Patent Application
20140037419
Methods, devices and processes for effectively loading catalysts into reactor vessels. In particular methods, devices and processes for effectively loading catalysts into fixed bed two-phase hydroprocessing reactor catalyst beds.
Catalytic fixed bed reactors have been utilized for many decades in the petroleum and petrochemical refining industry (i.e., the “industry”) for upgrading raw or intermediate petroleum-based feedstocks into more valuable fuel and chemical products and base stocks. Hydroprocessing currently utilizes the largest number of fixed bed reactors in operation in the refining and petrochemical industry. Over the years, economics and competition in the industry have continued to push existing refinery hydroprocessing to ever more efficient equipment configurations and processes. In response refiners have attempted to optimize their hydroprocessing operations to 1) maximize throughput, 2) minimize operating costs (feed, catalyst, etc.), and/or 3) maximize the value of the product slates obtained from such hydroprocessing operations.
However, due to tight economics, high costs of revamping/replacing existing equipment (including extended downtime of such related equipment), and increasing more difficult and stringent permitting of new construction, the refining industry has been forced to discover new and better ways to achieve the three objectives above, while minimizing new capital costs, expenses, and limiting downtime. Additionally, since only a very small number of refineries or new petroleum hydroprocessing units are being built in either the United States or elsewhere, the vast overall majority of product production quality and quantity improvements need to be achieved through physical and process modifications, limited by the use of the existing hydroprocessing equipment.
Since new hydroprocessing reactors are an extremely costly option for an upgrade consideration for any refinery, the most of the useful improvements to existing refining hydroprocessing operations have been in either 1) improvements to the catalysts, 2) modifications to the hydroprocessing reactor internals to increase the efficiencies of the existing processes/base equipment, or 3) increase the number of beds. These options allow the main capital portion of the hydroprocessing equipment (i.e., the exiting reactors and associated equipment) to be used in the modified system, thus keeping capital cost to a minimum.
Many conventional or heritage catalytic reactors utilized in petroleum/petrochemical hydroprocessing refining are single bed reactors, while many of these processes have more than one bed in a single reactor in a “stacked bed” configuration. Most of these hydroprocessing reactors are oriented in a vertical arrangement, in that the basic shape of the reactor is cylindrical, with the axis of the cylinder oriented in the vertical direction. In the stacked bed configuration, the catalysts beds are typically vertically stacked on each other so that the feedstock flow through the reactor beds occurs in series. While multiple catalyst beds may be situated in a reactor in segmented or radially situated orientation relative to one another (i.e., from a planar view of the reactor diameter, viewed down the cylindrical axis), by far, the vast majority of catalyst beds in petroleum/petrochemical hydroprocessing reactors have single, undivided catalyst bed(s) when viewed in a plane orthogonal to the cylindrical axis of the vertical reactor.
Chemicals hydroprocessing reactors typically have diameters usually not more than 10 ft, typically 3 to 6 feet. However, while the diameters of refining hydroprocessing reactors are typically greater than about 3 feet, or about 6 feet in diameter and can range up to about 24 feet or more, but are more typically in the range of about 8 to about 30 feet in diameter, or even more typically in the range of about 8 to about 18 feet in diameter. Although not limited as such, it is to the higher diameter reactor vessels that the current invention most beneficially applies. These fixed bed hydroprocessing reactors are quite different from “tubular” reactors typically utilized in reforming operations (gas phase, such as hydrogen reforming) or the chemical industry (such as ethylene crackers) which utilize small “tube” reactors, typically less than about 6 inches in diameter.
