Process and apparatus for removing solid catalyst

Abstract

Spent catalyst 500 is removed from the process microchannels 310 of a Fischer-Tropsch reactor by directing air jets 4 from an air knife 1 through slots in a guard member 2. The air knife traverses successive rows of process microchannels 310 in a direction A. The spacer member 2 protects the internal microchannel architecture 315 of the process microchannels against damage from the air jets 4, which may approach or exceed sonic speeds as they are directed into the process microchannels.

Description

Technical Field

[0001] The present invention relates to a process for the removal of spent catalyst from a microchannel reactor. The present invention relates in particular, but not exclusively, to a process for the removal of spent Fischer-Tropsch catalyst from the process microchannels of a Fischer-Tropsch reactor.

Background Art

[0002] The Fischer-Tropsch process is widely used to produce fuels from carbon monoxide and hydrogen and can be represented by the following equation. (2n + 1)H2 + nCO → C n H 2n+2 + nH2O

[0003] This reaction is highly exothermic and is catalyzed by a Fischer-Tropsch catalyst, typically a cobalt-based catalyst, under conditions of high temperature (typically at least 180 °C, such as 200 °C or higher) and high pressure (e.g., at least 10 bar). A product mixture is obtained, where n typically ranges from 1 to about 90. It is desirable to minimize the selectivity to methane in the product mixture, i.e., the proportion of methane (n = 1), and to maximize the selectivity to C5 and higher paraffins (n ≥ 5), typically to a level of 90% or higher. It is also desirable to maximize the conversion of carbon monoxide. Preferably, at least about 70% w / w of the product mixture is distributed between n = 10 and n = 30.

[0004] The hydrogen and carbon monoxide feedstocks are usually synthesis gas.

[0005] During the Fischer-Tropsch reaction, the catalyst gradually deteriorates, reducing its effectiveness and requiring a gradual increase in temperature to maintain acceptable carbon monoxide conversion. This is described in Steynberg et al., "Fischer-Tropsch catalyst deactivation in commercial microchannel reactor operation", Catalysis Today 299 (2018), pp10-13.

[0006] It is possible to periodically regenerate the catalyst during a certain time period, and the regeneration of the catalyst can be carried out in situ, for example, by subjecting the catalyst to a dewaxing, oxidation, and reduction process. However, during the life of the catalyst, there comes a point when the accumulation of irreparable harmful substances such as sulfur and other irreparable deactivation mechanisms such as sintering render the catalyst ineffective. At this point, the catalyst must be removed from the reactor and replaced with a new catalyst.

[0007] A number of different reactor types for Fischer-Tropsch synthesis are known, including fixed-bed reactors, slurry bubble-column reactors (SBCRs), and microchannel reactors (Rytter et al., "Deactivation and Regeneration of Commercial Type Fischer-Tropsch Co-Catalysts - A Mini-Review", Catalysts 2015, 5, pp478-499 at pp482-483).

[0008] Microchannel reactors are disclosed in the applicant's WO2016201218, which is incorporated by reference, and similarly in LeViness et al., "Velocys Fischer-Tropsch Synthesis Technology - New Advances on State-of-the-Art", Top Catal 2014 57, pp518-525. Such reactors have the particular advantage that very effective heat removal is possible because of the high ratio of heat exchange surface area to microchannel (and thus catalyst) volume.

[0009] However, microchannel reactors present special challenges when it is necessary to discharge the catalyst. This is particularly true for spent catalysts that may have deteriorated within the microchannels after thousands of hours of plant operation.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Documents

[0011]

Non-Patent Document 1

Non-Patent Document 2

[0012] The present invention relates, without limitation, in particular to the removal of spent catalyst from a microchannel reactor. A microchannel reactor typically includes a process layer including a microchannel architecture, the microchannel architecture being, for example, corrugated ridges located within the process layer, and effectively dividing the process layer into a linear array of process channels (process microchannels). The microchannel architecture is typically thinner than the pressure boundary (and may have a different material than the pressure boundary) and may be more easily damaged under harsh physical conditions such as the need to discharge spent catalyst from the microchannels. a plurality of Since the cross-section of the microchannels of such reactors is relatively small, it has been found to be difficult to remove spent catalyst from the microchannels of those reactors. In attempts to remove the spent catalyst by mechanical means (such as hammering) or using steam or high-pressure hot water, catalyst recovery is insufficient, typically less than 50% of the original catalyst charge, as described in the applicant's US Patent Application Publication No. 2009252658. a plurality of the process layer a plurality of effectively divides into a linear array of process channels (process microchannels). The microchannel architecture is typically thinner than the pressure boundary (and may have a different material than the pressure boundary) and may be more easily damaged under harsh physical conditions such as the need to discharge spent catalyst from the microchannels.

[0013] Since the cross-section of the microchannels of such reactors is relatively small, it has been found to be difficult to remove spent catalyst from the microchannels of those reactors. In attempts to remove the spent catalyst by mechanical means (such as hammering) or using steam or high-pressure hot water, catalyst recovery is insufficient, typically less than 50% of the original catalyst charge, as described in the applicant's US Patent Application Publication No. 2009252658.

