Regeneration tower for continuous catalytic reforming process

Abstract

A regeneration column having a cylindrical section and a conical section has a three-stage screen covering an opening in the conical section, which prevents any catalyst escaping from a cylindrical catalyst bed or a catalyst bed in the conical section from entering the oxychlorination zone. The regeneration column may also have one or more additional variations. The length of the cylindrical section may be increased. The inner screen in the cylindrical section may include a perforated plate or a slotted plate. A secondary screen may be added in front of the inner screen in the cylindrical section.

Description

[0001] Priority declaration

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 371,946 filed on August 19, 2022, the entire contents of which are incorporated herein by reference. Background Art

[0003] The regeneration tower for continuous catalytic reforming (CCR) process comprises an inner screen and an outer screen and a cylindrical section at the top of the inner screen. At present, the inner screen and the outer screen and the cylindrical section are made of a profiled wire with a support rod. At present, the low oxygen content regeneration gas flow in the combustion zone bed is a radial flow from the outer screen to the inner screen. The oxygen-enriched supplementary gas is an upflow from the chlorination zone to the inside of the inner screen through the opening at the bottom of the inner screen. The inner screen and the outer screen contain catalyst and form a catalyst bed. In this configuration, most of the strength of the screen comes from the support rod.

[0004] At present, the low oxygen content regeneration gas flow from the outer screen to the inner screen is generally 350°C to 550°C. The temperature of the spent catalyst arriving at the top of the annular catalyst bed in the combustion zone is generally 20°C to 250°C. When the low temperature downward moving spent catalyst mixes with the high temperature radial regeneration gas at the top of the combustion zone, a temperature transient state occurs. Since the regeneration gas is a radial flow toward the inner screen, the inner screen is subjected to a transient temperature state. The changes in the regeneration gas flow rate, regeneration gas temperature, spent catalyst flow rate and spent catalyst temperature entering the mixing zone at the top of the annular catalyst bed will form a dynamic thermal transient as a thermal cycle zone. The dynamic thermal transient includes a circumferential temperature gradient around the annular catalyst bed and the inner screen and a temperature gradient from top to bottom along the catalyst bed and the inner screen. The thermal cycle zone is located in the upper section of the annular catalyst bed, which is sandwiched between the cylindrical section of the outer screen and the inner screen at the top of the combustion zone.

[0005] As the downwardly flowing catalyst flows downwardly from the top of the combustion zone toward the chlorination zone, the heat of oxygen produced by the combustion of the coke causes the coked catalyst to burn, which stabilizes the thermal transient dynamics. The non-thermal cycle is located below the thermal cycle zone. The annular catalyst bed in the non-thermal cycle zone is sandwiched between the conical sections of the outer screen and the inner screen, and it is located below the thermal cycle zone in the combustion zone.

[0006] The upper cylindrical section is relatively short (eg 6"). This shorter section at the top of the inner screen is subject to the combustion zone gases, seal gas and catalyst.

[0007] The cylindrical sections sometimes suffer damage, usually from profile wire (fish eye) damage, separation of support rods from the profile wires, and separation of support rods and profile wires from the connections on the upper and lower ends of the cylindrical sections where the cylindrical sections are welded to the connection rings. Damage can occur at weld joints and weld locations.

[0008] Additionally, loss of catalyst content in the CCR unit due to damage to the profiled wires and support rods can allow coked catalyst to fall into the oxychlorination zone, resulting in a temperature surge which can cause damage to the regeneration tower and / or permanent catalyst damage which results in fouling of the CCR regeneration tower internal screens and equipment in the unit.

[0009] Therefore, a more robust regeneration tower configuration and a more robust catalyst content are needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagrammatic representation of one embodiment of a regeneration tower.

[0011] Figure 2 yes Figure 1 Exploded view of a portion of the regeneration tower.

[0012] Figure 3 Shows Figure 1 part of the reactor in which the catalyst accumulates on the tertiary screen.

