MAGNETIC SEPARATION COMBINED WITH DYNAMIC SETTLING FOR FISCHER-TROPSCH PROCESSES

• US 20090065437A1
• Filed: 09/08/2008
• Published: 03/12/2009
• Est. Priority Date: 09/10/2007
• Status: Active Grant

• Current Assignee: Res Usa, Llc (Rentech, Inc.)
• Original Assignee: Rentech, Inc.
• Inventors: MOHEDAS, Sergio
• Granted Patent: US 8,871,096 B2
• Time in Patent Office: Days
• US Class Current: 210/695
• CPC Class Codes: B01D 21/0009 Settling tanks making use of electricity or magnetism electric ultra filters B01D61/425; filters making use of electricity or magnetism B01D35/06; magnetic or electrostatic separation B03C
• CPC Class Codes: B01D 21/0045 Plurality of essentially parallel plates
• CPC Class Codes: B01J 8/005 Separating solid material from the gas/liquid stream separation processes per se B01D
• CPC Class Codes: B01J 8/228 externally, i.e. the particles leaving the vessel and subsequently re-entering it
• CPC Class Codes: B03C 1/02 acting directly on the substance being separated
• CPC Class Codes: B03C 1/286 disposed at the inner circumference of a recipient, e.g. magnetic drain bolt
• CPC Class Codes: B03C 1/288 disposed at the outer circumference of a recipient
• CPC Class Codes: B03C 1/30 Combinations with other devices, not otherwise provided for
• CPC Class Codes: B03C 2201/18 Magnetic separation whereby the particles are suspended in a liquid

Abstract

A system for separating particulate from a fluid stream having an inlet solids content, the system comprising: a magnetic dynamic settling vessel comprising at least one magnetic field inside the vessel and/or one magnetized component; at least one inlet for introduction of the fluid stream having a starting solids content; at least one exit for a stream comprising a solids content not greater than the inlet solids content; at least one exit for a fluid stream comprising a solids content not less than the inlet solids content; and a vertical feed conduit extending at least 70% of the distance from the at least one fluid inlet to the at least one exit for a fluid stream comprising a solids content not less than the inlet solids content. A method for separating particulate from a fluid stream having an inlet solids content is also provided.

Claims

1. A system for separating solid particles from a fluid stream having an inlet solids content, the system comprising:

a magnetic dynamic settling vessel comprising at least one magnetic field within the vessel, at least one fluid inlet for introduction of the fluid stream having a starting solids content, at least one exit for a fluid stream comprising a solids content not greater than the inlet solids content, at least one exit for a fluid stream comprising a solids content not less than the inlet solids content, and a vertical feed conduit extending at least 70% of the distance from the at least one fluid inlet to the at least one exit for a fluid stream comprising a solids content not less than the inlet solids content.

2. The system of claim 1 wherein the at least one magnetic field is supplied to the internal of the magnetic dynamic settling vessel in the absence of any magnetized physical component of the magnetic dynamic settling vessel itself.

3. The system of claim 1 wherein the at least one magnetic field is provided by at least one magnetized component.

4. The system of claim 3 wherein the at least one magnetized component is selected from the group consisting of at least a portion of the external walls of the magnetic dynamic settling vessel, at least a portion of the internal walls of the settling vessel, magnetic baffles, magnetic fins, magnetic rods, magnetic plates, another magnetized internal component, and combinations thereof.

5. The system of claim 3 wherein the at least one magnetized component comprises at least a portion of the walls of the magnetic dynamic settling vessel.

6. The system of claim 5 wherein the at least one magnetized component is an internal component.

7. The system of claim 1 wherein the magnetic dynamic settling vessel comprises an upper portion comprising vertical external walls and a narrower lower portion comprising inclined external walls.

8. The system of claim 7 wherein at least a portion of the vertical walls, at least a portion of the inclined walls, or at least a portion of both is magnetized.

9. The system of claim 7 wherein the at least a portion of the vertical walls, at least a portion of the inclined walls, or at least a portion of both is magnetized by at least one externally positioned magnet.

