Improvements Related to Catalyst Carriers for Tubular Reactors and Related Methods - Patent application

Abstract

A method of operating a tubular reactor (1), the tubular reactor (1) comprising a plurality of reaction tubes (8) configured to receive catalyst carriers (10) configured to hold a catalyst, the method comprising, for at least some of the reaction tubes (8), the following steps: a) connecting two or more catalyst carriers (10) together to form a linked set (10a); b) placing the combination set (10a) and a plurality of additional catalyst carriers (10b) not connected to the combination set (10a) within the reaction tube (8) such that the combination set (10a) and the plurality of additional catalyst carriers (10b) extend at least partway between the inlet end of the reaction tube (8) and the outlet end of the reaction tube (8), with the combination set (10a) adjacent the inlet end; c) operating the tubular reactor (1) to pass one or more reactants through the reaction tubes (8) from an inlet end to an outlet end; d) subsequently withdrawing the linked set (10a) from the inlet end of the reactor tube (8) while retaining an additional plurality of catalyst carriers (10b) within the reactor tube (8).

Description

[Technical field]

[0001] The present disclosure relates to a method of operating a tubular reactor and a linked set of catalyst carriers for use in a tubular reactor. [Background technology]

[0002] A conventional so-called fixed-bed tubular reactor comprises a reactor shell, usually cylindrical, containing a number of tubes, usually directly packed with catalyst particles. In use, a heat transfer medium flows through the reactor shell outside these tubes, thereby regulating the temperature of the catalyst within the tubes by heat exchange across the tube walls. Thus, if the reaction is exothermic, the heat transfer medium allows heat to be removed from the catalyst, and if the reaction is endothermic, the heat transfer medium provides heat to the catalyst.

[0003] For some reactions, the thermal effects of the reaction are so mild that they are either not a problem or they can be easily managed. In some cases, the thermal effects are small enough that a large diameter tube may be used. This has the advantage that there is a large amount of catalyst in the tube.

[0004] However, for larger exothermic or endothermic reactions, it is necessary that there be efficient heat transfer through the tube walls to the heat transfer medium so that conditions within the reactor can be controlled to maintain a stable operating temperature and avoid the occurrence of deleterious effects. For exothermic reactions, such effects may include the occurrence of side reactions, damage to the catalyst such as by sintering of catalytic active sites, and in the worst case, thermal runaway. For endothermic reactions, deleterious effects may include quenching of the reaction.

[0005] To achieve the desired efficiency, the surface area of ​​the tube wall per unit length must be maximized. This has been accomplished in the past by installing a larger number of smaller diameter tubes. In some reactions, size limitations mean that the tubes can only have an internal diameter of about 15-40 mm. However, the use of this large number of tubes increases the cost and complexity of the reactor.

[0006] Therefore, in an attempt to alleviate these problems, alternative approaches have been developed, particularly for larger exothermic or endothermic reactions, in which the catalyst is not loaded directly into the reactor tubes, but instead is contained in a number of catalyst carriers configured to be positioned within the reactor tubes.

[0007] WO 2011 / 048361, WO 2012 / 136971, and WO 2016 / 050520 describe several examples of catalyst carriers configured for use in tubular reactors.

[0008] The catalyst carriers can be usefully used in a wide range of processes. Examples of suitable applications include processes and reactors for exothermic reactions, such as reactions for the production of methanol, reactions for the production of ammonia, methanation reactions, and shift reactions, oxidation reactions such as the formation of maleic anhydride, and ethylene oxide reactions. One particular example in which the catalyst carriers can be used is also a process and reactor for carrying out Fischer-Tropsch reactions. The catalyst carriers can also be used in endothermic reactions, such as pre-reforming, dehydrogenation, etc.

[0009] During operation of the tubular reactor, one or more reactants flow through the reactor tubes and into and through the catalyst carrier, thereby contacting the catalyst contained therein. The catalyst and reactants selected depend on the desired process to be carried out in the tubular reactor, and they can vary widely. In one example, the tubular reactor may be configured for a Fischer-Tropsch process. In this example, the catalyst is a Fischer-Tropsch catalyst, such as a transition metal catalyst, e.g., a cobalt-containing Fischer-Tropsch catalyst. Reactants for the Fischer-Tropsch process can include hydrogen gas and carbon monoxide gas, which can be derived from synthesis gas.

[0010] The catalyst used in the catalyst carrier can be "poisoned" when it is exposed to a substance that damages the catalyst. In the example of a Fischer-Tropsch catalyst, when the syngas is formed it can contain poisons, e.g. sulfur, that can permanently damage the catalyst. Typically, the syngas is subjected to a pre-purification to remove the sulfur before reaching the tubular reactor. However, there remains a risk that the pre-purification may not completely remove all the toxic substances in the syngas, e.g. due to the use of off-spec syngas or due to a malfunction in the pre-purification.

[0011] Poisoning of catalyst in catalyst carriers typically affects carriers closer to the inlet of the tube first and may require replacement of those catalyst carriers. This requires taking the tubular reactor off line. A tubular reactor may contain a large number of reaction tubes, for example, there may be up to 5000 reaction tubes. Furthermore, each reaction tube may contain a large number of catalyst carriers. The reaction tubes may share a common head space for feeding reactants to the reaction tubes. Thus, an acute poisoning event or a more gradual poisoning over time may affect many, potentially all, reaction tubes of a tubular reactor. Even if the poisoning only affects the catalyst carriers near the inlet of the tube, if it affects many or all of the catalyst carriers of the tube, this may result in significant economic losses, resulting in a very long period of downtime of the tubular reactor while those catalyst carriers are replaced. Summary of the Invention

[0012] In a first aspect of the present disclosure, a method is provided for operating a tubular reactor, the tubular reactor comprising a plurality of reaction tubes configured to receive a catalyst carrier configured to hold a catalyst, the method comprising, for at least some of the reaction tubes, the following steps: a) connecting two or more catalyst carriers together to form a linked set; b) placing the coupling set and a plurality of additional catalyst carriers not connected to the coupling set within the reactor tube such that the coupling set and the plurality of additional catalyst carriers extend at least part way between the inlet end of the reactor tube and the outlet end of the reactor tube, the coupling set being adjacent to the inlet end; c) operating the tubular reactor to pass one or more reactants through the reaction tubes from an inlet end to an outlet end; d) subsequently withdrawing the linked set from the inlet end of the reactor tube while retaining an additional plurality of catalyst carriers within the reactor tube.