[0013] Figure 4 An alternative embodiment of a three-stage screen is shown, wherein the catalyst accumulates on the three-stage screen.

[0014] Figures 5 to 9 is a diagram of different types of three-stage screens.

[0015] Fig.10 An embodiment of a portion of a regeneration tower including a sensor is shown. DETAILED DESCRIPTION

[0016] The present invention solves the problems associated with screen damage in regeneration towers.

[0017] The regeneration tower may contain a cylindrical section and a conical section. The cylindrical section has an inner screen and an outer screen, between which an annular catalyst bed is defined. The conical section is below the cylindrical section. The conical section has an outer screen and a conical inner screen, between which a catalyst bed is defined. The annular catalyst bed is connected to the catalyst bed in the conical section. There is a three-stage screen, which covers the opening defined by the conical inner screen in the conical section. The opening is a circular cross-section of the conical inner screen perpendicular to the center line of the conical section. The opening allows supplementary air to be transmitted from the oxygen-rich chlorination zone to the combustion zone through the inside of the inner screen, so that it supplies oxygen to burn the coked catalyst in the combustion zone. The three-stage screen prevents any catalyst from escaping from the annular catalyst bed in the cylindrical section or the catalyst bed in the conical section from entering the oxygen-rich chlorination zone, and allows supplementary air to be transmitted from the oxygenation zone to the inside of the inner screen. It can be located in the reheat zone or at the bottom of the combustion zone.

[0018] The three-stage screen can be configured in a variety of ways. Suitable configurations include, but are not limited to, flat screens with or without chimneys, concave screens, or convex screens.

[0019] The three-stage screen can be made of any suitable screen material. Suitable screen materials include but are not limited to wire mesh, profiled wire mesh, perforated plate, punched plate or grooved plate.

[0020] The optional aspect of the improved regeneration tower includes increasing the length of the cylindrical catalyst bed. The length of the current bed is generally 15cm to 16cm. Extending the cylindrical section can increase the catalyst residence time. The length of the cylindrical section can be in the range of 12cm to 120cm, or 40cm to 75cm, or 45cm to 60cm. The width of the annular catalyst bed in the cylindrical section can be in the range of 7cm to 50cm, or 7cm to 40cm, or 7cm to 30cm, or 7cm to 20cm, or 7cm to 18cm, or 10cm to 50cm, or 10cm to 40cm, or 10cm to 30cm, or 10cm to 20cm, or 12cm to 50cm, or 12cm to 40cm, or 12cm to 30cm, or 12cm to 20cm. The catalyst volume in the cylindrical section is limited by the length of the cylindrical section and the catalyst bed depth. Another way to determine the length of the cylindrical catalyst bed is based on a fraction of the volumetric flow of catalyst on an hourly basis for a given catalyst bed depth when the CCR is under continuous catalyst circulation conditions. The cylindrical catalyst bed volume is defined by the length of the cylindrical section and the bed depth (i.e., the distance between the inner screen and the outer screen). The fraction of the catalyst volume in the cylindrical section can be in the range of 2% to 15%, or 2% to 10%, or 3% to 15%, or 3% to 10% of the volumetric catalyst circulation rate on an hourly basis. For example, if the CCR circulation rate is 30 m / s, the catalyst bed volume can be 20 m / s to 150 m / s. 3 / hour, the cylindrical bed should have 6m 3 / hour to 9m 3 / hour volume.

[0021] In some embodiments, the ratio of the length of the inner screen to the width of the annular catalyst bed in the cylindrical section ranges from 1:1 to 10:1, or 1:1 to 5:1, or 1:1 to 3.75:1.

[0022] The thermal cycling zone in the regeneration tower is at the top of the combustion zone and migrates downward as the internal screen plugging increases. The weld ring (i.e., the transition from the cylindrical section and the conical section) is sensitive to thermal temperature cycling conditions and may fail. Moving this weld ring to a lower height will allow sufficient residence time in the cylindrical area to inhibit thermal cycling of the weld ring.

