Multi-zone filtration device for downflow hydroprocessing reactors.

Abstract

A multi-zone filtration device for a downflow catalytic hydroprocessing reactor is disclosed. The filtration device can be used in the petroleum and chemical processing industries to remove contaminants from mixed gas and liquid feed streams into the reactor catalyst bed during catalytic reactions of hydrocarbon feedstocks in the presence of hydrogen at high temperatures and pressures. The filtration device can be provided for horizontal installation at the top of the reactor, whereby the feed stream liquid passes through a filtration media zone in a radial flow direction. In one zone, the flow is radially outward from the center of the filtration device zone toward the reactor wall. In another zone, the flow is radially inward from the reactor wall toward the center of the filtration device zone. After passing through the filtration device, the liquid flows into the reactor catalyst bed. The benefits include minimizing scale and small / fine particles reaching the catalyst bed below the device, reducing the pressure drop through the reactor even in the event of complete filter fouling, potentially adding catalyst volume due to reduced need to use catalyst grading material, and improved maintenance needs during reactor operation, such as potentially reducing upper bed skimming or filter media replacement, thereby extending reactor run time.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 418,189, filed October 21, 2022, and entitled "MULTI-ZONE FILTRATION DEVICE FOR A DOWN-FLOW HYDROPROCESSING REACTOR," the disclosure of which is incorporated herein by reference in its entirety.

[0002] A multi-zone filtration device for a downflow catalytic hydroprocessing reactor is disclosed. The filtration device can be used in the petroleum and chemical processing industries in catalytic reactions of hydrocarbon feedstocks in the presence of hydrogen at high temperatures and pressures to remove contaminants from mixed gas and liquid feed streams to the reactor catalyst bed. [Background technology]

[0003] In fixed-bed hydroprocessing reactors, gaseous and liquid reactants (e.g., hydrogen and hydrocarbon feedstock) flow downwardly through one or more solid catalyst beds (see, e.g., U.S. Pat. No. 4,597,854 to Penick). As the reactants flow downwardly through the reactor catalyst beds, they contact the catalytic material and react to produce desired products. The reactor feed stream may also contain fouling and contaminants, leading to undesirable deposition, including the formation of organic deposits such as gums.

[0004] Foulants carried in the liquid feed stream can cause fouling in the upper distributor tray and catalyst bed within the reactor, leading to undesirable increased pressure drop that limits reactor performance. Undesirable problems can result, including shorter run times, unplanned downtime, unused catalyst activity, uneven liquid distribution within the catalyst bed, hot spot formation within the catalyst bed, and increased maintenance such as distributor tray cleaning. Solutions to mitigate such problems include feedwater filters, bed grading, and in some cases, installing a filter tray above the upper distributor tray.

[0005] In some cases, grading products have been used in the first catalyst bed for feedwater decontamination. While such solutions generally offer performance benefits, they take valuable reactor volume away from active catalyst volume, thereby reducing run time and / or online performance. The use of a grading bed also does not prevent fouling on the upper distributor tray.

[0006] A feedwater filter may also be installed before the reactor inlet and, in some cases, may operate at a lower temperature than that used for the feed stream entering the reactor. The filtered liquid feed is then mixed with hydrogen and heated in a furnace before flowing into the reactor inlet; additional organic deposits, such as gums, may form after the feedwater filter during this heating step. Therefore, a means of removing sludge and contaminants within the reactor inlet header is desirable to protect the upper distributor tray and catalyst bed. Therefore, there is a continuing need for improvements in downflow reactors, including devices for removing feedstream contaminants. Summary of the Invention

[0007] The present invention is directed to a multi-zone filtration device for a downflow hydroprocessing reactor. The device provides effective removal of contaminants from a liquid feed stream to a catalyst bed within the hydroprocessing reactor. The filtration device provides effective removal of fine and other contaminants while minimizing pressure drop through the device. The device is well suited for retrofit applications and can be used in new reactor designs to achieve efficient feedstream contaminant removal, resulting in less fouling of the reactor catalyst bed and reactor internals and improved reactor operating performance.

[0008] In addition to minimizing the pressure drop through the filtration device during operation while contaminants are being removed, once the filtration media is completely fouled, i.e., filled with removed contaminants, there is no or minimal additional pressure drop through the device.

