KR20080098052A - Stripping apparatus and process - Google Patents

Abstract

A baffle-style stripping arrangement for an FCC process has downcomers (66) radially extending from a central axis in a stripping section (32). The baffles (35) may comprise radial sectors (58) with edges (58c, 58d) of adjacent sectors defining downcomers. Each sector may comprise a perforate section (60) and an imperforate section (62). The downcomer section of a superjacent baffle is aligned with the imperforate section of a subjacent baffle to assure horizontal movement of catalyst across the upper surface of the baffle.

Description

Decomposition Apparatus and Decomposition Method {STRIPPING APPARATUS AND PROCESS}

The present invention relates to an apparatus and a method for bringing a catalyst into fluidized contact with a hydrocarbon. More specifically, the present invention relates to an apparatus and method for decomposing droplet entrained or adsorbed hydrocarbons from catalyst particles.

Various processes contact the hydrocarbon-containing feed with the finely divided particulate material under conditions in which the fluid keeps the particles fluidized to effect delivery of the solid particles to the other stages of the process. Fluidized Catalytic Cracking (FCC) is a prime example of a process for contacting hydrocarbons in a reaction zone with a catalyst composed of finely divided particulate material.

The FCC process unit includes a reaction zone and a catalyst regeneration zone. In the reaction zone, the feed stream is contacted with finely divided fluidized solid particles or catalyst which are maintained at high temperature and at moderate static pressure. Contact of the feed with the catalyst typically takes place in the riser conduit, but may occur in any efficient configuration, such as known devices for contacting for short contact times. In the case of a riser, a generally vertical conduit contains the main reaction site, at which the discharge of the conduit is emptied into a large volumetric process vessel, which may be referred to as a reaction vessel or a separate vessel. The residence time in the riser of the catalyst and hydrocarbon necessary for the substantial completion of the decomposition reaction is only a few seconds or less. The vapor / catalyst stream flowing out of the riser may be led from the riser to a solid-steam separation device disposed within the separation vessel, or may enter the separation vessel directly without passing through the intermediate separation unit. If no intermediate device is provided, a large amount of catalyst is extracted from the flowing steam / catalyst stream as the flowing steam / catalyst stream exits the riser and enters the separation vessel. One or more additional solid / vapor separation devices, usually cyclone separators, are usually placed on top of this vessel in a large separation vessel. The product of the reaction is separated from the portion of the catalyst still carried by the vapor stream by the cyclone (s) and the vapor is evacuated from the cyclone and separation zone. The spent catalyst falls down to the lower position in the separation vessel.

The catalyst continues to circulate from the reaction zone to the regeneration zone and then back to the reaction zone. Thus, the catalyst not only provides the essential catalytic activity but also serves as a transfer medium for heat transfer between zones. Any FCC catalyst can be used in the process. The particle size will typically be less than 100 microns. The catalyst withdrawn from the regeneration zone is referred to as "regenerated" catalyst. The catalyst charged in the regeneration zone is brought into contact with an oxygen containing gas such as air or oxygen enriched air under conditions that result in the combustion of coke. This results in an increase in the temperature of the catalyst and the generation of a large amount of hot gas removed in the regeneration zone as a gas stream called a flue gas stream. The regeneration zone is typically operated at temperatures of 600 ° C. (1112 ° F.) to 800 ° C. (1472 ° F.). Further information regarding the operation of FCC reaction zones and regeneration zones can be obtained from US 4,541,922, US 4,541,923, US 4,431,749, US 4,419,221 and US 4,220,623.

The rate of conversion of the feedstock in the reaction zone is controlled by controlling the temperature maintained in the reaction zone, the activity of the catalyst and the amount of catalyst (ie the ratio of catalyst to oil). The most common way of controlling the temperature in the reaction zone is by controlling the rate of circulation of the catalyst from the regeneration zone to the reaction zone, which simultaneously changes the ratio of catalyst to oil. In other words, if it is desired to increase the rate of conversion in the reaction zone, the flow rate of catalyst from the regeneration zone to the reaction zone is increased. Because of this, more catalyst is present in the reaction zone if the reaction volume is filled with the same volume of oil. Since the temperature in the regeneration zone is much higher than the temperature in the reaction zone under normal operation, the temperature of the reaction zone is increased by increasing the rate of circulation of the catalyst from the regeneration zone to the reaction zone.