[0013] Advantageously, the method may allow the catalyst carrier located closest to the inlet end of the reactor tube during operation to be quickly and efficiently withdrawn. This may significantly reduce downtime of the tubular reactor, as the time savings incurred for a single reactor tube may be multiplied when considering that catalyst carriers may need to be withdrawn from all reactor tubes (which may amount to hundreds or even thousands in a single tubular reactor). It will be appreciated that since a poisoning event most severely affects the catalyst carriers closest to the inlet end, additional catalyst carriers may not be affected or may be less affected by the poisoning event, and therefore, by withdrawing and replacing only the connected set, the poisoning event may be significantly ameliorated while minimizing downtime.

[0014] Preferably, two or more catalyst carriers of a linked set are withdrawn at one time while remaining connected to one another, which may increase the efficiency of the process by allowing a linked set of catalyst carriers to be withdrawn in one operation.

[0015] The method comprises the steps of: c1) determining that a poisoning event has occurred that affected a catalyst retained in the coupled set, and proceeding to step d) based on that determination.

[0016] A particular advantage of the method is that it efficiently removes the catalyst carrier from the poisoned reactor tube. It may therefore be particularly beneficial to perform step d) only if it is determined that a poisoning event has occurred. This may be determined, for example, by observing a loss of production consistent with a temperature profile change in the catalyst carrier proximate the inlet end of the reactor tube and / or by observing a decrease in heat exchanged to the heat transfer fluid at the shell side of the reactor. For example, if the shell side contains boiling water, a decrease in steam production may be observed after a poisoning event, which may be consistent with a loss of production and / or a change in the temperature profile in the catalyst carrier. A poisoning event may be an acute event lasting a relatively short period of time, for example, a failure of a synthesis gas purification device as a pre-treatment, resulting in high concentrations of poisons, such as sulfur, reaching the tubular reactor. Alternatively, a poisoning event may be a longer-term gradual event that occurs over a long period of time, such as the deterioration of a catalyst due to prolonged exposure to very low concentrations of one or more poisons.

[0017] The method involves the following steps: e) installing a new connected set of two or more catalyst carriers into the reactor tube to replace the withdrawn connected set.

[0018] Beneficially, the tubular reactor can be prepared for subsequent operation by replacing the catalyst carriers, and a new connected set of catalyst carriers can be used in the event of a second subsequent poisoning event.

[0019] Preferably, the coupling set is installed in and withdrawn from the inlet end of the reactor tube. Advantageously, the additional catalyst carriers in the reactor tube do not need to be moved or disturbed during withdrawal and replacement of the coupling set.

[0020] Preferably, in step b), the additional plurality of catalyst carriers are installed first, followed by the connected set.

[0021] Two or more catalyst carriers of a linkage set may be connected together by permanent or releasable means. In some instances, the catalyst carriers may be welded together. In other more preferred instances, the connection means may include a push fit, e.g. an interference fit, between adjacent catalyst carriers. Alternatively, and most preferably, in some instances, the connection means may include a relative rotational coupling between adjacent catalyst carriers. Such means may be better adapted to maintain the connection when the linkage set is subjected to an axial pulling thrust. For example, a bayonet joint may be provided. Alternatively, a threaded connection may be provided.

[0022] The linked set may consist of only catalyst carriers, each of which contains a catalyst. However, in alternative examples, the linked set may additionally contain one or more elements that do not contain a catalyst. In some examples, the linked set may include a spacer unit connected to two or more catalyst carriers, which may be provided at one end of the linked set. Advantageously, when the linked set is installed in the reactor tube, the spacer unit may be aligned with the first or top sheet of the tubular reactor. The spacer unit may function to help ensure that all of the catalysts included in the linked set are located below the first or top sheet of the tubular reactor so as to be within the heat exchange zone of the tubular reactor.

[0023] Preferably, the spacer unit and two or more catalyst carriers of the coupling set are connected together. The connection means may be the same as those described above, for example a bayonet fit, an interference fit, etc.

[0024] In some embodiments, the linked set of catalyst carriers may include a catalyst different from the additional multiple catalyst carriers. For example, the linked set may include a catalyst designed to efficiently remove poisons. Such a poison removal catalyst may be, for example, a sulfur removal catalyst. Thus, the linked set may function as a replaceable guard section at the inlet of each reactor tube.

[0025] A combination set may, for example, contain 2-20, preferably 5-15, catalyst carriers, optionally with spacer units. A combination set of that size may be long enough to contain all catalyst carriers likely to be significantly affected by a poisoning event, yet still be of a practical size for efficient extraction with significant time savings compared to replacing all catalyst carriers in the tube.

[0026] The method may further include providing an attachment point at the inlet end of the coupling set, while withdrawing the coupling set from the inlet end of the reactor tube may include attaching a tool to the attachment point and, for example, using the tool to withdraw the coupling set out from the inlet end.

[0027] Advantageously, the provision of an attachment point allows for easy withdrawal of the coupling set, which may for example comprise or consist of a hook, eyelet, catch, aperture or other means that can be engaged by a tool to allow the tool to apply a thrust to the coupling set, for example a pulling force that urges the coupling set towards the inlet end of the reactor tube.

[0028] The attachment point may be provided on a catalyst carrier or spacer unit of the coupling set. Preferably, the attachment point is provided on the carrier or unit closest to the inlet end, for example on the end face of the carrier or unit facing the inlet end.

[0029] The tool may be manually, hydraulically, pneumatically, or electromechanically driven and may be used to place and extract the catalyst carriers in and from the reactor tubes.

[0030] The tool may comprise a moveable ram, for example a manually or hydraulically driven ram, configured to push the carrier into and / or pull the carrier out of the reaction tube.

[0031] In some instances, the tool a) a mounting frame; b) a movable ram mounted to the mounting frame and configured to push or pull one or more catalyst carriers into or out of a selected reactor tube; c) one or more anchors for engaging one or more reactor tubes positioned along the selected reactor tubes to releasably attach the mounting frame to the tubular reactor; The installation tool may comprise:

[0032] Preferably, at least one of the catalyst carriers of the coupled set includes a seal that engages against the inner surface of the reactor tube such that liquids and gases passing along the reactor tube are preferentially directed to flow through the interior of the catalyst carrier. If a spacer unit is present, the spacer may include a seal, but need not include a seal since the spacer unit typically does not include any catalyst.

