Channel Assembly

Abstract

A channel assembly for stacking with layered heat exchange elements in a Fischer-Tropsch reactor comprises a corrugated sheet (1) extending against a plate (4 / 5) having an inner surface that engages the ends of the corrugations of the sheet to define process microchannels between the corrugations, the peaks and troughs of the corrugations being laterally offset from the central longitudinal axis of the channel and higher than the outer edge plates (3). This ensures that pressure (arrow A) applied to the corrugated sheet during fabrication bends the process microchannel walls in the same direction, thereby maintaining a substantially constant cross-section rather than bending toward each other and reducing cross-section, resulting in differential flow rates through adjacent microchannels, and also maintaining improved thermal contact between the corrugations and the plate.

Description

[Technical Field]

[0001] The present invention relates particularly, but not exclusively, to an improved form of channel assembly for chemical reactors, such as Fischer-Tropsch reactors, that is resistant to deformation during the manufacturing process. [Background technology]

[0002] It is well known in the art to form transverse arrays of process microchannels in corrugated sheets, e.g., made of copper, stacked between metal plates welded around the edges. During this manufacturing process, significant pressure is typically applied to hold the corrugated sheets in contact with the metal plates. The applied pressure often leads to deformation of the peaks and troughs of the corrugated sheets, which is not always predictable. In particular, there is a risk that adjacent walls of a channel will buckle inward, thereby reducing the cross section of that channel and increasing the cross section of an adjacent channel. Corrugation deformation can lead to non-uniform flow patterns within the reactor, which is known to be highly undesirable in microchannel reactors.

[0003] WO 2008 / 091918 discloses a heat exchanger including a first flow path for a first working fluid, a second flow path for a second working fluid, a tube at least partially defining one of the first and second flow paths, and a corrugated insert secured to the tube and positioned along the first flow path, the insert having structural defects in some locations that make structural failure more likely than in other locations on the insert.

[0004] WO 2011 / 009080 discloses a hybrid plate-fin heat exchanger for exchanging heat between a first fluid and a second fluid. The hybrid plate-fin heat exchanger includes a plurality of plates, each including a channel for carrying a first fluid. Fins are brazed onto each plate to define a plurality of flow channels for a second fluid. The plates are connected to each other by friction stir welding so that the brazed portions are fluidly isolated from the first fluid during operation.

[0005] International Publication No. 2022 / 034640 discloses a heat exchange element in which partition plates and space-retaining members processed into a corrugated shape with multiple peaks connected by side walls are stacked so that the extension directions of the multiple peaks of adjacent space-retaining members intersect. This entire heat exchange element has multiple flow channels between two adjacent partition plates in the stacking direction, and these flow channels are surrounded by partition plates and side walls. The multiple flow channels include flow channels that are axisymmetric with respect to a line extending in the stacking direction and flow channels that are not axisymmetric with respect to a line extending in the stacking direction. The length of the side walls defining the flow channels that are not axisymmetric is longer than the length of the side walls defining the flow channels that are axisymmetric.

[0006] A typical corrugation deformation is illustrated in Figure 2, which shows in cross section a corrugated copper sheet 1' sandwiched between horizontally arranged upper and lower support plates 4 to define flow channels within the corrugations. During fabrication, pressure is applied to the plates 4, forcing them against the ends of the corrugations 1' and compressing the corrugated sheet, ensuring thermal contact at the contact lines between the support plates 4 and the sheet 1'. Because the central longitudinal axis X is laterally aligned with the peaks P and troughs T of the corrugations, and the channel sidewalls are nearly vertical, this pressure tends to unpredictably buckle the channels in either direction in the plane of the assembly, as indicated by arrow a. Undesired buckling can also occur when the corrugated copper sheet 1' has a Gaussian shape, and in configurations where the Gaussian shape is asymmetric or symmetric relative to a centerline intersecting the apex of the peaks P or troughs T.

[0007] As shown by the dashed lines in the left channel, there is a statistically high probability that some channels will buckle inward. This will result in a smaller transverse cross section for one channel and a larger transverse cross section for an adjacent channel, creating an undesirably highly non-uniform pattern. Inward buckling of the channel walls also undesirably reduces the accessibility of the channel, for example, for loading or removing catalyst.

