US 12,084,347 B2
Process and plant for producing hydrogen and for separating carbon dioxide from synthesis gas
Sophia Schmidt, Frankfurt am Main (DE); and Matthias Linicus, Eppstein (DE)
Assigned to L'Air Liquide, Societe Anonyme Pour l'Etude et l'Exploitation des Procedes Georges Claude, Paris (FR)
Filed by L'Air Liquide, Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude, Paris (FR)
Filed on Nov. 11, 2021, as Appl. No. 17/524,047.
Claims priority of application No. 20020522 (EP), filed on Nov. 11, 2020.
Prior Publication US 2022/0144634 A1, May 12, 2022
Int. Cl. C01B 3/52 (2006.01); B01D 53/00 (2006.01); B01D 53/047 (2006.01); B01D 53/14 (2006.01); B01D 53/26 (2006.01); C01B 3/56 (2006.01); C10K 1/00 (2006.01); C10K 1/16 (2006.01); C10K 3/04 (2006.01)
CPC C01B 3/52 (2013.01) [B01D 53/002 (2013.01); B01D 53/047 (2013.01); B01D 53/1418 (2013.01); B01D 53/1425 (2013.01); B01D 53/1475 (2013.01); B01D 53/263 (2013.01); B01D 53/265 (2013.01); C01B 3/56 (2013.01); C10K 1/005 (2013.01); C10K 1/16 (2013.01); B01D 53/1493 (2013.01); B01D 2252/2021 (2013.01); B01D 2252/20468 (2013.01); B01D 2252/20473 (2013.01); B01D 2256/16 (2013.01); C01B 2203/0283 (2013.01); C01B 2203/0415 (2013.01); C01B 2203/042 (2013.01); C01B 2203/0475 (2013.01); C01B 2203/0495 (2013.01); C01B 2203/0833 (2013.01); C01B 2203/0883 (2013.01); C01B 2203/146 (2013.01); C10K 3/04 (2013.01); Y02C 20/40 (2020.08)] 19 Claims
OG exemplary drawing
 
1. A process for producing hydrogen and for separating carbon dioxide from synthesis gas, comprising:
(a) providing a synthesis gas, wherein the synthesis gas comprises at least hydrogen, carbon monoxide and carbon dioxide;
(b) providing a physical absorption medium;
(c) cooling the synthesis gas and the absorption medium;
(d) removing carbon dioxide from the cooled synthesis gas via the cooled absorption medium in a physical absorption step at elevated pressure, wherein the cooled synthesis gas and the cooled absorption medium are run in countercurrent, wherein synthesis gas at least partially freed of carbon dioxide is obtained and absorption medium laden with carbon dioxide and partially co-absorbed carbon monoxide and hydrogen is obtained;
(e) treating the laden absorption medium in a plurality of serially arranged flash stages, wherein co-absorbed carbon monoxide and hydrogen are removed from the laden absorption medium in at least one first flash stage and carbon dioxide is removed from the laden absorption medium in a flash stage arranged downstream of the at least one first flash stage;
(f) separating hydrogen from the synthesis gas at least partially freed of carbon dioxide in a physical separation step, wherein hydrogen as a product gas and an offgas comprising hydrogen, carbon monoxide and carbon dioxide are obtained;
(g) compressing to absorption pressure and at least partially recycling to step (d) the offgas obtained in step (f) and the carbon monoxide and hydrogen obtained in step (e); and
(h) discharging the product gas (hydrogen) obtained in step (f) and the carbon dioxide obtained in step (e) from the process.