In the petroleum and petrochemical refining industry, three (3) methods have been utilized for catalyst loading of these fixed bed reactors as described and are both well known to those of skill in the art. The first can be typically referred to as the “dump loading” method. Here, the catalyst is simply dumped into the reactor (by such devices as individual catalyst containers or buckets). Here, if the vessel is large enough, an internal worker may (not required) be located in the vessel during catalyst loading and/or after the catalyst loading is complete to assist in distributing the catalyst within the vessel. The second method is typically referred to in the industry as a catalyst “sock loading” method. In this method a flexible hose (i.e., the “sock”) is connected to the catalyst hopper and down into the reactor where a worker moves the outlet line of the hose around the internal catalyst bed as the catalyst is being fed through the hose attempting to achieve a consistent and uniform loading of the catalyst in the bed (i.e., to reduce voidages and inconsistencies, such as “bridging”, in the installed catalyst bed). In the past few decades, a third method for catalyst loading of these large catalyst bed reactors has been utilized which is called “dense loading” (or “dense bed loading”). Here, a rotary device which is temporary located in the reactor during the catalyst loading process, is utilized which obtains a feed of catalyst from the catalyst hopper, and essentially sprays the catalyst in a radial pattern into the catalyst bed during loading. The underlying principal with this process is that the catalyst (typically a uniform, extrudated catalyst with an L/D ratio of greater than one) will uniformly orient and distribute within the catalyst bed, thereby reducing inconsistencies and voidages. It has been noted in the industry that the “dense loading” process typically results in a catalyst bed loading that has a final voidage that is a few percentage points less than the voidage obtained by using either the “dump loading” or “sock loading” methods.
These three (3) processes are the standards of the industry. The best catalyst bed loading (especially in larger diameter catalyst beds) that is typically achieved is via the “dense loading” process. However, what has been discovered herein is that even with the most current and advanced dense loading technologies inefficient and non-uniform operation in commercial hydroprocessing reactors often occurs. What is need in the industry is an improved catalyst loading process for commercial hydroprocessing reactors.
One aspect of the invention relates to a process for loading a catalyst into a reactor vessel comprising:
wherein the reactor vessel has an internal diameter of at least 1 foot.
Preferably, the vibration is mechanically or acoustically induced into the reactor vessel.
In one embodiment, the vibration is mechanically induced and the mechanical means for inducing the vibration is selected from electro/mechanical and pneumatic/mechanical devices. In another embodiment, the vibration is acoustically induced and the acoustical means for inducing the vibration is selected from pneumatically driven horns and electromagnetically driven horns.
In preferred embodiments, the energy generated by the vibration is sufficient to increase the packing density of the catalyst. In yet other preferred embodiments, the vibration is mechanically induced and the energy generated by the vibration is sufficient to increase the radial uniformity of the packing density of the catalyst.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
The invention as described in its preferred embodiments herein comprises methods and devices for improving the catalyst loading in “large” fixed bed reactors. Preferably, these reactors are arranged in a vertical orientation. More preferably, these reactors are essentially cylindrical in shape. The “large” fixed bed reactors utilized in conjunction with the processes of invention have an internal diameter of at least 1 foot, more preferably at least 3 feet. By the term “vertical” is meant that the vessel's longitudinal axis (i.e., the axis of its longest dimension) is in an essentially vertical orientation. For instance, where the basic shape of the reactor is cylindrical, the axis of the cylinder would be oriented in the vertical direction. In the cases herein where the term “diameter” may be used in context with a reactor vessel, it is meant to convey the term “internal diameter” unless otherwise noted. Also, in the cases herein where the term “diameter” may be used in context with a catalyst bed, it is meant to convey the term “external diameter” unless otherwise noted.
The current invention herein is preferable utilized in reactor catalyst beds that are essentially cylindrical in shape. As noted prior, as utilized herein, there may be one or more individual catalyst beds in a single reactor. These will typically be in a stacked bed configuration, wherein one bed is located at a higher vertical location with respect to the other bed or beds, the beds being situated along the cylindrical axis of the reactor. By the term “stacked”, it is only meant that the beds are oriented one on top of the other. The individual catalyst beds may or may not be separated from each other by a physical space, such as supported by individual catalyst bed supports and/or other internal reactor apparatus.
In the stacked bed configuration, the catalysts beds are typically vertically stacked on each other so that the feedstock flow through the reactor beds occurs in series. While multiple catalyst beds may be situated in a reactor in segmented or radially situated orientation relative to one another (i.e., from a planar view of the reactor diameter, viewed down the cylindrical axis), by far the oldest fixed bed reactors in the refining and chemical industry are single bed reactors, utilizing undivided catalyst bed(s) when viewed in a plane orthogonal to the cylindrical axis of the vertical reactor.
