Ethylene separation process

• US 9,688,591 B2
• Filed: 01/10/2013
• Issued: 06/27/2017
• Est. Priority Date: 01/10/2013
• Status: Active Grant

• Current Assignee: Equistar Chemicals LP (Lyondellbasell Industries NV), Lyondell Chemical Technology LP (Lyondellbasell Industries NV)
• Original Assignee: Equistar Chemicals LP (Lyondellbasell Industries NV), Lyondell Chemical Technology LP (Lyondellbasell Industries NV)
• Inventors: Bridges, Robert S., Coleman, Steven T., Hood, Jr., Allen David, Sawyer, Gary A.
• Primary Examiner(s): Nguyen, Tam M
• Application Number:
  US13/738,685
• Publication Number:
  US 20140194664A1
• Time in Patent Office: 1,629 Days
• Field of Search: 585643, 585644, 62620, 62632, 62634
• CPC Class Codes: C07C 11/04 Ethylene
• CPC Class Codes: C07C 11/06 Propene
• CPC Class Codes: C07C 4/06 Catalytic processes C07C4/025 takes precedence
• CPC Class Codes: C07C 6/04 at a carbon-to-carbon double bond
• CPC Class Codes: C07C 7/04 by distillation

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

1. A process for producing ethylene comprising:

introducing a feed stream comprising ethylene, propylene and butene into a de-ethenizer at a temperature of from 50-90°

F. and a fresh ethylene stream is introduced to the de-ethenizer at a temperature of −

20 to 10°

F. and a pressure of 400-900 psig;

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.

2. The 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.

3. 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;

introducing the metathesis product stream at a temperature of 50-90°

F. and a pressure of 250-350 psig and a fresh ethylene stream at a temperature of −

20 to 10°

F. into a de-ethenizer;

separating the ethylene from the propylene and butene via fractional distillation within a de-ethenizer using the ethylene separation process of claim 1 to form an overhead stream composed primarily of 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.

4. The ethylene separation process of claim 1, wherein fresh ethylene is introduced to the de-ethenizer at a pressure of from 400-900 psig.

5. The process of claim 3, wherein the de-ethenizer operates at a pressure of less than 300 psig.

6. 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 and butene via fractional distillation within a de-ethenizer using the ethylene separation process of claim 1 to form an overhead stream composed primarily of separated ethylene and a bottoms stream comprising separated butene and propylene;

recycling the overhead stream from the de-ethenizer to the metathesis reaction in the form of vapor;

introducing fresh ethylene at a temperature of −

20 to 10°

F. into the de-ethenizer at a pressure of from 400-900 psig.