Title of Invention	AN APPARATUS AND A PROCESS FOR SEPARATING SOLID PARTICLES SUSPENDED IN VAPOUR AND FOR STRIPPING ADSORBED AND ENTRAINED RESIDUE FROM THE SOLID PARTICLES
Abstract	An apparatus (2) for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from the solid particles comprising: a disengager vessel (3) having a primary fluidized-bed zone (10), and a primary injector (12) for injecting into the primary fluidized-bed zone (10) a gas for fluidizing or stripping solid particles; a vertical primary cyclone (6), which has a cylindrical side wall (15) and is closed at its upper end by means of a cover (17) provided with an outlet opening (19) and open at its lower end, which primary cyclone (6) is further provided with an inlet (24) for receiving a suspension of solid particles and vapour; and a first outlet conduit (30) for providing a flow path from the outlet opening (19) of the primary cyclone (6), wherein the open lower end (32) of the primary cyclone (6) projects downwardly into the primary fluidized-bed zone (10) so as to form a secondary fluidized-bed zone (35) within the open lower end (32) of the primary cyclone (6), and wherein suitably there is provided a secondary injector (41) for injecting into the secondary fluidized-bed zone (35) a gas for fluidizing or stripping solid particles.

Title of Invention

AN APPARATUS AND A PROCESS FOR SEPARATING SOLID PARTICLES SUSPENDED IN VAPOUR AND FOR STRIPPING ADSORBED AND ENTRAINED RESIDUE FROM THE SOLID PARTICLES

Abstract

An apparatus (2) for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from the solid particles comprising: a disengager vessel (3) having a primary fluidized-bed zone (10), and a primary injector (12) for injecting into the primary fluidized-bed zone (10) a gas for fluidizing or stripping solid particles; a vertical primary cyclone (6), which has a cylindrical side wall (15) and is closed at its upper end by means of a cover (17) provided with an outlet opening (19) and open at its lower end, which primary cyclone (6) is further provided with an inlet (24) for receiving a suspension of solid particles and vapour; and a first outlet conduit (30) for providing a flow path from the outlet opening (19) of the primary cyclone (6), wherein the open lower end (32) of the primary cyclone (6) projects downwardly into the primary fluidized-bed zone (10) so as to form a secondary fluidized-bed zone (35) within the open lower end (32) of the primary cyclone (6), and wherein suitably there is provided a secondary injector (41) for injecting into the secondary fluidized-bed zone (35) a gas for fluidizing or stripping solid particles.