The chemical composition and structure of the feed to the FCC unit will affect the amount of coke deposited on the catalyst in the reaction zone. Typically, the higher the molecular weight, Conradson carbon, heptane insolubles, and carbon to hydrogen ratio of the feedstock, the higher the level of coke on the spent catalyst. More conversion also increases the level of coke on the spent catalyst. In addition, higher levels of combined nitrogen, such as those found in oil from shale, will increase the level of coke on the spent catalyst. Treatment of heavier feedstocks, such as deasphalted oil or atmospheric bottoms from crude oil (commonly referred to as residue oil) sorting units, results in an increase in some or all of these factors. This, in turn, leads to an increase in coke level on the spent catalyst. The term "consumed catalyst" as used herein is intended to refer to the catalyst employed in the reaction zone, which is sent to the regeneration zone for removal of coke deposits. The term is not intended to indicate a lack of overall catalytic activity by the catalyst particles. The term "used catalyst" is intended to have the same meaning as the term "consumed catalyst".

Most of the hydrocarbon vapors in contact with the catalyst in the reaction zone are separated from the solid particles by ballistic separation and / or centrifugation in the reaction zone. However, catalyst particles employed in FCC processes have a large surface area due to the very large number of pores in these particles. As a result, when the catalyst material enters the decomposition zone, it retains hydrocarbons in the pores of the catalyst material, on the outer surface of the catalyst and in the spaces between the respective catalyst particles. The amount of hydrocarbons retained on each individual catalyst particle is very small, but due to the large amount of catalyst and the high catalyst circulation rate typically used in modern FCC processes, significant amounts of hydrocarbons are withdrawn from the reaction zone by the catalyst.

Accordingly, it is a common procedure to remove or decompose hydrocarbons from the spent catalyst before the spent catalyst reaches the regeneration zone. The high hydrocarbon concentration on the spent catalyst entering the regenerator increases the relative carbon combustion of the catalyst and results in a higher regenerator temperature. It is important to avoid unnecessary combustion of hydrocarbons during the processing of heavy (relatively high molecular weight) feedstocks, because treating these feedstocks during the reactions compared to the coking rate in the case of lightweight feedstocks. This is because it increases the deposition of coke on the catalyst and raises the temperature in the regeneration zone. Improved decomposition allows for lower regenerator temperatures and higher conversion rates.

The most common method of cracking the spent catalyst involves passing cracked gas, typically steam, into the flow stream countercurrently to the flow direction of the flow stream of catalyst. Such steam cracking processes of varying degrees of efficiency are entrained in the catalyst and remove hydrocarbon vapor adsorbed on the catalyst. The contact of the catalyst with the decomposition medium can be made in a simple open vessel as described in US Pat. No. 4,481,103.

The efficiency of catalytic cracking is increased by using vertically spaced baffles that cascade the catalyst from side to side as the catalyst moves downward in the cracking apparatus and countercurrently contacts the cracking medium. Moving the catalyst in the horizontal direction increases the contact of the catalyst with the decomposition medium, so that more hydrocarbons are removed from the catalyst. In this configuration, the catalyst passes through a maze path through a series of baffles located at different levels. Catalyst and gas contact is increased by this configuration through the cracking device through a nearly unopened vertical path of large cross section. Other examples of such disassembly devices for FCC units are shown in US 2,440,620, US 2,612,438, US 3,894,932, US 4,414,100 and US 4,364,905. These references present a typical decomposition vessel configuration having an decomposition vessel and a series of outer baffles in the form of truncated conical sections that guide the catalyst inwardly in a series of internal baffles. The inner baffle is a centrally placed conical or truncated conical section supported on the reactor riser that rises through the dissolution vessel. The inner baffle directs the catalyst outwards onto the outer baffle, and the outer baffle directs the catalyst inwardly onto the inner baffle to promote horizontal movement. The decomposition medium enters from below the lower baffle and continues to rise upwards from the bottom of one baffle to the bottom of the next subsequent baffle. Modifications to the baffle include the addition of a skirt around the trailing edge of the baffle as shown in US 2,994,659 and the use of multiple linear baffle sections at different baffle levels as shown in FIG. 3 of US 4,500,423. do. A variant of introducing a decomposition medium is shown in US Pat. No. 2,541,801 in which a large amount of fluidizing gas is introduced at a plurality of discrete positions. US 5,531,884 presents a modification of a baffle cracking device in which one or more large vertical conduits are integrated in the baffle to provide additional catalyst and gas circulation paths through the baffle. It is also known to concentrate the opening in the exact center of the decomposition baffle.

