor such as that of [Fig.1] at the first end illustrating the arrangement of the seal and spring retaining the catalytic powder bed, • [Fig.5] is a schematic representation of the hollow insert along the section plane AA' of [Fig.4], • Figure 6 is a schematic representation of a variant embodiment of a fixed-bed tubular reactor along a longitudinal section plane passing through a longitudinal axis of the reactor. • Figures 7A, 7B, 7C, 7D and 7E are views, respectively, along section planes A, B, C, D and E of the hollow insert shown in [Fig. 6], • Figure [8] is a schematic representation of another embodiment of a fixed-bed tubular reactor along a longitudinal section plane passing through a longitudinal axis of the reactor. • Figures 9 and 10 are views, respectively, along the section planes CC' and DD' of the hollow insert shown in [Fig. 8], • Figure

[11] is a schematic representation, in cross-section with respect to the longitudinal axis, of an example of an insert body of a tubular reactor according to the invention, • Figure 12 is a schematic representation, in cross-section with respect to the longitudinal axis, of another example of an insert body of a tubular reactor according to the invention, • Figure 13 is a schematic representation, in cross-section with respect to the longitudinal axis, of another example of an insert body for a hollow insert of a tubular reactor according to the invention, • [Fig. 14] is a partial schematic representation, according to a cross-section with respect to the longitudinal axis, of a variant embodiment of the example in [Fig. 13], • [Fig. 15] is a partial schematic representation, from a longitudinal view, of the first intermediate insert piece from the example in [Fig. 14], and • [Fig. 16] is a partial schematic representation, from a longitudinal view, of the second intermediate insert piece from the example in [Fig. 14],

[0074] Throughout these figures, identical references may designate identical or analogous elements.

[0075] Furthermore, the different parts shown in the figures are not necessarily to a uniform scale, in order to make the figures more legible. DETAILED DESCRIPTION OF THE INVENTION

[0076] The present invention relates to a tubular reactor-exchanger with a fixed catalytic powder bed. In particular, the catalytic powder bed is confined in an annular space delimited by a first wall of a hollow tube and a second wall of a hollow insert disposed in said tube and substantially coaxially therewith.

[0077] The hollow insert is arranged in particular to allow the admission of reactive gases through a first end of the reactor into a distribution chamber of the insert. These gases are then distributed over a section of the annular space extending over a length L, parallel to a longitudinal axis XX' of the reactor, by a distributing opening allowing the passage of gases from the distribution chamber to said annular space.

[0078] The products resulting from the reaction between reactive species are then collected, via a collecting opening, into a collection chamber of the hollow insert, isolated from the distribution chamber by a separating wall.

[0079] The evacuation of the products is carried out through an evacuation opening of the collection chamber at the level of the second end.

[0080] Figures 1 and 2 show an example of the realization of a fixed-bed tubular reactor.

[0081] The tubular reactor 1 comprises a hollow tube 10 which extends along a longitudinal axis XX', between a first end 11 and a second end 12.

[0082] The hollow tube 10 may have rotational symmetry about the longitudinal axis XX'. The hollow tube 10 may comprise a metal, and in particular a metal selected from: steel, aluminum alloy, copper, nickel, among others. The diameter of the internal surface of the hollow tube 10 may be between 5 mm and 100 mm. mm.

[0083] The wall, referred to as the first wall, forming the hollow tube 10 can have a thickness of between 0.5 mm and 10 mm. The hollow tube 10 can have a length of between 10 times and 200 times its internal diameter.

[0084] The tubular reactor 1 also includes a hollow insert 20 which also extends along the longitudinal axis XX' and has an external shape substantially cylindrical.

[0085] The hollow insert 20 is housed in the volume V of the hollow tube 10 in a manner substantially coaxial with the latter. In particular, the insert 20 comprises a wall, referred to as the second wall 21, which, together with the first wall of the hollow tube, delimits an annular space 30.

[0086] The annular space 30 is, in this respect, filled with a catalytic powder which will be the site of the conversion reactions of reactive gases likely to pass through the tubular reactor 1.

[0087] The annular space 30 can have a thickness, defined as the distance between the first wall and the second wall, of between 2% and 20% of the internal diameter of the first wall.