It should be noted that while the processes herein are particularly suited for loading of large cylindrical vertically oriented catalyst beds (i.e., wherein the outer diameter of the catalyst bed is essentially the same as the inner diameter, i.e., inner wall, of the reactor vessel), but it is not so limited. The methods herein may be utilized wherein (when viewed from a plane orthogonal to the vertical axis of the reactor) the catalyst bed is segmented into various sections, such as in the example of a cylindrical vertical reactor (which catalyst bed area when viewed in a plane as a circular area) wherein the catalyst bed is segmented into four catalyst bed quarters or for example two annular catalyst bed rings. Again while the preferred configuration is that the outer diameter of the catalyst bed be essentially the same as the inner diameter (i.e., inner wall) of the reactor vessel, this may not be the case such as in reactors where annular rings are present such as in the center or outer diameter of the catalyst bed for injection of gas or liquid feedstocks. Additionally, the methods as described herein are not limited to vertically oriented reactors. The methods herein are also well suited for example, to horizontal reactors, i.e., wherein the vessel's longitudinal axis (i.e., the axis of it longest dimension) is in an essentially horizontal orientation. In this case, the methods described herein in conjunction with the catalyst “sock loading” loading methods herein may be particularly beneficial. By the term “essentially the same” as used in this paragraph, it is meant that the outer diameter of the catalyst bed be at least 95% of the inner diameter of the reactor vessel.
It should be note that the terms “large reactor catalyst beds” or the like which are used in conjunction with the invention as described herein specifically excludes reactors and reactor catalyst beds that are less than 1 foot in diameter, as well as reactors/reactor shells encompassing multiple individual internal reactor tubes (generally such individual tubes are less than 2 to 4″). Such reactors are generally specialized for the generation of specific chemicals and are not included in the scope of the reactors/reactor catalyst beds as described herein in conjunction with the present invention.
As noted prior, in the petroleum and petrochemical refining industry, three main methods have been utilized for catalyst loading of these large fixed bed reactors as described and are both well known to those of skill in the art.
The first method can be typically referred to as the “dump loading” method. Here, the catalyst is simply dumped into the reactor (by such devices as individual catalyst containers or buckets). Here, if the vessel is large enough, an internal worker may (not required) be located in the vessel during catalyst loading and/or after the catalyst loading is complete to assist in distributing the catalyst within the vessel. The second method is typically referred to in the industry as a catalyst “sock loading” method. In this method a flexible hose (i.e., the “sock”) is connected to the catalyst hopper and down into the reactor where a worker moves the outlet line of the hose around the internal catalyst bed as the catalyst is being fed through the hose attempting to achieve a consistent and uniform loading of the catalyst in the bed (i.e., to reduce voidages and inconsistencies, such as “bridging”, in the installed catalyst bed). The term “voidage” as used herein, is a standard term of the art measuring the percentage of void space (i.e., space no occupied by the catalyst) per unit volume in a catalyst bed. The term “packing density” as used herein, is a standard term of the art measuring the density of the catalyst per unit volume in a catalyst bed.
The third method for catalyst loading of these large catalyst bed reactors has been utilized which is called “dense loading” (or “dense bed loading”). Here, a rotary device which is temporary located in the reactor during the catalyst loading process, is utilized which obtains a feed of catalyst from the catalyst hopper, and essentially sprays the catalyst in a radial pattern into the catalyst bed during loading. The underlying principal with this process is that the catalyst (typically a uniform, extrudated catalyst with an L/D ratio of greater than one) will uniformly directionally orient and distribute within the catalyst bed, thereby reducing inconsistencies and voidages. It has been noted in the industry that the “dense loading” process typically results in a catalyst bed loading that has a final voidage that is a few percentage points less than the voidage obtained by using either the “dump loading” or “sock loading” methods.
These three (3) processes are the standards of the industry with the most homogeneous and dense large vertical catalyst bed loading typically achieved via the dense loading process as described.