The baffle in the disassembly vessel for the FCC unit is typically oriented to have an angle of 45 ° with respect to the horizontal line. The inclined baffle ensures that the catalyst moves down the tray to the next level in the decomposition vessel to ensure that it is moved by the horizontal component. However, since each of the inclined trays occupies a considerable height, such trays limit the number of trays that can be installed in a disassembled vessel of a given height. The greater the number of trays in the disassembly vessel, the better the overall performance. On the other hand, by setting the baffle to a smaller slope, catalyst will accumulate on top of the baffle if fluidization throughout the baffle does not increase, which may require increasing the flow rate of the decomposition medium. US 2002/0008052 Al discloses a complete fluidized cracking baffle.

US 5,910,240 discloses a truncated conical decomposition baffle comprising vanes configured to impart rotational motion to a descending catalyst. US 5,549,814 discloses a disassembly vessel with a layer in which an inverted U-shaped grid extends radially from the inner riser. Perforations in the legs of the "U" allow passage of the dissolution medium.

WO 91/00899 discloses an exploded vessel with a perforated horizontal tray. Fluidization in the cracking vessel is such that the catalyst is lowered from one tray to another only substantially through the down flow section of the individual trays. The catalyst material forms a dense bed on the top of each tray so that a significant amount of catalyst does not seep through the perforations in the tray. This reference also teaches the use of a deflection plate over a down flow path that is aligned in a vertical direction to the center of the annular tray (s) comprising a network of tissues or bar arrays. US 2001/0027938 A1 also teaches a horizontal baffle.

It has now been found that providing a dissolution vessel with a downward flow passage having a baffle extending radially in the center or inner conduit of the baffle generally moves the catalyst horizontally in a plurality of angular directions across the surface of the baffle. . Thus, the catalyst spreads each baffle further in the horizontal direction across the surface, making more contact with the upwardly flowing decomposition medium.

In an embodiment, the present invention includes a decomposition apparatus for decomposing hydrocarbons from particulate material. The cracking device includes a cracking vessel and at least one port for receiving particles containing hydrocarbons formed by the cracking vessel and extracting cracked fluid and cracked hydrocarbons from the cracking vessel. The plurality of dissolution baffles are spaced in the vertical direction over at least a portion of the dissolution vessel. One of the plurality of baffles includes at least three descending flow paths extending radially from the center of the vertical direction of the disassembled vessel. A plurality of openings are distributed over at least a portion of the surface of one of the dissolution baffles. At least one fluid inlet directs the cracking fluid down one of the cracking baffles to break down the hydrocarbon from the particulate material. The cracking device includes at least one particle outlet for recovering the cracked particles from the cracking baffle.

In another embodiment, the conduit extends through the disassembly vessel and the downward flow path extends radially from the conduit.

In another embodiment, the present invention includes a decomposition method for breaking down hydrocarbons from particulate materials. The decomposition method involves feeding the hydrocarbon-containing particles into a vessel containing a plurality of decomposition baffles spaced apart in the vertical direction. One of the plurality of baffles includes a descending passage extending radially from the center of the disassembly vessel. The downward flow path is defined by non-parallel opposite sides. A plurality of openings are distributed over at least a predetermined section of the decomposition baffle surface of one of the decomposition baffles. The decomposition method includes guiding the decomposition fluid down the decomposition baffle of one of the decomposition baffles that degrades the hydrocarbon from the particulate material. The cracking fluid and cracked hydrocarbon are recovered from the vessel and the cracked catalyst is collected from the vessel.

Accordingly, it is an object of the present invention to increase the decomposition efficiency in a baffle decomposition vessel.

Further objects, examples and details of the invention are given in the following detailed description of the invention.

1 is a schematic elevation view of an FCC reactor of the present invention.

FIG. 2 is a partially enlarged perspective view of the disassembled section of the present invention shown in FIG. 1.

3 is a cross-sectional view taken along line 3-3 of FIG.