[0009] Multi-zone filtration devices generally include a first filtration zone and a second filtration zone. The first zone includes a top cover having an inner surface, an outer surface, a top cover outer edge, and a top cover aperture; a liquid-impermeable base plate generally juxtaposed to the top cover, the base plate having an inner surface, an outer surface, a base plate outer edge, a base plate aperture, and a removable base plate aperture cover; a first zone containment barrier; an optional base plate aperture containment barrier; a support structure for the top cover; and filtration media contained within a first zone filtration media volume above the base plate. The top cover and base plate are separated by a distance to define an interior volume of the first zone of the filtration device, such that the interior volume includes a filtration media volume located above and adjacent to the base plate inner surface. The first zone containment barrier retains the filtration media on the base plate and is generally located around the periphery of the base plate and extends from the base plate to the top of the filtration media volume or to the bottom surface of the top cover. The first zone base plate aperture containment barrier, if present, holds the filtration media within the first zone filtration media volume on the base plate and is generally located around the periphery of the base plate aperture and extends from the base plate to the top of the filtration media volume or to the bottom surface of the top cover. The support structure for the first zone top cover is generally located within the interior volume of the filtration device and includes one or more supports for creating and maintaining a separation distance between the top cover and the base plate. The first zone base plate and top cover, the top cover aperture, and the base plate aperture are centered about the same central vertical axis. The top cover and bottom plates have substantially the same areal dimensions, so that feed stream liquid can flow through the top cover and / or through the first zone base plate aperture containment barrier into the first zone of the filtration device. The base plate aperture cover is installed in the downflow reactor and is sized and configured to prevent liquid flow through the first zone base plate aperture during operation.

[0010] The second zone includes a top cover having an inner surface, an outer surface, a top cover outer edge, a top cover aperture, and a removable top cover aperture cover, a liquid-impermeable base plate generally juxtaposed to the top cover, having an inner surface, an outer surface, a base plate outer edge, and a base plate aperture, a base plate aperture containment barrier, a support structure for the top cover, a separator above the filtration media, and filtration media contained within a second-zone filtration media volume above the base plate. The top cover and base plate of the second zone are separated by a distance to define an interior volume of the second zone of the filtration device, such that the interior volume includes a filtration media volume located above and adjacent the base plate inner surface and a flow bypass volume located above the filtration media volume and adjacent the top cover inner surface. The second zone base plate aperture containment barrier retains the filtration media within the second zone filtration media volume on the base plate and is generally located around the periphery of the base plate aperture and extends from the base plate to the top of the filtration media volume or to the bottom surface of the top cover. The support structure for the second zone top cover is generally located within the interior volume of the filtration device and includes one or more supports for creating and maintaining a separation distance between the top cover and the base plate. The separator is located between the filtration media volume and the flow bypass volume. The separator is generally a thin, porous material juxtaposed to both the top cover and the bottom plate. The separator confines the filtration media within the filtration media volume and allows liquid to flow into the filtration media volume. The second zone base plate, top cover, separator, top cover aperture, and base plate aperture are centered about the same central vertical axis as the first zone. The separator generally has substantially the same areal dimensions as the bottom plate. The top cover has an areal dimension smaller than that of the bottom plate such that feed stream liquid and gas can flow into the inlet of the second zone between the outer edge of the top cover of the second zone and the outer edge of the base plate. A top cover aperture cover is installed in the downflow reactor and is sized to prevent the flow of liquid through the top cover aperture during operation thereof.

[0011] Generally, the base plates and top covers of the first and second zones and the separator of the second zone are centered about the same central vertical axis. The top cover and bottom plate of the first zone have substantially the same area dimensions, so that feed stream liquid can flow through the top cover and / or through the base plate aperture containment barrier of the first zone into the first zone of the filtration device. In the second zone, the separator generally has the same area dimensions as the bottom plate of the second zone. The top cover of the second zone generally has a smaller area dimension than the bottom plate, so that feed stream liquid and gas can flow into the filtration device inlet between the outer edge of the top cover and the outer edge of the base plate.

[0012] The present invention relates to a downflow hydroprocessing reactor including a multi-zone filtration device and a process for removing contaminants from a liquid feed stream within such a reactor. The process generally involves passing a feed stream containing liquid and gas into a downflow catalytic hydroprocessing reactor through a filtration device located at the top of the reactor, with the liquid component of the feed stream being passed through a filtration medium contained within a filtration medium volume in a first zone of the filtration device and a filtration medium contained within a filtration medium volume in a second zone of the filtration device. The feed stream liquid passes through the filtration medium contained within the filtration medium volumes in the first and second zones, and the feed stream gas passes through a flow bypass volume in the second zone of the filtration device.

[0013] Brief description of the drawings 1-11 provide representative illustrations of multi-zone filtration devices according to one or more embodiments of the present invention. It should be understood that the scope of the present invention is not limited by these representative illustrations, but rather is defined by the appended claims. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 shows a side view of an embodiment of the first zone of a filtering device of the present invention.

[0015] [Figure 2] FIG. 2 shows a side view of an embodiment of the second zone of a filtering device of the present invention.

[0016] [Figure 3] FIG. 3 shows a side view of an embodiment of the dual-zone filtration device of the present invention installed on top of a reactor, and also shows a side cross-sectional view of the reactor wall and existing distribution tray (also referred to herein as a perforated tray).

[0017] [Figure 4] FIG. 4 shows the same view of the dual-zone filtration device as in FIG. 2, and also shows the flow paths of the feed stream liquid and gas.

[0018] [Figure 5] FIG. 5 shows a three-quarter cutaway view of the lower section of the second zone of the filtration device with the top cover and separator removed (also showing the existing tray below the filtration device).