[0088] Particularly advantageously, the hollow insert 20 can be provided with centering means maintaining the latter in a substantially coaxial position with the hollow tube 10. For example, as shown in [Fig.6] relating to a second variant of tubular reactor 1 discussed later in the statement, the centering means include bosses 22 formed on the second wall 21.

[0089] These centering means 22 make it possible in particular to consider a hollow insert 20 with a length at least 20 times greater than the diameter of the insert 20. Furthermore, these centering means 22 also make it easier to assemble the tubular reactor 1.

[0090] The hollow insert 20 further comprises at least one distribution chamber 40 and at least one collection chamber 50. In particular, the hollow insert 20 may comprise between one and four distribution chambers 40 and between one and four collection chambers 50.

[0091] The distribution chambers 40 and the collection chambers 50 are advantageously arranged alternately, extend over the entire length of the hollow insert 20 and are separated from each other by separating walls 60.

[0092] More particularly, the separating walls 60 extend along the entire length of the hollow insert 20 in the volume defined by the hollow insert 20.

[0093] Furthermore, at least one distribution chamber 40 includes an inlet opening 41 at one end of the insert 20 through which one or more reactive gases are likely to be admitted.

[0094] Equivalently, at least one collection chamber 50 includes an evacuation opening 51 at the other end of the hollow insert 20 and through which one or more gases are likely to be evacuated.

[0095] The hollow insert 20 is also provided with at least one distributing opening 42, or distribution opening, and at least one collecting opening 52, or collection opening. In particular, the distributing opening 42 forms a passage permeable to reactive gases from the distributing chamber 40 to the annular space 30. Equivalently, the collecting opening 52 forms a passage permeable to gases from the annular space 30 to the collecting chamber 50. The distributing opening 42 and collecting opening 52 extend over a length L.

[0096] Advantageously, the length L is greater than half, advantageously three-quarters of the extension length along the longitudinal axis XX' of the annular space 30.

[0097] Furthermore, at least one distribution chamber 40 is closed at the second end 12, while at least one collection chamber 50 is closed at the first end 11. In this regard, as illustrated in [Fig. 1], the distribution chamber 40 is closed by a distribution wall 43, while the collection chamber 50 is closed by a collection wall 53.

[0098] Complementarily, the tubular reactor 1 may include at the first end 11 and at the second end 12, respectively, a distributor space 13 and a collector space 14 between which the hollow insert 20 is disposed.

[0099] Advantageously, the collection opening 52 and the distribution opening 42 have a width between 1 / 400 and 1 / 2, advantageously between 1 / 20 and 1 / 100, of the diameter of the hollow tube 10.

[0100] Advantageously, the collection opening 52 and the distribution opening 42 each include a filter 61 preventing the passage of catalytic powder into either of the collection chambers 50 or distribution chambers 40. Specifically, the filter(s) 61 make it possible to confine the catalyst in the annular space 30 due to their impermeability to the catalyst.

[0101] For example, and as illustrated in [Fig. 3], the filter 61 may comprise a plurality of planes 61a, 61b, 61c, and 61d comprising fibers. The example illustrated in [Fig. 3] in particular comprises four planes, each provided with rectangular or round fibers inclined at plus or minus 45° to the longitudinal axis XX'. More specifically, the fibers of two successive planes are oriented at two different angles, and are in particular perpendicular from one plane to the other.

[0102] During the operation of reactor 1, one or more reactive gases are admitted into the distribution chamber 40 through the inlet opening 4L. These gases then pass through the distribution opening 42 and flow into the annular space 30 to come into contact with the catalytic powder bed. During this flow into the annular space 30, which occurs essentially between a distribution opening 42 and an immediately adjacent collection opening 52, the reactive gases are converted, at least partially, into products. These products, along with the unreacted fraction of reactive gases, pass through the aforementioned collection opening 52 and are collected in the collection chamber 50. The collected products and unreacted gases are then discharged through the discharge opening 51.