Full Text	AND METHOD FOR THE SEPARATION AND STRIPPING OF FLUID CATALYST CRACKING PARTICLES FROM GASEOUS HYDROCARBONS This invention relates to an apparatus for the separation of solid particles from gaseous hydrocarbons and stripping of hydrocarbons from the separated solid particles. In yet another aspect, it relates to an improved method for separating solid particles, such as catalyst, from gaseous hydrocarbons and stripping hydrocarbons from the separated particles. Apparatus for separating solid particles from gaseous hydrocarbons have been available for years and have found commercial use, for instance in the separation of hydrocarbon cracking catalysts from gaseous products in a fluidized catalytic cracking process. In a process which uses solid particles, it is common for suspensions and other mixtures of fine particles to be entrained in a gaseous stream. Many times, the suspensions contain fine solid particles which contain adsorbed and/or entrained residue of the substance(s) involved in the reaction. It becomes necessary to both separate and recover the fine particles from the gaseous stream and to strip the residue from the fine particles in order to prevent possibly detrimental or undesirable reactions downstream. For example, in a typical catalytic cracking process, hydrocarbons are reacted in the presence of catalyst in a riser reactor. Hydrocarbon gases are formed which carry fine solid particles of the catalyst along as the gases flow downstream of the reactor. The suspended catalytic particles contained adsorbed and/or entrained hydrocarbons. The catalytic particles must be separated from the gases and stripped of the hydrocarbons to prevent catalytic reactions in zones where this is undesirable {commonly called "over cracking"). Stripping also increases yield and allows the catalyst to be recycled. While the apparatus and process of the present invention will be described with particular emphasis on catalytic cracking of hydrocarbons, it is to be understood that it is not so limited and that the apparatus and processes will function as well for other systems which use solid particles and generate mixtures of the solid particles in vapour flow. As new, highly reactive cracking catalysts, such as zeolites, came into common usage, new separation apparatus were developed to rapidly separate the reactive cracking catalyst from the cracked hydrocarbon vapour in order to avoid over cracking once the hydrocarbons exit a reactor. USA patent specifications No. 4 961 863 and No. 5 259 855 describe a twin-drum separator which may be located at the terminal end of a catalytic cracking riser reactor. An advantage of the twin-drum separator is that it does not easily choke from catalyst carryover. Most catalytic cracking processes require a high separation efficiency in order to reduce the catalyst carried outside of the reactor vessels, and the twin-drum separator may then not be that suitable to be used alone. . The twin-drum separator also does not integrate well with an internal stripper bed because the upflow of vapour from the stripper catalyst bed could disrupt the vertical flow within the twin-drum separator. USA patent specifications No. 4 693 808 and No. 4 731 228 describe a horizontal cyclone separator-The mass ratio of catalyst to gas in a horizontal separator limits the maximum amount of catalyst the separator can carry, and if the mass ratio of catalyst to gas is too high, the horizontal cyclone separator tends to choke. USA patent specification No. 4 692 311 describes a so-called "quick disengaging cyclone" to reduce separating and stripping time. The cyclone works on centrifugal separation and a reverse flow vortex of vapour. A vortex stabilizer is used to terminate the , vortex before it reaches the bottom of the cyclone, where, if not terminated, the vortex can pick-up separated catalyst at the bottom of the cyclone and carry the catalyst back up and out through the cyclone outlet. The quick disengaging cyclone has proven to work at high efficiency; however, the unit is fairly large due to the need for an internal catalyst stripping bed and a standpipe extending from the bottom of the cyclone. In addition to catalytic crackers, apparatus for separation and stripping are also used in fluid cokers, entrained coal gasifiers, and other industrial processes using fast-fluidized solid particles. These units may be retrofitted to achieve higher separation and stripping efficiencies in order to meet environmental and economic needs. While separator designs such as those just described have been used for retrofitting various fast-fluidized processes, their use can be limiting for retrofitting units which have limited space for placement of separators and strippers and/or which need to be retrofitted in order to increase efficiency. In many catalytic cracking plants, for example, a riser reactor exhausts into a disengager vessel where undesirable post-riser cracking takes place. Most of these disengager vessels have a fluidized catalyst bed in the bottom and some sort of separation means at the top. These disengager vessels are often too small to be retrofitted internally with a separator and stripper such those just described. Moreover, it is expensive and inefficient to disassemble working catalytic crackers in order to install improved separators. So it has not always been possible, or desirable, to place higher-efficiency separators and strippers, such as those just described, into existing disengager vessels. It is very desirable to provide a separator and stripper technology which has high efficiency, smaller size, and simpler design. It is an object of this invention to provide an integrated disengager and stripper which has a high separation efficiency. It is another object of this invention to provide a retrofit integrated disengager and stripper which can fit into existing catalytic cracker disengager vessels. It is yet another object of this invention to provide a retrofit integrated disengager and stripper which is less expensive to manufacture. To this end the integrated disengager and stripper for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from the solid particles according to the present invention comprises: (a) a disengager vessel having a primary fluidized-bed zone adapted to contain fluidized solid particles, and a primary means for injecting into the primary fluidized-bed zone a gas for fluidizing or stripping solid particles; (b) a vertical primary cyclone contained inside the disengager vessel, which primary cyclone has a cylindrical side wall and is closed at its upper end by means of a cover provided with an outlet opening and open at its lower end, which primary cyclone is further provided with at least one inlet for receiving a suspension of solid particles and vapour; and (c) a first outlet conduit for providing a flow path from the outlet opening of the primary cyclone, which has an end connected, to the outlet opening of the primary cyclone, wherein the open lower end of the primary cyclone projects downwardly into the primary fluidized-bed zone so as to form a secondary fluidized-bed zone within the lower open end of the primary cyclone. - — - -The invention further relates to a method for separating a mixture of solid particles and vapour and for stripping adsorbed and entrained residue from separated solid particles in a disengager vessel having a primary fluidized bed, which method according to the invention comprises: (a) flowing a mixture of solid particles and vapour through a transport conduit; {b) passing the mixture of solid particles and vapour from the transport conduit into a vertical primary cyclone having an open lower end contained inside the disengager vessel, wherein the open lower end of the primary cyclone is submerged in the primary fluidized bed; (c) controlling the level of the primary fluidized bed so that the top surface of the primary fluidized bed is maintained above the open lower end of the primary cyclone, and that a portion of the primary fluidized bed is contained within the primary cyclone at the open lower end, forming a secondary fluidized bed; (d) separating the mixture of solid particles and vapour into separated vapour and separated solid particles containing adsorbed or entrained residue; (e) collecting the separated solid particles in the secondary fluidized bed contained within the secondary cyclone; (f) introducing a gas to strip the residue from the separated solid particles, forming stripped vapours and stripped solid particles; (g) allowing the separated vapour and stripped vapour to pass upwards through the primary cyclone; and (h) allowing stripped solid particles to flow away from the open lower end of the primary cyclone into the primary