First, with more details of the FCC process in which the present invention can be used, a typical feed for an FCC unit is a gas oil, such as light gas oil or reduced pressure gas oil. Other feed streams extracted from petroleum to the FCC unit may comprise a diesel boiling range mixture of heavier hydrocarbons such as hydrocarbons or reduced crude oil. The feed stream preferably consists of a mixture of hydrocarbons having a boiling point above 230 ° C. (446 ° F.), more preferably above 290 ° C. (554 ° F.) as determined by appropriate ASTM test methods. FCC type units that treat heavier feedstocks, such as atmospheric residues, are commonly referred to as residual crude cracking units or resid cracking units. The method and apparatus of the present invention can be used for FCC or residue cracking processes. For convenience, the remainder of this specification refers only to FCC processes.

Due to the widespread use of vertical tubular conduits or pipes, the reaction zones of FCC processes, commonly referred to as "risers", are maintained at high temperature conditions, including temperatures generally above 425 ° C (797 ° F). Preferably, the reaction zone has a temperature of 480 ° C. to 590 ° C. (896 ° F. to 1094 ° F.) and a pressure of 65 to 500 kPa (9.4 to 72.5 psia) —but preferably less than 275 kPa (39.9 psia). Phosphorus decomposition is maintained. The ratio of catalyst to oil based on the weight of catalyst and feed hydrocarbon entering the bottom of the riser may range from a maximum of 20: 1, but is preferably between 4: 1 and 10: 1. Hydrogen is usually not added to the riser, but hydrogenation is known in the art. Depending on the situation, steam may enter the riser. The average residence time of the catalyst in the riser is preferably less than 5 seconds. The type of catalyst employed in the FCC process can be selected from a variety of commercially available catalysts. Catalysts comprising zeolite-based materials are preferred, but more outdated amorphous catalysts may be used if desired.

The catalyst regeneration zone is preferably operated at a pressure of 35 to 500 kPa (5.1 to 72.5 psia). The spent catalyst charged to the regeneration zone may contain from 0.2 to 15% by weight coke. This coke consists mainly of carbon and may contain 3 to 12% by weight of hydrogen together with sulfur and other elements. Oxidation of coke will produce common combustion products water, carbon oxides, sulfur oxides and nitrogen oxides. As is known to those skilled in the art, the regeneration zone may take on various configurations in which regeneration is performed in one or more stages. Other variations are possible due to the fact that regeneration can be achieved by the presence of the fluidizing catalyst in the lean or concentrated phase in the regeneration zone. The term "dilute phase" is intended to denote a catalyst / gas mixture having a density of less than 300 kg / m ³ (18.7 lb / ft ³ ). In a similar manner, the term "dense phase" is intended to denote a catalyst / gas mixture having a density of at least 300 kg / m ³ (18.7 lb / ft ³ ). Representative lean phase operating conditions often include catalyst / gas mixtures having a density of 15 to 150 kg / m ³ (0.9 to 9.4 lb / ft ³ ).

Figure 1 shows an FCC unit using a concentric riser and disassembly vessel. The regenerator standpipe 16 transfers the catalyst from the regenerator 10 at a rate regulated by the slave valve 11. The fluidizing medium from the nozzle 17 conveys the catalyst upward through the riser 14 at a relatively high density until the feed is injected over a stream of catalyst particles through which a plurality of feed injection nozzles 15 (only one is shown) flows. do. The final mixture tangentially connects the mixture of gas and catalyst via port 29 to a separation vessel 23 which conducts separation of the gas from the catalyst at the top 19 of the riser 14. It continues to be conveyed upwards through the riser 14 until discharge in the direction. Delivery conduit 22 carries hydrocarbon vapor, including cracked hydrocarbons, cracking medium, and droplet entrained catalyst, to one or more cyclones 24 in separation vessel 12 separating the spent catalyst from the hydrocarbon vapor stream. A collection chamber 25 in the separation vessel 12 collects the separated hydrocarbon vapor stream from the cyclone 24 and directs it to the outlet nozzle 20 and finally to the fractionation zone (not shown). The dipleg 18 is a decomposition section via a port 37 formed on the wall 29 of the separation vessel 23 for the catalyst from the cyclone 24, and finally the adsorbed or splash entrained hydrocarbon with the catalyst. It discharges to the lower part of the separator vessel 12 in the collection space 31 which guides to (32). The catalyst separated in separation vessel 23 enters the decomposition section 32 directly. Since the separation vessel 23 includes the decomposition section 32, it may also be referred to as a decomposition vessel. The cracking section 32 includes a baffle 35 that promotes contact and mixing between the cracking gas and the catalyst. The baffle is shown as being horizontal, but may take other shapes, such as a truncated cone shape. The cracking gas enters the bottom of the cracking section 32 through the inlets 33, 34. Inlets 33 and 34 may supply cracked gas to one or more distributors (not shown) that distribute the gas around the circumference of baffle 35. The spent catalyst exits digestion section 32 through reactor conduit 36 and enters regenerator 10.

