Process for removing oxygenated contaminates from an ethylene stream
View Patent ↗The present invention is 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 C2 splitter/deethanizer to produce a bottom stream comprising essentially ethane, oxygenates and C3+ hydrocarbons, an overhead comprising the remaining components, c) sending said overhead to a fixed bed CO2 adsorption zone to recover a stream essentially free of CO2, d) sending said stream essentially free of CO2 to a demethanizer/CO stripper to recover an overhead comprising H2, CH4 and CO, liquid ethylene at the bottoms. In another embodiment the CO2 removal step can be made on the recovered ethylene.
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 C 2 splitter/deethanizer to produce a bottom stream comprising essentially ethane, oxygenates and C 3+ hydrocarbons; and an overhead comprising the remaining components;
c) sending the overhead from the C 2 splitter/deethanizer to a fixed bed CO 2 adsorption zone to recover a stream essentially free of CO 2 ;
d) sending the stream from the fixed bed CO 2 adsorption zone, wherein the stream is essentially free of CO 2 , directly to a demethanizer/CO stripper without passing the stream through a wash column or a caustic wash to recover an overhead comprising H 2 , CH 4 and CO; and liquid ethylene at the bottoms.
2. The process of claim 1 , wherein the C 2 splitter/deethanizer and the demethanizer operate at the same pressure, except a pressure drop between the C 2 splitter/deethanizer and the demethanizer for transfer of fluids, wherein the pressure ranges from 15 to 45 barg.
3. The process of claim 1 , wherein a pressure of the C 2 splitter/deethanizer is lower than a pressure of the demethanizer/CO stripper, wherein the pressure of the C 2 splitter/deethanizer ranges from 15 to 25 barg, and a pressure difference between the demethanizer/CO stripper and the C 2 splitter/deethanizer ranges from 10 to 25 barg.
4. The process according to claim 3 , wherein the overhead of the C 2 splitter/deethaniser is condensed, sent to a decanter to obtain a liquid phase that is sent as a reflux to said C 2 splitter/deethaniser and to obtain a gaseous phase that is sent to a compressor to obtain a compressed stream that is sent to the CO 2 adsorption zone.
5. The process of claim 3 , wherein the overhead of the C 2 splitter/deethaniser is sent to a compressor, optionally cooled and sent to the CO 2 adsorption zone to recover a stream essentially free of CO 2 ;
wherein the stream essentially free of CO 2 is cooled and sent to a decanter to produce a liquid phase that is sent as a reflux to the C 2 splitter deethanizer and to produce a gaseous phase that is sent to the demethanizer/CO stripper.
6. 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.
7. 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 and above 0.1/99.9.
8. 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 5/95.
9. The process of claim 1 , wherein a proportion of oxygenates in the dried ethylene stream (A) is from 50 wppm to 7000 wppm.
10. The process of claim 1 , wherein a proportion of oxygenates in the dried ethylene stream (A) is up to 3000 wppm.
11. The process of claim 1 , wherein a proportion of oxygenates in the dried ethylene stream (A) is up to 2000 wppm.
12. The process of claim 1 , wherein a proportion of H 2 in the dried ethylene stream (A) is from 5 to 1000 wppm.
13. The process of claim 1 , wherein a proportion of H 2 in the dried ethylene stream (A) is up to 800 wppm.
14. The process of claim 1 , wherein a proportion of H 2 in the dried ethylene stream (A) is up to 500 wppm.
15. The process of claim 1 , wherein the dried ethylene stream (A) originates from the dehydration of ethanol.
16. A process for removing oxygenated contaminants from an ethylene stream comprising:
a1) 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;
b1) sending the dried ethylene stream (A) to a C 2 splitter/deethanizer to produce a bottom stream comprising essentially ethane, oxygenates and C 3+ hydrocarbons; and an overhead comprising the remaining components;
c1) sending the overhead stream to a demethanizer/CO stripper to recover an overhead comprising H 2 , CH 4 and CO; and a liquid ethylene stream at the bottoms, wherein the liquid ethylene stream comprises CO 2 ;
d1) sending the liquid ethylene stream from the demethanizer/CO stripper directly to a fixed bed CO 2 adsorption zone without passing the liquid ethylene stream through a wash column or a caustic wash to recover an ethylene stream essentially free of CO 2 .
17. The process of claim 16 , wherein the C 2 splitter/deethanizer and the demethanizer operate at the same pressure, except a pressure drop between the C 2 splitter/deethanizer and the demethanizer for transfer of fluids, and wherein the pressure ranges from 15 to 45 barg.
18. The process of claim 16 , wherein a pressure of the C 2 splitter/deethanizer is lower than a pressure of the demethanizer/CO stripper;
wherein the pressure of the C 2 splitter/deethanizer ranges from 15 to 25 barg; and
wherein a pressure difference between the demethanizer/CO stripper and the C 2 splitter/deethanizer ranges from 10 to 25 barg.
19. The process of claim 16 , wherein the overhead of the C 2 splitter/deethaniser is condensed and sent to a decanter to obtain a liquid phase that is sent as a reflux to said C 2 splitter/deethaniser and to obtain a gaseous phase that is sent to a compressor to obtain a compressed stream that is sent to the demethanizer/CO stripper.
20. The process of claim 16 , 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.
21. The process of claim 16 , 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 and above 0.1/99.9.
22. The process of claim 16 , 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 5/95.
23. The process of claim 16 , wherein a proportion of oxygenates in the dried ethylene stream (A) is from 50 wppm to 7000 wppm.
24. The process of claim 16 , wherein a proportion of oxygenates in the dried ethylene stream (A) is up to 3000 wppm.
25. The process of claim 16 , wherein a proportion of oxygenates in the dried ethylene stream (A) is up to 2000 wppm.
26. The process of claim 16 , wherein a proportion of H 2 in the dried ethylene stream (A) is from 5 to 1000 wppm.
27. The process of claim 16 , wherein a proportion of H 2 in the dried ethylene stream (A) is up to 800 wppm.
28. The process of claim 16 , wherein a proportion of H 2 in the dried ethylene stream (A) is up to 500 wppm.
29. The process of claim 16 , wherein the dried ethylene stream (A) originates from the dehydration of ethanol.