[0014] Also, it is known from US Patent Application Publication No. 2009 / 252658 that spent catalyst is removed from the microchannels of a Fischer-Tropsch reactor by placing a head for generating ultrasonic waves under sonic contact with the microchannels and applying ultrasonic energy to the microchannels. However, this method also has certain practical disadvantages. In particular, it has been found that existing ultrasonic equipment and techniques can only remove spent catalyst from the microchannels very slowly and / or incompletely.

Means for Solving the Problems

[0015] The present invention is a process for removing particulate catalyst from a packed catalyst bed within a process channel of a microchannel reactor, a plurality of process channel comprising one linear array of (linear array) hermetically sealing the distal end of the in the array a plurality of to form a blocked process channel, a plurality of introducing a high-speed gas flow into the open proximal end of the process channel, the velocity of the gas flow being sufficient to raise the pressure in at least a portion of the blocked process channel to at least about 34,473 Pa gauge (about 5 psig), introducing a high-speed gas flow, thereby creating a pressure gradient effective to drive particulate catalyst out of the catalyst bed and into any void space within the catalyst bed and / or adjacent to the catalyst bed in the blocked process channel, and providing a process comprising causing.

[0016] In another aspect, the present invention is a process for removing particulate catalyst from a process channel of a microchannel reactor, a plurality of hermetically sealing the distal end of a linear array of process channels, the in the array a plurality ofForming a blocked process channel, directing a high-speed gas flow to the open proximal end of the process channel, such that the velocity of the gas flow is sufficient to raise the pressure in at least a portion of the blocked process channel to at least about 34,473 Pa gauge (about 5 psig), directing the high-speed gas flow, and i. then removing the gas flow such that the accompanying release of pressure from the blocked process channel is effective to expel particulate catalyst from the process channel, and / or ii. creating, in the channel where the catalyst has been partially discharged, a pressure differential effective to expel particulate catalyst from the non-discharged channel portion to the discharged channel portion between the non-discharged channel portion and the discharged channel portion by the gas flow A process is provided that includes.

[0017] a plurality of The means provided for directing a high-speed gas flow to the open proximal end of the process channel may be referred to for convenience as an "air knife", but is a term that is not to be construed as limiting in any way.

[0018] The air knife can be one at either end of the process channel arrangement and can be moved end from one end end to the other. The "proximal end" of the process channel is the end at which the "air knife" is deployed (where the high-speed gas flow is directed), and the "distal end" is the end that is sealed by the hermetic seal. In the definitional sense, these ends are reversed if the "air knife" is re- arrangement positioned from one end of the process channel to the other.

[0019] Most appropriately, step i) can be initially deployed when the process channel is not fully or at least substantially emptied, whereas step ii) is then appropriately deployed such that the particulate catalyst is driven into the emptied channel portions that are in a free form for subsequent removal from the process channel. Step ii) is considered effective for driving the particulate catalyst out of the partially emptied process channel because the application of gas flow to the channel causes the pressure in the non-emptied portion of the channel to rise above the pressure in the (downstream, substantially empty) emptied channel portion. This pressure difference drives the packed catalyst in the non-emptied channel portion into the (downstream, substantially empty) emptied channel portion in a free form, and the catalyst can then be easily removed from this emptied channel portion.

[0020] In the process of the present invention, the non-emptied process channel can be partially emptied by means including step i), and then further emptied by means including step ii). In this case, the process can include, in step ii), hermetically sealing the opposite end of the process channel array from that sealed in step i), and introducing a high-speed gas flow into the process channel at the end opposite to that in step i).

[0021] In some aspects of the present invention, the velocity of the gas flow is sufficient to raise the pressure in at least a portion of the blocked process channel to about 34,473 to about 137,895 Pa gauge (about 5 to about 20 psig), preferably about 55,158 to about 103,421 Pa gauge (about 8 to about 15 psig), and can be, for example, at least about 68,947 Pa gauge (about 10 psig). The pressure is not uniform in the process channel unless the process channel is at least substantially completely emptied of the catalyst.

[0022] The relative rate at which pressure is increased (and / or subsequently released) in a blocked process channel, such as between a packed catalyst bed and any empty space adjacent to the catalyst bed, can also be an important factor in the successful expulsion of spent catalyst from the channel. Preferably, the pressure in the blocked process channel is increased in the process of the present invention by at least about 68.947 Pa (about 0.01 psi) per ms, more preferably in the range of about 344.73 to about 3,447.3 Pa (about 0.05 to about 0.5 psi) per ms. As in step i) described above, when the gas flow is removed, the pressure in any empty portion of the process channel can drop similarly rapidly, for example, by at least about 68.947 Pa (about 0.01 psi) per ms, more preferably in the range of about 344.73 to about 3,447.3 Pa (about 0.05 to about 0.5 psi) per ms, creating a pressure differential between the slow depressurization portion of the process channel (in the catalyst bed) and the rapid depressurization portion of the process channel (in any empty space adjacent to the catalyst bed), facilitating the expulsion of catalyst particles. As in step ii) described above, when a gas flow is introduced into the channel, causing the pressure in the unexhausted portion of the channel to rise above the pressure in the (downstream, substantially empty) exhausted channel portion, this pressure differential can gradually occur due to the pressure increase in the catalyst bed before any accompanying pressure increase in the empty space adjacent to the end of the catalyst bed downstream from the application of the gas flow.