[0019] [Figure 6] FIG. 6 shows a three-quarter view with one-quarter cut away of the second zone of the filtration device in FIG. 5 with the separator in place.

[0020] [Figure 7] FIG. 7 shows a three-quarter view with one-quarter cut away of the second zone of the filtering device in FIG. 6 with the top cover in place.

[0021] [Figure 8] FIG. 8 shows a three-quarter view of a dual-zone filtration device with the top cover removed, showing an open view of the first zone (circular manway aperture) at the top and the second zone at the bottom of the filtration device.

[0022] [Figure 9] FIG. 9 shows a three-quarter view of a dual-zone filtration device with the top cover installed, showing a view of the top first zone (circular manway aperture) and the bottom second zone of the filtration device.

[0023] [Figure 10] FIG. 10 shows a three-quarter view of a dual-zone filtration device with the top cover removed, showing an open view of the first zone (rectangular manway aperture) at the top and the second zone at the bottom of the filtration device.

[0024] [Figure 11] FIG. 11 shows a three-quarter view of a dual-zone filtration device with the top cover installed, showing a view of the top first zone (rectangular manway aperture) and the bottom second zone of the filtration device. DETAILED DESCRIPTION OF THE INVENTION

[0025] Certain embodiments and advantages are apparent from the detailed description provided herein. However, it should be understood that the detailed description, drawings, and any specific examples, including some preferred embodiments, are intended for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] The present invention is directed to a multi-zone filtration device for a downflow hydroprocessing reactor. The device includes a first filtration zone and a second filtration zone. The first zone includes a top cover having an inner surface, an outer surface, a top cover outer edge, and a top cover aperture; a base plate generally parallel to the top cover, the base plate having an inner surface, an outer surface, a base plate outer edge, a base plate aperture, and a removable base plate aperture cover; a first zone containment barrier; an optional base plate aperture containment barrier; a support structure for the top cover; and a filtration media contained within a filtration media volume of the first zone of the device and on top of the base plate. The second zone includes a top cover having an inner surface, an outer surface, a top cover outer edge, a top cover aperture, and a removable top cover aperture cover, a liquid-impermeable base plate generally parallel to the top cover, having an inner surface, an outer surface, a base plate outer edge, and a base plate aperture, a base plate aperture containment barrier, a support structure for the top cover, a separator above the filtration media, and filtration media contained within a filtration media volume in the second zone above the base plate.

[0027] The first zone top cover and base plate are separated by a distance that defines the first zone interior volume of the filtration device, such that the interior volume includes a filtration media volume located above and adjacent to the inner surface of the base plate. The first zone containment barrier retains the filtration media on the base plate. The containment barrier is generally located around the periphery of the base plate and extends from the base plate to the top of the filtration media volume or to the bottom surface of the top cover, retaining the filtration media within the first zone filtration media volume on the base plate. The first zone base plate aperture containment barrier, if present, also retains the filtration media within the first zone filtration media volume on the base plate. The aperture containment barrier is generally located around the periphery of the base plate aperture and extends from the base plate to the top of the filtration media volume or to the bottom surface of the top cover. The support structure for the first zone top cover is located within the interior volume of the filtration device and includes one or more supports for creating and maintaining the separation distance between the top cover and the base plate. The first zone base plate and top cover, the top cover aperture, and the base plate aperture are centered about the same central vertical axis. The top cover and bottom plate have substantially the same areal dimensions, such that feed stream liquid can flow through the top cover and / or through the first zone base plate aperture containment barrier into the first zone of the filtration device. The base plate aperture cover is installed in the downflow reactor and is sized and configured to prevent liquid flow through the first zone base plate aperture during operation.

[0028] The top cover and base plate of the second zone are separated by a distance that defines an internal volume of the filtration device. The internal volume of the second zone includes a filtration media volume located above and adjacent to the inner surface of the base plate and a flow bypass volume located above the filtration media volume and adjacent to the inner surface of the top cover. A base plate aperture containment barrier retains the filtration media within the filtration media volume of the second zone on the base plate. The base plate aperture containment barrier is typically located around the periphery of the base plate aperture and extends from the base plate to the top of the filtration media volume or to the bottom surface of the top cover. A support structure for the top cover is located within the internal volume of the filtration device and includes one or more supports for creating and maintaining a separation distance between the top cover and the base plate. A separator is disposed between the filtration media volume and the flow bypass volume. The separator is typically a thin, porous material juxtaposed to both the top cover and the bottom plate. The separator confines the filtration media within the filtration media volume and allows liquid to flow into the filtration media volume. The second zone's base plate, top cover, separator, top cover aperture, and base plate aperture are centered about the same central vertical axis as the first zone. The separator generally has substantially the same area dimensions as the bottom plate. The second zone's top cover has smaller area dimensions than the bottom plate, such that feed stream liquid and gas can flow into the second zone inlet between the outer edge of the second zone's top cover and the outer edge of the base plate. The second zone's top cover aperture cover is installed in the downflow reactor and is sized to prevent liquid flow through the top cover aperture during operation.