fluidized bed. The invention will now be described by way of example with reference to the drawings, wherein Figure 1 shows a cross-sectional view of the integrated disengager and stripper according to the present invent ion; Figure 2 shows a cross-sectional view of the primary cyclone of Figure 1 drawn to a scale larger than that of Figure 1; and Figure 3 shows a cross-sectional view of the secondary cyclone of Figure 1 drawn to a scale larger than that of Figure 1. Reference is now made to Figures 1 and 2. The integrated disengager and stripper 2 for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from the solid particles according to the present invention comprises a disengager vessel 3 and a vertical primary cyclone 6 which is contained inside the disengager vessel 3. The disengager vessel 3 has a primary fluidized-bed zone 10 adapted to contain a primary fluidized bed 11 of fluidized solid particles, and a primary means for injecting into the primary fluidized-bed zone a gas for fluidizing or stripping solid particles in the form of primary injector 12. The vertical primary cyclone 6 has a cylindrical wall in the form of circle-cylindrical side wall 15 and is closed at its upper end 16 by means of a cover 17 provided with an outlet opening 19. The primary cyclone 6 is further provided with at least one inlet 24 for receiving a suspension of solid particles and vapour. The inlet 24 of the primary cyclone is directly connected to an outlet conduit 25 of a transport conduit in the form of a reactor riser 27 extending into the disengager vessel 3. The integrated disengager and stripper 2 also comprises a first o\itlet conduit 30 for providing a flow path from the outlet opening 19 of the primary cyclone 5, which has an end that is connected to the outlet opening 19 of the primary cyclone 6. The vertical primary cyclone 6 is closed at its upper end 16, however, it is open at its lower end 32 having a discharge opening 34, wherein the inner diameter of the open lower end 32 is substantially equal to that of the upper end 15 of the primary cyclone 6. The open lower end 32 of the vertical primary cyclone 5 projects downwardly into the primary fluidized-toed zone 10 so as to form a secondary fluidized-bed zone 35 adapted to contain during normal operation a secondary fluidized bed 36 of fluidized solid particles within the lower end 32 of the primary cyclone 6. During normal operation, a mixture of solid particles in the form of catalyst particles and vapour in the form of reaction effluent from a catalytic cracking process flows upwards through the reactor riser 27, and passes through its outlet conduit 25 into the inlet 24 of the primary cyclone 6. In the primary cyclone 6 the catalyst particles are separated from the reaction effluent; the catalyst particles fall downwards towards the lower end 32 of the primary cyclone 6, and the reaction effluent passes upwards and leaves the primary cyclone 6 through the first outlet conduit 30. The lower part of the disengager vessel 3 contains the primary fluidized bed 11 of catalyst particles which are maintained in a fluidized state by the action of gas for fluidizing solid particles injected into the primary fluidi^ed-bed zone 10 through the primary injector 12. The gas also strips the catalyst particles and in this way adsorbed or entrained residue are removed therefrom to obtain stripped catalyst particles which are discharged from the disengager vessel 3 through discharge conduit 38. The catalyst particles are passed to a regenerator [not shown) where they are regenerated so that they can be used in the reactor riser 27. Since the open lower end 32 of the primary cyclone 6 projects downwardly into the primary fluidized-bed zone 10, the discharge opening 34 is submerged in the primary fluidized bed 11, and the level of the primary fluidized bed 11 is controlled so that the top surface 39 of the primary fluidized bed 11 is maintained above the discharge opening 34 of the primary cyclone 3. The portion of the primary fluidized bed 11 contained within the lower end 32 of the primary cyclone 6 forms the secondary fluidized bed 36. The separated catalyst particles which fall downwardly through the primary cyclone 6 are collected in the secondary fluidized bed 36. Gas introduced through the primary injector 12 also enters into the secondary fluidized bed 3 6 to strip the residue from the separated catalyst particles, forming stripped vapour and stripped catalyst particles. The stripped vapour and removed reaction effluent pass upwards through the primary cyclone 6, and are removed through the first outlet conduit 30. Vlhereas stripped catalyst particles are allowed to flow away from the discharge opening 34 of the primary cyclone 6 into the primary fluidized bed 11. The fluidized catalyst particles are thus partially contained in the secondary fluidized bed 36 inside the adsorbed and entrained hydrocarbon on the catalyst is stripped f roKi the catalyst in the £lu.idized-bed zone, recovering the hydrocarbon as hydrocarbon vapour and reducing undesired over cracking reactions. In a suitable embodiment, the integrated disengager and stripper 2 according to the present invention further comprises a secondary cyclone 55 contained within the disengager vessel 3, having a cylindrical side wall in the form of circle-cylindrical side wall 56. The secondary cyclone 55 is closed at its upper end by means of a cover 57 provided with an outlet opening 58. It comprises a lower portion 60 and an inlet 62 which is in fluid communication with the first outlet conduit 30. The integrated disengager and stripper 2 also includes a second outlet conduit 64 providing a flow path from the outlet opening 58 of the secondary cyclone 55. During normal operation, separated vapour and stripped vapour are removed from the primary cyclone 6 through the first outlet conduit 30. This vapour still contains entrained catalyst particles which have to be removed in the secondary cyclone 55. To this end the vapour is introduced into the secondary cyclone 55, entrained catalyst particles are separated from the vapour. The vapour is flows upwards in the secondary cyclone 55 through the outlet opening 58, and the catalyst particles are collected in the lower portion 60 of the secondary cyclone 55. Vapour and catalyst particles are discharged separately from the secondary cyclone 55, through the second outlet conduit 64 and an outlet opening 68 in the lower portion 60, respectively. The secondary cyclone 55 is operated at a pressure which is slightly below that in the primary cyclone 6, and since that pressure is below that in the disengager vessel 3, the pressure in the secondary cyclone 55 is lower than that in the disengager vessel 3. The secondary cyclone 55 is suitably provided with a dip-leg 69. The dip-leg 69, which is preferably provided with a valve (not shown) at the bottom to allow release of separated particles, extends into the primary fluidized bed ii. The secondary cyclone 55 is placed in series with the primary cyclone 6, which is called in the art "close-coupling" . The term "close-coupled" is commonly used when the exhaust of one cyclone is coupled to the inlet of another cyclone. Close-coupling cyclones reduces the undesirable, post-riser cracking of riser reactor products which can take place when, for example, (1) all separation is performed in the disengager vessel, or {2) the first cyclone exhausts into the disengager vessel. When both a primary cyclone with vortex stabilizer means and a secondary cyclone with vortex stabilizer means are used in series, the primary cyclone acts as a "quick disengaging cyclone" and the secondary cyclone acts as a "high efficiency cyclone." Suitably the inlet 62 of the secondary cyclone 55 is a tangential inlet 70 (see Figure 3) arranged in the upper end 71 of the secondary cyclone 55. Vapour and catalyst particles entering through the tangential inlet 70 of the secondary cyclone 55, are caused to form a vortex in the upper end 71 of the secondary cyclone 55. The upper end 71 is then the swirl zone of the secondary cyclone 55. The efficiency of the swirl zone can be improved when part 72 of the second outlet conduit 64 extends into the secondary cyclone 55, Part 72 forms the vortex outlet of the secondary cyclone 55. Suitably the secondary cyclone 55 further comprises a secondary dish-shaped vortex stabilizer 74 coaxially mounted in the middle part 76 of the secondary cyclone 55. The outer diameter of the secondary vortex stabilizer 74 is equal to or larger than the ciiameter of the second outlet conciuit 64, and smaller than the inner diameter of the circle-cylindrical side wall 56. The secondary vortex stabilizer 74 is positioned below the inlet opening 77 of the second outlet conduit 