[0103] Thus, the extent of the distribution openings 42 along the length L allows the reactive gases to be distributed in the annular space 30 along said length L. In other words, this arrangement allows the amount of heat likely to be produced during the conversion of the reactive gases into products to be distributed over the entire length L. This arrangement thus limits the local temperature increase of the catalytic powder bed. The extent of the collection openings 52 along the length L allows, according to an equivalent principle, the heating of the catalytic powder bed to be limited.

[0104] Furthermore, the arrangement of the inlet openings 41 and outlet openings 51 on opposite ends of the hollow insert 20 also contributes to a better distribution of the reactants within the annular space 30 and consequently to a better homogenization of the temperature of the catalytic powder bed.

[0105] All these aspects contribute to limiting the occurrence of hot spots and thus preserving the catalytic powder bed. This results in improved reliability of the tubular reactor 1 and an increase in its service life.

[0106] According to a particularly advantageous aspect illustrated in [Fig.4], the catalytic powder is retained in the annular space 30 by a fibrous material seal 31 at each end of the annular space 30.

[0107] Insofar as the seal is made of fibrous material, it is necessarily porous and therefore permeable to reactive gases. The fibrous material may in this respect comprise at least one of the following elements selected from: glass fibers, ceramic fibers, metal fibers, carbon fibers, polymer fibers, among others.

[0108] The seal 31 may, in particular, be in the form of a braid, a sheath, a cord, or simply consist of a filling of fibrous material. The fibrous material is advantageously a thermal insulator and has a thermal conductivity substantially equivalent to that of the catalyst used (0.2 W / m / K to 10 W / m / K).

[0109] According to an advantageous embodiment, the fibrous seal 31 is held in compression against the catalytic powder by a spring 32. For example, the spring 32 is against a retaining plate 33 mechanically linked to the tube by a ring 34.

[0110] The fibrous material seal 31 in combination with the spring(s) allows for better compaction of the catalytic powder and prevents attrition of the latter during handling or transport of the reactor.

[0111] Insofar as the seal 31 is porous, reactive gases can penetrate the annular space directly without passing through the distribution chamber 40.

[0112] In this case ([Fig. 4]), it is particularly advantageous to provide an arrangement of the hollow insert 20 that allows the reactive gas to follow a predetermined path within the annular space 30 in order to promote its conversion upon contact with the catalytic powder bed. This predetermined path length is between 2 and 100 times, advantageously between 3 and 10 times, the distance DI ([Fig. 5]) separating a distribution opening 42 from an immediately adjacent collection opening 52, and measured along the external surface of the second wall 21 of the insert 20.

[0113] To this end, the second wall 21 may be devoid of an opening onto a first section 21a and a second section which extend from, respectively, the first end 11 and the second end 12.

[0114] In this respect, the first section 21a and the second section overlap with the powder bed over a height H1. The height H1 being between 0.5 times and 10 times, advantageously between one time and 2 times, the distance DI separating a distribution opening 42 from an immediately adjacent collection opening 52, and measured along the external surface of the second wall 21.

[0115] Figure 6 illustrates a second embodiment which essentially retains the characteristics of the first embodiment. The hollow insert 20 of this second embodiment is advantageously manufactured using an additive manufacturing technique.

[0116] According to this second variant, the distribution chamber 40 has a convergent profile from the first end 11 to the second end 12.

[0117] In other words, the surface S40 of a section of the distribution chamber 40 along a cross-section plane to the longitudinal axis XX' decreases from the first end 11 to the second end 12 (figures 7A to 7E), advantageously, said surface is zero at the level of the second end 12.

[0118] Equivalently, the surface S50 of a section of the collection chamber 50 along a cross-section plane to the longitudinal axis XX' increases from the first end 11 to the second end 12, advantageously, said surface is zero at the first end 11.

[0119] This arrangement of the distribution chambers 40 and collection chamber 50 minimizes pressure losses related to gas circulation within them. Flow inhomogeneities in the annular space 30 are thus reduced.

[0120] Figure 8 shows a hollow insert 20 that can be implemented according to a third embodiment. This third embodiment essentially retains the characteristics of the first and second embodiments.

[0121] The insert 20 relating to this second variant can be manufactured by machining, cutting, electro-erosion, extrusion, among other methods.