[0023] Another aspect is to increase the strength of cylindrical sections. The special-shaped wire / support rod structure of the cylindrical sections of current regenerators needs to carry out a large amount of welding at each connection between each special-shaped wire and the support rod. Any welding that is not fully connected in these weldings will become a failure point. In some embodiments, replacing it with a perforated plate or a slotted plate will significantly reduce the number of weldings and reduce the number of possible failure points. The strength of the cylindrical section will come from the thickness of the slotted plate, and the slotted plate can have a variable thickness and a variable slot size / width / length / depth.

[0024] Circumferential reinforcements can be welded to the inside of the grooved plate to increase strength. This weld will be very strong because the reinforcement will be completely welded to the solid part of the grooved plate. Currently, similar welds are attachment welds between profiled wires and support rods.

[0025] The thickness of the plate may be constant or may vary. For example, the plate may have a thickness in the range of 2 mm to 12 mm.

[0026] The plate may have a first portion with grooves and a second portion without grooves. The first portion may have a thickness of 2 mm to 8 mm, and the second portion may have a thickness of 8 mm to 20 mm. The second portion is a blind portion of the plate, and the plate may be welded to a blind plate that is welded to the top cover to isolate the inlet from the outlet.

[0027] The slots in the plates can be vertical or horizontal. The slots will most likely be vertical to mimic current profile wire slot arrangements, but can be horizontal if desired.

[0028] The slot diameter can vary from top to bottom to control the pressure drop across the slotted plate. The purpose is to control the flow of gas into that section of the inner screen.

[0029] The groove should be small enough to accommodate the catalyst on the side of the grooved plate facing the catalyst. For example, for a catalyst with a diameter of 1.6 mm, the groove will be less than 1.6 mm on the side facing the catalyst. The groove width need not be constant and can change. The groove width on the side facing the catalyst can be the same as or smaller than the groove width on the opposite side of the grooved plate. The groove can be larger to help reduce blockage (similar to a triangular profiled wire), or they can be smaller to help steam distribution (however, this will increase pressure drop). The groove is manufactured by cutting the plate material from the inside, outside or both sides. The groove can be made by any suitable process. Suitable processes include but are not limited to laser cutting, water jet cutting, milling or other machining processes.

[0030] Compared to the profiled wire / support rod configuration, the grooved plate can be made into larger individual sections. The larger plate size reduces the number of welded joints, which increases reliability because welded joints generally have weaker mechanical strength. In some embodiments, there may be only two vertical welded joints and no horizontal joints.

[0031] In some embodiments, the weld between the top of the inner screen open section and the inner screen solid upper blind plate can be eliminated. The slotted plate can incorporate the upper solid blind plate section in a single piece construction, thereby eliminating this weld, which will greatly increase the reliability of the device.

[0032] The solid plate construction will allow for a more secure weld to lower conical screen connection than welding many individual profile wires to the lower conical screen. This will greatly increase the reliability of the device.

[0033] To avoid migration of coked catalyst to the chlorination zone, a secondary screen may be added on the center-facing side of the inner screen. The secondary screen may comprise a wire mesh.

[0034] Another aspect is to avoid burning of the coked catalyst in the chlorination zone as it slides from the combustion zone to the chlorination zone.

