RU2782503C1 - Apparatus and process for separating gases from the catalyst - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: field of the present invention is processes and apparatuses for separating entrained gaseous hydrocarbon products from catalyst particles. A method for separating catalyst particles from a stream of gaseous products includes: bringing the flow of hydrocarbon raw materials into contact with catalyst particles in an elongated riser to obtain gaseous products; bringing catalyst particles and gaseous products into a vortex-like motion in an angular direction when exiting the specified riser and entering the separation chamber to separate catalyst particles from the specified gaseous product; blocking the vortex-like motion of the specified catalyst particles and gaseous products when exiting the specified separation chamber and entering the annular space of the reactor. The apparatus for separating catalyst particles from the flow of gaseous products contains: an elongated riser in which the flow of hydrocarbon raw materials is brought into contact with the catalyst particles to obtain a gaseous product, and this riser includes the outlet of a swirling sleeve, made with the possibility of bringing solid particles of the catalyst and gaseous products into a vortex-like motion in the angular direction to separate the catalyst particles from the specified gaseous product; a separation vessel in communication with the specified outlet of the swirling sleeve of the specified riser, and the specified separation vessel includes an outer shell and a stripping section containing internal elements of the stripping section; a tunnel containing a vertical wall and providing communication of the specified separation vessel with the annular space of the reactor.

EFFECT: quenching the tangential pulse transferred from the outlet sleeves of the riser into a dense annular layer, reducing the entrance of the catalyst into the annular space of the reactor and erosion of equipment or catalyst circulation.

10 cl, 4 dwg

Description

Field of invention

The scope of the present invention is processes and apparatus for bringing a fluidized catalyst into contact with hydrocarbons. More specifically, the scope of the present invention is processes and apparatus for separating entrained gaseous hydrocarbon products from catalyst particles.

Prerequisites for the creation of the invention

Fluidized catalytic cracking (FCC) is a process in which, in a reaction zone, hydrocarbons are brought into contact with a catalyst composed of a fine powder material. The hydrocarbon feed stream and fluidizing gases such as steam fluidize the catalyst and typically carry it in a riser, the catalyst accelerating the cracking reaction. As the cracking reaction proceeds, significant amounts of hydrocarbon, called coke, are deposited on the catalyst. During the high temperature regeneration inside the regenerator vessel, the coke is burnt off the catalyst by bringing the latter into contact with an oxygen-containing stream, which again acts as a fluidizing medium. The coke-containing catalyst, herein referred to as the spent catalyst, is continuously removed from the reaction zone and replaced with a coke-free or less coke-containing catalyst from the regeneration zone. By fluidizing the catalyst particles with various gas streams, the catalyst can be transported between the reaction zone and the regeneration zone.

In the FCC process, the gaseous media are separated from the catalyst solids at the outlet of the reactor riser. The most common method for separating solid particles from a gaseous stream is using centripetal separation in a separation vessel. In centripetal separators, gases containing entrained solids are imparted a tangential velocity, which throws heavier solids outward from lighter gases for upper removal of gases and lower collection of solids. A curved tubular swirl sleeve is provided on the outlet channel from the riser, which imparts a swirling, helical motion to the gaseous products and catalyst particles as they exit the riser into the separating chamber. This vortex, helical movement of the materials in the separation vessel provides for the primary separation of the catalyst particles from the gases. The primary separation step is usually followed by a second step of more complete separation of solids from gases in cyclones. The gas extraction channel connects the separation chamber to the cyclones in the reaction vessel. The mixture of gases and entrained catalyst is drawn into the gas extraction channel and enters the cyclones for further separation of catalyst particles from gases.

Most of the hydrocarbon vapors in contact with the catalyst in the reaction zone are separated from the solid particles as a result of the aforementioned centripetal separation. However, the catalyst particles used in the FCC process have a large surface area due to the presence of many pores on the particles. As a result, at the entrance to the stripping zone, the catalytic materials retain hydrocarbons in their pores, on the outer surface of the catalyst and in the space between the individual catalyst particles. Although the amount of hydrocarbons retained on each individual catalyst particle is very small, the high amount of catalyst and the high catalyst turnover rates associated with the modern FCC process result in a significant amount of hydrocarbon being removed from the reaction zone with the catalyst.