64 at a distance which is equal to or larger than the diameter of the second outlet conduit 64. In the embodiment of the invention as shown in Figure 1 and 3, the second outlet conduit 64 has a tapered part 72, and the diameter is the smallest diameter of the tapered part 72. The secondary vortex stabilizer 74 is supported by means of supports 79. It is suitably provided with a vortex finder 80. Any means for compensating for thermal and vibrational movement between the primary and secondary cyclones 6 and 55 may be used in the connection between them. In the embodiment of Figure 1, there is provided a gap 82, between the outlet 83 of the first outlet conduit 30 and the inlet 62 of the secondary cyclone 55. The gap 82 further provides a means for stripper gas and stripped vapour in the disengager vessel 3 to enter the slightly lower pressure secondary cyclone 55. Suitably the integrated disengager and stripper according to the present invention further comprising a venturi (not shown) positioned in the outlet end 84 of the first outlet conduit 30 in the vicinity of the inlet 62 of the secondary cyclone 55. The venturi not only helps move the gases in the first outlet conduit 30 into the secondary cyclone 55, it also reduces the pressure differential between the interior of the disengager vessel 3 and the secondary cyclone 55. Suitably the inner surfaces of the circle-cylindrical side walls 15 and 56 of the primary and secondary cyclones 6 and 55 are lined with a refractory which is resistant to erosion, such as ceramic. This allows the shell of the disengager vessel 3 to be used without a refractory lining since the cyclones are lined. Tile lining is not needed in the disengager vessel 3 because the solid particles will not be flowing in the disengager vessel 3 in a manner which would erode the walls. Eliminating the lining in the disengager vessel 3 reduces the occurrence of two problems cottony seen. First, corrosion caused by uneven heating of the disengager vessel walls should be reduced. Second, the refractory lining in the disengager vessel 3 will spall over time. The spalled lining enters the system, where it will plug valves and equipment. Eliminating the refractory lining of the disengager vessel 3 should substantially reduce this problem. The combination of the primary and secondary cyclones 6 and 55 can suitably be used as a retrofit for fluid catalytic crackers, fluid cokers, entrained coal gasifiers, and other industrial processes with small disengager vessels or small internal cyclones. WE CLAIM: 1. An apparatus for separating solid particles suspended in vapour and for stepping adsorbed and entrained residue from the solid particles comprising (a) a disengager vessel having a primary fluidized-bed zone adapted to contain fluidized solid particles, and a primary means for injecting into the primary fluidized-bed zone a gas for fluidizing or stripping solid particles (b) a vertical primary cyclone contained inside the disengager vessel, which primary cyclone has a cylindrical side wall and is closed at its upper end by means of a cover provided with an outlet opening and open at its lower end, which primary cyclone is further provided with at least one inlet for receiving a suspension of solid particles and vapour; and (c) a first outlet conduit for providing a flow path from the outlet opening of the primary cyclone, which has an end connected to the outlet opening of the primary cyclone, wherein the open lower end of the primary cyclone projects downwardly into the primary fluidized-bed zone to form a secondary fluidized-bed zone within the lower open end of the primary cyclone. 2. The apparatus as claimed in claim 1, wherein secondary means is provided for injecting into the secondary fluidized-bed zone a gas for fluidizing or stripping solid particles. 3. The apparatus as claimed in claim 1 or 2, wherein the inlet is a tangential inlet arranged in the side wall near the closed end. 4. The apparatus as claimed in one of the claims 1- 3, wherein part of the first outlet conduit extends into the primary cyclone. 5. The apparatus as claimed in any one of the claims 1-4, wherein the primary cyclone comprises a primary vortex stabilizer coaxially mounted in the middle part of the primary cyclone, the outer diameter of the primary vortex stabilizer being equal to or larger theme the diameter of the first outlet conduit, which primary vortex stabilizer is positioned below the inlet opening of the first outlet conduit at a distance which is equal to or larger than the diameter of the first outlet conduit. 6. The apparatus as claimed in any one of the claims 1-5, further comprising: (a) a secondary cyclone contained within the disengager vessel, which secondary cyclone is closed at its upper end by means of a cover provided with an outlet opening and comprises a lower portion and an inlet which is in fluid communication with the first outlet conduit; and (b) a second outlet conduit providing a flow path from the outlet opening of the secondary cyclone. 7. The apparatus as claimed in claim 6, where the melt of the secondary cyclone is a tangential inlet arranged in the upper portion of the secondly cyclone. 8. The apparatus as claimed in claim 6 or 7, wherein part of the second outlet conduit extends into the secondary cyclones. 9. The apparatus as claimed in any one of claims 6-8, wherein the secondary cyclone comprises a secondary vortex stabilizer coaxially mounted in the middle part of the secondary cyclone, the outer diameter of the secondary vortex stabilizer being equal to or larger than the diameter of the second outlet conduit, which secondary vortex stabilizer is positioned below the inlet opening of the second outlet conduit at a distance which is equal to or larger than the dinette of the second outlet conduit. 10. The apparatus as claimed m any one of the claims 6-9, wherein a venture is positioned in the outlet end of the first outlet conduit in the vicinity of the inlet of the secondary cyclone. 11. The apparatus as claimed in say one of the claims 6-10, wherein there is a gap between the outlet end of the first outlet conduit and the inlet of die secondary cyclone. 12. A process for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue food separated solid particles in a disengager vessel having a primary fluidized bed comprising: (a) flowing a mixture of solid particles and vapour through a transport conduit; (b) passing the mixture of solid particles and vapour from the transport conduit into a vertical primary cyclone having an open lower end contained inside the disengager vessel, wherein the open lower end of the primary cyclone is submerged in the prunary fluidized bed; (c) controlling the level of the primary fluidized bed so that the top surface of the primary fluidized bed is maintained above the open lower end of the primary cyclone, and that a portion of the primary fluidized bed is contained within the primary cyclone at the open lower end, forming a secondly fluidized bed; (d) separating the mixture of solid particles and vapour into separated vapour and separated solid particles containing adsorbed or entrained residue; (e) collecting the separated solid particles in the secondary fluidized bed contained withui the secondly cyclone; (f) introducing a gas to strip the residue from the separated solid particles, forming stripped vapours and stripped solid particles; (g) allowing the separated vapour and stripped vapour to pass upwards through the primary cyclone; and (h) allowing stripped solid particles to flow away from the open lower end of the primary cyclone into the primary fluidized bed. 13. The process as claimed in claim 12, wherein the primary cyclone is operated at a slightly higher pressure than that in the disengager vessel, so that the top surface of the secondary fluidized bed is below that of the primary fluidized bed. 14. The process as claimed in claim 12 or 13, wherein the separated vapour and stripped vapour are removed to pass upwards from the primary cyclone, the vapour is introduced into a secondary cyclone, enfrained solid particles are separated m the secondary cyclone and the vapour and the solid particles are discharged separately from the secondary cyclone. 15. The process as claimed in any one of the claims 12 to 14, wherein the secondary cyclone is operated at a pressure which is slightly below the the primary cyclone. 16. An apparatus for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from the solid particles, substantially as herein described with reference to the accompanying drawings. 17. A process for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from separated solid particles substantially as herein described with reference to the accompanying drawings.