What has been discovered herein is that the even the catalyst dense loading process often results in inefficient and non-uniform operations in commercial hydroprocessing reactors. Uneven flow distribution in the reactors cause many problems, including lost catalytic conversion and selectivity efficiencies, safety problems (such as reactor hot spots than can lead to temperature runaway), shortened catalyst life, and off-specification products from the catalytic reactions. These problems associated with poor catalyst bed loading can cost refiners millions of dollars a year in lost profits, as well as contribute to unscheduled process/equipment outages and/or safety incidents. As can be seen, due to these high potential costs/losses, refiners typically pay a premium to have catalyst beds loaded via the dense catalyst loading method over the sock catalyst loading methods just to achieve marginally higher (denser) and more uniform loading of the catalyst in the beds of the reactors. However, the inventors herein have found that many commercial reactors, even when catalyst loaded via the dense catalyst loading method, can experience significant flow maldistribution during operation, again resulting in significant lost profits as have been described.
The methods described herein include the use of a means for inducing vibrations into the reactor vessel, or in embodiments to a specific part of the reactor vessel (e.g., the catalyst bed support structure) either during and/or after such reactor (or more specifically, such reactor catalyst bed volume) is loaded with catalyst. This method can specifically be utilized in conjunction with any of the three (3) noted industry methods for catalyst loading, i.e., the “dump loading”, “sock loading” or “dense loading” catalyst loading methods that have been discussed. One major difference is that when the embodiments herein are utilized with the “dump loading” or “sock loading” method, it is preferred that the vibrational energy is induced into the catalyst bed after at least a section of the catalyst bed is loaded, if an operator is utilized in the reactor vessel during the catalyst loading process. This however, can be remedied through the use of a sock that can be remotely directed within the vessel by an operator located outside of the vessel, in which case the vibrational energy can be induced into the catalyst bed while the catalyst bed is in the process of being loaded or if the vessel is small enough in diameter to allow for dump loading of the catalyst.
It has been discovered that even reactor beds that are carefully loaded with uniform, extrudated catalyst via the dense loading method can exhibit significant flow maldistribution.
The hydrotreating process is exothermic and improperly distributed flow through the catalyst bed can be indicated clearly by looking at the temperatures indicated by the bed thermocouples located radially and circumferentially in the catalyst bed during the process.
In
In embodiments of the processes herein, it has been discovered that catalyst uniformity and catalyst bed flow uniformity can be improved if vibrations are induced into the catalyst bed and supporting structures during and/or after the catalyst bed loading process. This can also be perform for a portion of the catalyst bed loading process wherein a particular catalyst bed is loaded in steps, or wherein separate catalyst are loaded in a single bed, one on top of the other. In these latter cases, the processes can be performed during and/or after each catalyst loading “step” or “section”. Any conventional or new method of catalyst loading process, such as the “dump loading”, “sock loading” or “dense loading” catalyst loading methods, can be used in conjunction with the processes herein.
In embodiments herein, such vibrations may be induced either mechanically (electro or pneumatically driven), acoustically, or both, by apparatus connected to the reactor or preferentially connected to specific components of the reactor vessel. Although a single device may be used to induce such vibrations, preferably more than one device will be attached to the reactor in order to more evenly distribute the vibration energy throughout the catalyst bed. Preferred mechanical devices for inducing vibrational energy into the reactor catalyst bed include: electro/mechanical and pneumatic/mechanical vibrational devices. These devices may either be attached directly to the shell or other structural components of the reactor, such as catalyst bed supports, or they may be hand held devices (such as vibrating wands) which can be inserted into the catalyst bed to induce vibrations therein. Preferred acoustical devices for inducing vibrational energy into the reactor catalyst bed include: air horns, sonic horns, and acoustic horns. While pneumatically driven horns are preferred, the selection sonic and acoustic horns may alternatively comprise the selection of electromagnetically driven horns. In preferred embodiments, the mechanical devices for inducing vibrational energy create vibrational frequencies from about 30 to about 600 Hz, more preferably from about 60 to about 420 Hz. The amplitudes and energies of the vibrational energy inducing devices selected can vary depending on the geometry and volume of the catalyst bed, as well as the number and location(s) of the devices utilized in practicing the invention.