[0008] In EP 4089359 a plate for a plate type heat exchanger is described which comprises a plurality of plates with a plurality of corrugations arranged in a stack configuration, with peaks and valleys formed in the plates defining flow channels between the plates.

[0009] This document does not describe how to prevent buckling or provide an improved channel assembly. Thus, there remains a need to provide a channel assembly that has improved buckling resistance compared to prior art configurations.

[0010] A welded microchannel reactor, such as that shown in U.S. Patent No. 9,174,387, details a manufacturing process in which a stack of alternating coolant panels and corrugations is aligned and then compressed before welding, e.g., by TIG welding, MIG welding, laser welding, etc. The welding occurs around the edges of the stack where the metal plates that provide containment for the corrugations contact each other. However, in such situations, pressure applied to the stack can result in deformation of the constituent corrugations, which is undesirable. Summary of the Invention [Problem to be solved by the invention]

[0011] It is an object of the present invention to provide an improved channel assembly and method of construction that is more resistant to wavy deformation during the manufacturing process, particularly during the compression step immediately prior to and during welding of the stack of metal plates. [Means for solving the problem]

[0012] The present invention provides an improved channel assembly comprising a corrugated sheet extending against a plate having an inner surface that engages the edges of the corrugations of the sheet to define flow channels between the corrugations, the peaks and troughs of the corrugations being laterally offset from a central longitudinal axis of the channel, and the corrugations being oversized relative to the gap space between the plates between which they are disposed, the height of the peaks of the corrugations being greater than the height of the metal edge strips.

[0013] By laterally offsetting the peaks and troughs of the corrugations, the walls of any particular channel are prevented from buckling toward each other when pressure is applied to the ends (peaks and troughs) of the corrugations (e.g., during manufacturing). Thus, the described corrugations act like springs, absorbing compression in a controlled manner, compressing as much as 10% while maintaining a specified channel gap. Maintaining a specified channel gap results in uniform spacing between channels, maintaining accessibility for catalyst loading and removal. The "spanked" corrugations described herein are oversized relative to the plates between which they are placed, so that when the stack is compressed, the corrugations are also compressed. After welding the edges of the constituent plates of the stack, the pressure is released and the corrugations remain compressed. As a result of the pressure the corrugations exert on the containment plate, the corrugations maintain improved thermal contact with the support plate and are held in place by the pressure of deformation.

[0014] Preferably, the opposing inner surfaces of the flow channel are concave and convex, respectively. Advantageously, this configuration has been found to be particularly effective in preventing buckling of the channel walls, as compared to prior art configurations. The concave and convex configuration of the inner surface of the flow channel has been found to unexpectedly prevent buckling of the channel walls when pressure is applied. This configuration results in controlled, uniform compression of the channel when pressure is applied, thereby providing a uniform flow channel and increasing channel accessibility, for example, facilitating loading and unloading of catalyst (as needed).

[0015] Preferably, the corrugated sheet is compressed between two plates. In this embodiment, the corrugated sheet may engage the inner surfaces of both plates, i.e., the corrugated sheet may extend against an upper plate having an inner surface that engages the upper ends of the corrugations of the sheet (e.g., channel wall peaks), and may extend against a lower plate having an inner surface that engages the lower ends of the corrugations of the sheet (e.g., channel wall troughs). This configuration has been found to advantageously promote uniform compression.

[0016] This is illustrated in Figure 1, which shows a corrugated copper sheet 1 sandwiched between horizontally disposed upper and lower support plates 4 and 5 and laterally disposed edge strips 3, defining flow channels within the corrugations. The peaks P' and troughs T' of the corrugated sheet 1 are laterally offset relative to the longitudinal axis X, as indicated by arrow a', and the concave and convex sidewalls are laterally offset. During fabrication, pressure (indicated by arrow A) is applied to the plates 4 and 5, forcing them against the ends of the corrugations 1 and the tops of the edge strips 3. This compresses the corrugations 1, ensuring a fluid-tight seal at the contact line W between the support plates 4 and 5 and the sheet 1. The illustrated spanked corrugations resist deformation when pressure is applied, ensuring a consistent cross-sectional area of ​​the microchannels.