It is standard practice to remove, or strip, hydrocarbons from the spent catalyst before sending it to the regeneration zone. The most common method for stripping a catalyst uses the passage of a stripping gas, usually steam, through a flowing stream of catalyst, countercurrent with respect to the direction of movement of the catalyst. These steam stripping operations, with varying degrees of efficiency, remove hydrocarbon vapors trapped in the catalyst and adsorbed on the surface of the catalyst.

The efficiency of catalyst stripping is increased by using the internal elements of the stripping section, which may contain baffles or profiled strips located with some vertical spacing for cascading the catalyst from one side to the other as it moves down the stripper and contacts the stripping medium in countercurrent. The stripping medium enters the apparatus from below under the lowest internal element and gradually rises upward through the internal elements.

The catalyst withdrawn from the vortex outlet of the riser for separating the spent catalyst from the gaseous products may continue to vortex. The downward swirling catalyst can cause erosion of internal equipment and improper distribution of flows to the stripper. Therefore, the dense bed of catalyst is placed at a sufficient height above the internals of the stripper to shield the internals of the stripper from being eroded by the rotating catalyst.

Brief summary of the invention

A method has been found to break up or dampen the rotational flow of the catalyst inside and outside the separation chamber, which uses a tangential withdrawal of the catalyst and gaseous products from the riser. The vortex-like catalyst particles cannot leave the separation chamber and enter the annular space of the reactor. Catalyst particles and gaseous products must pass through a tunnel containing a vertical wall to enter the annulus of the reactor. The vertical wall forms a surface opposite to the angular direction in which catalyst particles and gaseous products move in a vortex-like manner. As a consequence, the angular momentum of the catalyst particles and gaseous products decreases. In addition, the tunnel prevents catalyst particles and gaseous products from entering the annulus of the reactor until they change direction. Instead, the catalyst particles fall into the stripper section.

In addition, it was found that a large proportion of the catalyst particles bypassed the lower edges of the passages between the separation chamber and the annulus of the reactor. As a consequence, a baffle may be placed at the intersection between the reactor annulus and the separation chamber to divert the catalyst laterally into the stripper after it has been lowered below the reactor annulus passage. Openings can be provided in the baffle to fluidize a large amount of catalyst passing over this area for efficient pre-stripping of this catalyst before it enters the stripping section.

Additional details and embodiments of the present invention will be apparent from the following detailed description of the invention.

Brief description of graphic materials

In FIG. 1 is a schematic cross-sectional view of the FCC device.

In FIG. 2 is an enlarged partial view of the part of FIG. one.

In FIG. 3 is a schematic plan view of the alternative of FIG. 2.

In FIG. 4 is a schematic plan view of another alternative for FIG. 2.

Description of the invention

The tangential or swirling arms that provide the primary separation of the catalyst and product gases from the riser of the FCC reactor impart significant tangential momentum to the catalyst particles. It has been found that when swirled down the separation chamber, the gas and catalyst create a rotating bed of catalyst. This behavior causes extensive erosion of the upper layers of the internal elements of the stripper section in specific places separated from each other by a distance that corresponds to the distance between the outlets of the swirl arms from the riser.

In addition, under industrial plant conditions, it has been observed that a longer stay in the dense catalyst bed above the stripper section results in a drop in product yield. The reason for this may be the continuation of the cracking reactions while the gaseous products are in contact with the catalyst. An advantage would be to reduce the depth of the dense catalyst bed to reduce the residence time of the gaseous product. However, this requires the torque of the catalyst particles and gaseous products to be canceled out, since the dense catalyst layer is needed to protect the upper internal elements of the stripper section from erosion by the rotating catalyst stream.

The present document proposes blocking so that swirling catalyst particles cannot exit the separation chamber and enter the annular space of the reactor. Catalyst particles and gaseous products must pass through a tunnel containing a vertical wall to enter the annulus of the reactor. The vertical wall forms a surface opposite to the angular direction in which catalyst particles and gaseous products move in a vortex-like manner. To exit the separation chamber through the tunnel, the flow must change its tangential direction, then maintain this new direction across the entire width of the vertical wall, and then enter the annulus of the reactor around the separation chamber. In this way, the tangential momentum transferred from the riser outlet arms to the tight annular bed can be suppressed, catalyst entry into the annulus of the reactor is reduced, and unnecessary equipment erosion or catalyst circulation can be avoided.

Such an apparatus or process can be implemented in a facility using fluid catalytic cracking (FCC) in which catalyst particles and gaseous products are to be separated. A typical input stream for an FCC plant is a gas oil such as vacuum gas oil or atmospheric residue.