In some embodiments of the invention, the electro/mechanical and/or pneumatic/mechanical vibrational devices may be hand held devices such as vibrating wands) which can be inserted into the catalyst bed to induce vibrations therein. Here, an operator working inside the vessel can use the device to induce vibrations directly into discrete sections of the catalyst bed. This can be performed while catalyst bed loading is being performed, after sections of the catalyst bed loading have been completed, and/or after the catalyst bed loading is complete.
In preferred embodiments, the vibrational devices are attached directly to the shell of the reactor and/or they may be attached to other structural components of the reactor, such as, but not limited to, the catalyst bed supports, internal structural support rings, or to the external vessel support(s) themselves. When a mechanical means for inducing the vibration is utilized, it is preferred that the device is attached to at least one of the following reactor vessel components: reactor wall, catalyst bed support beams, internal structural support rings, outlet collector, vessel flanges, vessel manways, and vessel external supports. Alternatively, the mechanical means for inducing the vibration may be a handheld vibrational device which is not attached to the reactor vessel or components, but is instead utilized by an operator within the reactor vessel. When an acoustical means for inducing the vibration is utilized, it is preferred that the device is attached to at least one of the following reactor vessel components: catalyst bed support beams, internal structural support rings, distributor tray, vessel flanges, and vessel manways.
As shown in
In preferred embodiments herein, the vibrational energy is induced into the catalyst bed section of the reactor vessel in steps of increasing amplitudes followed by steps of decreasing magnitudes. Alternatively, the amplitudes may be increased followed by the decrease as described in a continuous, as opposed to step wise, manner. Although not so limited herein, this method is believed to be particularly effective in further improving the installation of the catalyst bed, and its resulting improved flow distribution properties, when utilized either after a particular catalyst bed has been loaded with catalyst, or alternatively, after a portion of a particular catalyst bed has been loaded with catalyst.
The processes herein are preferably for use in catalyst loading of “large” fixed bed reactors. These are reactors having an internal diameter of typically at least 1 to 3 feet. These are differentiated from “tube bundle” reactors, which are reactors with multiple catalyst tubes or sets of tubes in which the catalyst is inserted. The tubes of these tube bundle reactors are often externally heated (such as in hydrogen reforming) and radial heat transfer in the catalyst beds is poor. In order to transfer the required heat between the fluids inside the tubes and the heat transfer fluids outside the tubes, the tubes are typically less than 3 inches in diameter, more commonly on the order of 1 to 2 inches. These tubes do not have the flow distribution problems as experienced in the larger reactor vessels as described in embodiments of this invention and do not utilize either sock loading or dense loading techniques as described herein for large fixed bed reactors. Neither of these catalyst loading processes can be utilized for loading tube bundle reactors. In preferred embodiments herein, the internal diameter of the reactor vessel is at least 1 foot, or at least 3 feet, or at least 6 feet, or at least 10 feet, or at least 15 feet. It has been discovered the methods herein are particularly effective for reactor vessels with an internal diameter of from about 3 to about 6 feet, and reactor vessels with an internal diameter of at least 15 feet. Particularly in these size reactor ranges, it has been discovered that the dense loading process tends to produce non-uniform loadings results, especially in radial non-uniformities, as were discussed in conjunction with the findings in existing commercial reactors exemplified in
It has been discovered that flow maldistribution takes place more frequently in reactors with either very small or very large reactor diameter. Reactors with higher length/diameter ratios (i.e., “L/D ratio”) of greater than about 3 may also be more susceptible to maldistributed catalyst loadings. When the term “L/D” is used in the context of a reactor vessel herein, the L/D ratio is measured with the dimension L being determined along the longest central axis of the reactor vessel from the vessel tangent-to-tangent lines, and with the dimension D being determined as the maximum internal wall dimension of the reactor vessel as measured along an axis perpendicular to the L axis. In the case of a common cylindrical reactor with elliptical heads on each end, the dimension L would the length of the reactor between the two tangent lines along the axis of the cylinder, and the dimension D would be the internal diameter of the reactor vessel measured in a plane orthogonal to the cylinder axis. Preferably the method utilized herein is utilized in reactor vessels with L/D ratios greater than about 5, even more preferably greater than about 7.