[0017] The problem addressed by the present invention is particularly important when the corrugated sheet has relatively deep corrugations, such as in a Fischer-Tropsch reactor, and therefore the height-to-width ratio of the flow channels in the corrugated sheet is preferably at least 1.5, preferably at least 2.0, more preferably at least 3.0, and most preferably at least 5.0.

[0018] Preferably, the corrugated sheets are formed from a highly thermally conductive metal or alloy, which is preferably copper or aluminum, or may be stainless steel.

[0019] Preferably, the plate is made of stainless steel.

[0020] Preferably, each flow channel has a cross section that varies in width by less than ±20%, preferably less than ±15%, over at least the central 50% of its height, this feature ensuring relatively uniform flow when the flow paths are parallel.

[0021] The width of the flow channels may range from 0.5 mm to 10 mm, preferably 0.5 mm to 5 mm, most preferably 0.5 mm to 1.5 mm when the channel assembly is used in a Fischer-Tropsch reactor, but may vary substantially in other reactor applications.

[0022] Preferably, the thickness of the corrugated sheet material is in the range 0.05 mm to 2 mm, preferably 0.1 mm to 1 mm, for example 0.15 mm. In this range, the invention is particularly effective in preventing inward buckling when pressure is applied during the manufacturing process when the channel assembly is used in a Fischer-Tropsch reactor, although other reactor applications may vary substantially.

[0023] In some embodiments, the channel assembly may include at least one corrugated sheet, e.g., multiple corrugated sheets. In embodiments in which at least one corrugated sheet is present, the corrugated sheets are preferably positioned between plates (i.e., spacer plates) side-by-side and / or one above the other. Thus, when at least one corrugated sheet is present, the corrugated sheets are not in direct contact with each other. This configuration has been found to advantageously prevent buckling, provide uniform compression and contact with the heat transfer plates, and provide accessibility for catalyst loading and removal.

[0024] Further preferred features are defined in the dependent claims.

[0025] Preferred embodiments of the present invention will now be described, by way of example only, with reference to Figures 1 to 7 of the accompanying drawings. [Brief explanation of the drawings]

[0026] [Figure 1] 1A-1C are cross-sectional views illustrating the fabrication of a channel assembly according to an embodiment of the present invention (referenced above). [Figure 2] FIG. 1 is a schematic cross-sectional view of a channel assembly including a corrugated sheet sandwiched between two support plates (see above, outside the scope of this invention). [Figure 3] FIG. 13 is a cross-sectional view of an embodiment of the entire channel assembly. [Figure 4] FIG. 6 is a perspective view of a heat exchange unit that can be combined with the embodiment of a microchannel assembly shown in FIG. 5 for use in a Fischer-Tropsch reactor. [Figure 5] FIG. 1 is a perspective view of an embodiment microchannel assembly for use in a Fischer-Tropsch reactor. [Figure 6] FIG. 6 is a perspective view of a block comprising multiple assemblies of microchannel and heat exchanger combinations such as those shown in FIGS. 4 and 5. [Figure 7] FIG. 7 is a perspective view of a Fischer-Tropsch reactor incorporating the block of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0027] Referring to Figure 1, a copper corrugated sheet 1 having a metal thickness of 150 μm is positioned between two stainless steel edge strips 3 on spacer plates 5. The edge strips 3 have a height slightly less than the height h of the corrugated sheet 1. As shown in Figure 1, the peaks P' and troughs T' of the corrugations in the sheet 1 are offset laterally relative to the associated longitudinal center X' of the corrugations.

[0028] Additionally, the opposing walls of each channel are concave and convex, respectively. Although the illustrated embodiment shows a single symmetrically repeating corrugation unit, it is possible for adjacent corrugation units to have mirror images of each other.

[0029] The width w of the channel is suitably 1 mm and the height h is suitably 6.5 mm.

