Patent EA-000510-B1 (EA)
Title: Apparatus and method for the separation and stripping of fluid catalyst cracking particles from gaseous hydrocarbons
Inventor: DEWITZ THOMAS SHAWN
IPC: B01J8/00
Filed: 1997-05-07
Abstract: 1. Integrated disengager and stripper (2) for separating solid particles suspended in vapour and for stripping adsorbed and entrained residue from the solid particles comprising: (a) a disengager vessel (3) having a primary fiuidized-bed zone (10) adapted to contain fiuidized solid particles, and a primary means (12) for injecting into the primary fiuidized-bed zone (10) a gas for fluidizing or stripping solid particles; (b) a vertical primary cyclone (6) contained inside the disengager vessel (3), which primary cyclone (5) 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 at least one inlet (24) for receiving a suspension of solid particles and vapour; and (c) a first outlet conduit (30) for providing a flow path from the outlet opening (19) of the primary cyclone, which has an end connected to the outlet opening (19) of the primary cyclone (6), characterized in that the open lower end of the primary cyclone (6) projects downwardly into the primary fiuidized-bed zone (10) so as to form a secondary fiuidized-bed zone (35) within the lower open end (32) of the primary cyclone (6). 2. Integrated disengager and stripper (2) as claimed in Claim 1, further comprising secondary means (41) for injecting into the secondary fiuidized-bed zone (35) a gas for fluidizing or stripping solid particles. 3. Integrated disengager and stripper (2) as claimed in Claim 1 or 2, characterized in that the inlet (24) of the primary cyclone (6) is a tangential inlet (42) arranged in the side wail (15) near the closed end of the primary cyclone (6). 4. Integrated disengager and stripper (2) as claimed in any one of the Claims 1-3, characterized in that part (44) of the first outlet conduit (30) extends into the primary cyclone (6). 5. Integrated disengager and stripper (2) as claimed in any one of the Claims 1-4, characterized in that the primary cyclone (6) further comprises a primary vortex stabilizer (46) coaxially mounted in the middle part of the primary cyclone (6), the outer diameter of the primary vortex stabilizer (46) being equal to or larger than the diameter of the first outlet conduit (30), which primary vortex stabilizer (46) is positioned below the inlet opening (49) of the first outlet conduit (30) at a distance which is equal to or larger than the diameter of the first outlet conduit (30). 6. Integrated disengager and stripper (2) as claimed in any one of the Claims 1-5, further comprising: (a) a secondary cyclone (55) contained within the disengager vessel (3), which secondary cyclone (55) is closed at its upper end by means of a cover (57) provided with an outlet opening (58) and comprises a lower portion (60) and an inlet (62) which is in fluid communication with the first -outlet conduit (30); and b) a second outlet conduit (64) providing a flow path from the outlet opening (58) of the secondary cyclone (55). 7. Integrated disengager and stripper (2) as claimed in Claim 6, characterized in that the inlet (62) of the secondary cyclone (55) is a tangential inlet (70) arranged in the upper portion (71) of the secondary cyclone (55). 8. Integrated disengager and stripper (2) as claimed in Claim 6 or 7, characterized in that part of the second outlet conduit (64) extends into the secondary cyclone (55). 9. Integrated disengager and stripper (2) as claimed in any one of the Claims 6-8, characterized in that the secondary cyclone (55) further comprises a secondary vortex stabilizer (74) coaxially mounted in the middle part of the secondary cyclone (55), the outer diameter of the secondary vortex stabilizer (74) being equal to or larger than the diameter of the second outlet conduit (64), which secondary vortex stabilizer (74) is positioned below che 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). 10. Integrated disengager and stripper (2) as claimed in any one of the Claims 6-9, further comprising a Venturi positioned in the outlet end (84) of the first outlet conduit (30) in the vicinity of the inlet (62) of the secondary cyclone (55). 11. Integrated disengager and stripper as claimed in any one of the Claims 6-10, characterized in that there is a gap (82) between the outlet end (83) of the first outlet conduit (30) and the inlet (62) of the secondary cyclone (55). 12. 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 (3) having a primary fluidized bed (10) comprising: (a) flowing a mixture of solid particles and vapour through a transport conduit (27); (b) passing the mixture of solid particles and vapour from the transport conduit (27) into a vertical primary cyclone (6) having an open lower end contained inside the disengager vessel (3), wherein the open lower end of the primary cyclone (6) is submerged in the primary fluidized bed (10); (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 (36); (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 (36) contained within the primary cyclone (6); (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 (6); and (h) allowing stripped solid particles to flow away from the open lower end of the primary cyclone (6) into the primary fluidized bed (10). 13. The method as claimed in Claim 12, further comprising operating the primary cyclone (6) at a slightly higher pressure than that in the disengager vessel (3), so that the top surface (39) of the secondary fluidized bed (36) is below the top surface (40) of the primary fluidized bed (10). 14. The method as claimed in Claim 12 or 13, further comprising removing the separated vapour and stripped vapour to pass upwards from the primary cyclone (6), introducing the vapour into a secondary cyclone (55), separating entrained solid particles in the secondary cyclone (55) and discharging the vapour and the solid particles separately from the secondary cyclone (55). 15. The method as claimed in any one of the Claims 12-14, characterized in that the secondary cyclone (55) is operated at a pressure which is slightly below that in the primary cyclone (6). 16. Method for retrofitting an existing disengager vessel (3) having some sort of separation means at the top and a fluidized-bed zone at the bottom, hereinafter referred to as the primary fluidized-bed zone (10), adapted to contain fluidized solid particles, and a primary means (12) for injecting into the primary fluidized-bed zone (10) a gas for fiuidizing or stripping solid particles, characterized in that the retrofitting is performed by placing a vertical primary cyclone (6) inside the disengager vessel (3), which primary cyclone (6) 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 at least one 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, which has an end connected to the outlet opening (19) of the primary cyclone (6), wherein the open lower end 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 lower open end (32) of the primary cyclone (6). 17. Method for retrofitting as claimed in Claim 16, characterized in that secondary means (41) for injecting into the secondary fluidized-bed zone (35) a gas for fiuidizing or stripping solid particles are present. 18. Method for retrofitting as claimed in Claim 16 or 17, characterized in that the inlet (24) of the primary cyclone (6) is a tangential inlet (42) arranged in the side wall (15) near the closed end of the primary cyclone (6). 19. Method for retrofitting as claimed in any one of the Claims 16-18, characterized in that part (44) of the first outlet conduit (30) extends into the primary cyclone (6). 20. Method for retrofitting as claimed in any one of the Claims 16-19, characterized in that the primary cyclone (6) further comprises a primary vortex stabilizer (46) coaxiaily mounted in the middle part of the primary cyclone (6), the outer diameter of the primary vortex stabilizer (46) being equal to or larger than the diameter of the first outlet conduit (30), which primary vortex stabilizer (46) is positioned below the inlet opening (49) of the first outlet conduit (30) at a distance which is equal to or larger than the diameter of the first outlet conduit (30). 21. Method for retrofitting as claimed in any one of the Claims 16-20, characterized in that (a) a secondary cyclone (55) is contained within the resulting disengager vessel (3), which secondary cyclone (55) is closed at its upper end by means of a cover (57) provided with an outlet opening (58) and comprises a lower portion (60) and an inlet (62) which is in fluid communication with the first outlet conduit (30); and (b) a second outlet conduit (64) providing a flow path from the outlet opening (58) of the secondary cyclone (55). 22. Method for retrofitting as claimed in Claim 21, characterized in that the inlet (62) of the second