In preferred embodiments, the catalyst is a pelletized catalyst (preferably extruded). The catalysts lend themselves particularly well to the processes of invention. Some examples of preferred catalyst shapes are as follows: spherical spheroidal, ring, cylindrical, trilobe, and quadralobe.
Preferably the catalyst particle is in an elongated form; that is that the catalyst particles have a length/diameter ratio (i.e., “L/D ratio”) of greater than 1. More preferably, the catalyst pellets have an average L/D ratio of from about 1 to about 8, and even more preferably from about 2 to about 6. When the term “L/D” is used in the context of a catalyst herein, the L/D ratio is measured with the dimension L being determined by the maximum dimension of the catalyst along any axis of the catalyst, with the dimension D being determined as the maximum dimension of the catalyst measured along an axis perpendicular to the L axis. When using a catalyst pellet with an L/D ratio of greater than about 1, or even more particularly, of about 2 or greater, it is preferred that the processes herein are utilized in conjunction with the dense loading process, particularly when the reactor vessel has an internal diameter of at least about 8 feet, or even 12 feet or more.
It is believed herein that these methods of invention herein are particularly beneficial in improving reactor catalyst bed flow distributions in two-phase fixed bed reactor vessels. In a two-phase reactor process, the feedstream is a mixture of at least one gas phase component and at least one liquid phase component. Such flowstreams/feedstreams are typical in large hydroprocessing reactors used in the processing of base and intermediate stock hydrocarbon feedstreams in petroleum and petrochemical refineries. These processes include: hydrotreating, hydrodesulfurization, hydrodenitrogenation, hydrodemetalation, hydrogenation, hydroisomerization, and hydrocracking processes. In these processes, a hydrocarbon based liquid feedstream is mixed with a hydrogen containing gas stream and then exposed to the catalyst in the reactor vessel to produce an improved product slate. Typically such processes are useful in removing sulfur and other contaminants from hydrocarbon feedstreams (e.g., hydrodesulfurization, hydrodenitrogenation, or hydrodemetalation processes), reducing the average boiling point of hydrocarbon feedstreams (e.g., hydrocracking processes), and/or modifying the hydrocarbon compounds in the hydrocarbon feedstreams (e.g., hydrogenation or hydroisomerization processes). In each of these processes, specific types of catalysts will be utilized depending upon the feedstream composition and the product compositions to be sought.
Preferred hydroprocessing operating conditions for reactor vessels targeted by the methods of invention herein include two-phase flow including one or more of the following conditions: a temperature of at least about 260° C., for example at least about 300° C.; a temperature of about 425° C. or less, for example about 400° C. or less or about 350° C. or less; a liquid hourly space velocity (LHSV) of at least about 0.1 hr-1, for example at least about 0.3 hr-1, at least about 0.5 hr-1, or at least about 1.0 hr-1; an LHSV of about 10.0 hr-1 or less, for example about 5.0 hr-1 or less or about 2.5 hr-1 or less; a hydrogen partial pressure in the reactor from about 200 psig (about 1.4 MPag) to about 3000 psig (about 20.7 MPag), for example about 400 psig (about 2.8 MPag) to about 2000 psig (about 13.8 MPag); a hydrogen to feed ratio (hydrogen treat gas rate) from about 500 scf/bbl (about 85 Nm3/m3) to about 10000 scf/bbl (about 1700 Nm3/m3), for example from about 1000 scf/bbl (about 170 Nm3/m3) to about 5000 scf/bbl (about 850 Sm3/m3).
The Examples included herein were developed and run based on comparative testing of conventional catalyst loading processes and embodiments of the catalyst loading methods of the invention herein. The Examples shown herein clearly show the benefits embodiments of the present invention over the prior art techniques. Such benefits are shown and explained in further detail in the Examples herein.
Additionally or alternately, the invention can include one or more of the following embodiments.
A Process for loading a catalyst into a reactor vessel Comprising:
wherein the reactor vessel has an internal diameter of at least 1 foot.
The process of embodiment 1, wherein the vibration is mechanically or acoustically induced into the reactor vessel.
