Distillate production from olefins in moving bed reactors

Patent metadata

Field	Value
Publication number	US-11299443-B2
Application number	US-202016910027-A
Country	US
Kind code	B2
Filing date	Jun 23, 2020
Priority date	Apr 3, 2020
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

Systems and methods are provided for oligomerization of olefins to distillate boiling range products while also recycling naphtha boiling range olefins as part of the feed. By performing the olefin oligomerization while also recycling naphtha boiling range olefins, it has been discovered that the resulting distillate boiling range products can have an unexpected improvement in diesel combustion quality, such as an unexpected improvement in cetane rating. In order to manage coke formation and maintain consistent activity profile for the oligomerization catalyst, the reaction can be performed in a moving bed reactor. Additional temperature control can be maintained by the recycling of the naphtha boiling range portions of the oligomerization product back to the reactor.

First claim

The invention claimed is:

1. A method for upgrading a feed to form distillate boiling range compounds, comprising:
passing a catalyst flow comprising an olefin oligomerization catalyst into a first moving bed reactor of a plurality of serially connected moving bed reactors, the olefin oligomerization catalyst comprising a 1-D 10-member ring zeolite;
exposing an olefin-containing feed comprising C 3 -C 8 olefins and a recycle stream comprising at least 20 wt % C 5+ olefins to the catalyst flow in the plurality of moving bed reactors under olefin oligomerization conditions to form an oligomerized effluent, the olefin oligomerization conditions comprising substantially adiabatic operation of the plurality of moving bed reactors and an average reactor temperature of 170° C.-190° C.;
separating the oligomerized effluent to form a distillate boiling range fraction and one or more lower boiling fractions, the one or more lower boiling fractions comprising the recycle stream;
wherein exposing the olefin-containing feed and the recycle stream to the catalyst flow in the plurality of serially connected moving bed reactors comprises:
passing the catalyst flow comprising a catalyst into a first moving bed reactor of the plurality of serially connected moving bed reactors;
exposing the feed and the recycle stream to the catalyst flow in the first moving bed reactor under first olefin oligomerization conditions to form a partially reacted effluent, a temperature differential between the first reactor feed inlet and the first reactor effluent outlet being 85° C. or less;
stripping the catalyst flow with a first stripping fluid to separate at least a portion of the first partially reacted effluent from the catalyst flow, the at least a portion of the first partially reacted effluent comprising a liquid phase effluent portion and a vapor phase effluent portion;
passing the stripped catalyst flow into a second moving bed reactor of the plurality of serially connected moving bed reactors;
passing the liquid phase effluent portion into the second moving bed reactor as a substantially axial flow; and
exposing the vapor phase effluent portion to the stripped catalyst flow in the presence of the liquid effluent portion in the second moving bed reactor under second olefin oligomerization conditions to form the oligomerized effluent.

2. The method of claim 1 , wherein the olefin oligomerization conditions comprise a temperature differential across a moving bed reactor of 85° C. or less.

3. The method of claim 1 , wherein the olefin oligomerization catalyst comprises ZSM-48.

4. The method of claim 1 , wherein the olefin-containing feed comprises 60 wt % or more of C 3 -C 5 olefins relative to a weight of olefins in the olefin-containing feed.

5. The method of claim 1 , wherein the olefin-containing feed comprises 5.0 wt % or less of C 2 olefins relative to a weight of olefins in the olefin-containing feed, or wherein the olefin-containing feed comprises 5.0 wt % or less of water relative to a weight of the olefin-containing feed, or a combination thereof.

6. The method of claim 1 , wherein exposing the olefin-containing feed and the recycle stream to the catalyst flow comprises exposing the olefin-containing feed, the recycle stream, and a non-reactive co-feed to the catalyst flow.

7. The method of claim 6 , wherein a volume ratio of the recycle stream to the non-reactive co-feed is between 0.2 and 10.

8. The method of claim 1 , wherein the recycle stream comprises 90 wt % or more of 177° C.-compounds.

9. The method of claim 1 , wherein the recycle stream comprises 90 wt % or more of compounds having a boiling range of 30° C. to 177° C.

10. The method of claim 1 , wherein the recycle stream comprises 20 wt % or more of olefins relative to a weight of the recycle stream.

11. The method of claim 1 , wherein the recycle stream comprises 20 wt % or more of C 5+ olefins relative to a weight of the recycle stream.

12. The method of claim 1 , wherein the recycle stream comprises 20 wt % or more of C 6+ olefins relative to a weight of the recycle stream.

13. The method of claim 1 , wherein a molar ratio of olefins in the olefin-containing feed to olefins in the recycle stream is 0.5 to 2.0.

14. The method of claim 1 , wherein the olefin oligomerization conditions comprise an olefin partial pressure in the first moving bed reactor of 200 psig to 300 psig (1.4 MPa-g to 2.1 MPa-g).

15. The method of claim 1 , wherein the olefin oligomerization conditions comprise a partial pressure of olefins from the feed in the first moving bed reactor of 200 psig to 300 psig (1.4 MPa-g to 2.1 MPa-g).

16. The method of claim 1 , further comprising:
separating spent catalyst from the second effluent; and
passing the spent catalyst into a regenerator to form regenerated catalyst,
wherein at least a portion of the catalyst flow comprises regenerated catalyst.

17. The method of claim 1 , wherein the stripped catalyst flow into the second moving bed reactor forms a catalyst bed having a top surface comprising one or more cones at an angle of repose of the catalyst in the stripped catalyst flow, and wherein passing the liquid phase effluent portion into the second moving bed reactor comprises contacting at least a portion of the liquid phase effluent portion with the one or more cones.

18. The method of claim 1 , wherein the vapor flow within the second moving bed reactor comprises an axial vapor flow, or wherein the vapor flow within the second moving bed reactor comprises a radial vapor flow.

19. The method of claim 1 , wherein the plurality of serially connected moving bed reactors comprises a vertical stack, and wherein the stripped catalyst flow is passed into the second reactor without passing through a catalyst flow controller.

Assignees

• Exxonmobil Res & Eng Co

Inventors

• Behkish Arsam
• Zhang Lei
• O'Neill Brandon J
• Deimund Mark A
• Lin Alice

Classifications

• C10G50/00

  Production of liquid hydrocarbon mixtures from lower carbon number hydrocarbons, e.g. by oligomerisation · CPC title

• B01J38/02

  Heat treatment · CPC title

• B01J29/90

  Regeneration or reactivation · CPC title

• B01J2208/00752

  Feeding · CPC title

• C07C2529/70

  of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65 · CPC title