Regeneration gas, such as compressed air, enters regenerator 10 through conduit 30. The air distributor 28 spreads the air over the cross section of the regenerator 10 where the air and the spent catalyst contact. Coke is removed from the catalyst by burning with oxygen from the air distributor 28. Combustion by-products and unreacted air constituents, together with the entrained catalyst, rise upward through the regenerator 10 to the inlets of the cyclones 26 and 27. Relatively catalyst-free gas is collected in the inner chamber 38, which communicates with a gas outlet 40 that removes regenerated gas consumed in the regenerator 10. The catalyst separated by the cyclones 26, 27 is extracted through the discharge legs 42, 43 and returned to the bed 44 at the bottom of the regenerator 10.

2 shows a partially enlarged perspective view of the disassembled section 32 of FIG. 1. In order to fully illustrate the disassembly section 32 of the present invention, the plurality of parts of FIG. 2 are excluded or broken. The spent catalyst enters the decomposition section 32 in the collection space 31 via the top 23a or port 37 of the separation vessel 23. The degraded hydrocarbons and decomposition medium exit through the top of the separation vessel 23. Each baffle 35 is supported in the disassembly section 32 by a cantilevered support structure 50. The cantilevered support structure 50 may include an outer circumferential band 52 and an inner circumferential band 54. The outer circumferential band 52 is connected to the inner circumferential band 54 by an elongated bar or spoke 56 extending radially from the inner circumferential band 54 to the outer circumferential band 52. At each end of each spoke 56 an outer circumferential band 52 and an inner circumferential band 54 are fixed. The outer circumferential band 52 is fastened to the wall 39 of the separating vessel 23 including the disassembly section 32, or the inner circumferential band 54 is the remaining portion of the disassembling section 32 and the separating vessel 23. It is fastened to the outer wall 13 of the riser 14 extending upwardly through. In embodiments that do not include an inner riser inside the disassembly section 32, the spokes may extend radially across the outer circumferential band 52, with only one end of each spoke 56 being the outer circumferential band. 52 can be fastened. The other end of spoke 56 will be spaced apart from wall 39. This embodiment will eliminate the need for an inner circumferential band 54.

Each baffle 35 includes a plurality of sectors including a perforated section 60 and a non-perforated section 62. Perforated section 60 may consist of an opening in a plate, and may include a grating. In an embodiment, the opening in the baffle is large enough to allow the catalyst particles to pass through. The non-perforated section 62 may be part of a plate including a baffle sector 58 having no opening therein, or may include a non-perforated plate overlying the perforated section 60 of the baffle sector 58. Each lateral edge of the baffle sector 58 may include a skirt wall 64 suspended below this baffle sector. In an embodiment, all adjacent baffle sectors 58 are typically spaced to some extent, and adjacent edges of adjacent baffle sectors 58 form a down flow passage or a down flow passage section 66. Adjacent baffles 35 are arranged in staggered orientation along the height of the disassembly section 32. Thus, the downward flow path section 66 of the upper baffle 35 is aligned vertically with the non-perforated section 62 of the lower baffle 35. This configuration consisting of the alignment of the down flow section 66 and the non-perforated section 62 and the offset of the down flow section 66 of the baffle 35 adjacent to it, in particular across the surface of the baffle 35, in particular the baffle sector 58. Ensure horizontal movement of the catalyst across While the catalyst falls through the opening in the perforated section 60 of each baffle sector 58, most of the catalyst falls through the down flow passage section 66. Thus, the perforated plate aligned vertically with the downward flow path section 66 of the upper baffle 35 prevents the catalyst from falling straight through all of the baffle sections in the vertical direction without moving in the horizontal direction.

In an embodiment, the separation height between each successive tray is 31 to 76 cm (12 to 30 inches) apart. In another embodiment, the separation height between each successive tray is separated by 24 inches (61 cm), but the separation height is reduced by 18 inches (46 cm) to fill more baffles in the disassembly section 32. It may be desirable. If all baffles 35 are shown in FIG. 2, nine baffles 35 will be provided.