The process of embodiment 2, wherein the vibration is mechanically induced and the mechanical means for inducing the vibration is selected from electro/mechanical and pneumatic/mechanical devices.
The process of embodiment 2, wherein the vibration is acoustically induced and the acoustical means for inducing the vibration is selected from pneumatically driven horns and electromagnetically driven horns.
The process of any of embodiments 1-3, wherein the vibration is mechanically induced and the energy generated by the vibration is sufficient to increase the packing density of the catalyst.
The process of any of embodiments 1-3 and 5, wherein the vibration is mechanically induced and the energy generated by the vibration is sufficient to increase the radial uniformity of the packing density of the catalyst.
The process of any of embodiments 1, 2 and 4, wherein the vibration is acoustically induced and the energy generated by the vibration is sufficient to increase the packing density of the catalyst.
The process of any of embodiments 1, 2, 4 and 7, wherein the vibration is acoustically induced and the energy generated by the vibration is sufficient to increase the radial uniformity of the packing density of the catalyst.
The process of any prior embodiment, wherein the vibrations are induced at a frequency of from about 60 to about 420 Hz.
The process of any prior embodiment, wherein the catalyst is in a uniform pelletized or extruded catalyst shape.
The process of any prior embodiment, wherein the catalyst is selected from spherical spheroidal, ring, cylindrical, trilobe, and quadralobe shapes.
The process of any prior embodiment, wherein the L/D ratio of the catalyst is from 1 to 8.
The process of any prior embodiment, wherein the reactor vessel is a hydroprocessing reactor.
The process of any prior embodiment, wherein the reactor vessel further comprises an inlet distributor.
The process of any prior embodiment, wherein the reactor vessel has an internal diameter of at least 3 feet.
The process of any prior embodiment, wherein the reactor vessel is a vertical reactor and has an L/D ratio of at least 5.
The process of any prior embodiment, wherein the reactor vessel material is selected from steel and steel alloys.
The process of any prior embodiment, wherein the reactor vessel is designed for two-phase hydrocarbon hydroprocessing.
The process of any of embodiments 3, 5, 6 and 9-18, wherein the mechanical means for inducing the vibration is attached to at least one of the following reactor vessel components: reactor wall, catalyst bed support beams, internal structural support rings, outlet collector, vessel flanges, vessel manways, and vessel external supports.
The process of any of embodiments 3, 5, 6 and 9-18, wherein the mechanical means for inducing the vibration is a handheld vibrational device.
The process of any of embodiments 4 and 7-18, wherein the acoustical means for inducing the vibration is attached to at least one of the following reactor vessel components: catalyst bed support beams, internal structural support rings, distributor tray, vessel flanges, and vessel manways.
The process of any prior embodiment, wherein the loading of the catalyst into the reactor vessel is accomplished by either the catalyst dump loading method or the catalyst sock loading method.
The process of any of embodiments 1-22, wherein the loading of the catalyst into the reactor vessel is accomplished by the catalyst rotary dense loading method.
The process of any of embodiments 3, 5, 6, 9-20, 22 and 23, wherein the vibration is mechanically induced at least during the process of loading of the catalyst into the reactor vessel.
The process of any prior embodiment, wherein the vibration is induced after the process of loading at least a portion of the catalyst into the reactor vessel, wherein the vibration amplitude if successively increased and then decreased.
The process of any prior embodiment, wherein the external diameter of the catalyst bed section of the reactor vessel is essentially the same as the internal diameter of the reactor vessel.
The process of any prior embodiment, wherein the vibration is induced into the catalyst bed section of the reactor vessel in steps of increasing amplitudes followed by steps of decreasing magnitudes.
The process of any prior embodiment, wherein the process of inducing vibrations into the catalyst bed section of the reactor vessel in steps of increasing amplitudes followed by steps of decreasing magnitudes is performed after the process of loading of the catalyst into the catalyst bed section is complete.