In the context of this document, the term "boiling point" means the atmospheric pressure equivalent boiling point (AEBP) calculated from the observed boiling point and distillation pressure calculated using the equations presented in Annex A7 of ASTM D1160 under the heading "Methods for Converting Observed Vapor Temperatures at temperatures equivalent to atmospheric. In this document, the term "True Boiling Point" (TBP) means a test method for determining the boiling point of a material that complies with ASTM D-2892 for the production of liquefied gas, distillate fractions and standardized quality bottoms from which analytical data can be obtained, and the determination yields of the above fractions, both by mass and by volume, based on such data, plot the temperature dependence on the mass fraction of distillate using a column with fifteen theoretical plates and with a reflux ratio of 5: 1. In this document, the term T5 or T95 means the temperature at which, depending on the circumstances, boil respectively 5 mass percent or 95 mass percent of the sample according to ASTM D 86 or TBP. In this document, the term "initial boiling point" (IBP) means the temperature at which the sample begins to boil, according to ASTM D-7169, ASTM D-86 or TBP, as the case may be. In this document, the term "end point" (EP) means the temperature at which the sample completely boils away, according to ASTM D-7169, ASTM D-86, or TBP, as the case may be. As used herein, the term "vacuum gas oil" means a hydrocarbon material with an IBP of at least 232°C (450°F), a T5 of 288°C (550°F) to 392°C (700°F), typically not greater than 343° C (650°F), T95 from 510°C (950°F) to 570°C (1058°F) and/or EP not greater than 626°C (1158°F) obtained by vacuum fractionation of an atmospheric residue as determined by any by a standard simulated distillation gas chromatography method such as ASTM D2887, D6352, or D7169, all of which are used in the petroleum industry. As used herein, "atmospheric residue" means hydrocarbon material with an IBP of at least 232°C (450°F), a T5 of 288°C (550°F) to 392°C (700°F), typically not greater than 343° C (650°F), and T95 from 510°C (950°F) to 700°C (1292°F), obtained from the bottom product of the crude oil atmospheric distillation column.

The reaction zone of the FCC process is maintained under high temperature conditions, which may generally include temperatures above 425ºC (797ºF). In one embodiment, the reaction zone is maintained under cracking conditions that include temperatures from 480ºC (896ºF) to 590ºC (1094ºF) and pressures from 69 kPa (g) (10 psig) to 517 kPa (g) ( 75 psig), but typically less than 275 kPa(g) (40 psig). The catalyst-to-oil ratio, based on the mass of the catalyst and the hydrocarbon inlet stream coming through the bottom of the riser, can be up to 20:1, but is typically in the range of 4:1 to 10:1. Hydrogen is usually not added to the riser, which leads to the absence of a significant amount of added hydrogen in the reactor. Typically, steam is introduced into the riser to fluidize the catalyst and disperse the inlet feed stream. The average residence time of the catalyst in the riser can be less than 5 seconds. The type of catalyst used in the process can be selected from a variety of commercially available catalysts. A catalyst containing a Y-type zeolite as a base material is preferred, but older amorphous catalysts can be used if necessary. Zeolite MFI can be added to the catalyst mixture.

The catalyst regenerator is preferably operated at a pressure of 69 kPa(g) (10 psig) to 552 kPa(g) (80 psig). The spent catalyst entering the regenerator may contain from 0.2 to 15% by weight of coke. This coke mainly consists of carbon and may contain from 3 to 12 wt.% hydrogen, as well as sulfur and other elements. As a result of the oxidation of coke, standard combustion products are formed: water, carbon oxides, sulfur oxides and nitrogen oxides. The regenerator can take on several configurations, with the regeneration itself being carried out in one or more steps.

In FIG. 1 is a schematic view of the FCC device. The FCC device includes an elongated riser or riser 10 of the reactor. Hot catalyst enters the lower section of riser 10 from regenerator passage 54, from where fluidizing gas from distributor 8 pneumatically transports catalyst particles up riser 10. , steam into the catalyst. Contact with the hot catalyst vaporizes the hydrocarbons and results in further transfer of the gas/catalyst mixture down the riser 10 while cracking the hydrocarbons to the desired lower boiling gaseous products.