[0023] The mechanism for expelling spent catalyst is thought to be related at least in part to the intrinsic resistance to the flow of air through the densely packed particles. When a high pressure is achieved within the process channel, removal of the high-speed gas source makes it easier for the pressurized gas within the process channel to exit the channel. The intrinsic flow resistance of the catalyst bed generates a pressure gradient across the catalyst particles, thereby applying a force to the particles in the direction of gas escape, and as a result, the catalyst is expelled.

[0024] In step i), when high-pressure gas penetrates into the filling component, it tends to escape from that component (towards the proximal end) as soon as the pressurized gas source is removed. The high-pressure gas tries to escape from the densely packed particulate component at a higher speed than can be considered by the natural escape path through the tightly filled component, and due to this escape tendency associated with the ventilation resistance of the densely packed particulate component, catalyst expulsion occurs. This can be most easily understood by considering a partially discharged process channel where the catalyst particles remain only at the undischarged distal end. When a gas flow is applied to the partially discharged process channel, the pressure rises throughout the channel, including through the undischarged portion of the channel. When the gas flow is removed, the pressure is immediately released from the discharged proximal end of the channel, and subsequent escape of gas from the undischarged distal end causes expulsion as described above.

[0025] The same principle may apply to step ii), but there is a difference in that it may not be necessary to remove the gas flow to cause expulsion. When the channel is partially discharged by step i) (or by some other means), it results in a channel where the catalyst is densely packed at one of the two ends of the channel while the other end is substantially empty (discharged). By hermetically sealing the substantially empty end and applying a gas flow to the filled end, the pressure rises in the filled catalyst compared to the downstream empty channel portion. Due to this pressure difference, the filled catalyst in the undischarged channel portion is expelled in a free form into the (downstream, substantially empty) discharged channel portion, and the filled catalyst can then be easily removed from this discharged channel portion.

[0026] In many cases, a microchannel reactor includes a fragile architecture within the process channel, for example, a corrugated structure that houses particulate catalysts. In this case, to prevent or minimize damage to the process channel architecture, the process of the present invention is such that the spacer member is a plurality of the opening at the proximal end of the linear array of process channels toPositioning a spacer member adjacent to an opening in a state having at least one aperture or void that overlaps, and guiding a high-speed gas flow through the at least one aperture or void into a process channel can be included.

[0027] A microchannel reactor typically a plurality of process channel comprising one linear array of (linear array) forming one includes a microchannel architecture.

[0028] Typically, the particulate catalyst removed in the process of the present invention is a used catalyst.

[0029] Preferably, the reactor a plurality of of the process channel a plurality of includes a layer. When a fragile microchannel architecture is included within the process channel and thus it is desirable to have a spacer member, preferably in that case a plurality of each layer of the process channel is provided with the spacer member extending across the width of the layer. All of these features facilitate rapid and effective catalyst removal.

[0030] Preferably, the gas flow a plurality of across the openings of successive layers of the process channel a plurality of is moved. This feature facilitates rapid and effective catalyst removal.

[0031] Preferably, the gas flow is generated by an elongated slot opening. The slot opening a plurality of is elongated in the direction of the linear array of the process channel one layer of a plurality of process channels and can extend across two or more, preferably ten or more, more preferably twenty or more, and most preferably all of the process channel openings. This feature equalizes the pressure within the process channel and thus the forces acting on the walls of the process channel, protecting those walls from damage by the gas flow.

[0032] The lateral dimension of the slot opening, if present, can be smaller than the corresponding lateral dimension of the aperture or void of the spacer member. This feature further enhances the protection of the process-channel walls.

[0033] In certain aspects of the invention, the spacer member provides an important technical protection effect. In the absence of the spacer member, the high-speed gas flow directed directly into the process channels tends to damage some micro-channel architecture of those channels. Thus, for example, if the micro-channel architecture includes a corrugated insert or corrugations as described in the applicant's WO2008030467, which is incorporated herein by reference, they are likely to be damaged if the spacer member used in the process of the present invention is omitted.

[0034] a plurality of process channel comprising one The linear array one forms a process layer. a plurality of The process layer typically has a certain length, a certain height and a certain width, and a rectangular configuration. Typical lengths are from about 100 mm to about 1000 mm, or from about 200 mm to about 600 mm. Typical heights are from about 3 mm to about 10 mm, or from about 5 mm to about 7 mm. Typical widths are from about 50 mm to about 800 mm, or from about 100 mm to about 300 mm. The micro-channel architecture within the process layer typically has a generally width of 0.5 to 2 mm or 0.75 to 1.5 mm, and a length and height generally the same as the process layer a plurality of process channel ( a plurality of process micro-channel) one forms a linear array. Channels having a width of 2 mm or less are generally considered micro-process channels, i.e., micro-channels, and have a particularly high surface area, i.e., a volume ratio that conveniently serves heat exchange with the reactor during production and facilitates process control and selectivity.