[0035] The chlorination zone is an oxygen-rich environment because the upwardly flowing make-up air contains an oxygen content that is typically in the range of 5% to 20%. As a result, the combination of oxygen enrichment and coked catalyst can result in excessive coke combustion rates, generating combustion heat and carbon dioxide. This results in a temperature surge far exceeding 850°C. At high temperatures, the catalyst bed in the chlorination zone can be thermally damaged. In addition, the internal components of the regenerator in the chlorination zone may be thermally damaged. The sliding of the coked catalyst from the annular catalyst bed in the combustion zone to the chlorination zone may occur due to various conditions, such as incomplete coke removal in the combustion zone. This allows for coke remaining on the catalyst pellets to be greater than or equal to 0.2 wt%, or in the range of coke that migrates from the combustion zone to the chlorination zone, or from 0.2 wt% to 20 wt%, or from 0.2 wt% to 15 wt%, or from 0.2 wt% to 12 wt%, or from 0.2 wt% to 10 wt%, or from 0.2 wt% to 6 wt%, or from 0.2 wt% to 5 wt%, or from 0.3 wt% to 20 wt%, or from 0.3 wt% to 15 wt%, or from 0.3 wt% to 12 wt%, or from 0.3 wt% to 10 wt%, or from 0.3 wt% to 6 wt%, or from 0.3 wt% to 5 wt%, or from 1 wt% to 20 wt%, or from 1 wt% to 15 wt%, or from 1 wt% to 12 wt%, or from 1 wt% to 10 wt%, or from 1 wt% to 6 wt%. % to 12 wt %, or 5 wt % to 6 wt %, or 1 wt % to 5 wt %, or 2 wt % to 20 wt %, or 2 wt % to 15 wt %, or 2 wt % to 12 wt %, or 2 wt % to 10 wt %, or 2 wt % to 6 wt %, or 2 wt % to 5 wt %, or 3 wt % to 20 wt %, or 3 wt % to 15 wt %, or 3 wt % to 12 wt %, or 3 wt % to 10 wt %, or 3 wt % to 6 wt %, or 3 wt % to 5 wt %, or 5 wt % to 20 wt %, or 5 wt % to 15 wt %, or 5 wt % to 12 wt %, or 5 wt % to 10 wt %, or 5 wt % to 6 wt %, or 6 wt % to 20 wt %, or 6 wt % to 15 wt %, or 6 wt % to 12 wt %, or 6 wt % to 10 wt %.

[0036] In order to avoid the migration of coked catalyst to the chlorination zone, an online carbon dioxide and / or oxygen sensor can be installed in the supplementary air path between the combustion zone and the chlorination zone. It can be located below the three-stage screen, in the reheating zone, or at the top of the chlorination zone. The sampling probe of the online carbon dioxide and / or oxygen sensor extracts the upward flow of supplementary air from the catalyst bed in the chlorination zone to the bottom of the combustion zone and enters the inside of the internal screen. Since the combustion of coked catalyst forms carbon dioxide, when abnormal coked catalyst combustion occurs in the chlorination catalyst bed, the online carbon dioxide analyzer will detect abnormally high concentrations of carbon dioxide in the supplementary air. The detection system can be integrated into the automatic shutdown of the catalyst regeneration control system to prevent the combustion of coked catalyst in the chlorination zone.

[0037] Figure 1 One embodiment of a regeneration tower 100 is shown. The regeneration tower 100 includes a combustion zone 105, a reheating zone 107, a chlorination zone 110, a drying zone 115, and a cooling zone 120.

[0038] The regeneration tower 100 has a cylindrical section 125 and a conical section 130. Figure 1 to Figure 2 The combustion zone 105 includes the cylindrical section 125 and a portion of the conical section 130 . The reheating zone 107 includes the remaining portion of the conical section 130 .

[0039] Cylindrical section 125 has inner screen 135 and outer screen 140 defining an annular cylindrical catalyst bed 145. There is a secondary screen 150 adjacent inner screen 135 on the opposite side of inner screen 135 from cylindrical catalyst bed 145 and outer screen 140.

[0040] The conical section 130 has a conical inner screen 155 and an outer screen 160. The outer screen 160 is substantially vertical, while the conical inner screen 155 is conical. The space between the outer screen 160 and the conical inner screen 155 forms an annular catalyst bed 165 in the conical section 130.