[0033] Preferably, the seal may be configured to allow the catalyst carrier to be installed in the reactor tube in a first direction and withdrawn from the reactor tube in a second direction opposite the first direction. For example, the seal may be configured to accommodate movement of the catalyst carrier in both the first and second directions. The seal may be configured, for example, to form a sliding seal that slides against the inner surface of the reactor tube. The sliding seal may be slidable in both directions.

[0034] In some examples, the seals may include O-rings, ceramic fiber rings, or metal brush seals. In particular, these seals may be deformed during installation of the catalyst carrier into the reactor tube. The amount of deformation may be configured to achieve the required seal integrity while also allowing sliding movement in the first and second directions.

[0035] In some other examples, the seal may have a geometry that can be transformed from a first configuration that allows sliding movement in a first direction to a second configuration that allows sliding movement in a second direction. For example, the seal may be transformed to its first configuration upon installation of the catalyst carrier into the reactor tube, and the seal may be transformed to its second configuration upon withdrawal. For example, the seal may include one or more layers that extend outwardly from the catalyst carrier's container.

[0036] The seal may comprise at least a first seal layer and a second seal layer, each of the first seal layer and the second seal layer comprising a plurality of deflectable tongues separated by notches, the second seal layer being offset relative to the first seal layer in a rotational direction about a longitudinal axis of the catalyst carrier such that the notches of the second seal layer are aligned with the deflectable tongues of the first seal layer.

[0037] The seal may be deformed, upon installation, to a first configuration in which one or more layers are bent back toward the inlet end of the reactor tube. The seal may be deformed, upon withdrawal, to a second configuration in which one or more layers are bent back toward the outlet end of the reactor tube during withdrawal. The seal may be selected to be relatively flexible to allow the seal to adopt both the first and second configurations.

[0038] In a second aspect of the present disclosure, a connection set of two or more catalyst carriers is provided, the connection set including two or more catalyst carriers connected together end-to-end, the connection set including attachment points for withdrawing the connection set one at a time from the inlet end of a reactor tube.

[0039] The linkage set may additionally include a spacer unit connected to two or more catalyst carriers, the spacer unit being provided at one end of the linkage set and including an attachment point.

[0040] At least one of the catalyst carriers of the coupled set may be provided with a seal for engaging an inner surface of the reactor tube. The seal may be as described above in relation to the first embodiment.

[0041] For example, the seal may be configured to allow the catalyst carrier to be installed in a first direction within the reactor tube and withdrawn from the reactor tube in a second direction opposite the first direction. For example, the seal may be deformable. For example, the seal may include one or more layers extending outwardly from the catalyst carrier vessel. For example, the seal may comprise at least a first sealing layer and a second sealing layer, each of which comprises a plurality of deflectable tongues separated by notches, the second sealing layer being offset relative to the first sealing layer in a rotational direction about the longitudinal axis of the catalyst carrier such that the notches of the second sealing layer are aligned with the deflectable tongues of the first sealing layer. For example, the seal may be deformable during installation such that one or more layers bend back toward the inlet end of the reactor tube during installation. For example, the seal may be deformable during withdrawal such that one or more layers bend back toward the outlet end of the reactor tube during withdrawal. For example, the seals may include O-rings, ceramic fiber rings, or metal brush seals.

[0042] The method and combination set may be usefully employed in a wide range of processes. Examples of suitable applications include processes and reactors for exothermic reactions, such as reactions for the production of methanol, reactions for the production of ammonia, methanation reactions, shift reactions, oxidation reactions such as the formation of maleic anhydride, and ethylene oxide reactions. A particularly preferred use is in processes and reactors for carrying out Fischer-Tropsch reactions.

[0043] Endothermic reactions such as pre-reforming, dehydrogenation, etc. can also be carried out using the method and coupling set of the present invention.

[0044] The catalyst carrier of the present disclosure may be filled or partially filled with any catalyst suitable for the intended reaction. For example, a Fischer-Tropsch catalyst may be used for the Fischer-Tropsch reaction. A cobalt-containing Fischer-Tropsch catalyst is preferred. The catalyst may be provided as catalyst particles or catalyst monoliths. The catalyst may be provided as a single catalyst bed or multiple catalyst beds. The catalyst carrier may be configured to promote axial and / or radial flow through the catalyst. In some embodiments, the catalyst carrier may be configured to preferentially promote radial flow through the catalyst.

[0045] The catalyst carriers of the present disclosure can be formed from any suitable material. Such materials are generally selected to withstand the operating conditions of the tubular reactor. The catalyst carriers can be made from carbon steel, aluminum, stainless steel, other alloys, or any material capable of withstanding the reaction conditions. [Brief description of the drawings]

[0046] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a schematic side view of a tubular reactor. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a portion of the tubular reactor of FIG. [Diagram 3] FIG. 2 is a perspective view of a catalyst carrier. [Figure 4] FIG. 4 is a cross-sectional view of the catalyst carrier of FIG. [Diagram 5] FIG. 4 is an exploded perspective view of the catalyst carrier of FIG. 3. [Figure 6] FIG. 2 is a plan view of a sealing layer of the catalyst carrier. [Figure 7] FIG. 2 is a schematic side view showing an arrangement of multiple sealing layers. [Figure 8] FIG. 2 is a plan view of a first sealing layer and a second sealing layer of the catalyst carrier. [Figure 9] FIG. 13 is a perspective view of another catalyst carrier. [Figure 10]FIG. 10 is a side view showing two of the catalyst carriers of FIG. 9 connected to each other. [Figure 11] FIG. 11 is a cross-sectional view of the catalyst carrier of FIG. [Figure 12] FIG. 2 is a schematic diagram of the upper part of the tubular reactor of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] In the following, aspects and embodiments of the present disclosure are described by way of example only with reference to a vertically oriented tubular reactor having a plurality of vertical reactor tubes extending between an upper tube sheet and a lower tube sheet, however, it will be understood that the present disclosure may also be applied to other configurations of tubular reactors that may employ other orientations.