[0035] Preferably, the velocity of the gas flow entering the open proximal end of the process channel, or the aperture or void of the spacer member, is at least about 250 m / s, preferably at least about 300 m / s, most preferably at least about 330 m / s, and may be supersonic. These values have been found to result in a rapid and efficient increase in pressure within those channels for effective and rapid catalyst removal from the process channels when the pressure is released. On the other hand, the presence of the spacer member in certain embodiments of the present invention prevents damage to the microchannel architecture of the process channels.

[0036] The distal end of the process channel is closed. Thereby, when the gas flow enters the process channels at the proximal end of the process channels, the pressure within the process channels increases. Typically, the pressure within the process channels prior to operation of the process of the present invention is the ambient pressure, i.e., atmospheric pressure. The pressure within the process channels typically rises from the ambient pressure by more than 34,473.5 Pa gauge (5 psig), preferably up to or more than 137,895 Pa gauge (20 psig) upon application of the gas flow.

[0037] The distal end may optionally be sealed by any suitable means, such as a durable aluminum adhesive tape or other sealing means.

[0038] Preferably, the gas flow is air, but any other suitable, preferably inert gas may be used.

[0039] a plurality of The process channel openings are arranged in a linear array (linear) Preferably, the gas flow is generated by a nozzle having an elongated opening parallel to the linear array and attached to a carriage for lateral linear movement, and the carriage is supported by a reactor. This feature enables a relatively small device that can be easily attached to and detached from the reactor.

[0040] According to the present invention, a particulate catalyst is contained a plurality of Also provided is a microchannel reactor comprising a linear array of process channels, the linear array being provided at its distal end with means for hermetically sealing the process channels and at its proximal end having an opening with a spacer member having at least one aperture or void overlapping the opening, and means for movably mounting a nozzle for directing a high velocity gas flow through the at least one aperture or void and into the process channels.

[0041] It is also contemplated within the scope of the present invention that the simultaneous use of multiple high velocity gas flow nozzles may be used, whereby the nozzles may be used together to discharge catalyst from a single core of the reactor and / or may be used to discharge catalyst from multiple cores of the reactor simultaneously.

[0042] The air flow through the nozzle may be pulsed or continuous.

[0043] Further preferred features are defined in the dependent claims.

[0044] 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 description of the drawings]

[0045]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 7

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Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0046] Details of one suitable microchannel Fischer-Tropsch reactor in which the catalyst can be removed by the process according to the present invention are shown below with reference to FIGS. 1-3.

[0047] Referring to FIG. 1, the microchannel reactor 200 includes a storage container 210 that stores or houses three microchannel reactor cores 220. In other embodiments, the storage container 210 can be used to store or house from 1 to about 16 microchannel reactor cores, or from 1 to about 8 microchannel reactor cores, or from 1 to about 4 microchannel reactor cores. The storage container 210 can be a pressurizable container. The storage container 210 includes an inlet and an outlet 245 that allow the inflow and outflow of reactants to and from the microchannel reactor core 220. A heat exchange fluid is supplied to the microchannel reactor core through the inlet 230 and recovered from an outlet similarly disposed on the opposite side of the reactor.

[0048] The inlet 245 can be connected to a header or manifold (not shown) provided to flow reactants through the process microchannels in each of the microchannel reactor cores. The inlet 230 can be connected to a header or manifold (not shown) provided to flow a heat exchange fluid, such as saturated water, through the heat exchange channels in each of the microchannel reactor cores. One of the outlets 245 is connected to a manifold or footer (not shown) provided to flow products from the process microchannels in each of the microchannel reactor cores. One of the heat exchange fluid outlets 230 can be connected to a manifold or footer (not shown) provided to flow the heat exchange fluid from the heat exchange channels in each of the microchannel reactor cores.

[0049] The containment vessel 210 can be constructed using any suitable material sufficient to withstand the operating pressures that may develop within the microchannel reactor core. For example, the shell 240 and reinforcing ribs 242 of the containment vessel 210 can be constructed from cast steel or stainless steel. Flanges, couplings, and pipes can be constructed from, for example, stainless steel. The containment vessel 210 can have, for example, a diameter of 1.5 m. The axial length of the containment vessel 210 can be, for example, 1.5 m for each reactor core positioned within the containment vessel, i.e., 5.5 m for a 4-core reactor.

[0050] Referring to FIG. 2, the microchannel reactor core 220 houses an alternating stack of a layered unit 300 of process microchannels 310 and a layered unit 350 of heat exchange channels 355.

[0051] The microchannel reactor core 220 can optionally include a plurality of plates within a stack defining a plurality of process layers and a plurality of heat exchange layers, each plate having a periphery, and the periphery of each plate or shim being welded to the periphery of the next adjacent plate to provide an outer seal for the stack. This is shown in U.S. Patent Application Publication No. 20120095268, which is incorporated herein by reference.

[0052] The microchannel reactor core 220 may optionally have the form of a solid block having six faces that are square or rectangular. 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 parallel or solid block or a prism. The microchannel reactor core 220 can have, for example, a length, width, and height of 1 m.

[0053] The Fischer-Tropsch catalyst 500 is located within the process microchannel 310, and this catalyst can be in any suitable form, such as a fixed bed of particulate solids.

