Separation process and apparatus for removal of particulate material from flash zone gas oil
View Patent ↗A process and an apparatus for removing particulate material from a flash zone gas oil stream produced in a delayed coking unit. The process and apparatus of the invention employ cyclonic separation to remove particulate material from the flash zone gas oil stream. The stream can then be further processed, for example by passing the stream to a fixed bed catalytic hydroprocessing unit and then to a fluidized bed catalytic cracking unit, or to other processing units, thereby enhancing the value of the flash zone gas oil stream.
1. In a delayed coking process in which overhead vapors from a coking drum are fed to a coker fractionator where said vapors are separated into an overhead vapor stream, intermediate liquid streams, and a flash zone gas oil stream containing a substantial amount of particulate material of varying diameter, the improvement comprising:
supplying said flash zone gas oil stream to a first separator;
operating said first separator to remove particulate material having a diameter greater than about 500 micrometers from said flash zone gas oil stream and form a first reduced particulate stream;
supplying said first reduced particulate stream to a second separator comprising a cyclonic separator;
operating said second separator to remove particulate material having a diameter greater than about 25 micrometers from said first reduced particulate stream and form a second reduced particulate stream; and
supplying said second reduced particulate stream to a hydroprocessor.
2. The process of claim 1 comprising operating said first separator to remove at least about 80% of particulate having a diameter greater than about 500 micrometers from said flash zone gas oil stream.
3. The process of claim 1 comprising operating said first separator to remove at least about 90% of particulate having a diameter greater than about 500 micrometers from said flash zone gas oil stream.
4. The process of claim 1 comprising operating said first separator to remove at least about 80% of particulate having a diameter greater than about 100 micrometers from said flash zone gas oil stream.
5. The process of claim 1 comprising operating said first separator to remove at least about 90% of particulate having a diameter greater than about 100 micrometers from said flash zone gas oil stream.
6. The process of claim 1 comprising operating said first separator to remove at least about 80% of particulate having a diameter greater than about 75 micrometers from said flash zone gas oil stream.
7. The process of claim 1 comprising operating said first separator to remove at least about 90% of particulate having a diameter greater than about 75 micrometers from said flash zone gas oil stream.
8. The process of claim 1 comprising operating said second separator to remove at least about 80% of particulate having a diameter greater than about 25 micrometers from said flash zone gas oil stream.
9. The process of claim 1 comprising operating said second separator to remove at least about 90% of particulate having a diameter greater than about 25 micrometers from said flash zone gas oil stream.
10. The process of claim 1 comprising operating said second separator to remove at least about 80% of particulate having a diameter greater than about 15 micrometers from said flash zone gas oil stream.
11. The process of claim 1 comprising operating said second separator to remove at least about 90% of particulate having a diameter greater than about 15 micrometers from said flash zone gas oil stream.
12. The process of claim 1 comprising operating said second separator at a pressure drop of at least about 25 psig (241.32 kPa).
13. The process of claim 1 comprising operating said second separator at a pressure drop of at least about 50 psig (344.74 kPa).
14. The process of claim 1 wherein said first separator comprises a strainer.
15. The process of claim 14 wherein said strainer has a mesh size of about 75 to about 500 micrometers.
16. The process of claim 14 wherein said strainer comprises a basket strainer.
17. The process of claim 1 wherein said first separator comprises a cyclonic separator.
18. The process of claim 17 comprising operating said first separator at a pressure drop of at least about 10 psig (68.95 kPa).
19. The process of claim 17 comprising operating said first separator at a pressure drop of at least about 20 psig (137.90 kPa).
20. The process of claim 1 comprising supplying said flash zone gas oil stream to said first separator at between about 650° F. (343.3° C.) to about 800° F. (426.7° C.).
21. The process of claim 1 wherein said second separator comprises a plurality of cyclones contacting a manifold through a seal.
22. The process of claim 21 wherein said seal is maintained at temperatures ranging from ambient to about 800° F. (426.7° C.).
23. The process of claim 21 wherein said second separator comprises at least 7 cyclones, each having a diameter between about 0.5 inch to about 4 inches.
24. The process of claim 21 wherein each cyclone of said plurality of cyclones has a diameter between about 1 and about 2 inches.
25. The process of claim 21 wherein each cyclone of said plurality of cyclones has a diameter of about 1 inch.
26. The process of claim 1 further comprising supplying said first reduced particulate stream to a third separator prior to supplying said stream to said second separator.
27. The process of claim 26 wherein said third separator comprises a strainer.
28. The process of claim 27 wherein said strainer has a mesh size of about 75 to about 500 micrometers.
29. The process of claim 26 wherein said third separator comprises a cyclonic separator.
30. The process of claim 29 comprising operating said third separator at a pressure drop of at least about 10 psig (68.95 kPa).
31. The process of claim 29 comprising operating said third separator at a pressure drop of at least about 20 psig (137.90 kPa).
32. The process of claim 1 wherein one of the intermediate liquid streams comprises a heavy coker gas oil, the process further comprising mixing said heavy coker gas oil with said flash zone gas oil stream prior to supplying said flash zone gas oil stream to said first separator.
33. The process of claim 26 wherein one of the intermediate liquid streams comprises a heavy coker gas oil, the process further comprising mixing said heavy coker gas oil with said first reduced particulate stream prior to supplying said first reduced particulate stream to said third separator.