Process for producing a feed stream for a steam cracker

Patent metadata

Field	Value
Publication number	US-9302960-B2
Application number	US-201414267845-A
Country	US
Kind code	B2
Filing date	May 1, 2014
Priority date	May 1, 2014
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A process for producing a feed for a stream cracker. At least a portion of the C 6 cyclic hydrocarbons are removed from a stream prior to it being passed into an isomerization zone. Disproportionation reaction selectivity is increased, producing valuable C 3 hydrocarbons and C 4 hydrocarbons. Also, a higher ring opening conversion of C 5 cyclic hydrocarbons is observed. The yield may be adjusted by controlling an amount of C 6 cyclic hydrocarbons passed to the isomerization zone. The catalyst in the isomerization zone is free of chloride, and the streams including effluent from the isomerization zone may be passed to a steam cracker without requiring chloride removal.

First claim

What is claimed is:

1. A process for producing a feed for a steam cracker, the process comprising:
separating a portion of C6 cyclic hydrocarbons from a naphtha stream comprising C5+ hydrocarbons to provide a C6 cyclic hydrocarbons lean stream;
separating iC5 paraffinic hydrocarbons and iC6 paraffinic hydrocarbons from the C6 cyclic hydrocarbons lean stream; and,
passing a feed stream comprising at least one stream being rich in iC5 paraffinic hydrocarbons, iC6 paraffinic hydrocarbons, or both to an isomerization zone containing non-chlorided catalyst comprising a sulfated zirconia or a tungstated zirconia to disproportionate at least some isoparaffins to form iC4, iC5 and iC6 paraffinic hydrocarbons, and isomerize iC4, iC5, and iC6 isoparaffins to normal paraffins to form an isomerization effluent;
separating the effluent from the isomerization zone into an overhead stream comprising C4− hydrocarbons and a bottoms stream comprising C5+ hydrocarbons; and,
passing at least one stream from the isomerization zone to a steam cracker.

2. The process of claim 1 further comprising:
controlling an amount of C 6 cyclic hydrocarbons passed into the isomerization zone.

3. The process of claim 2 wherein the amount of C 6 cyclic hydrocarbons passed into the isomerization zone is controlled by at least one of the following:
selectively adding a stream of C 6 cyclic hydrocarbons to the isomerization zone; and,
controlling an operating parameter of a separation zone used to separate the C 6 cyclic hydrocarbons from the naphtha stream.

4. The process of claim 1 further comprising:
passing the naphtha stream to a first separation zone; and,
separating the naphtha stream in the first separation zone into an overhead stream and a bottoms stream, the overhead stream being the C 6 cyclic hydrocarbons lean stream and the bottoms stream being rich in n-hexane and C 6 cyclic hydrocarbons.

5. The process of claim 4 further comprising:
passing the overhead stream from the first separation zone to a second separation zone; and,
separating the overhead stream from the first separation zone in the second separation zone into the at least one stream being rich in iC 5 isoparaffinic hydrocarbons, iC 6 isoparaffinic hydrocarbons, or both.

6. The process of claim 5 further comprising:
separating the overhead stream from the first separation zone in a first separator column of the second separation zone into an overhead stream, an intermediate stream, a bottoms stream,
the overhead stream from the first separator column of the second separation zone being rich in C 5 hydrocarbons, and,
the intermediate stream of the first separator column of the second separation zone being rich in iC 6 isoparaffinic hydrocarbons.

7. The process of claim 6 , further comprising:
separating the overhead stream from the first separator column of the second separation zone in a second separator column of the second separation zone into an overhead stream and a bottoms stream,
the overhead stream of the second separator column of the second separation zone being rich in iC 5 isoparaffinic hydrocarbons.

8. The process of claim 7 further comprising:
recycling the bottoms stream from the isomerization zone to the first column from the second separation zone.

9. The process of claim 7 further comprising:
combining the bottoms stream from the first separator column and the second separator column; and,
passing the combined bottoms streams from the first separator columns and the second separator column to the steam cracker.

10. The process of claim 4 wherein the second separation zone comprises:
at least one adsorption zone.

11. The process of claim 10 further comprising:
separating the overheads stream from the first separation zone in the at least one absorption zone into a first stream and a second stream,
the first stream being rich in iC 5 hydrocarbons and iC 6 hydrocarbons and,
the second stream being rich in n-pentane and n-hexane.

12. The process of claim 11 further comprising:
recycling the bottoms stream from the isomerization zone to the first separation zone.

Assignees

• Uop Llc

Inventors

• Lapinski Mark P
• Lippmann Matthew

Classifications

• C07C4/04

  Thermal processes {(C07C4/025 takes precedence)} · CPC title

• C07C7/005 Primary

  Processes comprising at least two steps in series · CPC title

• C07C5/27

  Rearrangement of carbon atoms in the hydrocarbon skeleton · CPC title

• C07C5/2772

  with metal oxides · CPC title

• C07C7/04

  by distillation · CPC title