[0054] FIG. 3 shows a microchannel architecture in the form of a corrugated sheet 315 sandwiched between a plate 316 and a plate 317, with process microchannels 310 defined on both sides of the sheet 315. For clarity, the Fischer-Tropsch catalyst 500 is shown in only one of these microchannels, but in reality, each microchannel 310 is filled with the Fischer-Tropsch catalyst 500. Further details of this construction are disclosed in WO2008030467, which is incorporated herein by reference.

[0055] The Fischer-Tropsch catalyst 500 may optionally contain cobalt and a support. The catalyst may optionally have 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 wt% cobalt.

[0056] The Fischer-Tropsch catalyst 500 may optionally further contain a noble metal. The noble metal can be, for example, one or more of Pd, Pt, Rh, Ru, Re, Ir, Au, Ag, and Os. The noble metal can be one or more of Pt, Ru, and Re. The noble metal can be Ru. Alternatively or additionally, the noble metal can be Pt. The Fischer-Tropsch catalyst optionally contains, in total, about 0.01 to about 30% (based on the total weight of all noble metals present as a total weight percentage of the catalyst precursor or the activated catalyst), or optionally in total about 0.05 to about 20% of the noble metal, or optionally in total about 0.1 to about 5% of the noble metal, or optionally in total about 0.2% of the noble metal.

[0057] The Fischer-Tropsch catalyst 500 may optionally contain one or more other metal-based components as promoters or modifiers. These metal-based components may also optionally be present as carbides, oxides, or elemental metals in the catalyst precursor and / or the activated catalyst. Metals suitable for one or more other metal-based components can be, for example, one or more of Zr, Ti, V, Cr, Mn, Ni, Cu, Zn, Nb, Mo, Tc, Cd, Hf, Ta, W, Re, Hg, Tl, and the 4f-block lanthanides. Suitable 4f-block lanthanides can be La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and / or Lu. The metal of one or more other metal-based components can be, for example, one or more of Zn, Cu, Mn, Mo, and W. The metal of one or more other metal-based components can be, for example, one or more of Re and Pt. The catalyst optionally contains, in total, about 0.01 to about 10% (based on the total weight of all other metals present as a total weight percentage of the catalyst precursor or the activated catalyst) of other metals, or optionally in total about 0.1 to about 5% of other metals, or optionally in total about 3% of other metals.

[0058] The Fischer-Tropsch catalyst 500 may optionally be derived from a catalyst precursor, which can be activated to produce a Fischer-Tropsch catalyst, for example, by heating the catalyst precursor in hydrogen and / or hydrocarbon gas (e.g., methane), or in hydrogen and / or hydrocarbon gas diluted with another gas such as nitrogen and / or methane, to convert at least a portion of the carbide or oxide to elemental metal. In the active catalyst, cobalt may optionally be at least partially in the form of its carbide or oxide.

[0059] The Fischer-Tropsch catalyst 500 may optionally include a catalyst support. The support may optionally include a refractory metal oxide, carbide, carbon, nitride, or a mixture of two or more thereof. The support may optionally include alumina, zirconia, silica, titania, or a mixture of two or more thereof. The surface of the support may optionally be modified by treating the surface with silica, titania, zirconia, magnesia, chromia, alumina, or a mixture of two or more thereof. The materials used for the support and the materials used to modify the support may be different. The support may optionally include silica, and the surface of the silica may optionally be treated with a refractory solid oxide that is an oxide, such as titania. The materials used to modify the support can be used to increase the stability of the supported catalyst (e.g., by reducing deactivation).

[0060] The catalyst support may optionally contain up to about 30 wt% of an oxide (e.g., silica, titania, magnesia, chromia, alumina, zirconia, or a mixture of two or more thereof) used to modify the surface of the support, or, for example, 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%. 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 wishing to be bound by theory, the surface treatment shown herein is believed to help protect Co from sintering during the operation of the Fischer-Tropsch process.

[0061] The deactivation rate of the Fischer-Tropsch catalyst 500 may optionally be such that it can be used in Fischer-Tropsch synthesis for more than about 300 hours, or more than about 3000 hours, or more than about 12000 hours, or more than about 15000 hours, before any catalyst recovery or regeneration is required.

[0062] The Fischer-Tropsch catalyst 500 may optionally be used for an extended period (e.g., more than 300 hours) at a deactivation rate of less than about 1.4% per day, or less than about 1.2% per day, or between about 0.1% and about 1% per day, or between about 0.03% and about 0.15% per day.

[0063] The Fischer-Tropsch catalyst 500 can have any size and geometric configuration that fits within the process microchannel 310. The catalyst may optionally be in the form of a particulate solid (e.g., pellet, powder, fiber, etc.) having a median particle size of about 1 to about 1000 μm (microns), or about 10 to about 750 μm, or about 25 to about 500 μm. The median particle size may optionally be in the range of 50 to about 500 μm, or about 100 to about 500 μm, or about 125 to about 400 μm, or about 170 to about 300 μm. In one embodiment, the catalyst can be in the form of a fixed bed of particulate solid.

[0064] The microchannel reactor core 220 can include, for example, six layers 350 of heat exchange channels 355.

[0065] Referring to FIG. 3, each process microchannel 310 can have, for example, a height (h) of 6.35 mm and a width (w) of 1 mm. The length of each process microchannel can be, for example, 610 mm.