Full Text

AND METHOD FOR THE SEPARATION AND STRIPPING OF FLUID CATALYST CRACKING PARTICLES FROM GASEOUS
HYDROCARBONS
This invention relates to an apparatus for the separation of solid particles from gaseous hydrocarbons and stripping of hydrocarbons from the separated solid particles. In yet another aspect, it relates to an improved method for separating solid particles, such as catalyst, from gaseous hydrocarbons and stripping hydrocarbons from the separated particles.
Apparatus for separating solid particles from gaseous hydrocarbons have been available for years and have found commercial use, for instance in the separation of hydrocarbon cracking catalysts from gaseous products in a fluidized catalytic cracking process.
In a process which uses solid particles, it is common for suspensions and other mixtures of fine particles to be entrained in a gaseous stream. Many times, the suspensions contain fine solid particles which contain adsorbed and/or entrained residue of the substance(s) involved in the reaction. It becomes necessary to both separate and recover the fine particles from the gaseous stream and to strip the residue from the fine particles in order to prevent possibly detrimental or undesirable reactions downstream. For example, in a typical catalytic cracking process, hydrocarbons are reacted in the presence of catalyst in a riser reactor. Hydrocarbon gases are formed which carry fine solid particles of the catalyst along as the gases flow downstream of the reactor. The suspended catalytic particles contained adsorbed and/or entrained hydrocarbons. The catalytic particles must be separated from the gases and stripped

of the hydrocarbons to prevent catalytic reactions in zones where this is undesirable {commonly called "over cracking"). Stripping also increases yield and allows the catalyst to be recycled. While the apparatus and process of the present invention will be described with particular emphasis on catalytic cracking of hydrocarbons, it is to be understood that it is not so limited and that the apparatus and processes will function as well for other systems which use solid particles and generate mixtures of the solid particles in vapour flow.
As new, highly reactive cracking catalysts, such as zeolites, came into common usage, new separation apparatus were developed to rapidly separate the reactive cracking catalyst from the cracked hydrocarbon vapour in order to avoid over cracking once the hydrocarbons exit a reactor.
USA patent specifications No. 4 961 863 and No. 5 259 855 describe a twin-drum separator which may be located at the terminal end of a catalytic cracking riser reactor. An advantage of the twin-drum separator is that it does not easily choke from catalyst carryover. Most catalytic cracking processes require a high separation efficiency in order to reduce the catalyst carried outside of the reactor vessels, and the twin-drum separator may then not be that suitable to be used alone. . The twin-drum separator also does not integrate well with an internal stripper bed because the upflow of vapour from the stripper catalyst bed could disrupt the vertical flow within the twin-drum separator.
USA patent specifications No. 4 693 808 and No. 4 731 228 describe a horizontal cyclone separator-The mass ratio of catalyst to gas in a horizontal separator limits the maximum amount of catalyst the separator can carry, and if the mass ratio of catalyst to

gas is too high, the horizontal cyclone separator tends to choke.
USA patent specification No. 4 692 311 describes a so-called "quick disengaging cyclone" to reduce separating and stripping time. The cyclone works on centrifugal separation and a reverse flow vortex of vapour. A vortex stabilizer is used to terminate the , vortex before it reaches the bottom of the cyclone, where, if not terminated, the vortex can pick-up separated catalyst at the bottom of the cyclone and carry the catalyst back up and out through the cyclone outlet. The quick disengaging cyclone has proven to work at high efficiency; however, the unit is fairly large due to the need for an internal catalyst stripping bed and a standpipe extending from the bottom of the cyclone.
In addition to catalytic crackers, apparatus for separation and stripping are also used in fluid cokers, entrained coal gasifiers, and other industrial processes using fast-fluidized solid particles. These units may be retrofitted to achieve higher separation and stripping efficiencies in order to meet environmental and economic needs. While separator designs such as those just described have been used for retrofitting various fast-fluidized processes, their use can be limiting for retrofitting units which have limited space for placement of separators and strippers and/or which need to be retrofitted in order to increase efficiency.
In many catalytic cracking plants, for example, a riser reactor exhausts into a disengager vessel where undesirable post-riser cracking takes place. Most of these disengager vessels have a fluidized catalyst bed in the bottom and some sort of separation means at the top. These disengager vessels are often too small to be retrofitted internally with a separator and stripper such those just described. Moreover, it is expensive and

inefficient to disassemble working catalytic crackers in order to install improved separators. So it has not always been possible, or desirable, to place higher-efficiency separators and strippers, such as those just described, into existing disengager vessels. It is very desirable to provide a separator and stripper technology which has high efficiency, smaller size, and simpler design.
It is an object of this invention to provide an integrated disengager and stripper which has a high separation efficiency.
It is another object of this invention to provide a retrofit integrated disengager and stripper which can fit into existing catalytic cracker disengager vessels.
It is yet another object of this invention to provide a retrofit integrated disengager and stripper which is less expensive to manufacture.
To this end the integrated disengager and stripper for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from the solid particles according to the present invention comprises:
(a) a disengager vessel having a primary fluidized-bed zone adapted to contain fluidized solid particles, and a primary means for injecting into the primary fluidized-bed zone a gas for fluidizing or stripping solid particles;
(b) a vertical primary cyclone contained inside the disengager vessel, which primary cyclone has a cylindrical side wall and is closed at its upper end by means of a cover provided with an outlet opening and open at its lower end, which primary cyclone is further provided with at least one inlet for receiving a suspension of solid particles and vapour; and
(c) a first outlet conduit for providing a flow path

