Higher containment VSS with multi zone stripping

Patent metadata

Field	Value
Publication number	US-10443000-B2
Application number	US-201715613938-A
Country	US
Kind code	B2
Filing date	Jun 5, 2017
Priority date	Jun 3, 2016
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

This patent application discloses engineering design modifications to the VSS exit, stripper entrance and the primary cyclone diplegs that can significantly reduce the underflow of reactor riser products into the stripper and reactor vessel and thereby produce higher desired product selectivities, improved stripping efficiency and a stripper vent gas, that continuously flows through the reactor vessel, with a low coke forming potential due to its low concentration of ethylene and higher molecular weight material, that could, if desired, be recovered separately from the primary riser products.

First claim

I claim:

1. An improved vortex separation system comprising:
a VSS separation chamber;
a stripper zone;
at least one vent pipe wherein stripper vapers exit the system;
a baffle located between the stripper zone and the VSS separation chamber,
wherein the baffle is an inverted V-shape having distal ends extended beyond the VSS separation chamber to increase stripper vapor diversion around the VSS separation chamber.

2. An improved vortex separation system that generates significantly higher plug flow containment of primary riser products due to reduced back mixing within the chamber and a lower final vapor product underflow within a catalyst void that comprises of:
a VSS separation chamber;
a baffle located between an original stripping zone 23 and the VSS separation chamber, creating a three-zone stripping section having stripping zones 31 , 33 , and 23 ;
wherein the baffle is configured to direct stripper vapors 8 , exiting zones 23 and 33 , away from the VSS separation chamber; and
wherein the stripper vapors from zones 23 and 33 rise through zones 23 and 33 , bypassing the VSS chamber and exit the reactor vessel via an at least on vent pipe 7 into a VSS riser.

3. The improved vortex separation system of claim 2 wherein steam is injected in the cracked gas stripping zone 31 to maintain a bubble fluidized bed of 0.2 to 0.5 feet per second superficial gas velocity.

4. The improved vortex separation system of claim 2 wherein an open grid structure, or packing, is located in a fluidized bed free board region 29 to reduce catalyst re-entrainment into the VSS chamber.

5. The improved vortex separation system of claim 2 wherein an open grid structure, or packing, is located in a fluidized bed free board region 33 to reduce catalyst re-entrainment into the VSS chamber.

6. The improved vortex separation system of claim 2 wherein an open grid structure, or packing, is located in a fluidized bed free board regions 29 and 33 to reduce catalyst re-entrainment into the VSS chamber.

7. The improved vortex separation system of claim 2 wherein the baffle is designed to generate additional cross flow catalyst as it flows through zone 31 also improving the residence time distribution and allowing more efficient time for the various highly desirable soft coke cracking reactions to proceed.

8. The improved vortex separation system of claim 2 wherein baffle 41 and its openings for captured of vapor flow extend beyond the circumference of the VSS chamber to direct vapor products from stripping zone 23 into zone 33 and out a vent pipe 7 .

9. An improved vortex separation system comprising:
a VSS separation chamber;
a stripper zone; and
a cyclone separator having a dipleg wherein the circumference of the dipleg is expanded such that the flowing catalyst flux lb/ft 2 /sec in the dipleg is reduced to produce a flowing velocity less than the bubble rise velocity.

10. An improved vortex separation system comprising:
a VSS separation chamber;
a stripper zone;
at least one vent pipe wherein stripper vapers exit the system
a baffle configured to divert vapor from the stripper chamber away from the VSS separation chamber; and
a cyclone separator having a dipleg where in the circumference of the dipleg is, configured such that the flowing catalyst flux lb/ft 2 /sec in the dipleg is reduced to produce a flowing velocity less than the bubble rise velocity.

11. An improved vortex separation system comprising:
a reactor vessel having a bottom section;
a VSS chamber within the reactor vessel;
a stripping chamber with the bottom section of the reactor vessel
a baffle 35 that segregates the stripping chamber into three separate stripping zones, a cracked gas stripping zone 31 , a transition zone 33 , and a main stripper 23 .