[0066] a plurality of Each unit or layer 300 of the process microchannels 310 can have, for example, hundreds of process microchannels 310. The process microchannels 310 can have a cross-section with any shape, such as square, rectangular, circular, semi-circular, etc. The inner height of each process microchannel 310 can be considered to be the smaller of the inner dimensions perpendicular to the flow direction of the reactants and products passing through the process microchannel.

[0067] Each unit or layer 350 of the heat exchange channels 355 can have, for example, hundreds of heat exchange channels. The heat exchange channels 355 can be microchannels or can have larger dimensions that are classified as non-microchannels.

[0068] The microchannel reactor core 220 can be made from any material that provides sufficient strength, dimensional stability, and heat transfer characteristics to enable the operation of the desired process. These materials can include, for example, aluminum, titanium, nickel, platinum, rhodium, copper, chromium, alloys of any of the foregoing metals, brass, steel (e.g., stainless steel), quartz, silicon, or combinations of two or more of them. Each microchannel reactor can optionally be constructed from stainless steel, and one or more corrugated copper or aluminum can be used to form the channels.

[0069] The microchannel reactor core 220 may optionally be fabricated using known techniques including, for example, wire electrical discharge machining, conventional machining, laser cutting, photochemical machining, electrochemical machining, molding, water jet, stamping, etching (e.g., chemical etching, photochemical etching or plasma etching) and combinations thereof.

[0070] The microchannel reactor core 220 may optionally be constructed by forming a plate with some portions removed that allows for the passage of flow. The stack of plates can be assembled, for example, by diffusion bonding, laser welding, diffusion brazing, conventional welding, additive manufacturing methods and similar methods to form an integrated device. The microchannel reactor can be assembled, for example, using a combination of plates and partial plates or strips. In this method, channels or void regions can be formed by assembling the strips or partial plates, reducing the amount of material required.

[0071] The microchannel reactor core 220 may optionally include a plurality of plates in a stack defining a plurality of process layers and a plurality of heat exchange layers, each plate having a periphery, and the periphery of each plate or shim being welded to the periphery of the next adjacent plate to provide an outer peripheral seal for the stack. This is shown in U.S. Patent Application Publication No. 20120095268, which is incorporated herein by reference.

[0072] The storage container 210 may optionally include a control mechanism for maintaining the pressure within the storage container at a level at least as high as the internal pressure within the microchannel reactor core 220. The internal pressure within the storage container 210 may optionally be within the range of from about 10 to about 60 atmospheres, or from about 15 to about 30 atmospheres, during operation of the syngas conversion process (e.g., Fischer-Tropsch process). The control mechanism for maintaining the pressure within the storage container may optionally include a check valve and / or a pressure regulator. The check valve or regulator may optionally be programmed to function at any internal pressure desired for the storage container. Any or all of these may be used in combination with a system of pipes, valves, controllers, etc. to ensure that the pressure within the storage container 210 is maintained at a level at least as high as the internal pressure within the microchannel reactor core 220. This is done in part to protect the welds used to form the microchannel core 220. Without a corresponding decrease in the internal pressure within the microchannel reactor core 220, a significant drop in the pressure within the storage container 210 can result in a large-loss breakage of the welds within the microchannel reactor core 220. The control mechanism may optionally be designed to allow for the diversion of one or more process gases to the storage container in the event that the pressure exerted by the stored gas is reduced.

[0073] Here, an apparatus and process for removing spent Fischer-Tropsch catalyst from the process microchannels 310 of the reactor will be described with reference to FIGS. 4-10.

[0074] Referring to FIG. 4, an air knife 1 is shown, which is connected to a source of compressed air (not shown) and has a slit having a width generally equal to the width of the process microchannel unit or layer 300 that defines a high-speed air jet 4.

[0075] An elongated protective member or spacer 2 having two parallel slots 3 is shown aligned with an air knife 1 such that an air jet 4 passes through one of their parallel slots. The length of the slit of the air knife is equal to or slightly longer than the length of the slot 3, in either case corresponding to the full width W (Figure 2) of the reactor core 220. In use, the protective member or spacer 2 is fixed relative to a row of openings of the process microchannel 310, and the air knife 1 is traversed in direction A such that the air jet 4 passes successively through each slot 3. As best seen in Figure 7, an array of such protective members 2 is provided such that the air jet 4 enters a successive row of process microchannels 310 from there through successive slots of successive protective members. a plurality of fixed relative to a row of openings of the process microchannel 310, and the air knife 1 is traversed in direction A such that the air jet 4 passes successively through each slot 3. As best seen in Figure 7, an array of such protective members 2 is provided such that the air jet 4 enters a successive row of process microchannels 310 from there through successive slots of successive protective members. a plurality of rows.

[0076] As best seen in Figure 6, the protective member or spacer 2 is positioned under the coolant panel 350, with the slots of the protective member or spacer 2 aligned with the process microchannels 310. The coolant panel 350 includes coolant channels (not shown). The length of the spacer strip under the coolant panel extends across all installed reactor cores that determine the width of the reactor. The depth (vertical direction in Figure 6) of the protective member is suitably from 10 mm to 50 mm, for example 25 mm. Alignment of the slots with the process microchannels also results in alignment of the spacer strip with the corrugated-coolant panel contacts, which serves to protect those contacts from all forces of the gas flow conducted through the body of the slots during use. The depth of the protective member can also be suitably selected with respect to this most vulnerable location within the process channel.