[0029] The first and second zone containment barriers and aperture containment barriers may generally be liquid-permeable throughout the entire width and height of the barrier. In some embodiments, the containment barrier may be liquid-impermeable (or less liquid-permeable) to allow liquid to be retained within one or both of the first and second zone filtration volumes while being liquid-permeable across a portion of the barrier's width and / or height. The device need not, or necessarily, include an outer perimeter second zone containment barrier located around the perimeter of the base plate extending from the base plate to the top of the filtration media volume or the bottom surface of the top cover. The filtration media need not be contained around the perimeter of the base plate in the second zone through the use of an outer perimeter containment element.

[0030] Generally, the base plate, top cover, and second zone separator are centered about the same central vertical axis. The separator generally has the same area dimensions as the base plate. The second zone top cover also generally has an area dimension smaller than the bottom plate, so that feed stream liquid and gas can also flow into the filtration device inlet between the outer edge of the top cover and the outer edge of the base plate. While the filtration device is not necessarily limited to a particular shape or size, in most cases the device will match the cross-sectional shape of a new or existing reactor; typically, the filtration device is circular in shape; so that the top cover, base plate, and separator are each circular and sized to correspond to the internal dimensions of the reactor and fit horizontally within the headspace of the reactor. In the case where the device is generally circular, the distance between the outer periphery of the top cover (also referred to herein as the upper flow diverter plate) and the outer periphery of the base plate is an annular region around the outside of the second zone through which the feed stream liquid and gas diverted out of the reactor enters the second zone of the device and flows inward towards the base plate aperture.

[0031] The top cover, the base plates of the first and second zones, and the separator of the second zone may also be formed as multiple compartments that together form the respective top cover, base plate, or separator. The use of compartments for certain device components, such as the top cover, base plate, and separator, allows the compartments to be placed in or removed from the reactor through an internal reactor access location, such as a manway, thereby facilitating installation and maintenance.

[0032] Various support structures can be used to support the top cover of the first and / or second zones, or sections of the top cover, and to provide a distance between the top cover and the base plate. For example, to support the top cover of the second zone, multiple cross members, such as trusses, can be used that span the cross-sectional distance between the reactor walls. The support structures, or more specifically, the cross members, are typically supported by structures within the reactor, such as by support members remaining on top of existing trays or through other connections to the reactor or reactor interior. In some cases, for example, when cross members are used, support structures can also be used to support the separator or a section of the separator. The support structure can also support the base plate or a section of the base plate. In one embodiment, the support structure includes multiple cross member trusses that span the distance from one reactor wall to the other side of the reactor across a section of the reactor cross section, such that the base plate is supported on the lower portion of the trusses, the separator is supported on the middle portion of the trusses, and the top cover is supported by the upper portion of the trusses. In cases where the top cover, base plate, and separator each include a respective component section, each section may be constructed and arranged to be supported within the space between the trusses.

[0033] In general, a filtration device can use any arrangement of first and second zones or any number of zones within the device. However, in practice, the height available at the top of the downflow reactor may limit the device to two or three zones. In one embodiment, for example, the first and second zones may be arranged in a dual-zone configuration, with the first zone positioned above the second zone.

[0034] Depending on the arrangement of the first and second zones, one zone may be stacked on top of the other, thereby allowing the support truss used for the bottom zone to also be used to support one or more upper zones. For example, in an embodiment where the filtration device is a dual-zone device having one first zone positioned above one second zone, the support truss may be used for the bottom second zone. The top first zone can utilize the support provided by the second zone, thereby allowing the internal support required for the first zone to benefit from reduced load requirements.

[0035] The second zone separator generally defines the area between the filtration media volume and the bypass flow volume within the second zone of the filtration device. Typically, the separator is a thin, porous material that functions to hold the filtration media in place and within the filtration media volume. Various materials can be used, including wire-based ones, as well as grids, meshes, screens, or perforated metal or plates. While not particularly limited, the separator, or a section thereof, can be somewhat rigid to aid in installation and help maintain its position during operation. In some embodiments, the separator can be an optional component and may not be included in the device, for example, if the filtration media remains contained within the filtration media volume and the separator is not required.

[0036] The base plate apertures in the second zone allow the liquid and gas of the feed stream to pass through the filtration device and to other lower locations within the device or reactor, such as a distributor tray below the filtration device. The size of the apertures can be variable and is not particularly limited (other than to avoid introducing flow restrictions and to allow efficient use of the filtration volume). The base plate apertures can be shaped to provide manway access to the reactor interior below the filtration device.

[0037] The aperture covers of the base plate of the first zone and the top cover of the second zone can be formed from a variety of materials, including the materials used for the respective plates. The covers are typically made from a liquid-impermeable material, such as the same metal as that used for the plates, but are not limited thereto. The covers are generally removable, allowing access to the interior of the filtration device and manway access to the reactor interior in downflow reactors.