[0048] Additionally, any references to orientation herein, such as terms such as top, bottom, upper, lower, above, below, and the like, are used with respect to the orientation of the parts as shown in the referenced drawings, but should not be construed as limiting the potential orientation of such parts in actual use. For example, a part described as being oriented vertically may be oriented horizontally.

[0049] 1 shows a typical layout of a tubular reactor 1 of the present disclosure. The tubular reactor 1 includes a housing 2. The interior of the housing may be divided into a head space 3, a heat exchange zone 4, and a footer space 5 by two tube sheets, an upper tube sheet 6 and a lower tube sheet 7. The upper tube sheet 6 separates the head space 3 from the heat exchange section 4. The lower tube sheet 7 separates the footer space 5 from the heat exchange zone 4.

[0050] A plurality of reaction tubes 8 extend between the upper tube sheet 6 and the lower tube sheet 7. A large number of reaction tubes 8 may be provided, for example, there may be 20 to 5000 reaction tubes 8. Each reaction tube 8 may have an inner diameter of, for example, 20 to 150 mm. In some embodiments, the inner diameter may be about 85 mm.

[0051] Each reactor tube 8 is intended to be filled, or substantially filled, with a stacked arrangement of catalyst carriers 10. In particular, it is generally desirable for the catalyst carriers 10 to cover all or substantially all of the length of the reactor tubes 8 between the upper tube sheet 6 and the lower tube sheet 7, i.e., to cover all or substantially all of the length of the heat exchange zone 4.

[0052] The head space 3 may provide access to the upper ends of the reactor tubes 8 to allow loading of catalyst carriers 10 into the reactor tubes 8. An access opening 11 may be provided in the housing 2 to allow access to the head space 3. The access opening 11 may be, for example, a manhole or other access panel that can be selectively opened and closed.

[0053] The footer space 5 may provide access to the lower end of the reactor tube 8 to allow removal of the catalyst carrier 10 from the reactor tube 8. For example, access to the footer space 5 may be provided by an access opening (not shown) similar to the access opening 11 into the headspace 3.

[0054] According to the present disclosure, a method for operating a tubular reactor 1 is provided. In general, the method comprises the steps of: a) connecting two or more catalyst carriers 10 together to form a linked set 10a; b) placing the connection set 10a and a plurality of additional catalyst carriers 10b not connected to the connection set 10a in the reactor tube 8 such that the connection set 10a and the plurality of additional catalyst carriers 10b extend at least partway between an inlet end (e.g., an upper end) of the reactor tube 8 and an outlet end (e.g., a lower end) of the reactor tube 8, with the connection set 10a adjacent to the inlet end as shown in FIG. 2; c) operating the tubular reactor 1 to pass one or more reactants through the reaction tube 8 from the inlet end to the outlet end; d) subsequently withdrawing the linked set 10a from the inlet end of the reactor tube 8 while retaining an additional plurality of catalyst carriers 10b within the reactor tube 8.

[0055] 2 shows a total of seven catalyst carriers 10, it will be understood that a commercial reactor reactor tube 8 will likely contain 50 or more catalyst carriers 10. Typically, there will be about 2-20, preferably 5-15, catalyst carriers 10 in a linked set 10a, with the remainder being an additional plurality of catalyst carriers 10b.

[0056] To better understand the present disclosure, an example of a general configuration of the catalyst carrier 10 will first be described with reference to Figures 3-5. This general configuration may be used for both the catalyst carrier 10 of the linked set 10a and the additional plurality of catalyst carriers 10b. (The differences between the two are described below.) However, it will be understood that the catalyst carrier 10 may take a variety of forms. For example, as well as the examples described herein, the catalyst carrier 10 may take other general configurations, including but not limited to those disclosed in WO 2011 / 048361, WO 2012 / 136971, and WO 2016 / 050520, the contents of which are incorporated herein by reference in their entireties.

[0057] Each catalyst carrier 10 may generally comprise a container sized to be smaller than the interior dimensions of the reactor tube 8 in which it will be placed during use. Typically, a seal is provided that is sized to interact with the interior wall of the reactor tube 8 when the catalyst carrier 10 is in place within the reactor tube 8. Parameters such as length and diameter of the carrier may be selected to accommodate different reactions and configurations of reactor tubes 8.

[0058] 3-5, the container 100 may generally have a bottom surface 101 that closes a lower end of the container 100 and a top surface 102 at an upper end of the container 100. An outer carrier wall 103 may extend from the bottom surface 101 to the top surface 102. A seal 104 (described in more detail below) may extend from the container 100 a distance that extends beyond the outer carrier wall 103. The outer carrier wall 103 may have an opening 105 located below the seal 104.

[0059] As shown in FIG. 4, the catalyst carrier 10 may more specifically comprise an annular vessel 110 for holding the catalyst during use. The annular vessel 110 may comprise a perforated inner vessel wall 111 defining an interior channel 112 and a perforated outer vessel wall 113 that may be concentrically disposed about the perforated inner vessel wall 111. An annular top surface 114 may close an upper end of the annular vessel 110, and an annular bottom surface 115 may close a lower end of the annular vessel 110. The lower end of the interior channel 112 may be closed by a channel end surface 116, except for one or more discharge openings (not shown) that may be provided at the lower end of the interior channel 112. The channel end surface 116 may be formed integrally with or separate from the inner vessel wall 111.

[0060] 5, the catalyst carrier 10 may be formed from several individual components that may be assembled together by any suitable means including, for example, welding. In some embodiments, such components may include a perforated inner tube 120, a perforated middle tube 121, an outer tube 122, a bottom cap 123, an annular top ring 124, a top cap 125, and annular seal rings 126 and 127.

[0061] The catalyst carrier 10 may be formed from any suitable material. Such materials are generally selected to withstand the operating conditions of the reactor. Typically, the catalyst carrier is fabricated from carbon steel, aluminum, stainless steel, other alloys, or any material capable of withstanding the reaction conditions.

[0062] The appropriate thickness of the component would be about 0.05 mm to about 1.0 mm, preferably about 0.1 mm to about 1.0 mm, and more preferably about 0.3 mm to about 1.0 mm.

