Olefin conversion process

Patent metadata

Field	Value
Publication number	US-9242908-B2
Application number	US-201414548500-A
Country	US
Kind code	B2
Filing date	Nov 20, 2014
Priority date	Nov 20, 2013
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

A process for the production of C 4 olefins, which may include: contacting a hydrocarbon mixture comprising alpha-pentenes with an isomerization catalyst to form an isomerization product comprising beta-pentenes; contacting ethylene and the beta-pentenes with a first metathesis catalyst to form a first metathesis product comprising butenes and propylene, as well as any unreacted ethylene and C 5 olefins; and fractionating the first metathesis product to for an ethylene fraction, a propylene fraction, a butene fraction, and a C 5 fraction.

First claim

What is claimed:

1. A process for the production of C 4 olefins, the process comprising:
contacting a hydrocarbon mixture comprising alpha-pentenes with an isomerization catalyst to form an isomerization product comprising beta-pentenes;
contacting ethylene and the beta-pentenes with a first metathesis catalyst to form a first metathesis product comprising butenes and propylene, as well as any unreacted ethylene and C 5 olefins;
fractionating the first metathesis product to form an ethylene fraction, a propylene fraction, a butene fraction, and a C 5 fraction; and
contacting the propylene with a second metathesis catalyst, which may be the same or different than the first metathesis catalyst, to convert at least a portion of the propylene to ethylene and 2-butene and form a second metathesis product.

2. The process of claim 1 , further comprising feeding the first metathesis product and the second metathesis product to a common fractionation system.

3. The process of claim 2 , further comprising withdrawing a propylene product stream.

4. The process of claim 3 , further comprising adjusting a rate of withdrawing the propylene product stream to produce a selected ratio of butene to propylene product.

5. The process of claim 1 , further comprising recycling at least one of the ethylene fraction and the C 5 fraction to at least one of the step of contacting a hydrocarbon mixture and the step of contacting ethylene and the beta-pentenes.

6. The process of claim 1 , further comprising at least one of:
separating isobutene in the butene fraction from normal butenes in the butene fraction via at least one of isomerization and fractionation;
skeletal isomerizing the isobutene to form normal butenes; and
etherifying the isobutene.

7. A process for the production of C 4 olefins, the process comprising:
feeding ethylene and a C 5 olefin stream comprising a mixture of C 5 olefins including at least one of 1-pentenes, 2-methyl-1-butene, and 3-methyl-1-butene to an isomerization/metathesis reactor including a first reaction zone comprising an isomerization catalyst and a second reaction zone comprising a first metathesis catalyst;
contacting the C 5 -olefin stream with the isomerization catalyst in the first reaction zone to form an isomerization product comprising internal-pentenes including at least one of 2-pentenes and 2-methyl 2-butene;
contacting the internal pentenes with ethylene in the presence of the metathesis catalyst in the second reaction zone to form a first metathesis product comprising propylene and butenes, including at least one of 1-butene and isobutene, as well as any unreacted ethylene and unreacted C 5 olefins;
feeding the first metathesis product to a fractionation system;
fractionating the first metathesis product in the fractionation system to form an ethylene fraction, a propylene fraction, a butene fraction, and a pentene fraction;
feeding the propylene fraction to a metathesis reactor and contacting the propylene with a second metathesis catalyst, which may be the same or different than the first metathesis catalyst, to convert at least a portion of the propylene to ethylene and 2-butene and recover a second metathesis product;
feeding the second metathesis product to the fractionation system.

8. The process of claim 7 , wherein the ethylene is fed to the isomerization/metathesis reactor intermediate the first reaction zone and the second reaction zone.

9. The process of claim 7 , further comprising recycling at least one of the ethylene fraction and the pentene fraction to at least one of the step of contacting the C 5 -olefin stream and the step of contacting the internal pentenes with ethylene.

10. The process of claim 7 , further comprising fractionating a hydrocarbon stream comprising mixed C 5 hydrocarbons to form the C 5 olefin stream comprising a mixture of C 5 olefins, wherein the C 5 olefin stream comprises less than 0.5 wt % cyclopentene.

11. The process of claim 10 , further comprising selectively hydrogenating dienes in at least one of the hydrocarbon stream and the C 5 olefin stream.

12. The process of claim 7 , further comprising at least one of:
separating isobutene in the butene fraction from normal butenes in the butene fraction via at least one of isomerization and fractionation;
skeletal isomerizing the isobutene to form normal butenes;
etherifying the isobutene.

13. The process of claim 7 , further comprising withdrawing a propylene product stream.

14. The process of claim 13 , further comprising adjusting a rate of withdrawing the propylene product stream to produce a selected ratio of butene to propylene product.

15. The process of claim 7 , wherein the isomerization/metathesis reactor is a downflow reactor, the isomerization reaction zone comprising one or more beds of isomerization catalyst in an upper portion of the reactor and one or more beds of metathesis catalyst in a lower portion of the reactor.

Assignees

• Lummus Technology Inc

Inventors

• Choi Sukwon
• Ramachandran Bala

Classifications

• C07C2521/06

  Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof · CPC title

• C07C2523/30

  Tungsten · CPC title

• C07C5/2512

  with metal oxides · CPC title

• C07C2521/08

  Silica · CPC title

• C07C2521/04

  Alumina · CPC title