Method for removing CO
The present invention relates to a method for removing carbon dioxide (CO 2 ) from a CO 2 -containing stream, the method at least comprising the steps of: a) providing a CO 2 -containing stream ( 10 ), preferably air wherein the CO 2 -containing stream ( 10 ) has a CO 2 content in the range of from 10 to 1000 ppmv, preferably from 100 to 1000 ppmv; b) removing CO 2 from the CO 2 -containing stream ( 10 ) provided in step a) in a first CO 2 removal unit ( 2 ), thereby obtaining a first CO 2 -enriched stream ( 30 ) and a first CO 2 -depleted stream ( 20 ); c) liquefying the first CO 2 -enriched stream ( 30 ) obtained in step b) in a liquefaction unit ( 3 ); d) removing from the liquefaction unit ( 3 ) at least a liquefied CO 2 stream ( 40 ) and a gaseous stream ( 15 ) containing at least nitrogen [N 2 (g)], oxygen [O 2 (g)] and CO 2 (g).
1 . A method for removing carbon dioxide (CO 2 ) from a CO 2 -containing stream, the method at least comprising the steps of:
a) providing a CO 2 -containing stream, wherein the CO 2 -containing stream has a CO 2 content in the range of from 10 to 1000 ppmv;
b) removing CO 2 from the CO 2 -containing stream provided in step a) in a first CO 2 -removal unit, thereby obtaining a first CO 2 -enriched stream and a first CO 2 -depleted stream;
c) liquefying the first CO 2 -enriched stream obtained in step b) in a liquefaction unit;
d) removing from the liquefaction unit at least a liquefied CO 2 stream and a gaseous stream containing at least nitrogen, oxygen and CO 2 ,
wherein at least a part of the gaseous stream removed in step d) is combined with the CO 2 -containing stream provided in step a), and
wherein the CO 2 -containing stream is air.
2 . The method according to claim 1 , wherein the first CO 2 -enriched stream obtained in step b) has a CO 2 content (excluding water) of at least 60 vol. %.
3 . The method according to claim 1 , wherein the first CO 2 -enriched stream obtained in step b) has a pressure of 0.5 to 1.5 bara.
4 . The method according to claim 1 , wherein at least a part of the gaseous stream removed in step d) is separated in a second CO 2 removal unit, thereby obtaining a second CO 2 -enriched stream and a second CO 2 -depleted stream, wherein the second CO 2 -enriched stream is combined with the first CO 2 -enriched stream.
5 . The method according to claim 4 , wherein the second CO 2 -enriched stream has a CO 2 content (excluding water) of at least 90 vol. %.
6 . The method according to claim 1 , wherein at least a part of the gaseous stream removed in step d) is used as a sweep gas in the CO 2 removal unit of step b).
7 . The method according to claim 1 , wherein the liquefied CO 2 stream removed in step d) is used in a conversion process, sequestration or transport, after optional storage and pumping.
8 . The method according to claim 1 , wherein the CO 2 -containing stream has a CO 2 content in the range of from 100 to 1000 ppmv.
9 . The method according to claim 1 , wherein the first CO 2 -enriched stream obtained in step b) has a CO 2 content (excluding water) of at least 80 vol. %.
10 . The method according to claim 1 , wherein the first CO 2 -enriched stream obtained in step b) has a CO 2 content (excluding water) of at least 90 vol. %.
11 . The method according to claim 1 , wherein the first CO 2 -enriched stream obtained in step b) has a pressure of from 0.9 to 1.1 bara.
12 . The method according to claim 4 , wherein the second CO 2 -enriched stream has a CO 2 content (excluding water) of at least 95 vol. %.