The riser 10 extends upwardly into the reaction vessel 12. The riser 10 preferably has a vertical orientation within the reaction vessel 12 and may extend upward through the bottom of the reaction vessel 12. The reaction vessel comprises an outer wall 13. The catalyst particles and gaseous products then exit through the top of the reactor riser 10 and are separated on gaseous cracked products and catalyst particles coated with a significant amount of coke and generally referred to as "spent catalyst". A swirl sleeve assembly 26 is provided at the downstream end of the reactor riser 10 to improve the primary separation of the catalyst particles from the cracked gases. The swirl arm assembly 26 includes a curved tubular arm 14 that swirls the catalyst solids and gaseous products in an angular direction to impart tangential angular velocity to the outgoing mixture of catalyst particles and cracked gaseous products as they exit the swirl arm outlet 22. The swirl arm assembly 26 may be placed in the upper region of the separation chamber 16. The separation chamber 16 includes an outer shell 17. The swirl arm assembly 26 may comprise a plurality of sleeves 14 with a corresponding number of swirl arm outlets 22. The separation chamber 16 is in communication downstream with the outlet 14 of the swirl sleeve. The term "message" means that between the listed components, the flow of fluid is functionally acceptable. The term "downstream communication" means that at least a portion of the fluid flowing into the object in question, which is in communication downstream, can operably flow away from the object with which it is in fluid communication. The stripping section 28 may be placed in the separation chamber 16 below the outlet 26 of the swirling sleeve. Separated by the swirl arm assembly 26, the catalyst falls down into the stripper section 28. The stripper section 28 includes an outer wall 29.

Gaseous cracked products, including cracked hydrocarbons and entrained spent catalyst particles, enter from separation chamber 16 through gas recovery passage 18 . The cyclones 32 are in communication downstream with the swirl arm outlet 22 via the gas recovery channel 18 . Inside the cyclones 32, a tangential vortex motion is created, providing centripetal forces that further separate solid particles from gases. The flow of gaseous products, relatively free of catalyst particles, exits the cyclones 32 through the vapor outlet pipes 50 into the accumulation chamber 56. The product flow then exits the reaction vessel 12 through the outlet 25. The solid catalyst particles separated by the cyclones 32 exit the lower part of the cyclone through the downcomers. tubes 34. Downpipes 34 extend downward in reaction vessel 12 and may terminate at a hinge valve that prevents gas from entering downtube 34 but allows catalyst particles to escape into a dense bed 20 at the bottom of reaction vessel 12 that surrounds separation chamber 16, including the annular space 37 of the reactor.

Catalyst particles in reaction vessel 12 are passed by passages 36 into separation chamber 16. Passages 36 may include openings between reaction vessel 12 and separation chamber 16 so that catalyst can flow from reactor annulus 37 into separation chamber 16. Separation chamber 16 is in the communication below. downstream with the reaction vessel 12 and/or the cyclones contained therein through the passages 36 due to pressure. Catalyst particles in dense catalyst bed 20 enter a stripper section 28 located in separation chamber 16. Catalyst particles pass downward through stripper internals 44, which may include a plurality of elongated metal strips arranged in a particular manner within stripper section 28, and/or Around them. The strips may have straight parts set at some angles to other strips or other straight parts of the same strip. In the stripping section, several layers or sets of strips can be superimposed on each other. The metal strips may form a structural packing or may form gratings with or without overflow channels. Examples of suitable structured packings can be found in US 2005/0205467 and corresponding grids in US 6,680,030 for use in stripping vessels.

The stripping fluid, typically steam, enters through the bottom of the stripper section 28 through at least one distributor 46. Counterflow contact of the catalyst with the stripping fluid on the metal strips 44 displaces gaseous products adsorbed on the catalyst as it travels down through the stripper section. 28. The stripped catalyst from stripper 28 may pass through spent catalyst conduit 48 to catalyst regenerator 52. In the regenerator, coke deposits are burned off the surface of the catalyst by bringing them into contact with an oxygen-containing gas at high temperature. After regeneration, the particles of the regenerated catalyst are returned to the lower part of the riser 10 through the channel 54 of the regenerator. Exhaust gas exits regenerator 52 through nozzle 56.

It has been found that the swirling movement caused by the release of gaseous products and catalyst particles from the outlet(s) 22 of the swirl sleeve of the riser 10 can continue when the catalyst is lowered down the separation chamber 16. The swirling gas and catalyst create a rotating catalyst bed 20, which can cause extensive erosion of the upper layers of the internal elements of the stripper and bypass part or all of the stripper 28.