[0041] There is a tertiary screen 170 that covers the opening in the conical section 130 formed by the conical inner screen 155. The tertiary screen 170 prevents any catalyst escaping from the cylindrical catalyst bed 145 and / or the annular catalyst bed 165 in the conical section 130 from entering the chlorination zone 110. The tertiary screen is located in the reheat zone 107, or at the bottom of the combustion zone 105.

[0042] Figure 1 The three-stage screen 170 shown is a flat screen. The three-stage screen 170 can be other forms.

[0043] Makeup air 250 from the chlorination zone 110 is delivered through the tertiary screen 170 in the conical section 130 of the combustion zone 105 to the interior of the inner screen 135 .

[0044] Figure 3A layer of slipping catalyst bed 255 is shown on top of the tertiary screen 170 in the conical section 130. This increases the pressure drop, resulting in only a portion of the make-up air 250 being passed from the chlorination zone 110 to the interior of the inner screen 135 through the tertiary screen 170. The remainder of the make-up air 260 from the chlorination zone will flow upward along the annular bed between the inner screen 155 and the outer screen 160 at the lower section of the conical section 130 of the combustion zone 105. The make-up air is oxygen-enriched, typically maintained or controlled in the range of 5 mol% to 21 mol%, and the radial regeneration gas flow from the outer screen 160 to the inner screen 155 is typically controlled to less than 3 mol%.

[0045] This misdirected flow path of the make-up air 260 may contaminate the radial flow of the regeneration gas, resulting in a higher oxygen content in the annular catalyst bed 165 in the conical section 130 of the combustion zone 105 .

[0046] Figure 4 A concave tertiary screen 265 is shown that includes a chimney 270 that provides a bypass flow path 275 for make-up air from the chlorination zone 110 to pass to the interior of the inner screen 135 without passing through the escape catalyst bed 255 located at the top of the tertiary screen 265. A chimney cap 280 at the top of the chimney 270 prevents escaped catalyst from passing from the tertiary screen 265 to the chlorination zone 110. The chimney cap 280 and chimney 270 can be made of perforated plates (such as grooved plates, profiled wires, screens, punched plates, or wire mesh) that allow make-up gas to flow through. These reduce the pressure drop of the make-up gas in the flow path from the chlorination zone 110 to the interior of the inner screen 135.

[0047] Figures 5 to 9 Other embodiments of three-stage screens are shown. Figure 5 A planar three-stage screen 175 with a chimney 180 is shown. Figure 6 A concave tertiary screen 185 is shown with a support 190 for the concave tertiary screen 185. The angle of inclination of the screen from horizontal may be deeper than the angle of repose of the catalyst pellets, which is typically in the range of 15 to 30 degrees. Figure 7 A concave tertiary screen 195 is shown with a chimney 200 and a support 205 for the chimney 200 and / or the concave tertiary screen 195. The angle of inclination of the screen from the horizontal may be deeper than the angle of repose of the catalyst pellets as described above. Figure 8 A convex tertiary screen 210 is shown, with a support 215 for the convex tertiary screen 210. The angle of inclination of the screen from the horizontal may be greater than the angle of repose of the catalyst pellets, which is typically in the range of 15 to 30 degrees. Fig. 9A convex tertiary screen 220 is shown with a chimney 225 and a support 230 for the chimney 225 and / or the convex tertiary screen 220. The screen may be tilted from the horizontal at an angle greater than the angle of repose of the catalyst pellets as described above. The chimney may be made of solid rolled plate or perforated plate or screen that reduces the pressure drop as make-up air travels through from the chlorination zone.

