# US 2014/0194664 A1 · Ethylene separation process

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- Number: US 2014/0194664 A1
- Document ID: US20140194664A1
- Status: Published application
- Kind: A1
- Application number: 13/738,685
- Filed: 2013-01-10
- Published: 2014-07-10
- Earliest claimed: 2013-01-10
- Assignees: Equistar Chemicals, LP; Lyondell Chemical Technology, L.P.
- Inventors: Gary A. Sawyer; Robert S. Bridges; Steven T. Coleman; Allen David Hood, JR.
- Web page: https://patentgrep.com/patent/US20140194664A1

## CPC

- C07C 7/04: by distillation
- C07C 4/06: Catalytic processes {(C07C4/025 takes precedence)}
- C07C 6/04: at a carbon-to-carbon double bond
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

Ethylene separation processes are described herein. The ethylene separation processes generally include introducing a feed stream including ethylene and butene into a de-ethenizer; and separating the ethylene from the butene via fractional distillation within the de-ethenizer to form an overhead stream including separated ethylene and a bottoms stream including separated butene, wherein the de-ethenizer operates at a pressure of less than 350 psig.

## Claims

### Claim 1

An ethylene separation process comprising:
introducing a feed stream comprising ethylene and butene into a de-ethenizer; and
separating the ethylene from the butene via fractional distillation within the de-ethenizer to form an overhead stream comprising separated ethylene and a bottoms stream comprising separated butene, wherein the de-ethenizer operates at a pressure of less than 350 psig.

### Claim 2 (depends on 1)

The ethylene separation process of claim 1 further comprising compressing the overhead stream from a first pressure to a second pressure.

### Claim 3 (depends on 2)

The ethylene separation process of claim 2, wherein the first pressure ranges from 250 psig to 350 psig and the second pressure ranges from 300 psig to 400 psig.

### Claim 4 (depends on 2)

The ethylene separation process of claim 2, wherein a difference between the second pressure and the first pressure is from 50 psig to 100 psig.

### Claim 5 (depends on 2)

The ethylene separation process of claim 2 further comprising condensing a portion of the overhead stream to form a recycle ethylene stream and introducing the recycle ethylene stream to the de-ethenizer, wherein the overhead stream is compressed prior to condensing.

### Claim 6 (depends on 1)

The ethylene separation process of claim 1 further comprising introducing fresh ethylene to the de-ethenizer as reflux supplement.

### Claim 7 (depends on 1)

The ethylene separation process of claim 1, wherein the de-ethenizer operates at a pressure of less than 350 psig.

### Claim 8 (depends on 1)

The ethylene separation process of claim 1, wherein the feed stream further comprises propylene.

### Claim 9 (depends on 1)

The ethylene separation process of claim 1 further comprising condensing a portion of the overhead stream to form a recycle ethylene stream and introducing the recycle ethylene stream to the de-ethenizer.

### Claim 10 (depends on 1)

The ethylene separation process of claim 1, wherein the fresh ethylene is introduced to the de-ethenizer at a temperature of from −20° F. to 10° F.

### Claim 11 (depends on 1)

The ethylene separation process of claim 1, wherein the metathesis product stream is introduced to the de-ethenizer at a temperature of from 50° F. to 90° F.

### Claim 12 (depends on 1)

The ethylene separation process of claim 1, wherein the metathesis product stream is introduced to the de-ethenizer at a pressure of from 250 psig to 350 psig.

### Claim 13

A process for producing propylene comprising:
reacting a metathesis feed stream comprising butene with ethylene in the presence of a metathesis catalyst via a metathesis reaction to form a metathesis product stream comprising propylene, ethylene and butene;
separating the ethylene from the propylene via fractional distillation within a de-etherizer to form an overhead stream comprising separated ethylene and a bottoms stream comprising separated butene and propylene; and
recycling the overhead stream from the de-ethenizer to the metathesis reaction in the form of vapor.

### Claim 14 (depends on 13)

The process of claim 13, wherein the de-ethenizer operates at a pressure of less than 350 psig.

### Claim 15 (depends on 13)

The process of claim 13, wherein the feed stream further comprises propylene.

### Claim 16 (depends on 13)

The process of claim 13 further comprising compressing the overhead stream from a first pressure to a second pressure and condensing a portion of the overhead stream comprising the second pressure to form a recycle ethylene stream and introducing the recycle ethylene stream to the metathesis feed stream.

### Claim 17 (depends on 16)

The process of claim 16, wherein the first pressure ranges from 250 psig to 350 psig and the second pressure ranges from 300 psig to 400 psig.

### Claim 18 (depends on 13)

The process of claim 13, wherein the fresh ethylene is introduced to the de-ethenizer at a temperature of from −20° F. to 10° F.

### Claim 19 (depends on 13)

The process of claim 13, wherein the metathesis product stream is introduced to the de-ethenizer at a temperature of from 50° F. to 90° F.

### Claim 20 (depends on 13)

The process of claim 13, wherein the metathesis product stream is introduced to the de-ethenizer at a pressure of from 250 psig to 350 psig.