Provided herein is a process and apparatus that quenches or dampens the angular momentum of descending catalyst particles and product gases in separation chamber 16. Such a process and apparatus is further illustrated with reference to FIG. 2, which is an enlarged partial view of the bottom of the separation chamber 16 of FIG. 1. Swirling catalyst particles and gaseous products descend down the separation chamber in the form of a rotating vortex. Some of the swirling catalyst particles and gaseous products can exit through the passages 36 located around the circumference of the separation chamber. The passageways 36 are provided with tunnels 60 which communicate the separation chamber 16 with the annulus 37 of the reactor and vice versa. The tunnels 60 block the vortex of catalyst particles and gaseous products, preventing the catalyst particles and gaseous products from leaving the separation chamber 16 and entering the reactor annular space 37 . Tunnel 60 and passageways 36 nevertheless form a large opening that allows pressure to be released in the event of a sudden buildup of pressure in the system.

The tunnel 60 includes at least a first vertical wall 62 which forms a surface 64 oriented opposite to the angular direction in which the catalyst particles and gaseous products are swirled. The first vertical wall 62 has a width that provides a surface 64 capable of blocking and resisting the angular momentum of swirling catalyst particles and gaseous products. The first vertical wall 62 may provide a surface 64 that resists angular momentum on its outer surface. In one embodiment, the first vertical wall 62 extends radially in the separation chamber 16. In a further embodiment, the first vertical wall 62 extends inwardly from the outer shell 17 in the separation chamber 16.

In one embodiment, the tunnel 60 comprises on a second vertical wall 66 which forms a surface 68 oriented opposite to the angular direction in which the catalyst particles and product gases swirl. The second vertical wall 66 has a width that provides a surface 68 capable of blocking and resisting the angular momentum of swirling catalyst particles and gaseous products. The second vertical wall 66 may provide a surface 68 that resists angular momentum on its inner surface. In one embodiment, the second vertical wall 66 extends in the separation chamber 16 in the radial direction. In a further embodiment, the second vertical wall 66 extends inwardly from the outer shell 17 in the separation chamber 16.

In a further embodiment, the tunnel 60 includes an upper horizontal wall 70 located upward from the first vertical wall 62 and said second vertical wall 66. In one aspect, the upper horizontal wall 70 is at the top of the tunnel 60. In a further aspect, the upper horizontal wall is above the first vertical wall. 62 and a second vertical wall 66. The upper horizontal wall 70 of the tunnel 60 may overhang the passageway 36. The tunnel 60 may not have a lower horizontal wall that is opposite the upper horizontal wall 70 so that the tunnel 60 forms an inverted U.

In operation, the swirling catalyst particles and gaseous products descend down the separation chamber 16 and meet the surface 64 of the first vertical wall 62 and the surface 68 of the second vertical wall 66, which are oriented opposite to the direction of the swirl and block and reduce the angular momentum of the catalyst particles and gaseous products. Some of the catalyst particles and product gases will still exit separation chamber 16 through passages 36 and enter the reactor annulus 37, but tunnel 60 will reduce the amount of entry into the passages because the swirling catalyst particles and product gases will have to change direction from their original rotation and move outward in a radial direction along a tunnel 60 comprising a first vertical wall 62, a second vertical wall 66, and/or an upper horizontal wall 70.

The passage 36 has a lower edge 72 which is at the intersection 15 of the wall 13 of the reaction vessel 12 and the shell 17 of the separation chamber 16. It is believed that such an intersection may be formed between the annulus 37 of the reactor and the separation chamber 16. The lower edge 72 may be directly above the intersection 15, but at a distance of no more than half the diameter of the riser, and preferably no more than a quarter of the diameter of the riser. This positioning of the bottom edge 72 of the passages 36 allows the top of the dense bed 20 to be placed at a lower height in the separating vessel 16, thus reducing the height of the dense bed and shortening the residence time of the gaseous products in the dense bed. It has been found that reducing the residence time of the gaseous products in the dense bed 20 improves the yield of gasoline and reduces non-selective cracking of the products.