A laboratory scale, cold-flow reactor unit was fabricated to test the concept of embodiments of the present invention. The reactor unit that was utilized in the testing associated with these examples is shown schematically in
The reactor contained a high efficiency liquid/gas flow distribution system with distributor tray 603 to ensure very even mixing and flow distribution of the two-phase feed (liquid and gas) to the top of the catalyst bed 601. Intra-bed probes 604 were installed at various levels in the reactor to monitor pressure drop across the catalyst bed. The data from the intra-bed probes was continuously monitored and fed into a data acquisition system 605. The distribution of liquid flow was semi-continuously monitored and recorded via an outlet pattern collector 606 attached to the bottom of the reactor. The outlet pattern collector 606 monitored the real-time liquid flow distribution through the catalyst bed via sixty-one (61) individual flow cells each with the identical cross-sectional square area (as is illustrated in
The gas phase flow was collected at the top of the reactor outlet reservoir 607 and recycled back during the testing via a gas recycle compressor loop 608. In a similar fashion, the liquid phase flow was collected at the bottom of the reactor outlet reservoir 607 and recycled back during the testing via a liquid recycle pump loop 609. During testing, nitrogen was utilized as the feed gas phase component and an iso-paraffin hydrocarbon solvent mixture was utilized as the feed liquid phase component.
This testing apparatus was used in all of the following examples described herein.
In this example, the catalyst was loaded into the reactor via an industry dense loading method to a bed height of 1 meter, m (39.4 inches, in). The reactor system was run various two-phase flow conditions, with the liquid flow being varied at 9 gpm, 14.1 gpm, and 35 gpm (horizontal axis in
The results of these tests are shown in
As can be seen, the effects of liquid flow maldistribution due to non-optimal dense catalyst loading appear to be a further function of flow rate with the higher flow rates showing lesser effects of liquid flow maldistribution.
The Relative Standard Deviation (RSD) shown for each case equals the standard deviation (STDEV) divided by the mean flow rate (MEAN) based on the flow through each of the sixty-one (61) individual flow cells of the outlet pattern collector located at the outlet of the catalyst bed.
In this example, the unit was set up in the same configuration as in Example 1, except that an air-driven mechanical (i.e., pneumatic/mechanical) vibration inducing device as shown in
In the first case, the catalyst was loaded into the reactor via the “sock loading” method without vibrations being induced. The results of the reactor cold flow testing associated with this case are shown in the upper left hand corner of
In the second case (embodiment of the invention) the catalyst was loaded into the reactor via the “sock loading” method and then vibrations were induced after the conventional loading process was completed. This was done in an effort to simulate commercial operations wherein the vibrations could not be induced while an operator was in the vessel facilitating the sock loading process. The results of the reactor cold flow testing associated with this case are shown in the upper right hand corner of
In the third case, the catalyst was loaded into the reactor via the “dense loading” method without vibrations being induced. The results of the reactor cold flow testing associated with this case are shown in the lower left hand corner of
In the fourth case (embodiment of the invention) the catalyst was loaded into the reactor via the “dense loading” method while vibrations were being induced during the conventional loading process. This was done in an effort to simulate commercial operations wherein the vibrations could be induced while the dense loading process was in progress. As noted prior, the dense loading process is operated remotely with no operator located in the reactor vessel. The results of the reactor cold flow testing associated with this case are shown in the lower right hand corner of
The reactor system was run under one two-phase flow condition in all four (4) cases of this example, with the liquid flow at 14.1 gpm and the gas flow at 168 scfm (mid-range of the prior Example 1).
As can be seen in the cold flow reactor system comparative results shown in
It can be seen that the case of simultaneous use of vibrational energy with the dense loading resulted in significant improvements in the reactor flow distribution. As shown in the two comparative figures at the bottom of FIG. 10, the use of vibrational energy during the dense loading process reduced the reactor flow maldistribution by about one-half. This is a significant improvement over the prior art technology.
While the present invention has been described and illustrated by reference to particular embodiments, those of ordinary skill in the art will appreciate that the invention can lend itself to variations not necessarily illustrated herein. For this reason, then, reference should be made solely to the appended claims for purposes of determining the enforceable scope of the present invention.
This application claims priority to U.S. Provisional Application Ser. No. 61/680,003 filed Aug. 6, 2012, which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61680003 | Aug 2012 | US |