[0063] The perforated inner tube 120 may comprise a perforated inner vessel wall 111. The perforated intermediate tube 121 may comprise a perforated outer vessel wall 113. The outer tube 122 may comprise the carrier outer wall 103 and may define an opening 105. The bottom cap 123 may comprise a bottom surface 101 and / or an annular bottom surface 115. The bottom cap 123 may also extend across the perforated inner tube 120 to include the channel end surface 116. The annular top ring 124 and the top cap 125 may include an annular top surface 114 and may include at least a portion of the top surface 102. The annular seal rings 126 and 127 may comprise the seal 104.

[0064] The size of the holes in the perforated inner tube 120 and the perforated intermediate tube 121 are selected to allow uniform flow of reactants and products through the catalyst while maintaining the catalyst within the annular vessel 110. It will be appreciated that their size will therefore depend on the size of the catalyst particles used. In an alternative configuration, the holes may be larger but sized with a filter mesh covering the holes to ensure that the catalyst is maintained within the annular vessel 110.

[0065] It will be understood that the holes may be of any suitable configuration, and indeed where a wall or tube is described as being perforated, all that is required is that there be a means to allow reactants and products to pass through the wall or tube.

[0066] The bottom surface 101, e.g., bottom cap 123, may be shaped to engage with the top end of another catalyst carrier 10. For example, the bottom surface 101 may include an annular recess 130 about the perforated inner tube 120. The top cap 125 may be shaped to engage with the annular recess 130 of another catalyst carrier 10. For example, the top cap 125 may include an annular ring 131 upstanding from an annular plug body 132. The annular ring 131 may be shaped and sized to be received within the annular recess 130.

[0067] The bottom surface 101, such as the bottom cap 123 and / or the channel end surface 116, may include one or more drain holes. If one or more drain holes are present, they may be covered by a filter mesh.

[0068] The annular top ring 124 may be shaped and sized to engage the upper end of the outer tube 122. The annular plug body 132 of the top cap 125 may have an outer diameter configured to engage with a central opening in the annular top ring 124. The engagement between the top cap 125 and the annular top ring 124 may function to sandwich and hold the annular seal rings 126 and 127 in place.

[0069] The top cap 125 may include a central inlet 134 in annular plug body 132 to allow liquids and gases to enter the upper end of the interior channel 112. The annular ring 131 may include side openings 133 to allow liquids and gases to reach the central inlet 134.

[0070] The carrier outer wall 103 may be smooth or shaped. Suitable shapes include pleated, corrugated, and the like.

[0071] The openings 105 in the carrier outer wall 103 may be of any configuration. In some embodiments, the openings 105 may be holes or slots.

[0072] The carrier outer wall 103 may continue above the seal 104. Thus, the seal 104 may be located at the top of the catalyst carrier 10, optionally as part of the top surface 102, or at any suitable point on the carrier outer wall 103, provided that it is located above an opening 105 in the carrier outer wall 103.

[0073] The seal 104 may be sufficiently compressible to accommodate the smallest diameter of the reactor tube 8. The seal 104 may generally be a flexible sliding seal. The seal 104 may engage against an inner surface of the reactor tube 8 such that liquids and gases passing along the reactor tube 8 are preferentially directed to flow through the interior of the catalyst carrier 10. The seal 104 may be configured, for example, to form a sliding seal that slides against the inner surface of the reactor tube 8.

[0074] In the example illustrated in FIGS. 3-5, the seal 104 may include a deformable flange 140 extending from the carrier outer wall 103 or the top surface 102 of the catalyst carrier 10. The flange 140 may be sized larger than the inner diameter of the reactor tube 8 so that it is deformed to fit inside and interact with the reactor tube 8 when the catalyst carrier 10 is inserted into the reactor tube 8. The deformable flange 140 includes outer portions of the annular seal rings 126 and 127. The inner portions 141 of the annular seal rings 126 and 127 may define clamping surfaces that are sandwiched and held between the top cap 125 and the annular top ring 124. The deformable flange 140 may be inclined relative to the inner portions 141. The deformable flange 140 may be inclined toward the top end of the catalyst carrier 10.

[0075] Although described above with reference to two annular sealing rings 126 and 127, the example seal 104 may, for example, include a single layer of material. Thus, sealing ring 127 may not be present and sealing ring 126 may, for example, be configured as a continuous annular ring to provide seal 104. Figures 6-8 show further details of an example seal 104 comprised of at least a first sealing layer 126 and a second sealing layer 127. Seal 104 may include more than two sealing layers 126, 127. For example, it may include four, five, or six sealing layers.

[0076] Figure 6 shows an example of one seal layer 126. Figure 7 shows how multiple seal layers 126a-126f can be provided to form the seal 104. Figure 8 shows another example of a seal 104 formed from two seal layers 126, 127.

[0077] The sealing layers 126, 127 may form part of a unitary sealing element, for example a spiral element, or, as shown in Figures 6-8, each sealing layer 126, 127 may comprise a separate sealing element.

[0078] The first sealing layer 126 and the second sealing layer 127 overlap each other. Preferably, the layers 126, 127 are in face contact. Each sealing layer 126, 127 may comprise a separate sealing ring. Each sealing layer 126, 127 may be flexible. Each sealing layer 126, 127 may comprise an annular element. The outer edge of each annular element may be configured to generally match the shape of the inner surface of the reactor tube. The annular element may be circular. In some examples, the outer diameter may be 80-90 mm, optionally about 85 mm. The annular element may have a central opening 162 for receiving the container of the catalyst carrier 10. The central opening 162 may have a diameter of 55-65 mm, optionally about 60 mm. The outer diameter may be selected to achieve a desired insertion force of the catalyst carrier 10, taking into account the inner diameter of the reactor tube in which the catalyst carrier 10 is to be installed.

[0079] Each sealing layer 126, 127 may include a plurality of deflectable tongues 160 separated by notches 161. Thus, each of the first sealing layer 126 and the second sealing layer 127 (and any additional sealing layers) may include a notched outer edge 163. Each sealing layer 126, 127 may include between 5 and 80 deflectable tongues 160, optionally between 8 and 60 deflectable tongues 160, optionally about 40 deflectable tongues 160. Each pair of deflectable tongues 160 may be separated by one notch 161.