To retrofit the higher passages 36 to further reduce the entry of catalyst particles and gaseous products from the separation chamber 16 through the passages 36 into the reactor annulus 37 and to further reduce the height of the dense catalyst bed 20, caps 74 can be secured in the upper region of the passages 36. The caps 74 allow positioning the top edge 76 of the passages 36 is at a lower height than if the covers were not installed. Covers 74 may be welded to passages 36 or secured in any other suitable manner. Covers 74 can be equipped with a vent tube 78 to relieve pressure build-up in the event that the top of the catalyst bed 20 rises above the top edge 76 of the passages 36 and seals them during a surge of pressure. Releasing pressure prevents equipment damage. The drain tubes 78 are located above the top edge 76 of the passages 36.

It has been found that equipping the passages 36 with tunnels 60 without a bottom wall, in one aspect without a bottom wall opposite the upper horizontal wall 70, results in a large portion of the catalyst particles bypassing the bottom edge 72 of the passage 36. A transverse baffle 80 is installed below the tunnel 60. The transverse baffle 80 may extend from the intersection 15 of the wall 13 of the reaction vessel 12 and the shell 17 of the separation chamber 16, considered to provide between the annulus 37 of the reactor and the separation chamber 16. The transverse baffle 80 may be located from the intersection 15 at a distance of not more than one eighth of the diameter of the riser. The transverse baffle 80 enters the separation chamber 16 at a slight downward slope, such as 5 to 30 degrees from horizontal, preferably no more than 20 degrees. The transverse baffle 80 deflects catalyst particles moving laterally downward after passing through the tunnel 60 or upon entering the separation chamber 16 from the reactor annulus 37 below the tunnel. The transverse baffle 80 may deflect the catalyst particles from the outer wall 29 of the stripper section 28. The transverse baffle 80 may be an annular baffle that circumnavigates the entire perimeter of the separation chamber 12 over the stripper section 28. An upper horizontal wall 70 overhangs the transverse baffle 80 so as to guide the catalyst particles over the baffle as they enter said separation chamber 16 from the tunnel 60 and/or annular space 37 of the reactor.

The transverse baffle 80 may further include openings in the baffle to release boil-off gas to fluidize the catalyst particles deflected above the baffle with the fluidizing gas. A large proportion of the catalyst particles passing over the cross baffle 80 undergo an efficient pre-stripping before being lowered and entering the stripper section 28. A distribution ring 82 can be placed directly below the cross baffle 80 to distribute boil-off gas, such as steam, under the cross baffle 80. It has been found that the pre-stripping catalyst at this point reduces the average residence time of gasoline vapors in a mixture with catalyst particles in the stripping section 28. Due to the lateral deviation of the catalyst particles, possibly from the outer wall 29 of the stripping section 28, and the violation of the rotational products, it is possible to reduce the height of the catalyst bed 20 above the stripper section 28 while still protecting the top of the internal elements 44 of the stripper section from erosion. The transverse baffle 80 may include a vertical weir 84 that is vertically dependent on the transverse baffle 80. The weir 84 may also include openings to fluidize catalyst passing down the baffle.

An additional riser baffle 86 can be placed on the riser 10 in the separation chamber 16 on the continuation of the line of inclination of the transverse baffle 80 along the separation chamber from the shell 17 to the riser 10. The riser baffle 86 can be placed above the internal elements 44 of the stripping section and provide openings for transfer to a fluidized state , dependent overflow wall and can optionally be provided with a steam ring under the wall 82 of the riser (not shown). The riser baffle 86 may have a greater slope than the transverse baffle 80, such as 30-70 degrees from horizontal. The riser baffle may be annular and circumnavigate the entire perimeter of the riser 10. In addition, a baffle 88 may be placed above the stripper section 28 over the internal elements 44 of the stripper section in the center of the annular structure to protect the internal elements from the catalyst directed to them by the transverse baffle 80 and baffle 86 riser. The deflector 88 may also be annular.

In FIG. 3 shows a further embodiment of a separation chamber 16 containing tunnels 60. The first vertical wall 62, which forms an outer surface 64 to the swirl direction S, is wider than the second vertical wall 66.

In FIG. 4 shows a further embodiment of a separation chamber 16 containing tunnels 60 surrounded by a reaction vessel 12. The direction of the vortex movement is opposite to that of FIG. 3. The first vertical wall 62 extends more outward from the shell 17 of the separation chamber 16 than the second vertical wall 64, and the second vertical wall extends more inward from the shell of the separation chamber than the first vertical wall. A vertical baffle 90 seals the spent catalyst passage 48 from catalyst particles to prevent catalyst particles from bypassing the stripper section.