[0030] An upper spacer plate 4, similar to the lower spacer plate 5, is positioned on top of the corrugated sheet 1 and pressed downward in a press until the corrugations are distorted sufficiently to bring the upper spacer plate 5 into contact with the edge strips, as shown by arrow A. This distortion causes opposing channel sides to bend in the same direction a', as shown in Figure 1, which is determined by the curvature of the channel sides, as opposed to distortion (and possible buckling) of the upright profile channel sides in either direction a, as shown in Figure 2 above. As a result, inward collapse of the channel walls is largely prevented.

[0031] The above pressing process creates a line contact between each peak / trough of the corrugated sheet 1 and the associated upper or lower plate 4 / 5, allowing for intimate (thermal) contact of the channels (due to residual pressure) when the upper / lower plate 4 / 5 is welded with the edge strip 3.

[0032] In fact, because the peaks P' and troughs T' are offset from the longitudinal center X', the upper and lower ends of the channel side walls also contact the plates 4 and 5, so the thickness of the line contact area is greater than in the configuration shown in Figure 2. This increased thickness (width) of the line contact area improves the thermal contact between the corrugated sheet and the plates 4 and 5, which is particularly advantageous in chemical reactors such as, for example, Fischer-Tropsch reactors.

[0033] In a variant, as shown in Figure 3, a plurality of (e.g., three) corrugated sheets are arranged side by side in a stack between repeating spacer plates 4 and 5 and edge strips 3, with a further edge strip 2 between each of the corrugated sheets. The top and bottom plates are connected by corner struts 6 which maintain the corrugated sheets 1 in compression, so that they are held in sealing contact against the spacer plates.

[0034] The entire stack consists of repeating units 10 of spacer plates 5 on which a central corrugated sheet 1 is supported between two edge strips 2 and flanked by two further corrugated sheets 1 bounded by edge strips 3 .

[0035] In a variant, before stacking the repeating units 10, the corrugated sheets are secured with a temporary tack weld at the end of each corrugation to the lower spacer plate 5 at the trough nearest the edge / spacer strip 2 / 3. This temporary tack weld serves to secure the corrugations in place during the subsequent stacking, pressing, and welding steps, facilitating the maintenance of thermal contact and mechanically stable positioning of the plates.

[0036] In a variant, each repeating unit 10 may alternate in the stack with layered heat exchange units 350 as shown in Figure 4, which include channels 355 for a heat exchange fluid (e.g., steam) and are oriented and dimensioned so that the channels 355 are perpendicular to the channels of the corrugated sheet 1. This takes advantage of the improved thermal contact between the spun channels and the contacting plates discussed above, resulting in more effective heat exchange between the process channels and the heat exchange fluid. Alternatively, the plates themselves may be provided with channels for the heat exchange fluid.

[0037] The channel assembly according to the present invention is suitable for use in a Fischer-Tropsch reactor, for example as a process microchannel unit.

[0038] The Fischer-Tropsch process is widely used to produce fuels from carbon monoxide and hydrogen, and is represented by the formula (2n+1)H2+nCO→C n H 2n+2 +nH2O The reaction is highly exothermic and is catalyzed by a Fischer-Tropsch catalyst, typically a cobalt-based catalyst, under conditions of high temperature (typically above 180°C, e.g., above 200°C) and pressure (e.g., above 10 bar). A product mixture is obtained, where n typically ranges from 1 to 120. It is desirable to minimize methane selectivity, i.e., the proportion of methane in the product mixture (n=1), and maximize selectivity to C5 and higher (n≧5) paraffins, preferably to levels above 90%. It is also desirable to maximize carbon monoxide conversion.

[0039] The source of hydrogen and carbon monoxide is typically synthesis gas, which can be obtained from a wide range of carbonaceous sources, including biomass and solid municipal waste.

[0040] Referring to Figure 5, a process microchannel unit 330 according to the present invention is shown comprising a spanked corrugated sheet 1 sandwiched between support plates 4 and 5, defining process microchannels 310 on either side of the sheet 1. Each microchannel 310 is packed with catalyst 500 (Figure 6). The Fischer-Tropsch catalyst 500 may be in any form, including a fixed bed of particulate solids or various structured catalyst forms.

