Process for removing oxygenated contaminates from an ethylene stream

Patent metadata

Field	Value
Publication number	US-9701598-B2
Application number	US-201214235251-A
Country	US
Kind code	B2
Filing date	Jul 13, 2012
Priority date	Jul 28, 2011
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

The present invention is, in a first embodiment, a process for removing oxygenated contaminants from an ethylene stream comprising:
a) providing a dried ethylene stream (A) comprising essentially ethylene, up to 1 w % oxygenates, ethane, CO, CO2, H2, CH4 and C3+ hydrocarbons, b) sending said stream (A) to a stripper (also referred to as a demethanizer) to produce an overhead stream comprising essentially CO, H2 and CH4, a bottom stream comprising essentially ethylene, oxygenates, ethane, CO2 and C3+ hydrocarbons, c) sending said bottom stream of step b) to a deethanizer to produce a bottom stream comprising essentially ethane, oxygenates and C3+ hydrocarbons, an overhead stream consisting essentially of ethylene and CO2, d) sending said overhead of step c) to a fixed bed CO2 adsorption zone to recover an ethylene stream essentially free of CO2.

In another embodiment the CO2 adsorption zone can be located at the inlet of the deethanizer.
In another embodiment the demethanizer is replaced by two demethanizers.
In another embodiment the deethanizer is replaced by two C2 splitters.

First claim

The invention claimed is:

1. A process for removing oxygenated contaminants from an ethylene stream comprising:
a) providing a dried ethylene stream (A) comprising essentially ethylene, up to 1 w % oxygenates, ethane, CO, CO 2 , H 2 , CH 4 and C 3+ hydrocarbons;
b) sending the dried ethylene stream (A) to a stripper to produce an overhead stream comprising essentially CO, H 2 and CH 4 ; and a bottom stream comprising essentially ethylene, oxygenates, ethane, CO 2 and C 3+ hydrocarbons; and

performing step (i) or step (ii);
wherein step (i) comprises:
c) sending said bottom stream of step b) to a deethanizer to produce a bottom stream comprising essentially ethane, oxygenates and C 3+ hydrocarbons; and an overhead stream consisting essentially of ethylene and CO 2 ;
d) sending the overhead of step c) to a fixed bed CO 2 adsorption zone to recover an ethylene stream essentially free of CO 2 ;

wherein step (ii) comprises:
c1) sending the bottom stream of step b) to a fixed bed CO 2 adsorption zone to recover a stream essentially free of CO 2 , then sending the stream essentially free of CO 2 to a deethanizer to produce a bottom stream comprising essentially ethane, oxygenates and C 3+ hydrocarbons; and an overhead stream consisting essentially of ethylene essentially free of CO 2 .

2. The process of claim 1 , wherein the fixed bed CO 2 adsorption zone is located at an inlet of the deethanizer.

3. The process of claim 1 , wherein a weight ratio of ethane+CO+CO 2 +H 2 +CH 4 +C 3 + hydrocarbons to ethylene in the dried ethylene stream (A) is less than 10/90.

4. The process of claim 3 , wherein the weight ratio of ethane+CO+CO 2 +H 2 +CH 4 +C 3 + hydrocarbons to ethylene in the dried ethylene stream (A) is above 0.1/99.9.

5. The process of claim 4 , wherein the weight ratio of ethane+CO+CO 2 +H 2 +CH 4 +C 3 + hydrocarbons to ethylene in the dried ethylene stream (A) is less than 5/95.

6. The process of claim 1 , wherein a proportion of oxygenates in the dried ethylene stream (A) is from 50 wppm to 7000 wppm.

7. The process of claim 1 , wherein a proportion of oxygenates in the dried ethylene stream (A) is up to 3000 wppm.

8. The process of claim 1 , wherein the proportion of oxygenates in the dried ethylene stream (A) is up to 2000 wppm.

9. The process of claim 1 , wherein a proportion of H 2 in the dried ethylene stream (A) is from 5 to 1000 wppm.

10. The process of claim 1 , wherein a proportion of H 2 in the dried ethylene stream (A) is up to 800 wppm.

11. The process of claim 1 , wherein a proportion of H 2 in the dried ethylene stream (A) is up to 500 wppm.

12. The process of claim 1 , wherein the dried ethylene stream (A) is originated from the dehydration of ethanol.

Assignees

• Arratia Manuela
• Boutrot Catherine
• Total Res & Technology Feluy

Inventors

• Das Babua
• Arratia Manuela
• Boutrot Catherine

Classifications

• C07C7/00 Primary

  Purification; Separation; Use of additives (working-up undefined gaseous mixtures obtained by cracking hydrocarbon oils C10G70/00) · CPC title

• C07C7/005 Primary

  Processes comprising at least two steps in series · CPC title

• C07C7/12

  by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers · CPC title