[0080] Each sealing layer 126, 127 may be formed from a single piece of sheet material. The notched outer edge 163 may be formed by suitable means such as cutting, stamping, or the like. The material of each sealing layer 126, 127 may be the same or different. Each sealing layer 126, 127 may be formed from carbon steel, aluminum, stainless steel, other alloys, or any material capable of withstanding the reaction conditions. The thickness of each sealing layer 126, 127 may be the same or different. For example, different thicknesses may be used to construct different sealing layers having different properties including flexibility, stiffness, compressibility, and the like. Each sealing layer 126, 127 may have a thickness selected to achieve the required insertion force and flexibility of the deflectable tongue 160. In some examples, the thickness of each sealing layer 126, 127 may be between 15 microns and 500 microns (0.015 mm to 0.5 mm).

[0081] The notches 161 may vary in width from a relatively narrow width, as in the example of Figure 6, to a relatively wide width, as in the example of Figure 8. The notches 161 may include side walls 164 (as seen most clearly in Figure 8) that are parallel or diverge toward the outer edge of the respective sealing layers 126, 127. The notches 161 may be U-shaped or V-shaped.

[0082] The second sealing layer 127 is preferably rotationally offset relative to the first sealing layer 126 about the longitudinal axis of the catalyst carrier 10 such that the notch 161 of the second sealing layer 127 is aligned with the deflectable tongue 160 of the first sealing layer 126. Such a rotational offset advantageously minimizes gas bypass.

[0083] The first and second sealing layers 126, 127 may extend vertically from the container 100. Alternatively, the first and second sealing layers 126, 127 may be angled toward the top of the container 100, such as toward the top surface 102.

[0084] In some embodiments, the catalyst carrier 10 may include three or more seal layers 126, 127, each seal layer including multiple deflectable tongues 160 separated by notches 161. Each seal layer 126, 127 may be rotationally offset about the longitudinal axis of the catalyst carrier 10 relative to at least one of the other seal layers 126, 127 such that the notches 161 of each seal layer 126, 127 may be aligned with the deflectable tongues 160 of at least one of the other seal layers 126, 127. Preferably, the notches 161 of each seal layer 126, 127 may be aligned with the deflectable tongues 160 of one or both adjacent seal layers 126, 127. For example, as shown in FIG. 7, the notch 161 of seal layer 126c is aligned with the deflectable tongues 160 of both seal layers 126b and 126d.

[0085] The inner edges of the sealing layers 126, 127 may be attached to one another, which may occur before or after the sealing layers 126, 127 are attached to the container 100, for example by welding.

[0086] Each sealing layer 126, 127 may include a key or keyway (not shown) for engaging a complementary keyway or key on the container 100 to maintain relative rotational alignment of the sealing layers 126, 127 with respect to one another.

[0087] An inner portion of each sealing layer 126 , 127 may define a clamping surface that is sandwiched and held between the top cap 125 and the annular top ring 124 .

[0088] As mentioned above, according to the present disclosure, some of the catalyst carriers 10 inserted in the reactor tubes 8 are connected to one another to form a linked set 10a. The catalyst carriers 10 of the linked set 10a are for this purpose equipped with means allowing them to be attached together. For example, adjacent catalyst carriers 10 of the linked set 10a may be connected together by the engagement of one or more cooperating formations.

[0089] In some examples, each catalyst carrier 10 of the linked set 10a may include an upper cooperating formation 150 provided on or toward an upper end of the vessel 100 and a lower cooperating formation 151 provided on or toward a lower end of the vessel 100, as shown in Figures 9-11. Adjacent catalyst carriers 10 may thereby be engaged together by engagement of the lower cooperating formation 151 on one catalyst carrier 10 with the upper cooperating formation 150 of an adjacent catalyst carrier 10 of the linked set 10a.

[0090] The upper and lower cooperating formations 150, 151 may be configured to be engaged and disengaged by relative rotational movement of the adjacent catalyst carriers 10. For example, the upper and lower cooperating formations 150, 151 may take the form of bayonet fittings as shown.

[0091] In some examples, the upper cooperating formation 150 is provided above the seal 104. For example, the upper cooperating formation 150 may be provided on or as part of the annular ring 131 and / or the carrier outer wall 103.

[0092] The additional plurality of catalyst carriers 10b may be separated from each other. Alternatively, in some examples, two or more catalyst carriers 10 of the additional plurality of catalyst carriers 10b may be engaged with each other to form an insertion set. However, the additional plurality of catalyst carriers 10b, whether separate or arranged in an insertion set, remain separate from the interlocking set 10a. Each insertion set of the additional plurality of catalyst carriers 10b may comprise, for example, two, three or more catalyst carriers 10 stacked one on top of the other. The catalyst carriers 10 may be permanently engaged with each other by means such as welding. However, more preferably, the catalyst carriers 10 are releasably engaged with each other. The releasable engagement may be achieved, for example, by cooperating formations 150, 151 of the same type as described above.

[0093] The connection set 10a may consist of only catalyst carriers 10 each containing a catalyst. However, in an alternative example, the connection set 10a may additionally contain one or more units that do not contain a catalyst. For example, as shown in FIG. 2, the connection set 10a may comprise a spacer unit 200 connected to the catalyst carriers 10 of the connection set 10a. The spacer unit 200 may be connected to one end of the connection set 10a. Preferably, the spacer unit 200 may be aligned with the upper tube sheet 6 of the tubular reactor 1 when the connection set 10a is installed in the reaction tube 8. The spacer unit 200 may function to help ensure that all of the catalysts contained in the connection set 10a are located below the upper tube sheet 6 in the heat exchange zone 4. The spacer unit 200 may also function to prevent upward creep of the catalyst carriers 10 during operation, which may occur if a gap is left at the height of the upper tube sheet 6 without the spacer unit 200. The spacer unit 200 may include a protruding flange 202 as shown in FIG. 2 that may engage with the upper tube sheet 6 to provide a reference level for the insertion position of the spacer unit 200, thereby providing the connection set 10a.

[0094] The means for connecting the spacer unit 200 with adjacent catalyst carriers 10 of the linkage set 10a may be the same as those described above for the catalyst carriers 10 themselves, for example a bayonet fit, an interference fit, or the like.

[0095] The spacer unit 200 may include an attachment point 201 to aid in withdrawing the coupling set 10a from the upper inlet end of the reactor tube 8. In Figure 2, the attachment point 201 is illustrated as a ring.