from the outlet opening of the primary cyclone, which has an end connected, to the outlet opening of the primary cyclone,
wherein the open lower end of the primary cyclone projects downwardly into the primary fluidized-bed zone so as to form a secondary fluidized-bed zone within the lower open end of the primary cyclone. - — - -The invention further relates to a method for separating a mixture of solid particles and vapour and for stripping adsorbed and entrained residue from separated solid particles in a disengager vessel having a primary fluidized bed, which method according to the invention comprises:
(a) flowing a mixture of solid particles and vapour through a transport conduit;
{b) passing the mixture of solid particles and vapour from the transport conduit into a vertical primary cyclone having an open lower end contained inside the disengager vessel, wherein the open lower end of the primary cyclone is submerged in the primary fluidized bed;
(c) controlling the level of the primary fluidized bed so that the top surface of the primary fluidized bed is maintained above the open lower end of the primary cyclone, and that a portion of the primary fluidized bed is contained within the primary cyclone at the open lower end, forming a secondary fluidized bed;
(d) separating the mixture of solid particles and vapour into separated vapour and separated solid particles containing adsorbed or entrained residue;
(e) collecting the separated solid particles in the secondary fluidized bed contained within the secondary cyclone;
(f) introducing a gas to strip the residue from the separated solid particles, forming stripped vapours and

stripped solid particles;
(g) allowing the separated vapour and stripped vapour to pass upwards through the primary cyclone; and (h) allowing stripped solid particles to flow away from the open lower end of the primary cyclone into the primary fluidized bed.
The invention will now be described by way of example with reference to the drawings, wherein
Figure 1 shows a cross-sectional view of the integrated disengager and stripper according to the present invent ion;
Figure 2 shows a cross-sectional view of the primary cyclone of Figure 1 drawn to a scale larger than that of Figure 1; and
Figure 3 shows a cross-sectional view of the secondary cyclone of Figure 1 drawn to a scale larger than that of Figure 1.
Reference is now made to Figures 1 and 2. The integrated disengager and stripper 2 for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from the solid particles according to the present invention comprises a disengager vessel 3 and a vertical primary cyclone 6 which is contained inside the disengager vessel 3.
The disengager vessel 3 has a primary fluidized-bed zone 10 adapted to contain a primary fluidized bed 11 of fluidized solid particles, and a primary means for injecting into the primary fluidized-bed zone a gas for fluidizing or stripping solid particles in the form of primary injector 12.
The vertical primary cyclone 6 has a cylindrical wall in the form of circle-cylindrical side wall 15 and is closed at its upper end 16 by means of a cover 17 provided with an outlet opening 19.
The primary cyclone 6 is further provided with at

least one inlet 24 for receiving a suspension of solid particles and vapour. The inlet 24 of the primary cyclone is directly connected to an outlet conduit 25 of a transport conduit in the form of a reactor riser 27 extending into the disengager vessel 3.
The integrated disengager and stripper 2 also comprises a first o\itlet conduit 30 for providing a flow path from the outlet opening 19 of the primary cyclone 5, which has an end that is connected to the outlet opening 19 of the primary cyclone 6.
The vertical primary cyclone 6 is closed at its upper end 16, however, it is open at its lower end 32 having a discharge opening 34, wherein the inner diameter of the open lower end 32 is substantially equal to that of the upper end 15 of the primary cyclone 6. The open lower end 32 of the vertical primary cyclone 5 projects downwardly into the primary fluidized-toed zone 10 so as to form a secondary fluidized-bed zone 35 adapted to contain during normal operation a secondary fluidized bed 36 of fluidized solid particles within the lower end 32 of the primary cyclone 6.
During normal operation, a mixture of solid particles in the form of catalyst particles and vapour in the form of reaction effluent from a catalytic cracking process flows upwards through the reactor riser 27, and passes through its outlet conduit 25 into the inlet 24 of the primary cyclone 6.
In the primary cyclone 6 the catalyst particles are separated from the reaction effluent; the catalyst particles fall downwards towards the lower end 32 of the primary cyclone 6, and the reaction effluent passes upwards and leaves the primary cyclone 6 through the first outlet conduit 30.
The lower part of the disengager vessel 3 contains the primary fluidized bed 11 of catalyst particles which

are maintained in a fluidized state by the action of gas for fluidizing solid particles injected into the primary fluidi^ed-bed zone 10 through the primary injector 12. The gas also strips the catalyst particles and in this way adsorbed or entrained residue are removed therefrom to obtain stripped catalyst particles which are discharged from the disengager vessel 3 through discharge conduit 38. The catalyst particles are passed to a regenerator [not shown) where they are regenerated so that they can be used in the reactor riser 27.
Since the open lower end 32 of the primary cyclone 6 projects downwardly into the primary fluidized-bed zone 10, the discharge opening 34 is submerged in the primary fluidized bed 11, and the level of the primary fluidized bed 11 is controlled so that the top surface 39 of the primary fluidized bed 11 is maintained above the discharge opening 34 of the primary cyclone 3. The portion of the primary fluidized bed 11 contained within the lower end 32 of the primary cyclone 6 forms the secondary fluidized bed 36.
The separated catalyst particles which fall downwardly through the primary cyclone 6 are collected in the secondary fluidized bed 36.
Gas introduced through the primary injector 12 also enters into the secondary fluidized bed 3 6 to strip the residue from the separated catalyst particles, forming stripped vapour and stripped catalyst particles. The stripped vapour and removed reaction effluent pass upwards through the primary cyclone 6, and are removed through the first outlet conduit 30. Vlhereas stripped catalyst particles are allowed to flow away from the discharge opening 34 of the primary cyclone 6 into the primary fluidized bed 11.
The fluidized catalyst particles are thus partially contained in the secondary fluidized bed 36 inside the