10. The system of claim 1 further comprising a second dynamic settler, the second dynamic settler comprising at least one secondary dynamic settler inlet in fluid connection with the at least one exit for a fluid stream comprising a solids content not less than the inlet solids content;

at least one secondary dynamic settler concentrated solids exit; and

at least one secondary dynamic settler liquid product exit.

11. The system of claim 10 wherein the at least one secondary dynamic settler concentrated solids exit is in fluid communication with the slurry inlet of a Fischer-Tropsch reactor.

12. The system of claim 1 wherein the magnetic dynamic settling vessel is capable of producing an exit fluid stream comprising a solids content not greater than 5000 ppm by weight.

13. The system of claim 12 wherein the magnetic dynamic settling vessel is capable of producing an exit fluid stream comprising a solids content not greater than 2500 ppm by weight.

14. The system of claim 13 wherein the magnetic dynamic settling vessel is capable of producing an exit fluid stream comprising a solids content not greater than 1000 ppm by weight.

15. The system of claim 12 wherein the magnetic dynamic settling vessel is operable at a liquid linear upward velocity greater than least 15 cm/h.

16. The system of claim 15 wherein the magnetic dynamic settling vessel is operable at a liquid linear upward velocity greater than 45 cm/h.

17. The system of claim 16 wherein the magnetic dynamic settling vessel is operable at a liquid linear upward velocity greater than 90 cm/h.

18. The system of claim 1 further comprising a secondary separation system, the secondary separation system fluidly connected to the at least one exit for a fluid stream comprising a solids content not greater than the inlet solids content;

a clarified liquid product exit; and

a waste exit.

19. The system of claim 18 wherein the secondary separation system comprises an apparatus selected from cross-flow filtration devices, press filters, sand filters, other filtration devices, electrostatic separators, centrifugal separators, hydro-cyclones, high gradient magnetic separation devices, and combinations thereof.

20. The system of claim 1 wherein the magnetic dynamic settling vessel is downstream of a multi-phase catalytic reactor comprising catalyst.

21. The system of claim 20 wherein the reactor is a Fischer-Tropsch reactor comprising a feedstream inlet, a slurry inlet, a vapor product exit, and a liquid product exit.

22. The system of claim 21 wherein the at least one exit for a fluid stream comprising a solids content not less than the inlet solids content is in fluid communication with the slurry inlet of the Fischer-Tropsch reactor.

23. The system of claim 20 wherein the at least one fluid inlet for introduction of the fluid stream having an inlet solids content of the magnetic dynamic settling vessel is in fluid communication with a liquid outlet from a vapor/liquid separator, said vapor/liquid separator located downstream of the multi-phase catalytic reactor, and an inlet of said vapor/liquid separator in fluid communication with a fluid outlet of the multi-phase reactor.

24. The system of claim 1 wherein the solid particles comprise FT catalyst comprising a metal selected from the group consisting of iron, cobalt, and combinations thereof.

25. The system of claim 24 wherein the majority of the catalyst particles have a size in the range of from about 10 microns and about 200 microns.

26. The system of claim 25 wherein the majority of the catalyst particles have a size in the range of from about 20 microns and about 150 microns.

27. A method for separating solid particles from a fluid stream having an inlet solids content, the method comprising:

introducing the fluid stream into a magnetic dynamic settler vessel, the magnetic dynamic settler vessel comprising at least one magnetic field within the vessel, at least one fluid inlet for introduction of the fluid stream having an inlet solids content, at least one exit for a liquid product stream comprising a solids content not greater than the inlet solids content, at least one exit for a fluid stream comprising a solids content not less than the inlet solids content, and a vertical feed conduit extending at least 70% of the distance from the at least one fluid inlet to the at least one exit for a fluid stream comprising a solids content not less than the inlet solids content;

removing from the magnetic dynamic settler vessel at least one liquid product stream comprising a solids content not greater than the inlet solids content; and

removing from the magnetic dynamic settler vessel at least one stream comprising a solids content not less than the inlet solids content.