[0038] A variety of filtration media can be used to provide contaminant removal within the filtration volumes of the first and second zones. Suitable materials generally include any known in the art, and typically, absorbent materials are used that are convenient to load, maintain, and remove. Such materials are commercially available and are typically provided in pellets or other conventional shapes for hydroprocessing reactors. In some cases, absorbent filtration media in pellet form having a nominal length ranging from about 5 mm to about 20 mm can be useful. The filtration media used in the first and second zones can be the same or different and are generally selected depending on the filtration needs of each zone.

[0039] The present invention further relates to the use of the filtration device in a hydroprocessing system, and to a hydroprocessing reactor system employing the filtration device. In certain embodiments, the filtration device may be advantageously used in a downflow hydroprocessing reactor, for example, as a contaminant removal tray located internally in the upper portion of such a reactor.

[0040] In an embodiment of the present invention, as shown in FIGS. 1-11, a filtration device may have a central cross-sectional view of a first zone in FIG. 1 and a second zone in FIG. 2. In FIG. 1, a first zone base plate 10a forms the lower portion of the first zone of the filtration device, and a first zone top cover 20a forms the upper portion. The base plate 10a has an opening, referred to as a base plate aperture, which is generally centrally located on the base plate to allow manway access through the device, for example, to a distribution tray below the filtration device. As shown in FIG. 1, a base plate aperture cover 12a is installed within or above the aperture during normal downflow reactor operation. Supports or cross members, which may be trusses 30a, are shown for supporting the base plate and top cover. The filtration volume 15a (first zone) is located between the base plate 10a and the top cover 20a, and also between the cross members 30a (also referred to herein as supports, support members, and trusses). The support may be of any suitable arrangement or structure to support the top cover. Containment barrier 55a is located around the outer periphery and perimeter of the base plate and confines the filtration media on the base plate. Aperture containment barrier 50a surrounds the interior or central base plate aperture of the filtration device. Filtration media 60a is contained within first zone filtration media volume 15a. Top cover 20a may also have openings (as shown) generally corresponding to the base plate apertures to allow access to the interior of the filtration device. While not required, base plate 10a and top cover 20a may each be provided in the form of multiple compartments located on and between supports 30a. In some cases, one or more of base plate 10a and top cover 20a may be provided as an undivided, overall component of the filtration device.

[0041] In FIG. 2, a second-zone base plate 10b forms the lower portion of the second zone of the filtration device, and the upper portion is formed by a second-zone top cover 20b. The base plate 10b has an opening, referred to as the base plate aperture, which is generally centered on the base plate to allow manway access through the device, for example, to a distribution tray below the filtration device. As shown in FIG. 2, a top cover aperture cover 12b is installed within or above the aperture during normal downflow reactor operation. A support or cross member, which may be a truss 30b, is shown for supporting the base plate and top cover. A separator 40b is located between the lower (second-zone) filtration volume 15b and the upper-flow bypass volume 25b, separating the second zone's internal volume into two flow compartments, and is also supported by the cross member 30b (also referred to herein as a support, support member, and truss). Filtration volume 15b is located between base plate 10b and top cover 20b, and also between cross members 30b. The supports may be of any suitable arrangement or structure to support the top cover. An aperture containment barrier 50b surrounds the interior or central base plate aperture of the filtration device. Filtration media 60b is contained within filtration media volume 15b. Top cover 20b may also have openings, generally corresponding to the base plate apertures, to allow access to the interior of the filtration device. Although not required, base plate 10b and top cover 20b may each be provided in the form of multiple compartments located on and between supports 30b. In some cases, one or more of base plate 10b and top cover 20b may be provided as an undivided, overall component of the filtration device.

[0042] In one embodiment, the first and second zones can be combined into a dual-zone filtration device, with the first zone directly above the second zone. In such an arrangement, only one of the base plate of the first zone and the top cover of the second zone need be used. For example, the base plate aperture cover 12a and top cover aperture cover 12b of the first zone can be simplified to using only one aperture cover instead of both, depending on the configuration and assembly.

[0043] FIG. 3 shows the same central cross-sectional view as FIGS. 1 and 2, but of an embodiment in which a dual-zone filtration device is installed in a downflow reactor. Reference numerals for features described in FIGS. 1 and 2 apply to FIG. 3. As shown, the filtration device can be installed in the top of the reactor, positioned between the sidewalls of the reactor shell 110 and, for example, below the catch basin 100, if one is present. While FIG. 3 illustrates one possible installation embodiment of the device in a downflow reactor, other configurations may be used. A top cover 20b and aperture cover 12b for the second zone are shown, with the top cover replacing the base plate 10a for the first zone. Other elements identified in the preceding description of FIGS. 1 and 2 are also shown in FIG. 3 and are incorporated herein by reference and for completeness. Also included in FIG. 3 for illustrative purposes are a distribution tray (also referred to as a perforated tray) 70, a spacer ring 80 disposed between the distribution tray 70 and the base plate 10, and a seal ring 90 for providing a seal between the base plate and the reactor sidewall. The distribution tray 70, spacer ring 80, and seal ring 90 are not required components of the filtration device or of the installation of the device in the reactor, but are provided herein to illustrate possible installation embodiments.