[0048] Fig.10 One embodiment of a portion of a regeneration tower including a three-stage screen is shown. A sensor 285 is present in the reheat zone 107 between the combustion zone 105 and the chlorination zone 110 to monitor the makeup air composition leaving the chlorination zone 110. The sensor 285 can be a carbon dioxide sensor and / or an oxygen sensor. If coke combustion occurs in the chlorination zone 110, the drying zone 115 and / or the cooling zone 120, the carbon dioxide content increases due to the combustion of the coked catalyst and the oxygen content decreases to below 21%. When the coked catalyst begins to burn, the sensor detects the change in carbon dioxide and / or oxygen content. The use of high velocity makeup air 275 reduces the detection time of the combustion of the coked catalyst in the chlorination zone 110. The bottom of the internal screen with a chimney directs the makeup air 275 for the sensor probe. It can be used Figures 3 to 9 In some embodiments, sensor 285 may activate an automatic shutdown of the process if carbon dioxide levels increase and / or oxygen levels decrease beyond set limits.

[0049] Specific implementation plan

[0050] While the following is described in conjunction with specific embodiments, it should be understood that this description is intended to illustrate and not to limit the scope of the foregoing description and the appended claims.

[0051] The first embodiment of the present invention is a catalyst regeneration tower, the catalyst regeneration tower comprising: a cylindrical section, the cylindrical section having an inner screen and an outer screen, an annular catalyst bed is formed between the inner screen and the outer screen; a conical section, the conical section having an outer screen and a conical inner screen, a catalyst bed is formed between the outer screen and the conical inner screen, the conical section is positioned below the cylindrical section, the annular catalyst bed is connected to the catalyst bed in the conical section; a three-stage screen, the three-stage screen is in the conical section, covering the opening defined by the conical inner screen; and a shell, the shell contains the cylindrical section and the conical section. One embodiment of the present invention is one, any one or all of the previous embodiments in this paragraph to the first embodiment in this paragraph, wherein the three-stage screen comprises a flat screen, a flat screen with a chimney, a concave screen, a concave screen with a chimney, a convex screen or a convex screen with a chimney. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the first embodiment in this paragraph, wherein the three-stage screen comprises a wire mesh, a profiled wire screen, a perforated plate, a punched plate or a slotted plate. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the first embodiment in this paragraph, wherein the cylindrical section has a bed length in the range of 12 cm to 120 cm. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the first embodiment in this paragraph, wherein the volume of catalyst in the cylindrical section is in the range of 2% to 15% of the volume catalyst circulation rate based on one hour. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the first embodiment in this paragraph, wherein the internal screen in the cylindrical section comprises a punched plate or a slotted plate. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the first embodiment in this paragraph, wherein the ratio of the length of the inner screen to the width of the annular catalyst bed in the cylindrical section is in the range of 1:1 to 5:1. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the first embodiment in this paragraph, wherein the inner screen in the conical section comprises a profiled wire. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the first embodiment in this paragraph, wherein the inner screen has a first side facing the outer screen and a second side facing the center of the cylindrical section, and further comprises a secondary screen adjacent to the second side of the inner screen in the cylindrical section, and wherein the secondary screen comprises a wire mesh.An embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the first embodiment in this paragraph, and also includes: a combustion zone, the combustion zone includes the cylindrical section, and a portion of the conical section; a reheating zone, the reheating zone includes the remaining portion of the conical section below the combustion zone; a chlorination zone, the chlorination zone is below the reheating zone; a drying zone, the drying zone is below the chlorination zone; a cooling zone, the cooling zone is below the drying zone; and a carbon dioxide sensor or an oxygen sensor or both, the carbon dioxide sensor or the oxygen sensor or both are between the chlorination zone and the combustion zone; wherein the tertiary screen is at the bottom of the combustion zone or in the reheating zone; and wherein the shell also contains the chlorination zone, the drying zone and the cooling zone.