adsorbed and entrained hydrocarbon on the catalyst is stripped f roKi the catalyst in the £lu.idized-bed zone, recovering the hydrocarbon as hydrocarbon vapour and reducing undesired over cracking reactions.
In a suitable embodiment, the integrated disengager and stripper 2 according to the present invention further comprises a secondary cyclone 55 contained within the disengager vessel 3, having a cylindrical side wall in the form of circle-cylindrical side wall 56. The secondary cyclone 55 is closed at its upper end by means of a cover 57 provided with an outlet opening 58. It comprises a lower portion 60 and an inlet 62 which is in fluid communication with the first outlet conduit 30. The integrated disengager and stripper 2 also includes a second outlet conduit 64 providing a flow path from the outlet opening 58 of the secondary cyclone 55.
During normal operation, separated vapour and stripped vapour are removed from the primary cyclone 6 through the first outlet conduit 30. This vapour still contains entrained catalyst particles which have to be removed in the secondary cyclone 55. To this end the vapour is introduced into the secondary cyclone 55, entrained catalyst particles are separated from the vapour. The vapour is flows upwards in the secondary cyclone 55 through the outlet opening 58, and the catalyst particles are collected in the lower portion 60 of the secondary cyclone 55. Vapour and catalyst particles are discharged separately from the secondary cyclone 55, through the second outlet conduit 64 and an outlet opening 68 in the lower portion 60, respectively. The secondary cyclone 55 is operated at a pressure which is slightly below that in the primary cyclone 6, and since that pressure is below that in the disengager vessel 3, the pressure in the secondary cyclone 55 is lower than that in the disengager vessel 3.

The secondary cyclone 55 is suitably provided with a dip-leg 69. The dip-leg 69, which is preferably provided with a valve (not shown) at the bottom to allow release of separated particles, extends into the primary fluidized bed ii.
The secondary cyclone 55 is placed in series with the primary cyclone 6, which is called in the art "close-coupling" . The term "close-coupled" is commonly used when the exhaust of one cyclone is coupled to the inlet of another cyclone. Close-coupling cyclones reduces the undesirable, post-riser cracking of riser reactor products which can take place when, for example, (1) all separation is performed in the disengager vessel, or {2) the first cyclone exhausts into the disengager vessel.
When both a primary cyclone with vortex stabilizer means and a secondary cyclone with vortex stabilizer means are used in series, the primary cyclone acts as a "quick disengaging cyclone" and the secondary cyclone acts as a "high efficiency cyclone."
Suitably the inlet 62 of the secondary cyclone 55 is a tangential inlet 70 (see Figure 3) arranged in the upper end 71 of the secondary cyclone 55. Vapour and catalyst particles entering through the tangential inlet 70 of the secondary cyclone 55, are caused to form a vortex in the upper end 71 of the secondary cyclone 55. The upper end 71 is then the swirl zone of the secondary cyclone 55.
The efficiency of the swirl zone can be improved when part 72 of the second outlet conduit 64 extends into the secondary cyclone 55, Part 72 forms the vortex outlet of the secondary cyclone 55.
Suitably the secondary cyclone 55 further comprises a secondary dish-shaped vortex stabilizer 74 coaxially mounted in the middle part 76 of the secondary cyclone 55. The outer diameter of the secondary vortex

stabilizer 74 is equal to or larger than the ciiameter of the second outlet conciuit 64, and smaller than the inner diameter of the circle-cylindrical side wall 56. The secondary vortex stabilizer 74 is positioned below the inlet opening 77 of the second outlet conduit 64 at a distance which is equal to or larger than the diameter of the second outlet conduit 64. In the embodiment of the invention as shown in Figure 1 and 3, the second outlet conduit 64 has a tapered part 72, and the diameter is the smallest diameter of the tapered part 72.
The secondary vortex stabilizer 74 is supported by means of supports 79. It is suitably provided with a vortex finder 80.
Any means for compensating for thermal and vibrational movement between the primary and secondary cyclones 6 and 55 may be used in the connection between them. In the embodiment of Figure 1, there is provided a gap 82, between the outlet 83 of the first outlet conduit 30 and the inlet 62 of the secondary cyclone 55. The gap 82 further provides a means for stripper gas and stripped vapour in the disengager vessel 3 to enter the slightly lower pressure secondary cyclone 55.
Suitably the integrated disengager and stripper according to the present invention further comprising a venturi (not shown) positioned in the outlet end 84 of the first outlet conduit 30 in the vicinity of the inlet 62 of the secondary cyclone 55. The venturi not only helps move the gases in the first outlet conduit 30 into the secondary cyclone 55, it also reduces the pressure differential between the interior of the disengager vessel 3 and the secondary cyclone 55.
Suitably the inner surfaces of the circle-cylindrical side walls 15 and 56 of the primary and secondary cyclones 6 and 55 are lined with a refractory which is resistant to erosion, such as ceramic. This allows the

shell of the disengager vessel 3 to be used without a refractory lining since the cyclones are lined. Tile lining is not needed in the disengager vessel 3 because the solid particles will not be flowing in the disengager vessel 3 in a manner which would erode the walls. Eliminating the lining in the disengager vessel 3 reduces the occurrence of two problems cottony seen. First, corrosion caused by uneven heating of the disengager vessel walls should be reduced. Second, the refractory lining in the disengager vessel 3 will spall over time. The spalled lining enters the system, where it will plug valves and equipment. Eliminating the refractory lining of the disengager vessel 3 should substantially reduce this problem.
The combination of the primary and secondary cyclones 6 and 55 can suitably be used as a retrofit for fluid catalytic crackers, fluid cokers, entrained coal gasifiers, and other industrial processes with small disengager vessels or small internal cyclones.