[0044] Figure 4 shows the same central cross-sectional view as Figure 3 to illustrate a simplified diagram of the general liquid and gas flow paths in an embodiment in which the dual-zone filtration device is installed in a downflow reactor below catch basin 100. The flow paths of liquid 120 and gas 130 are generally shown through first zone filtration media 15a, second zone filtration media 15b, and flow bypass volume 25b within the second zone filtration media volume, respectively. As shown, the flow of feed stream liquid is radially outward in the first zone and radially inward from the reactor sidewall in the second zone, passing through the second zone filtration device inlet and the second zone filtration media volume, then through the containment barrier and the centrally located base plate aperture of the filtration device.

[0045] 5 shows a three-quarter cross-sectional isometric view of an embodiment of the second zone of the filtration device with the top cover and separator removed so that the supports for the cross members 30b and the internal arrangement of the containment barrier 50b can be easily seen. As shown, a centrally located base plate aperture in the base plate 10b provides manway access to the interior of the reactor below the filtration device. While the cross members 30b are shown as truss supports, suitable alternative support members can be used.

[0046] Figure 6 shows a three-quarter cross-sectional isometric view according to Figure 5 with the second zone separator 40b installed (also referred to as a hold-down screen) and supported in an intermediate position on the cross member 30b. The separator generally has the same area dimensions as the base plate and includes a central opening aperture corresponding to the opening of the base plate aperture. Also shown is the upper support of the cross member 30b, which supports the top cover when installed.

[0047] Figure 7 shows the three-quarter cross-sectional isometric view according to Figures 5 and 6 with top cover 20b installed (also referred to as a deflector tray) and supported on top of cross members 30b. Top cover 20b is shown with the aperture cover (center manway panel) removed. The aperture cover (12a in Figure 1 or 12b in Figure 2, also referred to as a manway panel) is installed for normal reactor operation and can be removed for service access. For reference, other components are also shown in Figures 4 and 5, including, for example, second zone separator 40b.

[0048] FIG. 8 shows a three-quarter cross-sectional isometric view of the first zone support member 30a installed on the second zone top cover 20b, which serves as the first zone base plate. Note that the first zone base plate 10a in FIG. 1 and the second zone top cover 20b in FIG. 2 can be used for both the first and second zones, respectively, or either the base plate 10a or the top cover 20b can be used individually, but not both. The perimeter containment barrier 55a and the interior opening containment barrier 50a are also shown. The top cover aperture cover (manway panel) 12b is shown in the center of the first zone, aligned with the second zone manway access (i.e., the second zone aperture). Note that the aperture cover 12a shown in FIG. 1 can also be used in conjunction with or instead of the aperture cover 12b shown in FIG. 2. The compartments for the first zone filtration volume 15a and the second zone separator 40b are also shown.

[0049] Figure 9 shows a view according to Figure 8 with the first zone top cover 20a in place. Figures 8 and 9 show a circular central opening manway access area bounded by an aperture containment barrier 50a. Also shown for the first zone are first zone aperture cover 12a (which may be identical to second zone top cover aperture cover 12b, as shown), base plate outer edge 14a, base plate aperture 16a, top cover outer edge 24a, and top cover aperture 26a; and for the second zone are base plate outer edge 14b, base plate aperture 16b, top cover outer edge 24b (which may be identical to first zone base plate outer edge 14a, as shown), top cover aperture 26b (which may be identical to first zone base plate aperture 16a, as shown), and top cover aperture cover 12b (which may be identical to first zone aperture cover 12a, as shown). Also shown is second zone separator 40b.

[0050] Figures 10 and 11 show views and components of the first zone corresponding to Figures 8-9, but including a rectangular central opening manway access area extending through the first zone top cover 20a and a containment barrier 50a surrounding the manway access aperture. Certain features identified in Figures 1-9 and described above are incorporated herein for reference and completeness, including the first zone base plate 10a (which may be identical to the second zone top cover 20b), the first zone aperture cover 12a (which may be identical to the second zone top cover aperture cover 12b, as shown), the first zone base plate outer edge 14a (which may be identical to the second zone top cover outer edge 24b, as shown), the top cover outer edge 24a, and the support member 30a. The first zone filtration volume 15a (Figure 10) and the second zone separator 40b compartment are also shown. FIG. 11, like FIG. 9, shows the top cover aperture 26a and the base plate aperture 16b.