[0077] Referring to FIG. 6A, in a modified example of the protection member, the slot 3 can be omitted, and instead of each protection member 2 shown in FIG. 5, three narrower and spaced-apart protection members 2A, 2B, and 2C individually positioned across each coolant layer 350 can be used, through the gaps g between these protection members, the air jet 4 is guided.

[0078] As shown in FIG. 5, the air knife 1 crosses a continuous a plurality of row of the process channel 310 and extrudes the catalyst 500. The width W of the micro-process channel is suitably 1 mm, and the inner height h is suitably 6.35 mm.

[0079] When the air knife 1 is aligned with any given protection member, the distance from the slit of the air knife to the protection member 2 is as short as possible within practical tolerances, typically between 0.5 and 19 mm. The length of the slit of the air knife is equal to or slightly longer than the width of the process layer for all cores corresponding to the full width of the reactor.

[0080] The dimensions of the slit of the air knife and the upstream air pressure are set such that the air flows through the slit at near sonic or approximately sonic or even supersonic speeds. The slit width is typically in the range of 150 - 180 mm, but can be made up to or slightly wider than the width of the process layer.

[0081] During use, the air knife 1 is moved from one end of the reactor to the other end at a speed of 0.01 - 0.2 ms -1 After crossing the entire length under the reactor core 220 or a selected portion of the reactor core, the air knife returns to the other end of the reactor core 220 or the starting position at the reactor core portion at the same speed. This movement is repeated using a continuous flow of air through the slit of the air knife until the flow of catalyst from the channel stops. Then, the reactor is inspected to determine whether complete catalyst discharge has been achieved.

[0082] For any partially unexhausted channel, the process of the invention in step ii) can then be carried out. Open the sealed end of the process channel, and then hermetically seal the opposite ends of the linear array of process channels to form a blocked process channel in the array, and the spacer member a plurality of Position the spacer member adjacent to the opening with at least one aperture or void overlapping the opening of the (then) open end of the linear array of process channels, and direct a high-speed gas flow through at least one aperture or void into the process channel, wherein the velocity of the gas flow is sufficient to raise the pressure in the blocked process channel to at least about 34,473 Pa gauge (about 5 psig) in at least a portion of the blocked process channel. By causing the associated increase in pressure in the unexhausted catalyst, the packed catalyst in the unexhausted channel portion is displaced in a free form into the (downstream, substantially empty) exhausted channel portion. Preferably, the pressure difference between the pressure in the packed catalyst bed and the pressure in the adjacent unfilled portion of the process microchannel is at least about 6,894.7 Pa gauge (about 1 psig), preferably at least about 13,789.5 Pa gauge (about 2 psig).

[0083] As an alternative to step ii), the process of the invention in step i) can be applied from the opposite side of the process channel, i.e., open the sealed end of the process channel and then a plurality of Hermetically seal the opposite ends of the linear array of process channels to form a blocked process channel in the array, and the spacer member a plurality ofPositioning a spacer member adjacent to the opening in a state having at least one aperture or void overlapping the opening of the open end of the linear array of process channels (at that time), and guiding a high-speed gas flow into the process channels through at least one aperture or void, wherein the velocity of the gas flow is sufficient to raise the pressure in the blocked process channels to at least about 34,473 Pa gauge (about 5 psig), guiding into the process channels, and then removing the gas flow such that the accompanying release of pressure from the blocked process channels is effective to expel particulate catalyst from the process channels, can be repeated.

[0084] If there are a few remaining channels containing some catalyst, non-automated methods such as solvent washing and / or mild physical excitation can be applied to those channels.

[0085] As best seen in FIG. 8, the air knife 1 is carried by the slide 6, and the slide is attached to four support arms 7. The tips of these support arms have fixtures (e.g., machine screws) for fixing the resulting assembly 5 to the underside of the reactor core 220. The protective member 2 is not shown in this figure.

[0086] During operation, when the air knife 1 is moved along the length of the reactor to sequentially guide the air flow into the voids between the spacer strips, air continuously passes upward through the slit of the air knife. The slit of the air knife extends across all the process microchannels 310 at 315.

[0087] When the air flow crosses the depth of the protection member 2 (Figs. 5 and 6) and reaches the process microchannel 310, an air blast impinges on the catalyst 500 within each reactor channel, increasing the pressure within the channel (whose distal end is blocked) to above 34,473 Pa gauge (5 psig), or up to 68,947 Pa gauge (10 psig) or above 68,947 Pa gauge (10 psig). As the air knife passes across the channel, the pressure is released and at least a portion of the catalyst within the channel is pushed out into the released flow. The air knife continues to move back and forth along the length of the reactor at a preset speed and is propelled by an automated air knife movement system until no more catalyst is removed from the reactor.

[0088] The extruded catalyst can be collected within a vacuumed chamber (not shown) installed beneath the reactor core 200.