WE CLAIM:
1. An apparatus for separating solid particles suspended in vapour and for stepping adsorbed and entrained residue from the solid particles comprising (a) a disengager vessel having a primary fluidized-bed zone adapted to contain fluidized solid particles, and a primary means for injecting into the primary fluidized-bed zone a gas for fluidizing or stripping solid particles (b) a vertical primary cyclone contained inside the disengager vessel, which primary cyclone has a cylindrical side wall and is closed at its upper end by means of a cover provided with an outlet opening and open at its lower end, which primary cyclone is further provided with at least one inlet for receiving a suspension of solid particles and vapour; and (c) a first outlet conduit for providing a flow path from the outlet opening of the primary cyclone, which has an end connected to the outlet opening of the primary cyclone, wherein the open lower end of the primary cyclone projects downwardly into the primary fluidized-bed zone to form a secondary fluidized-bed zone within the lower open end of the primary cyclone.
2. The apparatus as claimed in claim 1, wherein secondary means is provided for injecting into the secondary fluidized-bed zone a gas for fluidizing or stripping solid particles.
3. The apparatus as claimed in claim 1 or 2, wherein the inlet is a tangential inlet arranged in the side wall near the closed end.

4. The apparatus as claimed in one of the claims 1- 3, wherein part of the first outlet conduit extends into the primary cyclone.
5. The apparatus as claimed in any one of the claims 1-4, wherein the primary cyclone comprises a primary vortex stabilizer coaxially mounted in the middle part of the primary cyclone, the outer diameter of the primary vortex stabilizer being equal to or larger theme the diameter of the first outlet conduit, which primary vortex stabilizer is positioned below the inlet opening of the first outlet conduit at a distance which is equal to or larger than the diameter of the first outlet conduit.
6. The apparatus as claimed in any one of the claims 1-5, further comprising: (a) a secondary cyclone contained within the disengager vessel, which secondary cyclone is closed at its upper end by means of a cover provided with an outlet opening and comprises a lower portion and an inlet which is in fluid communication with the first outlet conduit; and (b) a second outlet conduit providing a flow path from the outlet opening of the secondary cyclone.
7. The apparatus as claimed in claim 6, where the melt of the secondary cyclone is a tangential inlet arranged in the upper portion of the secondly cyclone.
8. The apparatus as claimed in claim 6 or 7, wherein part of the second outlet conduit extends into the secondary cyclones.

9. The apparatus as claimed in any one of claims 6-8, wherein the
secondary cyclone comprises a secondary vortex stabilizer coaxially
mounted in the middle part of the secondary cyclone, the outer diameter
of the secondary vortex stabilizer being equal to or larger than the
diameter of the second outlet conduit, which secondary vortex stabilizer
is positioned below the inlet opening of the second outlet conduit at a distance which is equal to or larger than the dinette of the second outlet conduit.
10. The apparatus as claimed m any one of the claims 6-9, wherein a venture is positioned in the outlet end of the first outlet conduit in the vicinity of the inlet of the secondary cyclone.
11. The apparatus as claimed in say one of the claims 6-10, wherein there is a gap between the outlet end of the first outlet conduit and the inlet of die secondary cyclone.
12. A process for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue food separated solid particles in a disengager vessel having a primary fluidized bed comprising: (a) flowing a mixture of solid particles and vapour through a transport conduit; (b) passing the mixture of solid particles and vapour from the transport conduit into a vertical primary cyclone having an open lower end contained inside the disengager vessel, wherein the open lower end of the primary cyclone is submerged in the prunary fluidized bed; (c) controlling the level of the primary fluidized bed so that the top surface of

the primary fluidized bed is maintained above the open lower end of the primary cyclone, and that a portion of the primary fluidized bed is contained within the primary cyclone at the open lower end, forming a secondly fluidized bed; (d) separating the mixture of solid particles and vapour into separated vapour and separated solid particles containing adsorbed or entrained residue; (e) collecting the separated solid particles in the secondary fluidized bed contained withui the secondly cyclone; (f) introducing a gas to strip the residue from the separated solid particles, forming stripped vapours and stripped solid particles; (g) allowing the separated vapour and stripped vapour to pass upwards through the primary cyclone; and (h) allowing stripped solid particles to flow away from the open lower end of the primary cyclone into the primary fluidized bed.
13. The process as claimed in claim 12, wherein the primary cyclone is operated at a slightly higher pressure than that in the disengager vessel, so that the top surface of the secondary fluidized bed is below that of the primary fluidized bed.
14. The process as claimed in claim 12 or 13, wherein the separated vapour and stripped vapour are removed to pass upwards from the primary cyclone, the vapour is introduced into a secondary cyclone, enfrained solid particles are separated m the secondary cyclone and the vapour and the solid particles are discharged separately from the secondary cyclone.
15. The process as claimed in any one of the claims 12 to 14, wherein the

secondary cyclone is operated at a pressure which is slightly below the the primary cyclone.
16. An apparatus for separating solid particles suspended in vapour and for
stripping adsorbed and entrained residue from the solid particles,
substantially as herein described with reference to the accompanying
drawings.
17. A process for separating solid particles suspended in vapour and for
stripping adsorbed and entrained residue from separated solid particles
substantially as herein described with reference to the accompanying
drawings.

Documents:

947-mas-1997 abstract duplicate.pdf

947-mas-1997 abstract.pdf

947-mas-1997 claims duplicate.pdf

947-mas-1997 claims.pdf

947-mas-1997 correspondence others.pdf

947-mas-1997 correspondence po.pdf

947-mas-1997 description (complete) duplicate.pdf

947-mas-1997 description (complete).pdf

947-mas-1997 drawings duplicate.pdf

947-mas-1997 drawings.pdf

947-mas-1997 form-1.pdf

947-mas-1997 form-26.pdf

947-mas-1997 form-4.pdf

947-mas-1997 form-6.pdf

947-mas-1997 petition.pdf

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Patent Number

196356

Indian Patent Application Number

947/MAS/1997

PG Journal Number

20/2006

Publication Date

19-May-2006

Grant Date

07-Feb-2006

Date of Filing

05-May-1997

Name of Patentee

M/S. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B V

Applicant Address

CAREL VAN BYLANDTLAAN 30, 2596 HR THE HAGUE

Inventors:

#	Inventor's Name	Inventor's Address
1	THOMAS SHAWN DEWITZ	1022 ORCHARD HILL, HOUSTON, TEXAS 77077

PCT International Classification Number

C10G 11/18

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	646607	1996-05-08	U.S.A.