The process and apparatus allow the FCC device to be operated at very low bed levels without potential erosion of the internals of the stripper. Tests have shown benefits in terms of lower dry gas yield and higher gasoline selectivity.

Specific Embodiments

While the following description refers to specific embodiments, it should be understood that the present description is intended to be illustrative and not to limit the scope of the foregoing description and the appended claims.

A first embodiment of the invention is a process for separating catalyst particles from a gaseous product stream, comprising contacting a hydrocarbon feed stream with catalyst particles in an elongate riser to produce gaseous products; bringing the catalyst particles and gaseous products into a vortex motion in an angular direction at the outlet of the riser and the entrance to the separation chamber to separate the catalyst particles from the gaseous product; blocking so that catalyst particles and gaseous products cannot exit the separation chamber and enter the annulus of the reactor. An embodiment of the invention is one, any or all of the preceding embodiments presented in this section, up to the first embodiment presented in this section, which further includes requiring the passage of catalyst particles and gaseous products through a vertical wall tunnel to exit the separating chamber and entrance to the annular space of the reactor. An embodiment of the invention is one, any or all of the preceding embodiments presented in this section, up to the first embodiment presented in this section, in which the vertical wall of the tunnel forms a surface opposite to the angular direction in which the catalyst particles swirl and gaseous products. An embodiment of the invention is one, any or all of the previous embodiments presented in this section, up to the first embodiment presented in this section, which further comprises stripping the downgoing catalyst particles with stripping gas over elongated strips in a stripping section; and separating the catalyst particles entrained in the ascending gaseous products from the gaseous products. An embodiment of the invention is one, any or all of the previous embodiments presented in this section, up to the first embodiment presented in this section, which further includes lateral deflection of the downward movement of the catalyst particles when entering the separation chamber from the tunnel. An embodiment of the invention is one, any, or all of the preceding embodiments presented in this section, up to the first embodiment presented in this section, which further comprises fluidizing the deflected catalyst particles with a fluidizing gas through openings in the deflecting baffle.

The second embodiment of the invention is an apparatus for separating catalyst particles from a stream of gaseous products, containing an elongated riser, in which the hydrocarbon feed stream is brought into contact with catalyst particles to obtain a gaseous product, and the riser includes a swirl sleeve outlet configured to bring solid the catalyst particles and gaseous products in a vortex motion in an angular direction to separate the catalyst particles from the gaseous product; a separating chamber in communication with the outlet of the riser swirl arm, the separating chamber including an outer shell and a stripping section containing the internal elements of the stripping section; a tunnel containing a vertical wall that provides communication between the separation chamber and the annulus of the reactor. An embodiment of the invention is one, any, or all of the previous embodiments presented in this section, up to and including the second embodiment presented in this section, in which the vertical wall extends inwardly from the shell. An embodiment of the invention is one, any or all of the previous embodiments presented in this paragraph, up to the second embodiment presented in this paragraph, in which the tunnel comprises a first vertical wall and a second vertical wall. An embodiment of the invention is one, any or all of the previous embodiments presented in this paragraph, up to the second embodiment presented in this paragraph, in which the first vertical wall is wider than the second vertical wall. An embodiment of the present invention is one, any or all of the previous embodiments presented in this section, up to the second embodiment presented in this section, in which the first vertical wall extends more outward from the shell and the second vertical wall extends more inward from the shell. An embodiment of the invention is one, any or all of the previous embodiments presented in this paragraph, up to the second embodiment presented in this paragraph, in which the tunnel comprises an upper horizontal wall upward from the first vertical wall and the second vertical wall. An embodiment of the invention is one, any or all of the previous embodiments presented in this section up to the second embodiment presented in this section, which further comprises a baffle under the tunnel that enters the separation chamber at a downward slope. An embodiment of the invention is one, any, or all of the previous embodiments presented in this section, up to the second embodiment presented in this section, which further includes openings in the baffle to release boil-off gas to fluidize the catalyst above the baffle. An embodiment of the invention is one, any or all of the preceding embodiments presented in this paragraph, up to the second embodiment presented in this paragraph, in which the upper horizontal wall of the tunnel overhangs the partition and the tunnel forms an inverted U without a horizontal wall opposite the upper horizontal wall to guide the catalyst over the baffle as it enters the separation chamber from the annulus of the reactor. An embodiment of the invention is one, any or all of the previous embodiments presented in this paragraph, up to the second embodiment presented in this paragraph, in which the baffle extends from the intersection of the separation chamber with the annulus of the reactor. An embodiment of the invention is one, any or all of the previous embodiments presented in this section, up to the second embodiment presented in this section, which further comprises a weir dependent vertical weir.