[0041] The Fischer-Tropsch catalyst 500 may optionally comprise cobalt and a support. The catalyst may optionally have a cobalt loading in the range of about 10 to about 60 wt%, or about 15 to about 60 wt%, or about 20 to about 60 wt%, or about 25 to about 60 wt%, or about 30 to about 60 wt%, or about 32 to about 60 wt%, or about 35 to about 60 wt%, or about 38 to about 60 wt%, or about 40 to about 60 wt%, or about 40 to about 55 wt%, or about 40 to about 50% cobalt.

[0042] The Fischer-Tropsch catalyst 500 may optionally further comprise a precious metal. The precious metal may be one or more of Pd, Pt, Rh, Ru, Re, Ir, Au, Ag, and Os. The precious metal may be one or more of Pd, Pt, Rh, Ru, Re, Ir, and Os. The precious metal may be one or more of Pt, Ru, and Re. The precious metal may be Ru. The precious metal may be Re. Alternatively or additionally, the precious metal may be Pt. The Fischer-Tropsch catalyst may optionally comprise from about 0.01 to about 30% total precious metal(s), or from about 0.05 to about 20% total precious metal(s), or from about 0.1 to about 5% total precious metal(s), or about 0.2% total precious metal(s) (based on the total weight of all precious metals present as a percentage of the total weight of the catalyst precursor or activated catalyst).

[0043] The Fischer-Tropsch catalyst 500 may optionally include one or more other metal-based components as promoters or modifiers. These metal-based components may optionally be present in the catalyst precursor and / or activated catalyst as carbides, oxides, or elemental metals. Suitable metals for the one or more other metal-based components may be, for example, one or more of Zr, Ti, V, Cr, Mn, Ni, Cu, Zn, Nb, Mo, Cd, Hf, Ta, W, Re, Hg, Tl, and a 4f-block lanthanide. Suitable 4f-block lanthanides may be La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and / or Lu. The metal for the one or more other metal-based components may be, for example, one or more of Zn, Cu, Mn, Mo, and / or W. The metal for the one or more other metal-based components may be, for example, one or more of Re and / or Pt. The catalyst may optionally comprise from about 0.01 to about 10% total other metal(s), or optionally from about 0.1 to about 5% total other metal(s), or optionally about 3% total other metal(s) (based on the total weight of all other metals as a percentage of the total weight of the catalyst precursor or activated catalyst).

[0044] The Fischer-Tropsch catalyst 500 may optionally include a catalyst support. The support may optionally comprise alumina, zirconia, silica, titania, or a mixture of two or more thereof. The surface of the support may optionally be modified by treatment with silica, titania, zirconia, magnesia, chromia, alumina, or a mixture of two or more thereof. The material used for the support and the material used to modify the support may be different. The support may optionally comprise silica, and the surface of the silica may be treated with a refractory solid oxide such as titania. The material used to modify the support may be used to increase the stability of the supported catalyst (e.g., by reducing deactivation). The catalyst support may optionally comprise, for example, up to about 30 wt. %, or about 1 wt. % to about 30 wt. %, or about 5 wt. % to about 30 wt. %, or about 5 wt. % to about 25 wt. %, or about 10 wt. % to about 20 wt. %, or about 12 wt. % to about 18 wt. % of an oxide (e.g., silica, titania, magnesia, chromia, alumina, or a mixture of two or more thereof) used to modify the surface of the support. The catalyst support may optionally be in the form of a structured shape, pellet, or powder. The catalyst support may optionally be in the form of a particulate solid. Without being bound by theory, it is believed that the surface treatments provided herein help prevent sintering of Co during operation in a Fischer-Tropsch process. The median particle size may optionally range from 50 to about 500 μm, or from about 100 to about 500 μm, or from about 125 to about 400 μm, or from about 170 to about 300 μm. In one embodiment, the catalyst may be in the form of a fixed bed of particulate solids.