[0052] A second embodiment of the present invention is a catalyst regeneration tower, the catalyst regeneration tower comprising: a combustion zone, the combustion zone comprising a cylindrical section, the cylindrical section having an inner screen and an outer screen, an annular catalyst bed is formed between the inner screen and the outer screen, wherein the inner screen comprises a perforated plate or a grooved plate, and wherein the cylindrical section has a bed length in the range of 12 cm to 120 cm; a first part of a conical section, the first part having an outer screen and a conical inner screen, a catalyst bed is formed between the outer screen and the conical inner screen, the conical section is positioned below the cylindrical section, the annular catalyst bed is connected to the catalyst in the conical section a chemical bed; a reheating zone, the reheating zone comprising a second portion of the conical section, the second portion being below the combustion zone; a tertiary screen, the tertiary screen being in the conical section, covering an opening defined by the conical inner screen, and wherein the tertiary screen comprises a wire mesh, a profiled wire mesh, a perforated plate, a punched plate, or a slotted plate, wherein the tertiary screen is at the bottom of the combustion zone or in the reheating zone; a chlorination zone, the chlorination zone being below the combustion zone; a drying zone, the drying zone being below the chlorination zone; a cooling zone, the cooling zone being below the drying zone; and a shell containing the combustion zone, the chlorination zone, the drying zone, and the cooling zone. An embodiment of the invention is one, any, or all of the previous embodiments in this paragraph up to the second embodiment in this paragraph, wherein the tertiary screen comprises a flat screen, a flat screen with a chimney, a concave screen, a concave screen with a chimney, a convex screen, or a convex screen with a chimney. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the second embodiment in this paragraph, wherein the three-stage screen comprises a wire mesh, a profiled wire screen, a perforated plate, a punched plate or a slotted plate. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the second embodiment in this paragraph, wherein the volume of catalyst in the cylindrical section is in the range of 2% to 15% of the volume catalyst circulation rate based on one hour. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the second embodiment in this paragraph, wherein the ratio of the length of the inner screen to the width of the ring between the inner screen and the outer screen in the cylindrical section is in the range of 1:1 to 5:1. One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the second embodiment in this paragraph, wherein the inner screen in the conical section comprises a profiled wire.One embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the second embodiment in this paragraph, wherein the inner screen has a first side facing the outer screen and a second side facing the center of the cylindrical section, and also includes a secondary screen adjacent to the second side of the inner screen in the cylindrical section, and wherein the secondary screen includes a wire mesh.

[0053] A third embodiment of the present invention is a catalyst regeneration tower, comprising: a cylindrical section having an inner screen and an outer screen, an annular catalyst bed formed between the inner screen and the outer screen, wherein the inner screen has a first side facing the outer screen and a second side facing the center of the cylindrical section, and further comprising a secondary screen adjacent to the second side of the inner screen, and wherein the secondary screen comprises a wire mesh, and wherein the cylindrical section has a bed length in the range of 12 cm to 120 cm; a cone A conical section, the conical section having an outer screen and a conical inner screen, a catalyst bed is formed between the outer screen and the conical inner screen, the conical section is positioned below the cylindrical section, the annular catalyst bed is connected to the catalyst bed in the conical section; a three-stage screen, the three-stage screen is in the conical section, covers the opening defined by the conical inner screen, and wherein the three-stage screen comprises a wire mesh, a profiled wire mesh, a perforated plate, a punched plate or a slotted plate; and a shell, the shell containing the cylindrical section and the conical section. An embodiment of the present invention is one, any one or all of the previous embodiments in this paragraph up to the third embodiment in this paragraph, wherein the inner screen comprises a punched plate or a slotted plate; or the three-stage screen comprises a wire mesh, a profiled wire mesh, a perforated plate, a punched plate or a slotted plate; or both of the above. An embodiment of the present invention is one, any or all of the previous embodiments in this paragraph up to the third embodiment in this paragraph, and also includes: a combustion zone, the combustion zone includes the cylindrical section, and a portion of the cylindrical section; a reheating zone, the reheating zone includes the remaining portion of the conical section below the combustion zone; a chlorination zone, the chlorination zone is below the reheating zone; a drying zone, the drying zone is below the chlorination zone; a cooling zone, the cooling zone is below the drying zone; and a carbon dioxide sensor or an oxygen sensor or both, the carbon dioxide sensor or the oxygen sensor or both are between the chlorination zone and the combustion zone; wherein the tertiary screen is at the bottom of the combustion zone or in the reheating zone; and wherein the shell also contains the chlorination zone, the drying zone and the cooling zone.

