Olefin conversion process

Patent metadata

Field	Value
Publication number	US-9611193-B2
Application number	US-201514874789-A
Country	US
Kind code	B2
Filing date	Oct 5, 2015
Priority date	Nov 20, 2013
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

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 system for the production of C 4 olefins, the system comprising:
an isomerization reaction zone for contacting a hydrocarbon mixture comprising alpha-pentenes with an isomerization catalyst to form an isomerization product comprising beta-pentenes;
a first metathesis reaction zone for 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;
a separation system for fractionating the first metathesis product to form an ethylene fraction, a propylene fraction, a butene fraction, and a C 5 fraction; and
a second metathesis reaction zone for 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 system of claim 1 , further comprising a flow conduit for feeding the first metathesis product and the second metathesis product to a common fractionation system.

3. The system of claim 2 , further comprising a flow conduit for withdrawing a propylene product stream.

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

5. The system of claim 1 , further comprising one or more flow conduits for recycling at least one of the ethylene fraction or the C 5 fraction to at least one of the isomerization reaction zone or the first metathesis reaction zone.

6. The system of claim 1 , further comprising at least one of:
a separation zone or a reaction/separation zone for separating isobutene in the butene fraction from normal butenes in the butene fraction via at least one of isomerization and fractionation;
a reaction zone comprising a catalyst for the skeletal isomerization of the isobutene to form normal butenes; or
a reaction zone for etherifying the isobutene.

7. A system for the production of C 4 olefins, the process comprising:
one or more flow conduits for feeding, together or separately, 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, or 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;
the isomerization/metathesis reactor for 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 or 2-methyl 2-butene and for 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 or isobutene, as well as any unreacted ethylene and unreacted C 5 olefins;
a fractionation system for fractionating the first metathesis product in the fractionation system to form an ethylene fraction, a propylene fraction, a butene fraction, and a pentene fraction;
a metathesis reactor for 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;
a flow conduit for feeding the second metathesis product to the fractionation system.

8. The system of claim 7 , wherein the flow conduit for feeding the ethylene to the isomerization/metathesis is disposed for feeding the ethylene to the reactor intermediate the first reaction zone and the second reaction zone.

9. The system of claim 7 , further comprising one or more flow conduits for recycling at least one of the ethylene fraction or the pentene fraction to the isomerization/metathesis reactor.

10. The system of claim 7 , further comprising a separation zone for fractionating a hydrocarbon stream comprising mixed C 5 hydrocarbons to form the C5 olefin stream, wherein the C5 olefin stream comprises less than 0.5 wt % cyclopentene.

11. The system of claim 10 , further comprising a reaction zone for selectively hydrogenating dienes in at least one of the hydrocarbon stream or the C5 olefin stream.

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

13. The system of claim 7 , further comprising a flow conduit for withdrawing a propylene product stream.

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

15. The system 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.

16. A system for the production of C 4 olefins, the system comprising:
an isomerization/metathesis reactor including
a first reaction zone comprising an isomerization catalyst;
a second reaction zone comprising a first metathesis catalyst;
an inlet for introducing 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 the isomerization/metathesis reactor for 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 or 2-methyl-2-butene;
an inlet for introducing ethylene to the isomerization/metathesis reactor for contacting the ethylene and the internal pentenes with 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 or isobutene, as well as any unreacted ethylene and unreacted C 5 olefins;

a metathesis reactor for contacting a propylene fraction 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;
a fractionation system for fractionating the first metathesis product and the second metathesis product to form an ethylene fraction, the propylene fraction, a butene fraction, and a pentene fraction.

17. The system of claim 16 , further comprising a control system and associated flow conduits to selectively withdraw a propylene product stream and control a ratio of butene product to propylene product.

18. The system of claim 16 , further comprising a recycle stream for recycling a portion of the pentene fraction to the isomerization/metathesis reactor, and a purge stream for purging a portion of the pentene fraction.

19. The system of claim 16 , further comprising a catalytic distillation reactor system for concurrent reaction and separation of a mixed C5 hydrocarbon-containing stream, wherein the catalytic distillation reaction system comprises

Assignees

• Lummus Technology Inc

Inventors

• Choi Sukwon
• Ramachandran Bala

Classifications

• C07C2521/10

  Magnesium; Oxides or hydroxides thereof · CPC title

• B01J8/001

  Controlling catalytic processes (B01J8/1809 takes precedence) · CPC title

• C07C2523/02

  of the alkali- or alkaline earth metals or beryllium · CPC title

• C07C11/09

  Isobutene · CPC title

• C07C2521/06

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