[0051] The multi-zone filtration devices of the present invention, including certain embodiments described herein, provide certain advantages and improvements in hydroprocessing applications, including minimizing scale and small particles or fines that reach the catalyst bed(s) underlying the filtration device and the interior of the reactor; reducing the increase in pressure drop throughout the operation of the reactor, thereby allowing for full or extended run operation; minimizing the additional pressure drop through the reactor even when the filtration bed is completely fouled, i.e., full of contaminants; and potentially reducing the amount of grading material required on top of the catalyst bed, thereby increasing the volume of active catalyst within the reactor.

[0052] The present disclosure is not limited with respect to the specific embodiments described in this application, which are intended as illustrative of various aspects. Obviously, many modifications and variations can be made without departing from the spirit and scope thereof. Functionally equivalent methods and systems, other than those recited herein, that are within the scope of the present disclosure may be apparent from the above exemplary description. It is intended that such modifications and variations be included within the scope of the appended exemplary claims. The present disclosure is limited only by the terms of the appended exemplary claims, along with the full scope of equivalents to which such exemplary claims are entitled. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0053] The above description, and the embodiments related thereto, have been presented for illustrative purposes only. They are not exhaustive and do not limit the invention to the precise form disclosed. Those skilled in the art will appreciate from the above description that modifications and variations are possible in light of the above teachings or may result from practice of the disclosed embodiments. For example, in some cases, the steps described need not necessarily be performed in the same order or with the same degree of separation as described. Similarly, various steps or features may be omitted, repeated, or combined as necessary to achieve the same or similar purposes. Therefore, the present invention, in its full scope and in terms of equivalents, is not limited to the embodiments described above, but is defined by the appended claims.

[0054] In the foregoing specification, various preferred embodiments have been described with reference to the accompanying drawings. However, it will be apparent that various modifications and changes may be made thereto and further embodiments may be implemented without departing from the broader scope of the invention as set forth in the claims that follow. Accordingly, the specification and drawings should be regarded in an illustrative rather than a restrictive sense.

[0055] Where permitted, all publications, patents, and patent applications cited herein are incorporated by reference in their entirety to the extent that such disclosure is not inconsistent with the present invention.

Claims

1. 1. A multi-zone filtration device for removing contaminants from a liquid feed stream in a downflow catalytic hydroprocessing reactor, the filtration device comprising a first filtration zone and a second filtration zone; a first zone top cover, the first zone having an inner surface, an outer surface, a first zone top cover outer edge, and a top cover aperture; a first zone liquid-impermeable base plate generally juxtaposed to the top cover, the first zone liquid-impermeable base plate having an inner surface, an outer surface, a base plate outer edge, a base plate aperture, and a removable base plate aperture cover, the first zone top cover and base plate being separated by a distance to define a first zone interior volume of the filtration device, the first zone interior volume comprising a first zone filtration media volume located above and adjacent to the first zone base plate inner surface; a first zone containment barrier positioned around the periphery of the base plate and extending from the base plate to the top of the filtration media volume or to a bottom surface of the top cover to retain filtration media within the first zone filtration media volume on the base plate; Optionally, a first zone base plate aperture containment barrier positioned around a periphery of the top cover aperture and the base plate aperture and extending from the base plate to the top of the filtration medium volume or to an inner surface of the top cover, the first zone base plate aperture containment barrier retaining the filtration medium on the base plate; a first zone support structure for a first zone top cover disposed within the interior volume of the first zone of the filtering device, the first zone support structure comprising one or more supports that provide and maintain a separation distance between the top cover and the base plate; a filtration medium contained within the filtration medium volume of the first zone; the base plate and top cover, the top cover aperture, and the base plate aperture of the first zone are centered about the same central vertical axis, the top cover and bottom plates have substantially the same areal dimensions such that feed stream liquid can flow through the top cover and / or through a first zone base plate aperture containment barrier into the first zone of the filtration device, and the base plate aperture cover is sized to prevent liquid flow through the base plate aperture when installed during reactor operation; a second zone top cover, the second zone having an inner surface, an outer surface, a second zone top cover outer edge, a top cover aperture, and a removable top cover aperture cover; a second zone liquid-impermeable base plate generally juxtaposed to the top cover, the second zone liquid-impermeable base plate having an inner surface, an outer surface, a base plate outer edge, and a base plate aperture, the top cover and the base plate being separated by a distance to define a second zone interior volume of the filtration device, the second zone interior volume comprising a second zone filtration media volume located above and adjacent the second zone base plate inner surface, and a flow bypass volume located above the second zone filtration media volume and adjacent the cover inner surface; a second zone support structure for a second zone top cover disposed within the interior volume of the second zone of the filtering device, the second zone support structure comprising one or more supports that provide and maintain a separation distance between the top cover and the base plate; a separator disposed between the second zone filtration media volume and the flow bypass volume, the separator generally being thin and parallel to both the second zone top cover and bottom plate, the separator having a top surface and a bottom surface, the separator containing the filtration media within the second zone filtration media volume and allowing liquid to flow into the second zone filtration media volume during downflow reactor operation; a second zone base plate aperture containment barrier positioned around a periphery of the base plate aperture and extending from the base plate to the top of the filtration media volume or to the bottom surface of the separator to retain filtration media within the second zone filtration media volume on the base plate; a filtration medium contained within the filtration medium volume of the second zone; the base plate, the top cover, the separator, the top cover aperture, and the base plate aperture of the second zone are centered about the same central vertical axis as the first zone, the separator generally has substantially the same area dimensions as the bottom plate, and the top cover has smaller area dimensions than the bottom plate, such that feed stream liquid and gas can flow into the inlet of the second zone between the outer edge of the top cover of the second zone and the outer edge of the base plate, and the top cover aperture cover is sized to prevent the flow of liquid through the top cover aperture when installed during reactor operation.

