US 12,337,276 B2
Device and a membrane process for separating gas components from a gas stream having varying composition or flow rate
Steven Kristian Pedersen, Nottawa (CA); Hendrik Derk Hoving, Mountain lakes, NJ (US); Markus Priske, Salzburg (AT); Kah Peng Lee, Seewalchen (AT); and Norbert Krutzler, Pühret (AT)
Assigned to Evonik Operations GmbH, Essen (DE)
Appl. No. 17/427,555
Filed by EVONIK OPERATIONS GMBH, Essen (DE)
PCT Filed Jan. 22, 2020, PCT No. PCT/EP2020/051497
§ 371(c)(1), (2) Date Jul. 30, 2021,
PCT Pub. No. WO2020/156902, PCT Pub. Date Aug. 6, 2020.
Claims priority of provisional application 62/800,168, filed on Feb. 1, 2019.
Prior Publication US 2022/0134274 A1, May 5, 2022
Int. Cl. C07C 7/144 (2006.01); B01D 53/22 (2006.01); B01D 53/26 (2006.01); C10L 3/10 (2006.01)
CPC B01D 53/226 (2013.01) [B01D 53/227 (2013.01); B01D 53/26 (2013.01); C07C 7/144 (2013.01); C10L 3/104 (2013.01); C10L 2290/10 (2013.01); C10L 2290/548 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A device for separating a gas stream, comprising a first gas component and
a second gas component, comprising:
(a) a first membrane separation unit receiving said gas stream through a feed conduit, said first membrane separation unit comprising a gas separation membrane having higher permeance for said first gas component than for said second gas component, providing a first permeate stream enriched in said first gas component and a first retentate stream;
(b) a first permeate conduit connected to said first membrane separation unit to receive said first permeate stream;
(c) a first retentate conduit connected to said first membrane separation unit to receive said first retentate stream;
(d) a second membrane separation unit, connected to said first retentate conduit to receive the first retentate stream as feed, said second membrane separation unit comprising a gas separation membrane having higher permeance for said first gas component than for said second gas component, providing a second retentate stream and a second permeate stream;
(e) a second retentate conduit connected to said second membrane separation unit to receive said second retentate stream;
(f) a second permeate conduit connected to said second membrane separation unit to receive said second permeate stream;
(g) a third membrane separation unit, connected to said second retentate conduit to receive the second retentate stream as feed, said third membrane separation unit comprising a gas separation membrane having higher permeance for said first gas component than for said second gas component, providing a third retentate stream and a third permeate stream;
(h) a product conduit connected to said third membrane separation unit to receive said third retentate stream;
(i) a first recycle conduit connected to said third membrane separation unit to receive said third permeate stream, and connected to a first recycle feedpoint on said feed conduit;
(j) a gas compressor arranged in said feed conduit between said first recycle feed point and said first membrane separation unit or arranged in said first recycle conduit;
(k) a second recycle conduit connected to a second recycle feed point on said feed conduit or on said first recycle conduit, said second recycle feed point being located upstream of said gas compressor and said second recycle conduit being connected to said second permeate conduit to receive all or a fraction of said second permeate stream; and
(l) a control device controlling the fraction of said second permeate stream being passed to said second recycle conduit and passing the remainder of said second permeate stream to a discharge conduit;
wherein said first permeate conduit and said discharge conduit are connected to a joint discharge conduit; and wherein:
i) said first membrane separation unit comprises a gas separation membrane with:
a pure gas selectivity at 20° C. for the first gas component over the second gas component that is from 1.05 to 2 times higher than the pure gas selectivity of a gas separation membrane in the second membrane separation unit for said first gas component over said second gas component at the same temperature and for the same gas components;
a permeance at 20° C. for said first gas component that is lower than the permeance of a membrane in the second membrane separation unit;
ii) said second membrane separation unit comprises a gas separation membrane with:
a pure gas selectivity at 20° C. for the first gas component over the second gas component that is higher than the selectivity of a membrane in the third membrane separation unit for said first gas component over said second gas component; and
a permeance at 20° C. for said first gas component that is lower than the permeance of a membrane in the third membrane separation unit.