[0096] At least one of the catalyst carriers 10 of the linked set 10a may be provided with a seal 104. In some examples, the seal 104 of the catalyst carrier 10 of the linked set 10a may be different in configuration than the seal 104 provided on the catalyst carrier 10 of the additional plurality of catalyst carriers 10b. For example, the seal 104 of the catalyst carrier 10 of the linked set 10a may have a higher flexibility than the seal 104 provided on the catalyst carrier 10 of the additional plurality of catalyst carriers 10b. In other respects, the catalyst carriers 10 of the linked set 10a may have the same general configuration as described above and illustrated in FIGS. 3-5.

[0097] Preferably, one or more seals 104 of the coupling set 10a are configured to allow the coupling set 10a to be installed in a first direction within the reactor tube 8 and withdrawn from the reactor tube 8 in a second direction opposite the first direction. For example, each seal 104 may be configured to form a sliding seal that slides against an inner surface of the reactor tube 8. The sliding seal may be slidable in both directions. In some examples, the seal 104 may include an O-ring, a ceramic fiber ring, or a metal brush seal.

[0098] In some examples, the seal 104 may be one of the types described above, such as a deformable flange 140, or multiple sealing layers 126, 127 acting together as a seal. When the seal 104 includes a deformable flange 140 extending from the carrier outer wall 103 or the top surface 102 of the catalyst carrier 10, the material and / or thickness of the deformable flange 140 may be selected such that the seal 104 is more flexible than the seal 104 of the catalyst carrier 10 of the additional multiple catalyst carriers 10b. When the seal 104 includes multiple sealing layers 126, 127, the material and / or thickness and / or number of the sealing layers may be selected such that the seal 104 is more flexible than the seal 104 of the catalyst carrier 10 of the additional multiple catalyst carriers 10b. For example, a more flexible seal 104 may allow the seal 104 to adopt a different configuration during installation into and removal from the reactor tube 8. For example, the seal 104 may be deformed, upon installation, into a first configuration such that the flange 140 or layers 126, 127 bend back toward the inlet end of the reactor tube 8. The seal 104 may be deformed, upon withdrawal, into a second configuration such that the flange 140 or one or more layers 126, 127 bend back toward the outlet end of the reactor tube 8 during withdrawal.

[0099] The loading of the catalyst carrier 10 (both the linked set 10a and the additional plurality of catalyst carriers 10b) into the reactor tube 8 may be performed with the aid of a tool. The tool may be manually, hydraulically, pneumatically or electromechanically driven. The tool may be used to place the catalyst carrier 10 in and extract it from the reactor tube 8. The tool may comprise a moveable ram, e.g. a manually or hydraulically driven ram, configured to push the catalyst carrier 10 into and / or pull it out of the reactor tube 8.

[0100] 12 shows an example of a tool configured as an installation tool 20 comprising an installation frame, a hydraulic ram attached to the installation frame, and one or more anchors for fastening the installation frame to the upper tube sheet 6 of the tubular reactor 1. The anchors serve to releasably engage the installation frame, and thus the installation tool 20, to the tubular reactor 1. The installation tool can form part of an installation system that additionally comprises a power source. The power source may be located outside the tubular reactor 1 and configured to move the movable ram of the installation tool 20.

[0101] During insertion into the reactor tube 8, the seal 104 of the catalyst carrier 10 may sealingly engage with the inner surface of the reactor tube 8. In particular, the engagement of the seal 104 with the reactor tube 8 may cause deformation of the seal 104. The deformation of the seal 104 may generate a resistive force that may help maintain the axial position of the catalyst carrier 10 within the reactor tube 8 after installation. Furthermore, the deformation of the seal 104 may be used to facilitate a liquid-tight and / or gas-tight seal between the upper end of the catalyst carrier 10 and the inner surface of the reactor tube 8.

[0102] When installed within the reactor tube 8, the catalyst carriers 10 may form a stacked arrangement one on top of the other with their longitudinal axes aligned and coincident.

[0103] In use, the catalyst carriers 10 are first installed within the reactor tubes 8 of the tubular reactor 1, preferably to fill or substantially fill the tubular reactor 1. For at least some of the reactor tubes 8, and preferably most if not all of the reactor tubes 8 including the stack of catalyst carriers 10, the linked set 10a of the catalyst carriers 10 is installed behind and above the additional plurality of catalyst carriers 10b, such that the linked set 10a is proximate to the inlet end of the reactor tube 8. The linked set 10a and the additional plurality of catalyst carriers 10b extend at least partway between the inlet end of the reactor tube 8 and the outlet end of the reactor tube 8. Importantly, the additional plurality of catalyst carriers 10b is not connected to the linked set 10a.

[0104] A linked set 10a can include, for example, 2-20, preferably 5-15, catalyst carriers 10, optionally with spacer units 200. A linked set of that size may be long enough to include all catalyst carriers 10 likely to be significantly affected by a poisoning event, yet be of a practical size to efficiently extract with significant time savings compared to replacing all catalyst carriers 10 in the tube.

[0105] The tubular reactor 1 is then operated to pass one or more reactants through the reaction tubes 8 from their respective inlet ends to their outlet ends. In the tubular reactor 1 with downward flow utilizing the catalyst carrier 10 shown in Figures 3-5 and 9-11, the reactants flow downward through each reaction tube 8 and thus first contact the top surface 102 of the top catalyst carrier 10 of the linked set 10a. The seals 104 impede the passage of the reactants around the sides of the catalyst carrier 10. The top surface 102 thus directs the reactants inwardly through the side openings 133 into the central inlet 134 at the top end of the interior channel 112 in the inner vessel wall 111 defined by the perforated inner tube 120.

[0106] The reactants then enter the annular vessel 110 through a perforated inner tube 120 and then pass radially through the catalyst bed toward the outer vessel wall 113 defined by a perforated middle tube 121. During this passage, the reactants contact the catalyst and react to form products.

[0107] The unreacted reactants and products then exit the annular vessel 110 through the perforated intermediate tube 121. The carrier outer wall 103 defined by the outer tube 122 then directs the reactants and products upward between the inner surface of the carrier outer wall 103 and the perforated intermediate tube 121 until they reach the openings 105 in the carrier outer wall 103. The reactants and products are then directed through the openings 105 and flow downward between the outer surface of the carrier outer wall 103 and the inner surface of the reaction tube 8 where heat transfer occurs.