12. The improved vortex separation system of claim 11 wherein the cracked gas stripping zone 31 has a 0.2-0.5 Ft/sec superficial gas velocity.

13. The improved vortex separation system of claim 12 wherein the transition zone 33 has an increased residence time.

14. The improved vortex separation system of claim 13 wherein the net product underflow is reduced from 8.46 wt % Fresh Feed to 2.50 wt % Fresh Feed.

15. The improved vortex separation system of claim 11 wherein stripper packing 36 is added at stripping zone 31 to further suppress freeboard activity and J values.

16. A cyclone separator comprising:
a cyclone separator; and
a dipleg wherein the circumference of the dipleg is expanded such that the flowing catalyst flux lb/ft 2 /sec in the dipleg is reduced to produce a flowing velocity less than the bubble rise velocity.

17. The cyclone separator of claim 16 wherein the cyclone separator is used in a high containment Direct Coupled Cyclone, Rough-Cut Cyclone, RS2, or VSS application.

18. The cyclone separator of claim 16 wherein the catalyst flux is reduced to less than 20 pounds/ft2/sec.

19. An improved crossflow vortex separation system comprising:
a chamber 27 ;
a baffle 41 that segregates a stripper into three zones 31 , 33 and 23 ;
a VSS separation chamber 1 having at least one outer wall; and
at least one deflection shield 43 engaged with at least one outer wall and angularly disposed with the at least one outer wall, the defection shield acting to deflect catalyst falling through the VSS separation chamber 1 toward the center of the VSS separation chamber.

20. The improved crossflow vortex separation system of claim 19 wherein the baffle 41 is angularly disposed in an opposing direction to engage with and deflect the falling catalyst toward the walls of the chamber 27 .

21. The improved crossflow vortex separation system of claim 20 wherein catalyst continues to fall into a main stripping zone 23 where it is further stripped by steam from a pipe 13 rising through chamber 23 and engaging with the baffle 41 and being directed away from the VSS chamber 1 .

22. An improved vortex separation system comprising:
a chamber 27 ;
a baffle that segregates the stripping chamber into three separate stripping zones, a cracked gas stripping zone 31 , a transition zone 33 , and a main stripper 23 ;
a VSS separation chamber 1 having at least one outer wall; and
wherein as catalyst falls from the VSS chamber 1 , the baffle directs the falling catalyst into the cracked gas stripping zone 31 , which is then directed into the transition zone 33 , before entering the main stripper 23 .

23. The improved vortex separation system of 22 wherein the three stripping zones increase the residence time of the falling catalyst in the cracked gas stripping zone 31 and the transition zone 33 .

24. The improved vortex separation system of claim 23 having at least one deflection shield 43 engaged with at least one outer wall and angularly disposed with the at least one outer wall, the defection shield acting to deflect catalyst falling through the VSS separation toward the center of the VSS separation chamber 1 .

25. The improved vortex separation system of claim 24 having a cyclone separator wherein the dipleg is expanded, such that the flowing catalyst flux lb/ft 2 /sec in the dipleg is reduced to produce a flowing velocity less than the bubble rise velocity.

26. The improved vortex separation system of claim 25 wherein the catalyst bed level is raised or lowered to control residence time i

Assignees

• Marathon Petroleum Co Lp

Inventors

• Lomas David

Classifications

• C10G11/18

  according to the "fluidised-bed" technique · CPC title

• C10G11/05 Primary

  Crystalline alumino-silicates, e.g. molecular sieves · CPC title

• B01D45/16

  generated by the winding course of the gas stream {, the centrifugal forces being generated solely or partly by mechanical means, e.g. fixed swirl vanes} · CPC title

• C10B3/00

  Coke ovens with vertical chambers · CPC title

• B01J8/1872

  Details of the fluidised bed reactor (B01J8/1836 takes precedence) · CPC title