[0054] Although there is no further detailed description, it is believed that those skilled in the art can utilize the present invention to the greatest extent by using the foregoing description and can easily determine the essential characteristics of the present invention without departing from the spirit and scope of the present invention to make various changes and modifications of the present invention and adapt it to various usages and conditions. Therefore, the aforementioned preferred specific embodiments should be understood as merely illustrative and not to limit the rest of the present disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0055] In the foregoing, all temperatures are set forth in degrees Celsius and all parts and percentages are by weight unless otherwise indicated.

Claims

1. A catalyst regeneration tower, comprising: a cylindrical section (125) having an inner screen (135) and an outer screen (140) between which an annular catalyst bed (145) is formed; a conical section (130) having an outer screen (160) and a conical inner screen (155), between which a catalyst bed (165) is formed, the conical section (130) being positioned below the cylindrical section (125), the annular catalyst bed (145) being connected to the catalyst bed (165) in the conical section (130); a tertiary screen (170) located in the conical section (130) and covering the opening defined by the conical inner screen (155); and A housing contains the cylindrical section (125) and the conical section (130).

2. The catalyst regeneration tower according to claim 1, wherein the three-stage screen (170) comprises a flat screen (170), a flat screen (175) with a chimney (180), a concave screen (185), a concave screen (195) with a chimney (200), a convex screen (210) or a convex screen (220) with a chimney (225).

3. The catalyst regeneration tower according to claim 1, wherein the tertiary screen (170) comprises a wire mesh, a profiled wire mesh, a perforated plate, a punched plate or a grooved plate.

4. The catalyst regeneration tower according to claim 1, wherein the cylindrical section (125) has a bed length in the range of 12 cm to 120 cm.

5. The catalyst regeneration tower according to claim 1, wherein the volume of the catalyst in the cylindrical section (125) is in the range of 2% to 15% of a volume catalyst circulation rate on an hourly basis.

6. The catalyst regeneration tower according to claim 1, wherein the inner screen (135) in the cylindrical section (125) comprises a perforated plate or a grooved plate.

7. The catalyst regeneration tower according to claim 1, wherein the ratio of the length of the inner screen (135) to the width of the annular catalyst bed (145) in the cylindrical section (125) is in the range of 1:1 to 5:

1.

8. The catalyst regeneration tower of claim 1, wherein the conical inner screen (155) in the conical section (130) comprises a profiled wire.

9. The catalyst regeneration tower according to claim 1, wherein the inner screen (135) has a first side facing the outer screen (140) and a second side facing the center of the cylindrical section (1255), and further comprises a secondary screen (150) adjacent to the second side of the inner screen (135) in the cylindrical section (125), and wherein the secondary screen (150) comprises a wire mesh.

10. The catalyst regeneration tower according to claim 1, further comprising: a combustion zone (105), the combustion zone comprising the cylindrical section (125), and a portion of the conical section (130); a reheating zone (107) comprising a remaining portion of the conical section (130) below the combustion zone (105); a chlorination zone (110), the chlorination zone being below the reheating zone (107); a drying zone (115), the drying zone being located below the chlorination zone (110); a cooling zone (120) located below the drying zone (110); and a carbon dioxide sensor or an oxygen sensor or both, wherein the carbon dioxide sensor or the oxygen sensor or both are located between the chlorination zone (110) and the combustion zone (105); wherein the tertiary screen (170) is located at the bottom of the combustion zone (105) or in the reheating zone (107); and The housing further comprises the chlorination zone (110), the drying zone (115) and the cooling zone (120).

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