[0108] The unreacted reactants and products can then contact the upper surface 102 of the catalyst carrier 10 below in the stacked formations, and the aforementioned process can be repeated. This pattern can be repeated as the reactants and products pass through the stacked formations until they are collected from the lower end of the reactor tube 8.

[0109] A portion of the products, particularly liquid products, may be discharged from the inner channel 112 into the underlying inner channel 112 of the catalyst carrier 10 through discharge holes provided in the channel end face 116. Such products may then continue to be discharged down the stacked formations of the catalyst carrier 10 and be collected from the lower end of the reactor tube 8.

[0110] During or after operation, for example, if it is determined that a poisoning event has occurred, the method includes withdrawing the linkage set 10a out of the inlet end of the reactor tube 8 while retaining an additional plurality of catalyst carriers 10b within the reactor tube 8. The linkage set 10a may be withdrawn, for example, by securing a hydraulic ram of the installation tool 20 to the attachment point 201 and withdrawing the linkage set 10a upwardly and out of the reactor tube 8 such that all of the units of the linkage set 10a (e.g., catalyst carriers 10 and spacer units 200) are withdrawn at one time.

[0111] Optionally, a tool, such as installation tool 20, may be configured to extract connection sets 10a from two or more reactor tubes 8 simultaneously.

[0112] Further, the method may then continue by installing a new connected set 10a of two or more catalyst carriers 10 into the reactor tube 8 to replace the withdrawn connected set 10a.

[0113] The withdrawal and replacement of the coupling set 10 a may be performed for each of the reaction tubes 8 of the tubular reactor 1 , for example, if the reaction tubes 8 share a common headspace 3 .

Claims

1. A method for operating a tubular reactor, the tubular reactor comprising a plurality of reaction tubes configured to receive catalyst carriers configured to hold a catalyst, wherein the method involves, for at least some of the reaction tubes, the following steps: a) Connecting two or more catalyst carriers together to form a linked set, b) Installing the connecting set and an additional number of catalyst carriers not connected to the connecting set inside the reaction tube, such that the connecting set and the additional number of catalyst carriers extend at least partway between the inlet end and the outlet end of the reaction tube, and the connecting set is close to the inlet end. c) Operating the tubular reactor to allow one or more reactants to pass through the reaction tube from the inlet end to the outlet end, d) A method comprising subsequently withdrawing the coupling set from the inlet end of the reaction tube while retaining the additional catalyst carriers inside the reaction tube.

2. The method according to claim 1, wherein the two or more catalyst carriers of the connecting set remain connected to each other, and the connecting set is withdrawn all at once.

3. The following steps: c1) The method according to claim 1 or 2, further comprising determining that a poisoning event has occurred that has affected the catalyst held in the linked set, and proceeding to step d) based on that determination.

4. The following steps: e) The method according to claim 1, further comprising installing two or more new sets of catalyst carriers in the reaction tube to replace the withdrawn set of connectors.

5. The method according to claim 1, wherein the connecting set is installed inside the reaction tube from the inlet end and withdrawn from the inlet end.

6. The method according to claim 1, wherein the two or more catalyst carriers of the connecting set are integrally connected by bayonet fitting, interlocking fit, or threaded fitting.

7. The method according to claim 1, wherein the connecting set further includes spacer units connected to the two or more catalyst carriers, and the spacer units are provided at one end of the connecting set.

8. The method according to claim 7, wherein when the connecting set is installed in the reaction tube, the spacer unit is aligned with the first or uppermost seat of the tubular reactor.

9. The method according to claim 1, further comprising providing a mounting point at the inlet end of the connecting set, wherein withdrawing the connecting set from the inlet end of the reaction tube comprises attaching a tool to the mounting point and using the tool to pull the connecting set out of the inlet end.

10. The method according to claim 9, wherein the tool is driven manually, hydraulically, pneumatically, or electromechanically.

11. The method according to claim 1, wherein at least one of the catalyst carriers of the coupling set is provided with a seal that engages with the inner surface of the reaction tube such that liquids and gases passing along the reaction tube are preferentially guided to flow through the inside of the catalyst carrier.

12. The method according to claim 11, wherein the seal is configured to allow the catalyst carrier to be installed in the reaction tube in a first direction and to be withdrawn from the reaction tube in a second direction opposite to the first direction.

13. The method according to claim 11, wherein the seal is deformed when the catalyst carrier is placed inside the reaction tube.

14. The method according to claim 11, wherein the seal comprises one or more layers extending outward from the container of the catalyst carrier.

15. The seal comprises at least a first sealing layer and a second sealing layer, The first sealing layer and the second sealing layer each comprise a plurality of deflectable tongues separated by notches, The method according to claim 14, wherein the second seal layer is rotationally offset with respect to the first seal layer about the longitudinal axis of the catalyst carrier such that the notch of the second seal layer is aligned with the deflectable tongue of the first seal layer.

16. The method according to claim 14, wherein the seal is deformed during installation such that one or more layers bend back toward the inlet end of the reaction tube during installation.

17. The method according to claim 14, wherein the seal is deformed during withdrawal such that one or more layers bend back toward the outlet end of the reaction tube during withdrawal.

18. The method according to claim 11, wherein the seal includes an O-ring, a ceramic fiber ring, or a metal brush seal.

19. A coupling set of two or more catalyst carriers, wherein the two or more catalyst carriers are connected end to end, and the coupling set includes a mounting point for withdrawing the coupling set at once from the inlet end of a reaction tube.

20. The coupling set according to claim 19, wherein the coupling set further includes a spacer unit connected to the two or more catalyst carriers, the spacer unit being provided at one end of the coupling set and including the mounting point.

21. The coupling set according to claim 19 or 20, wherein at least one of the catalyst carriers of the coupling set is provided with a seal for engaging with the inner surface of a reaction tube.

22. The seal comprises at least a first sealing layer and a second sealing layer, The first sealing layer and the second sealing layer each comprise a plurality of deflectable tongues separated by notches, The coupling set according to claim 21, wherein the second sealing layer is rotationally offset with respect to the first sealing layer about the longitudinal axis of the catalyst carrier such that the notch of the second sealing layer is aligned with the deflectable tongue of the first sealing layer.

23. The coupling set according to claim 21, wherein the seal includes an O-ring, a ceramic fiber ring, or a metal brush seal.

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