[0122] In particular, the insert 20 comprises according to this variant a main body 20a interposed between two terminal bodies 20b, 20c, and assembled by means of a joint 20d.

[0123] The two terminal bodies 20b, 20c, illustrated in [Fig.8], comprise a cylindrical wall that is not permeable to gas, reproducing the first section 21a described in the first variant, and include distribution openings 42 (or collection openings 52).

[0124] In the examples described above, the insert 20 is typically made in one piece. The manufacturing techniques envisaged, such as additive manufacturing, machining, cutting, electrical discharge machining or extrusion, allow the direct production of one-piece inserts.

[0125] Advantageously, the invention proposes the production of a plurality of intermediate insert pieces which, joined together, form the insert body. The insert is then obtained with such an insert body and the other elements that compose it, such as centering means 22, filters 61, etc.

[0126] The joining of the intermediate insert parts can, for example, consist of an assembly by interlocking, welding, brazing or even by joining collars whose section is substantially circular.

[0127] The intermediate parts can be produced by means of an industrial tube drawing process through a die, or by means of a rolling and welding process of a metal strip, in particular a sheet metal strip, by successive passage through rollers.

[0128] The production of an insert body by assembling several intermediate insert parts, obtained in particular by a drawing process and / or a rolling and welding process, has many advantages compared with the production of a one-piece insert body and the processes for obtaining such a one-piece insert.

[0129] Thus, unlike extrusion, which only allows the use of aluminum alloys for complex geometries, it is possible here to produce an insert body made of iron, nickel, iron alloy, and / or nickel alloy. This type of material may be necessary for the mechanical strength and chemical resistance of the insert under the intended operating conditions.

[0130] Furthermore, unlike machining, electrical discharge machining (EDM), and additive manufacturing, manufacturing time can be reduced by using intermediate insert parts obtained by drawing and / or rolling and welding. It is also possible, unlike these manufacturing techniques, to produce part lengths exceeding 1 m with external insert body diameters of less than 5 cm, or even less than 3 cm.

[0131] In addition, unlike machining, electro-erosion and cutting, the amount of material lost is greatly reduced.

[0132] We will now describe with reference to figures 11 to 16 the making of hollow inserts 20 for a tubular reactor 1 according to the invention, for example a tubular reactor 1 as described previously.

[0133] Advantageously, the hollow insert 20 comprises an insert body 20i obtained by assembling a first intermediate hollow insert piece 20ipl with a second separate intermediate hollow insert piece 20ip2. The first intermediate insert piece 20ipl is located inside the second intermediate insert piece 20ip2, as shown in Figures 11 to 14.

[0134] The first intermediate insert piece 20ipl is advantageously in the form of a first profiled tube formed by rolling and welding sheet metal or by drawing a blank through a die. The second intermediate insert piece 20ip2 is advantageously in the form of a second tube of substantially cylindrical shape.

[0135] As can be seen in Figures 11 to 14, the first intermediate insert piece 20ipl, when viewed in cross-section with respect to the longitudinal axis XX', has a substantially circular shape comprising recessed portions, here in the form of distinct concave arc segments Cl, C2, C3, oriented towards the center of the substantially circular shape. Alternatively, the orientation could be convex rather than concave. Similarly, shapes other than arcs could be considered, for example, straight, curved, or polygonal. These recessed portions Cl, C2, C3 are located between contact portions NI, N2, N3, the outer surface of which conforms to the shape of the inner surface of the second intermediate hollow insert piece 20ip2.

[0136] In the example of figures 11, 13 and 14, two portions of circular arc Cl, C2 are present and allow to delimit, with the second intermediate insert piece 20ip2, three chambers, for example a distribution chamber 40 or a collection chamber 50 inside the first intermediate insert piece 20ipl, and respectively two collection chambers 50 or two distribution chambers 40 in the spaces between each portion of circular arc Cl, C2 and the second intermediate insert piece 20ip2.

[0137] In the example of [Fig. 12], three portions of arc of circle Cl, C2, C3 are present and allow to delimit, with the second intermediate piece of insert 20ip2, four chambers, of distribution 40 or of collection 50.