[0089] As best seen in Figs. 2, 3, and 5, each row of the process microchannel 310 is defined by a corrugated sheet 315 positioned between the facing walls of adjacent cooling panels 350. The corrugated sheet is made of a heat-conductive material, typically copper, and is shaped to form a plurality of vertical reactor channels 310. The walls of the coolant panels are typically parallel stainless steel plates. The parallel plates are usually internally cooled by a coolant. During operation, the reactor channels are filled with a particulate catalyst material.

[0090] The spent catalyst 500 can be replaced with fresh catalyst after being removed.

[0091] The described catalyst removal method can be applied to chemical reactors other than Fischer-Tropsch reactors to remove spent catalyst from the chemical reactor.

[0092] The variations shown above can be combined in any combination.

Claims

1. A process for removing catalyst from a packed catalyst bed within a process channel of a microchannel reactor, comprising: hermetically sealing a distal end of one linear array of a plurality of said process channels to form a blocked process channel in said linear array, said one linear array of said plurality of process channels forming one process layer; directing a high-speed gas flow from a proximal end forming an open aperture of each of said plurality of process channels toward said distal end, said gas flow being of a velocity sufficient to raise the pressure in at least a portion of said blocked process channel to at least 34,473 Pa gauge (5 psig); thereby creating a pressure gradient effective to drive particulate catalyst out of said catalyst bed and into any void space within said catalyst bed and / or adjacent said catalyst bed in said blocked process channel; and wherein said plurality of process channels of said one linear array are configured such that the apertures at the proximal ends of said plurality of process channels are arranged linearly and continuously.

2. A process for removing particulate catalyst from a process channel of a microchannel reactor, comprising: hermetically sealing a distal end of one linear array of a plurality of said process channels to form a blocked process channel in said linear array, said one linear array of said plurality of process channels forming one process layer; directing a high-speed gas flow from a proximal end forming an open aperture of each of said plurality of process channels toward said distal end, said gas flow being of a velocity sufficient to raise the pressure in at least a portion of said blocked process channel to at least 34,473 Pa gauge (5 psig); and i. then removing said gas flow such that the attendant release of pressure from said blocked process channel is effective to drive particulate catalyst out of said process channel; and / or ii. In the process channel from which the catalyst has been partially discharged, creating, by means of the gas flow, a pressure difference effective to drive particulate catalyst from the non-discharged portion of the process channel to the discharged portion of the process channel between the non-discharged portion of the process channel and the discharged portion of the process channel comprising the process, wherein the plurality of process channels of the one linear array are configured such that the openings of the proximal ends of the plurality of process channels are arranged linearly and continuously **Claim 3** i. Removing the gas flow and / or ii. In the process channel from which the catalyst has been partially discharged, creating, by means of the gas flow, a pressure difference effective to drive particulate catalyst from the non-discharged portion of the process channel to the discharged portion of the process channel between the non-discharged portion of the process channel and the discharged portion of the process channel The process according to claim 1, comprising **Claim 4** The process according to claim 2, wherein in step ii), the particulate catalyst is driven into the discharged portion of the process channel in a free form for subsequent removal from the process channel **Claim 5** The process according to claim 2, wherein the non-discharged process channel is partially discharged by means including step i) and then further discharged by means including step ii) **Claim 6** In step ii) hermetically sealing the end of the linear array of process channels opposite to the one sealed in step i); and directing the high-speed gas flow to the plurality of process channels at the end opposite to the one in step i) The process according to claim 5, comprising **Claim 7** The process according to claim 2, wherein the gas flow is moved across the openings of the plurality of successive process layers arranged continuously in a direction perpendicular to the direction in which the openings of the proximal ends of the plurality of process channels are arranged linearly and continuously **Claim 8** The process according to claim 2, wherein the reactor comprises a plurality of the process layers arranged continuously in a direction perpendicular to the direction in which the openings at the proximal ends of the plurality of process channels are arranged linearly in succession.

9. The process according to claim 8, wherein each of the plurality of process layers is provided with a spacer member extending across the width of the process layer in the direction in which the openings at the proximal ends are arranged linearly in succession.

10. positioning the spacer member adjacent to the openings at the proximal ends with the spacer member having at least one aperture or void overlapping the openings at the proximal ends of the linear array of the plurality of process channels; guiding the high-speed gas flow into the plurality of process channels through the at least one aperture or void The process according to claim 2, comprising:

11. The process according to claim 10, wherein the gas flow is generated by an elongated slot opening, and a lateral dimension of the slot opening is smaller than a corresponding lateral dimension of the aperture or void of the spacer member.

12. The process according to claim 10, wherein the aperture or void of the spacer member is elongated in the direction in which the openings at the proximal ends of the plurality of process channels are arranged linearly in succession and extends across two or more of the openings of the plurality of process channels in one process layer.

13. The process according to claim 2, wherein a velocity of the gas flow entering the process channels is at least 250 m / s.

14. The process according to claim 2, wherein the pressure in the process channels rises from ambient pressure to 137,895 Pa gauge (20 psig) or above 137,895 Pa gauge (20 psig) when the gas flow is applied.

15. The process according to claim 2, wherein the gas flow has an elongated opening parallel to the direction in which the openings at the proximal ends of the plurality of process channels are arranged linearly in succession and is generated by a nozzle attached to a carriage for linear movement in a direction perpendicular to the direction, and the carriage is supported by the reactor.

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