2. 10. The filtration device of claim 1, wherein the device is a two-zone filtration device having a first zone located above and adjacent to a second zone, and wherein the device, when installed in a downflow reactor, is configured such that during operation, liquid flows through the first zone, followed by liquid and gas flows through the second zone.

3. 3. The filtering device according to claim 1, wherein the base plate of the first zone is used as the top cover of the second zone, or the top cover of the second zone is used as the base plate of the first zone.

4. 4. The filtration device of claim 1, wherein the apertures in the first zone and the apertures in the second zone are centered about the same vertical axis in the first zone and the second zone and are aligned to provide manway reactor access through the filtration device when installed in a downflow reactor.

5. The filtering device of any one of claims 1 to 4, wherein the first zone comprises a baseplate aperture containment barrier.

6. The filtration device of any one of claims 1 to 5, wherein the first zone containment barrier, the first zone aperture containment barrier, and / or the second zone aperture containment barrier are liquid permeable.

7. 7. The filtration device of claim 1, wherein the device, and each of the top cover, the base plate, and the separator are generally circular and sized to fit horizontally within the headspace of a downflow reactor.

8. 8. The filtration device of claim 1, wherein the first zone has smaller areal dimensions than the second zone and, when installed in a downflow reactor, defines a first zone outlet area around a periphery of the first zone during operation, through which feed stream liquid flows outwardly through the containment barrier of the first zone.

9. 9. The filtration device of claim 1, wherein the top cover of the second zone has an area dimension smaller than that of the base plate of the second zone and, when installed in a downflow reactor, defines a second zone inlet area around the periphery of the second zone during operation, through which feed stream liquid and gas enter the second zone and flow inwardly toward the base plate aperture of the second zone.

10. 10. The filtration device of claim 1, wherein one or more of the top cover, base plate, or separator of the first and / or second zone comprises a plurality of compartments that together form the respective top cover, base plate, or separator, such that the compartments can be placed in or removed from the downflow reactor through reactor interior access locations.

11. 11. The filtering device of claim 1, wherein the support structure of the first zone and / or the second zone comprises a plurality of cross members to provide support for the top cover or a section of the top cover, the separator or a section of the separator, the base plate or a section of the base plate, or a combination thereof.

12. The filtering device of claim 11 , wherein the cross member supporting the first zone comprises a support extending from the base plate to the top cover or a section of the top cover.

13. 12. The filtering device of claim 11, wherein the cross member supporting the second zone includes an upper support portion and an intermediate support portion between the upper and lower portions of the cross member, the upper support portion supporting the upper cover of the second zone or a section of the upper cover of the second zone, and the intermediate support portion supporting the separator or a section of the separator.

14. 14. The filtration device of any one of claims 1 to 13, wherein the top cover of the first zone and / or the separator of the second zone comprises a wire, grid, mesh, screen, or perforated metal material or plate that retains the filtration medium within the filtration medium volume.

15. 15. The filtration device of any one of claims 1 to 14, wherein the first zone containment barrier and / or the first and / or second zone base plate aperture containment barrier comprises a wire, grid, mesh, screen, or perforated metal material or plate that retains the filtration medium within the filtration medium volume and, when installed in a downflow reactor, allows feed stream liquid to flow through the filtration medium volume during operation.

16. 16. The filtering device of any one of claims 1 to 15, wherein the filtering media in the first zone and / or the second zone comprises a particulate filtering absorbent material having a nominal size in the range of about 5 mm to about 20 mm.

17. 17. The filtering device of any of claims 1-16, wherein the second zone does not include a containment barrier located around the perimeter of the base plate extending from the base plate to the top of the filtration medium volume or the bottom surface of the top cover, or the filtration medium is not contained around the perimeter of the base plate, or a combination thereof.

18. A downflow catalytic hydroprocessing reactor comprising a filtration device according to any one of claims 1 to 17.

19. 18. A process for removing contaminants from a liquid feed stream in a downflow catalytic hydroprocessing reactor, said process comprising passing the feed stream to a downflow catalytic hydroprocessing reactor through a filtration device according to any one of claims 1 to 17 located in an upper portion of the reactor, said liquid feed stream passing through the filtration medium contained within the filtration medium volume in the first zone and passing through the filtration medium contained within the filtration medium volume in the second zone of the filtration device.

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