3 is a cross-sectional view taken along line 3-3 of FIG. 3 shows eight baffle sectors 58 constituting riser 14 and baffle 35. Each baffle sector 58 has an inner circumferential edge 58a, an outer circumferential edge 58b and radial edges 58c, 58d. The inner circumferential edge 58a is supported on the upper ridge 54a of the inner circumferential band 54, and the outer circumferential edge 58b is supported on the upper ridge 52a of the outer circumferential band 52. . The inner circumferential edge 58a forms an arc shorter than the arc formed by the outer circumferential edge 58b. The non-perforated section 62 covers the spokes 56 shown in dashed lines, which support respective circumferential bands 52, 54 that are not fastened to the respective walls 39, 13. Opposite radial edges 58c and 58d of adjacent baffle sectors 58 define a down flow section 66. Thus, in the embodiment the perforated section 60 lies between the down passage sections 66. Moreover, in the embodiment the non-perforated section 62 lies between two perforated sections 60 and two descending flow path sections 66. The skirt wall 64 may extend downward at the radial edges 58c, 58d of each baffle sector 58 only between the inner circumferential band 54 and the outer circumferential band 52. In an embodiment, each baffle sector 58, each non-perforated section 62, and / or each down flow section 66 extends radially in the center of the decomposition section 32. In an embodiment, the opposing lateral edges of each baffle sector 58, each non-perforated section 62 and each falling flow path section 66 are non-parallel so that the decomposing section ( 32 toward each other towards the center of the

When the catalyst falls from the down flow section 66 of the upper baffle 35, it strikes the non-perforated section 62 and spreads in a horizontal direction at an angle towards the down flow section 66. In such an embodiment with eight baffle sections each having two non-perforated sections 62 between two descending flow path sections 66, the catalyst falling from the upper baffle 35 will spread horizontally in nearly 16 angular directions. will be.

Perforated section 60 may include many openings drilled into the plate. In the embodiment of the present invention, the baffle openings are distributed over the entire area of the perforated section 60 of the baffle 35. The spacing of the perforations on the on-side of the perforated section 60 may be determined in any manner to remove a wide band or area that does not include a hole for delivery of the fluidizing medium. The distribution of the holes advantageous to the invention can be explained by the maximum circle width comprising at least one opening. In general, it is desirable for any circle of at least 0.09 m ² (1 ft ² ) to enclose at least a portion of one or more openings in that region. It is desirable that the circle area that can be circumscribed without enclosing a hole does not necessarily exceed 0.05 m ² (0.5 ft ² ). Following this type of criterion for the minimum geometry of the area that should include a perforation will facilitate sufficient fluidization.

In an embodiment, the perforated section 60 may include a grating 68 forming an opening 70 as shown in FIG. 3. The grating 68 may comprise a grid of long strips in which the major surfaces of each of the long strips intersect each other. In another embodiment, the grating 68 may comprise a series of elongated strips, which elongate parallel to a series of parallel or patterned rods supported on top of the elongated strip. Those skilled in the art will be familiar with the various methods of making the perforated section 60. However, in the embodiment the opening in the perforated section 60 must be large enough to allow a significant amount of catalyst to pass through this opening. This is most easily achieved by the perforated section 60 comprising the grating 68. The term "equivalent amount of catalyst" means at least 20% by weight of the catalyst descending down through the opening 70 in each baffle 35. It is typically estimated that 60% by weight of catalyst will descend through the opening of each baffle 35 that includes the grating 68 for the perforated section 60. The remaining catalyst will descend through the down flow section 66 of each baffle 35. In an embodiment, at least 35% of the area of the perforated section 60 is large enough to allow the catalyst particles and decomposition medium to pass through and small enough to reduce the formation of large gas bubbles at the bottom of the baffle 35. An opening. In an embodiment, the decomposition fluid phase must rise through the opening without major obstacles. As such, the velocity of the decomposition fluid passing through the opening should be no greater than 0.15 m / s (0.5 ft / s). Opening dimensions of 1.0 to 1.3 cm (0.375 to 0.5 inch) would be appropriate. Moreover, steam rates of 0.015 to 0.6 m / s (0.05 to 2 ft / s) and steam ratios of 0.5 to 3.0 kg steam / kg catalyst (0.5 to 3.0 lb steam / lb catalyst) will be appropriate for the present invention.