[0045] Microchannel reactors are disclosed in WO 2016 / 201218 A in the name of the applicant, which is incorporated by reference, as well as in LeViness et al., "Velocys Fischer-Tropsch Synthesis Technology—New Advances on State-of-the-Art," Top. Catal. 2014, 57, pp. 518-525. Such reactors have the particular advantage of a high ratio of heat exchange surface area to microchannel (and catalyst) volume, allowing for very effective heat removal. According to the present invention, compression of the spun channels of the corrugated sheet 1 ensures good thermal contact with adjacent heat exchange layers, resulting in improved process control.

[0046] Further details of a suitable microchannel reactor are provided below with reference to FIGS.

[0047] Referring to Figure 6, a microchannel reactor core 220 for use in a Fischer-Tropsch reactor is shown, which includes a stack of alternating layered units 300 of process microchannels 310 (see Figure 5) and layered units 350 of heat exchange channels 355 (see Figure 4).

[0048] The microchannel reactor core 220 may optionally comprise a stack of plates defining process layers and heat exchange layers, each plate having a periphery, the periphery of each plate or shim being welded to the periphery of the next adjacent plate to provide a peripheral seal for the stack, as shown in US2012 / 0095268A1, which is incorporated herein by reference.

[0049] The microchannel reactor core 220 may optionally have the shape of a three-dimensional block with six square or rectangular sides. The microchannel reactor core 220 may optionally have the same cross section along its length. The microchannel reactor core 220 may optionally be in the form of a parallelepiped or cubic block or prism.

[0050] 7, the microchannel reactor 200 includes a containment vessel 210 that houses or accommodates three microchannel reactor cores 220. In other embodiments, the containment vessel 210 can be used to house or accommodate from 1 to about 12 microchannel reactor cores, or from 1 to about 8 microchannel reactor cores, or from 1 to about 4 microchannel reactor cores. The containment vessel 210 can be a pressurizable vessel. The containment vessel 210 includes inlets and outlets 230 that allow the flow of reactants into the microchannel reactor cores 220, the flow of products from the microchannel reactor cores 220, and the flow of heat exchange fluids into and out of the microchannel reactor cores 220.

[0051] One of the inlets 230 may be connected to a header or manifold (not shown) provided for flowing reactants to the process microchannels in each of the microchannel reactor cores 220. One of the inlets 230 is connected to a header or manifold (not shown) provided for flowing a heat exchange fluid, such as superheated steam, to the heat exchange channels in each of the microchannel reactor cores 220. One of the outlets 230 is connected to a manifold or footer (not shown) for flowing product from the process microchannels in each of the microchannel reactor cores 220. One of the outlets 230 is connected to a manifold or footer (not shown) for flowing heat exchange fluid from the heat exchange channels in each of the microchannel reactor cores 220.

[0052] The containment vessel 210 may be constructed of any suitable material sufficient to withstand the operating pressures that may occur within the microchannel reactor core 220. For example, the shell 240 and reinforcing ribs 242 of the containment vessel 210 may be constructed of cast steel. The flanges 245, fittings, and pipes may be constructed of, for example, 316 stainless steel.

[0053] The microchannel reactor core 220 may be manufactured using known techniques, including, for example, wire electrical discharge machining, conventional machining, laser cutting, photochemical machining, electrochemical machining, molding, water jetting, stamping, etching (e.g., chemical, photochemical, or plasma etching), 3D printing, and combinations thereof.

[0054] The microchannel reactor core 220 may optionally be constructed by forming plates with portions removed to provide the flow channels. For example, stacks of plates may be assembled by diffusion bonding, laser welding, diffusion brazing, and similar methods to form an integrated device. For example, the microchannel reactor may be assembled using a combination of plates and partial plates or strips. In this method, channels or void areas may be formed by assembling strips or partial plates to reduce the amount of material required.

[0055] The microchannel reactor core 220 may optionally comprise a stack of plates defining process layers and heat exchange layers, each plate having a periphery, the periphery of each plate or shim being welded to the periphery of the next adjacent plate to provide a peripheral seal for the stack, as shown in US2012 / 0095268A1, which is incorporated herein by reference.