[0138] The assembly of the first 20ipl and second 20ip2 intermediate insert pieces is carried out by co-stretching which allows the diameter of the second intermediate insert piece 20ip2 to be reduced around the first intermediate insert piece 20ipl so that a contact is established between them at the contact portions NI, N2, N3 of the substantially circular shape of the first intermediate insert piece 20ipl without circular arc portions Cl, C2, C3.

[0139] At the level of these contact portions NI, N2, N3, the first 20ipl and second 20ip2 intermediate insert pieces can be fixed together in fixing areas S, for example by transparency welding (see [Fig. 13]).

[0140] Advantageously, the assembly described here for the hollow insert 20 makes it easier to produce straight inserts because the cross-section has planes of symmetry. It is also possible to straighten the assembly using conventional methods employed for cylindrical tubes, in case of any lack of straightness. Furthermore, it is possible to better control the diameter of the insert, and consequently the dimensions of the annular space. In addition, numerous distribution and collection chambers can be formed with only two tubes and few manufacturing steps, resulting in savings in time and material. It is possible to avoid leaving gaps between the chambers and also to reduce resistance to the flow of gases within the chambers.

[0141] Moreover, as can be seen in Figures 13 and 14, the second intermediate insert piece 20ip2 here has collection openings 52. These openings can be in the form of longitudinal grooves, as can be seen in [Fig. 16].

[0142] Furthermore, according to a first variant shown in [Fig.13], the first intermediate insert piece 20ipl has passage openings 66, which can advantageously also be in the form of longitudinal grooves, opposite the collection openings 52 of the second intermediate insert piece 20ip2.

[0143] According to a second embodiment shown in Figures 14 and 15, the first intermediate insert piece 20ipl comprises, opposite the collection openings 52 of the second intermediate insert piece 20ip2, intermediate chambers 65, in particular in the form of longitudinal channels, comprising a plurality of passage openings 66, in particular of circular form as seen in [Fig. 15] but a longitudinal groove form is also possible, opening into the interior of the first intermediate insert piece 20ipl.

[0144] Advantageously, the intermediate chambers 65 allow for better control of pressure losses in the gas circuit. The passage openings 66 of the first room The intermediate insert 20ipl is advantageously created before the co-drawing step with the second intermediate insert 20ip2. After this step, the distribution or collection openings 42 of the second intermediate insert 20ip2 are created. By making few passage openings 66 and / or small passage openings 66 on the first intermediate insert 20ipl, it is possible to create controlled pressure drops at the passage of these openings 66. Each intermediate chamber 65 allows the reactants to be distributed axially, and the distribution openings 42 of the second intermediate insert 20ip2 allow the reactants to be contacted with the catalytic medium.

[0145] Advantageously, the insert body 20i, and in particular the first intermediate insert piece 20ipl and / or the second intermediate insert piece 20ip2, are made of iron, nickel, iron alloy and / or nickel alloy.

[0146] Moreover, as can be seen in [Fig. 11], the external diameter De of the insert body 20i is advantageously less than 5 cm, better less than 3 cm.

[0147] It should be noted that the features stated above in connection with the first, second, and third embodiments, described with reference to Figures 1 to 10, are applicable to the present invention when technically compatible with it. In particular, the inserts 20 described with reference to Figures 11 to 13 can be incorporated into the tubular reactors 1 described with reference to Figures 1 to 10. Furthermore, the inserts 20 described with reference to Figures 1 to 10 can be made in several parts as described with reference to Figures 11 to 13.

[0148] The tubular reactor according to the present invention is advantageously implemented for the synthesis of methane, methanol, dimethyl ether or for carrying out Fisher-Tropsch synthesis.

[0149] Of course, the invention is not limited to the embodiments just described. Various modifications can be made to them by a person skilled in the art.