A third embodiment of the invention is an apparatus for separating catalyst particles from a gaseous product stream, comprising an elongated riser in which the hydrocarbon feed stream is brought into contact with catalyst particles to produce a gaseous product, the riser including an outlet for withdrawing solid catalyst particles and gaseous products into a separating chamber, wherein the separating chamber includes an outer shell and a lower stripping section containing the internal elements of the stripping section; a passage for communicating the separation chamber with the annular space of the reactor and a deflecting baffle extending from the intersection of the separation chamber with the annulus of the reactor into the separation chamber. An embodiment of the invention is one, any or all of the previous embodiments presented in this section, up to the third embodiment presented in this section, in which the lower edge of the passage is directly above the intersection. An embodiment of the present invention is one, any or all of the previous embodiments presented in this section, up to the third embodiment presented in this section, which further comprises a gas distributor directly below the baffle.

A fourth embodiment of the invention is a process for separating catalyst particles from a gaseous product stream, comprising contacting the hydrocarbon feed stream with catalyst particles in an elongate riser to produce gaseous products; output of catalyst particles and gaseous products from the riser to the separation chamber; separation of catalyst particles from gaseous products; passing the catalyst particles and gaseous products from the passage into the annular space of the reactor into the separation chamber; and lateral deflection of the downward movement of the catalyst particles when entering the separation chamber from the passage.

Without further elaboration, it is believed that with the use of the foregoing description, a person skilled in the art can make full use of the present invention and easily establish the main characteristics of the present invention, without departing from the essence and scope of the invention, to make various changes and modifications of the invention and adapt it to various applications and conditions. Thus, the foregoing preferred specific embodiments are to be considered as illustrative only, without imposing any limitation on the remainder of the description, and covering various modifications and equivalent constructions falling within the scope of the appended claims.

Unless otherwise indicated, in the above description, all temperatures are in degrees Celsius and all fractions and percentages are by weight.

Claims (10)

1. A method of separating catalyst particles from a stream of gaseous products, including: bringing the stream of hydrocarbon feed into contact with catalyst particles in an elongated riser to obtain gaseous products; bringing the catalyst particles and gaseous products in a vortex motion in an angular direction at the exit from the specified riser and the entrance to the separation chamber for separating the catalyst particles from the specified gaseous product; blocking the vortex-like movement of said catalyst particles and gaseous products at the exit from said separation chamber and entering the annular space of the reactor. 2. The method of claim 1 further comprising passing said catalyst particles and said gaseous products through a vertical wall tunnel as it exits said separation chamber and enters said reactor annulus. 3. The method according to claim 2, wherein said vertical wall of said tunnel forms a surface opposite to the angular direction in which catalyst particles and gaseous products move in a vortex-like manner. 4. The method of claim 3, further comprising deflecting the downward movement of said catalyst particles in a lateral direction upon entering said separation chamber from said tunnel. 5. The method of claim 4, further comprising fluidizing said deflected catalyst particles with a fluidizing gas through openings in the deflecting baffle. 6. An apparatus for separating catalyst particles from a stream of gaseous products, comprising: an elongated riser, in which the hydrocarbon feed stream is brought into contact with catalyst particles to obtain a gaseous product, and said riser includes a swirl sleeve outlet configured to bring solid catalyst particles and gaseous products in a vortex-like movement in the angular direction to separate the particles of the catalyst from the specified gaseous product; a separating vessel in communication with said swirl sleeve outlet of said downcomer, said separating vessel including an outer shell and a stripping section containing internal elements of the stripping section; a tunnel containing a vertical wall and providing communication of the specified separating vessel with the annular space of the reactor. 7. Apparatus according to claim 6, wherein said vertical wall extends inwardly from said shell. 8. Apparatus according to claim 6, wherein said tunnel comprises a first vertical wall and a second vertical wall. 9. Apparatus according to claim 8, wherein said tunnel comprises an upper horizontal wall located above said first vertical wall and said second vertical wall. 10. Apparatus as claimed in claim 9, further comprising a baffle under said tunnel that enters said separating chamber at a downward slope.

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