[0056] The containment vessel 210 may optionally include a control mechanism for maintaining the pressure within the containment vessel at a level equal to or greater than the internal pressure within the microchannel reactor core 220 and / or the pressure within any associated coolant channels. The internal pressure within the containment vessel 210 may optionally range from about 10 to about 60 atmospheres, or from about 15 to about 30 atmospheres, during operation of the syngas conversion process (e.g., a Fischer-Tropsch process). The control mechanism for maintaining the pressure within the containment vessel may optionally include a check valve and / or a pressure regulator. The check valve or regulator may optionally be programmed to operate at any desired internal pressure of the containment vessel. Either or both of these may be used in combination with a system of piping, valves, controllers, and the like to ensure that the pressure within the containment vessel 210 is maintained at a level equal to or greater than the internal pressure within the microchannel reactor core 220. Part of this is done to protect the welds used to form the microchannel core 220. A significant reduction in pressure within the containment vessel 210 without a corresponding reduction in internal pressure within the microchannel reactor core 220 can result in costly failure of welds within the microchannel reactor core 220. The control mechanism can optionally be designed to allow for diverting one or more process gases within the containment vessel when the pressure exerted by the confinement gas is reduced.

[0057] The channels of the channel assembly of the present invention have a very uniform cross-section due to the collapse resistance provided by the spanked nature of the corrugations, allowing for uniform loading of catalyst, resulting in uniform flow rates within the channels of a chemical (e.g., Fischer-Tropsch) reactor and maximizing process efficiency.

Claims

1. A channel assembly comprising a corrugated sheet extending against a plate having an inner surface that engages the ends of the corrugations of the sheet to define flow channels between the corrugations, the peaks and troughs of the corrugations being laterally offset from a central longitudinal axis of the channel.

2. The channel assembly of claim 1 , wherein each of the flow channels has opposing inner surfaces that are concave and convex, respectively.

3. The channel assembly of claim 1 or claim 2, wherein the corrugated sheet is compressed between two plates.

4. The channel assembly according to any one of claims 1 to 3, wherein the corrugated sheet is formed of a metal or alloy with high thermal conductivity.

5. The channel assembly of claim 4 , wherein the corrugated sheet is formed of copper, aluminum, or stainless steel.

6. A channel assembly according to any preceding claim, wherein the or each plate is formed from stainless steel.

7. A channel assembly according to any preceding claim, wherein each flow channel has a cross section which varies in width by less than ±20%, preferably less than ±15%, over at least the central 50% of its height.

8. A channel assembly according to any preceding claim, wherein the width of the flow channel is in the range of 0.5mm to 10mm, preferably 0.5mm to 5mm, most preferably 0.5mm to 1.5mm.

9. A channel assembly according to any preceding claim, wherein the thickness of the corrugated sheet material is in the range of 0.05 mm to 2 mm, preferably 0.1 mm to 1 mm.

10. A channel assembly stack comprising a stack of channel assemblies according to any one of claims 1 to 9, wherein the corrugations of the channel assemblies are preferably parallel.

11. 11. The channel assembly stack of claim 10, wherein the channel assemblies are preferably held in contact with heat exchange elements alternating with the channel assemblies in the stack.

12. 12. The channel assembly stack of claim 11, wherein the heat exchange elements comprise flow paths for a heat exchange fluid, the flow paths preferably being transverse to the corrugations of the channel assemblies.

13. The channel assembly or channel assembly stack of any preceding claim, further comprising a reactant or catalyst material within the flow channels.

14. A channel assembly or channel assembly stack according to any preceding claim, wherein the flow channels communicate with manifolds arranged to pass fluid flow in parallel through the flow channels.

15. A chemical reactor comprising a channel assembly or a channel assembly stack according to claim 13 or 14.

16. 16. The chemical reactor of claim 15, wherein the channel assembly or channel assembly stack is enclosed within a pressure vessel.

17. 17. The chemical reactor of claim 15 or claim 16, which is a Fischer-Tropsch reactor and the catalytic material is a Fischer-Tropsch catalyst.

18. 16. The Fischer-Tropsch reactor of claim 15, wherein the or each of the plates is in thermal contact with a flow path for a heat transfer fluid.

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