Claims

1. Demands Tubular reactor (1) with a fixed bed extending, along a longitudinal axis (XX'), between a first end (11) and a second end (12), the reactor (1) comprising a bed of catalytic powder confined in an annular space (30) delimited by a first wall of a hollow tube (10) and a second wall (21) of a hollow insert (20), disposed in the hollow tube (10) and substantially coaxially therewith, the hollow insert (20) comprising at least one distribution chamber (40) and at least one collection chamber (50), separated from each other by a separating wall (60), and comprising, respectively, a gas inlet opening (41) and a gas outlet opening (51), the second wall (21) comprising at least one distribution opening (42) and at least one collection opening (52), which extend over a length (L),the distributing opening (42) allowing the distribution of a gas that can be admitted through the inlet opening (41) of the distribution chamber (40) to the annular space (30), and the collecting opening (52) allowing the collection of the distributed gas in the annular space (30) by the collecting chamber (50), characterized in that the hollow insert (20) comprises an insert body (20i) obtained by assembling at least one first intermediate hollow insert piece (20ipl) with a second separate intermediate hollow insert piece (20ip2), said at least one first intermediate insert piece (20ipl) being located inside the second intermediate insert piece (20ip2), said at least one first intermediate insert piece (20ipl) having, by observation in cross-section with respect to the longitudinal axis (XX'), one or more contact portions (NI, N2,N3) whose external surface conforms to the shape of the internal surface of the second intermediate hollow insert piece (20ip2), and one or more recess portions (Cl, C2, C3) located at a distance from the second intermediate hollow insert piece (20ip2), the interior of said at least one first intermediate insert piece (20ipl) defining a distribution chamber (40) or a chamber of, collection (50), and the space(s) located each between a portion of withdrawal (Cl, C2, C3) and the second intermediate insert piece (20ip2) defining the other chamber(s), respectively collection (50) or distribution (40).

2. Reactor according to claim 1, wherein one or more of the shrinkage portions (Cl, C2, C3), in particular all shrinkage portions (Cl, C2, C3), have(s) an arc shape, in particular concave or convex with respect to the longitudinal axis (XX').

3. Reactor according to claim 1 or 2, wherein the second intermediate insert piece (20ip2) has, by observation in cross-section with respect to the longitudinal axis (XX'), a substantially circular shape.

4. Reactor according to any one of the preceding claims, wherein said at least one first intermediate insert piece (20ipl) comprises at least two withdrawal portions (Cl, C2, C3), in particular at least three withdrawal portions (Cl, C2, C3), in particular distributed regularly around the longitudinal axis (X).

5. Reactor according to any one of the preceding claims, wherein the second intermediate insert piece (20ip2) has distributing openings (42) or collecting openings (52), in particular in the form of longitudinal grooves.

6. Reactor according to claim 5, wherein said at least one first intermediate insert piece (20ipl) has passage openings (66), in particular in the form of longitudinal grooves, opposite the distributing openings (42) or collecting openings (52) of the second intermediate insert piece (20ip2).

7. Reactor according to claim 5, wherein said at least one first intermediate insert piece (20ipl) comprises, opposite the distributing openings (42) or collecting openings (52) of the second intermediate insert piece (20ip2), intermediate chambers (65), in particular in the form of longitudinal channels, comprising a plurality of passage openings (66), in particular in circular form and / or in the form of a longitudinal groove, opening into the interior of said at least one first intermediate insert piece (20ipl).

8. Reactor according to any one of the preceding claims, wherein said at least one first intermediate insert piece (20ipl) is fixed to the second intermediate insert piece (20ip2), in particular in the contact portion(s) (NI, N2, N3), at the level of fixing areas (S), in particular by transparency welding.

9. Reactor according to any one of the preceding claims, wherein said at least one first intermediate insert piece (20ipl) is obtained from a first profiled tube by rolling and welding or by drawing.

10. Reactor according to any one of the preceding claims, wherein the second intermediate insert piece (20ip2) is in the form of a second profiled tube of substantially cylindrical shape.

11. Reactor according to any one of the preceding claims, wherein the assembly of said at least one first intermediate insert piece (20ipl) with the second intermediate insert piece (20ip2) is obtained by co-stretching, resulting in particular in a reduction in diameter of the second intermediate insert piece (20ip2) in contact with said at least one first intermediate insert piece (20ipl).

12. Reactor according to any one of the preceding claims, wherein the insert body (20i) is made of iron, nickel, iron alloy and / or nickel alloy.

13. Reactor according to any one of the preceding claims, wherein the external diameter (De) of the insert body (20i) is less than 5 cm, in particular less than 3 cm.

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