28. The method of claim 27 wherein the at least one liquid product stream comprising a solids content not greater than the inlet solids content comprises a solids content not greater than 5000 ppm by weight.

29. The method of claim 27 wherein the at least one liquid product stream comprising a solids content not greater than the inlet solids content comprises a solids content not greater than 2500 ppm by weight.

30. The method of claim 27 wherein the at least one liquid product stream comprising a solids content not greater than the inlet solids content comprises a solids content not greater than 1000 ppm by weight.

31. The method of claim 27 wherein the magnetic dynamic settler vessel has a liquid linear upward velocity of greater than 15 cm/h.

32. The method of claim 31 wherein the magnetic dynamic settler vessel has a liquid linear upward velocity of greater than 45 cm/h.

33. The method of claim 32 wherein the magnetic dynamic settler vessel has a liquid linear upward velocity of greater than 90 cm/h.

34. The method of claim 27 wherein the solid particles comprise Fischer-Tropsch catalyst particles.

35. The method of claim 34 wherein the Fischer-Tropsch catalyst particles comprise at least one metal selected from the group consisting of iron, cobalt, or a combination thereof.

36. The method of claim 35 wherein the majority of the catalyst particles have a particle size in the range of from about 10 microns to about 200 microns.

37. The method of claim 36 wherein the majority of the catalyst particles have a particle size in the range of from about 20 microns to about 150 microns.

38. The method of claim 27 wherein the at least one magnetic field is provided by at least one magnetized component selected from the group consisting of at least a portion of the external walls of the magnetic dynamic settler vessel, at least a portion of the internal walls of the settler vessel, magnetic baffles, magnetic fins, magnetic rods, magnetic plates, another magnetized internal component, and combinations thereof.

39. The method of claim 38 wherein the at least one magnetized component comprises at least a portion of the walls of the magnetic dynamic settler vessel.

40. The method of claim 39 wherein the at least one magnetized component is an internal component.

41. The method of claim 27 wherein the at least one magnetic field is supplied to the internal of the magnetic dynamic settling vessel in the absence of any magnetized physical component of the magnetic dynamic settling vessel itself.

42. The method of claim 27 wherein the magnetic dynamic settler comprises an upper portion comprising vertical external walls and a narrower lower portion comprising inclined external walls.

43. The method of claim 42 wherein at least a portion of the vertical walls, at least a portion of the inclined walls, or at least a portion of both is magnetized by at least one externally positioned magnet.

44. The method of claim 27 further comprising introducing the stream comprising a solids content not less than the inlet solids content into a second dynamic settler.

45. The method of claim 44 further comprising removing from the second dynamic settler at least one secondary dynamic settler concentrated slurry stream and at least one secondary dynamic settler liquid product stream.

46. The method of claim 45 further comprising introducing the at least one secondary dynamic settler concentrated slurry stream into a Fischer-Tropsch reactor.

47. The method of claim 27 further comprising introducing the liquid product stream comprising a solids content not greater than the inlet solids content into a secondary separation system.

48. The method of claim 47 wherein the secondary separation system comprises an apparatus selected from cross-flow filtration devices, press filters, sand filters, other filtration devices, electrostatic separators, centrifugal separators, hydro-cyclones, high gradient magnetic separation devices, and combinations thereof.

49. The method of claim 27 wherein the fluid stream having a solids content comprises effluent removed from a multi-phase catalytic reactor, said effluent comprising solid magnetic catalyst particles.

50. The method of claim 49 wherein the multi-phase catalytic reactor comprises a Fischer-Tropsch reactor.

51. The method of claim 50 wherein the solid magnetic catalyst particles are selected from iron-based catalyst particles, cobalt-based catalyst particles and combinations thereof.

52. The method of claim 49 further comprising removing vapor from the effluent via a vapor/liquid separator to produce the fluid stream having an inlet solids content.

53. The method of claim 49 further comprising removing at least a portion of the solid particles from the effluent upstream of the magnetic dynamic settler.

54. The method of claim 27 further comprising introducing the at least one stream comprising a solids content not less than the inlet solids content to a Fischer-Tropsch reactor.