The non-perforated section 62 may include a blank-off plate supported on the perforated section 60 of the baffle 25 in an embodiment. The obstruction plate constituting the non-perforated section 62 may be secured to the perforated section 60. The obstruction plate may be supported flat on the perforated section 60 and may include one inclined top or two inclined tops that guide the catalyst and effluent.

In an embodiment, the cross section of the disassembly section 32 and each baffle 35 is divided into eight baffle sectors 58 having the same area. Each baffle sector 58 may include a 36 ° partially open baffle area including a perforated section 60 and a non-perforated section 62, and a 9 ° fully open down flow path section 66. Can be. In an embodiment, the non-perforated sections 62 make up 9 ° of each baffle sector 58 and the perforated sections 60 make up 27 ° of each baffle sector 58.

In other embodiments, instead of using spokes 56 to support the baffles, the inner and outer edges of the skirt wall 64 may be secured to the outer circumferential band 52 and the inner circumferential band 54, respectively. . The outer circumferential band 52 or the inner circumferential band 54 will then be fixed to either the wall 39 or the wall 13 of the riser 14. In another embodiment, the baffle configuration may be provided in the disassembly vessel that does not include the inner riser 14. Other support means may be acceptable.

In the examples, the baffles are typically formed of alloy steel that withstands high temperature conditions in the reaction zone. Such steels are often corroded and it would be advantageous to use inserts or nozzles that form openings and provide resistance to corrosion conditions imposed by the circulation of the catalyst over the top of the baffle. Moreover, the baffles are routinely covered with a refractory material that provides additional corrosion resistance. Details regarding corrosion resistant nozzles and fire resistant linings are well known to those skilled in the art.

Claims (10)

A hydrocarbon cracking device for decomposing hydrocarbons from particulate material, The decomposition vessel 32, At least one port 29, 37 for receiving hydrocarbon-containing particles formed by the cracking vessel and withdrawing cracked fluid and cracked hydrocarbons from the cracking vessel, A plurality of decomposition baffles 35 spaced in a vertical direction over at least a portion of the decomposition vessel, one of the plurality of decomposition baffles being at least three descending flow paths 66 extending radially from the center of the vertical direction of the decomposition vessel; ) And the decomposition baffle to include, A plurality of openings distributed over at least a portion (60) of the decomposition baffle surface of one of said decomposition baffles. At least one fluid inlet (33, 34) for guiding the cracking fluid under the cracking baffle of one of the cracking baffles to crack the hydrocarbon from the particulate material, and At least one particle outlet 36 for recovering the degraded particles from the decomposition baffle Hydrocarbon decomposition apparatus comprising a. 2. The hydrocarbon cracking apparatus according to claim 1, wherein one of said at least three descending passages is defined by non-parallel opposite sides (58c, 58d). 3. The hydrocarbon cracking apparatus according to claim 1 or 2, wherein one cracking baffle of said cracking baffle is horizontal. The hydrocarbon decomposition of claim 1, wherein the one baffle further comprises a non-perforated section 62 and a perforated section 60 comprising the plurality of openings. Device. 5. The hydrocarbon cracking device according to claim 1, wherein said non-perforated section is disposed between two said descending flow paths. 6. 6. The hydrocarbon cracking device according to claim 1, wherein the perforated section is disposed between the descending flow path and the non-perforated section. 7. The hydrocarbon cracking device according to claim 1, wherein a conduit 14 extends through the cracking vessel and the cracking baffle is supported at least indirectly by the pipe. . 8. A hydrocarbon cracking device according to any one of the preceding claims wherein said one cracking baffle comprises a grate. As a hydrocarbon decomposition method for decomposing hydrocarbons from particulate material, Feeding hydrocarbon-containing particles into a decomposition vessel 32 comprising a plurality of decomposition baffles 35 spaced apart in a vertical direction, one of the plurality of decomposition baffles being radially from the center of the decomposition vessel; A downward flow path 66 defined by the non-parallel opposing side portions 58c, 58d and a plurality of openings distributed over at least a predetermined section 60 of the decomposition baffle surface of one of the decomposition baffles. Steps, Directing the cracking fluid down a cracking baffle of one of the cracking baffles to crack hydrocarbons from the particulate material; Recovering cracked fluid and cracked hydrocarbons from the cracking vessel; and Collecting the cracked catalyst from the cracking vessel Hydrocarbon decomposition method comprising a. 10. The method of claim 9, wherein said one cracking baffle comprises at least three said descending flow paths.

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