Hydrophobic Alkyl-Ester Physical Solvents for CO2 Removal from H2 Produced from Synthesis Gas

Patent metadata

Field	Value
Publication number	US-2026084095-A1
Application number	US-202519397134-A
Country	US
Kind code	A1
Filing date	Nov 21, 2025
Priority date	Jul 19, 2021
Publication date	Mar 26, 2026
Grant date	—

Abstract

One or more embodiments relate to a method for removing CO2 from a gaseous stream containing CO2 having the steps of contacting the gaseous stream containing CO2 with a solvent at a first temperature and a first pressure to dissolve said CO2 in said solvent, where the solvent is made up of at least one ester, and where said at least one ester has two or more alkyl-ester functional groups on a central hydrocarbon chain.

First claim

What is claimed is:

1 . A method for removing CO 2 from a gaseous stream containing CO 2 comprising: contacting the gaseous stream containing CO 2 with a solvent at a first temperature and a first pressure to dissolve said CO 2 in said solvent, wherein the solvent comprises at least one ester, selected from the group of esters consisting of

and combinations thereof,
wherein 2<n≤10, and wherein R 1 and R 2 are alkyl groups having between and including one and six carbons.

2 . The method of claim 1 wherein the solvent is a diester selected from the group consisting of diethyl sebacate, diisobutyl adipate, diethyl adipate, diethyl glutarate, and combinations thereof.

3 . The method of claim 1 wherein the first temperature is between approximately −15° C. and approximately 100° C. and, and wherein the first pressure is between approximately 5 bar and approximately 100 bar.

4 . The method of claim 1 wherein the gaseous stream containing CO 2 comprises products from a syngas-generating process selected from the group of gasses consisting of CO 2 , CO, H 2 , and H 2 O.

5 . The method of claim 1 wherein the gaseous stream containing CO 2 also comprises H 2 and H 2 O.

6 . The method of claim 6 wherein the solvent has a water capacity of between approximately 0.2 mol/L of H 2 O and approximately 2 mol/L of H 2 O at 25° C.

7 . The method of claim 6 wherein the solvent has a CO 2 /H 2 selectivity at 25° C. between approximately 60 and approximately 90.

8 . The method of claim 1 further comprising regenerating the solvent by at least one of reducing the pressure of the solvent to a second pressure and heating the solvent to a second temperature, wherein regenerating the solvent results in CO 2 leaving the solvent.

9 . The method of claim 8 wherein the solvent is heated using waste heat.

10 . The method of claim 8 wherein the second temperature is between approximately 10° C. and approximately 180° C., and wherein the second pressure is between approximately 1 bar to approximately 25 bar.

11 . The method of claim 1 wherein the solvent has a corrosion rate of less than around 0.005 mm/year when a carbon steel or stainless steel coupon is immersed in the solvent at a temperature of about 21° C. and in the presence of CO 2 at a pressure of 100 psig.

12 . The method of claim 1 wherein the gaseous stream contains CO 2 at a partial pressure between approximately 15 bar and approximately 30 bar.

13 . The method of claim 1 wherein the solvent is a physical solvent, and wherein contacting the gaseous stream containing CO 2 with a solvent results in CO 2 dissolved in the solvent without bonds formed between the CO 2 and solvent.

14 . The method of claim 1 wherein the solvent is hydrophobic.

15 . The method of claim 1 wherein the solvent has a CO 2 solubility between approximately 6.5 mol CO 2 per liter of solvent and approximately 9.0 mol CO 2 per liter of solvent.

16 . The method of claim 1 wherein the solvent has a viscosity between approximately 1 cP and approximately 15 cP while the gaseous stream containing CO 2 contacts the solvent.

17 . The method of claim 1 wherein the solvent has a CO 2 /H 2 selectivity greater than 50.

18 . The method of claim 17 wherein the solvent has a CO 2 /H 2 selectivity between approximately 60 and approximately 90.

19 . The method of claim 1 wherein the solvent has a boiling point between approximately 180° C. and approximately 300° C.

20 . A method for removing CO 2 from a gaseous stream containing CO 2 comprising: contacting the gaseous stream containing CO 2 with a solvent at a first temperature and a first pressure to dissolve said CO 2 in said solvent, wherein the solvent comprises:

and wherein R 1 and R 2 are alkyl groups having between and including one and six carbons.

21 . The method of claim 20 wherein the gaseous stream containing CO 2 comprises products from a syngas-generating process selected from the group of gasses consisting of CO 2 , CO, H 2 , and H 2 O.

22 . The method of claim 21 wherein the gaseous stream containing CO 2 also comprises H 2 and H 2 O.

23 . The method of claim 22 wherein the solvent has a water capacity of between approximately 0.2 mol/L of H 2 O and approximately 2 mol/L of H 2 O at 25° C.

24 . The method of claim 23 wherein the solvent has a CO 2 /H 2 selectivity at 25° C. between approximately 60 and approximately 90.

25 . The method of claim 21 wherein the solvent is hydrophobic.

26 . The method of claim 21 wherein the solvent has a CO 2 solubility between approximately 6.5 mol CO 2 per liter of solvent and approximately 9.0 mol CO 2 per liter of solvent.

27 . The method of claim 21 wherein the solvent has a viscosity between approximately 1 cP and approximately 15 cP while the gaseous stream containing CO 2 contacts the solvent.

28 . The method of claim 21 wherein the solvent has a CO 2 /H 2 selectivity greater than 50.

29 . The method of claim 28 wherein the solvent has a CO 2 /H 2 selectivity between approximately 60 and approximately 90.

30 . The method of claim 21 wherein the solvent has a boiling point between approximately 180° C. and approximately 300° C.

31 . A method for removing CO 2 from a gaseous stream containing CO 2 comprising: contacting the gaseous stream containing CO 2 with a solvent at a first temperature and a first pressure to dissolve said CO 2 in said solvent, wherein the solvent comprises:

and wherein R 1 , R 2 , and R 3 are alkyl groups having between and including one and six carbons.

32 . The method of claim 31 wherein the gaseous stream containing CO 2 comprises products from a syngas-generating process selected from the group of gasses consisting of CO 2 , CO, H 2 , and H 2 O.

33 . The method of claim 31 wherein the gaseous stream containing CO 2 also comprises H 2 and H 2 O.

34 . The method of claim 33 wherein the solvent has a water capacity of between approximately 0.2 mol/L of H 2 O and approximately 2 mol/L of H 2 O at 25° C.

35 . The method of claim 34 wherein the solvent has a CO 2 /H 2 selectivity at 25° C. between approximately 60 and approximately 90.

36 . The method of claim 31 wherein the solvent is hydrophobic.

37 . The method of claim 31 wherein the solvent has a CO 2 solubility between approximately 6.5 mol CO 2 per liter of solvent and approximately 9.0 mol CO 2 per liter of solvent.

38 . The method of claim 31 wherein the solvent has a viscosity between approximately 1 cP and approximately 15 cP while the gaseous stream containing CO 2 contacts the solvent.

39 . The method of claim 31 wherein the solvent has a CO 2 /H 2 selectivity greater than 50.

40 . The method of claim 31 wherein the solvent has a CO 2 /H 2 selectivity between approx

Assignees

• Us Energy

Inventors

• Culp Jeffrey T
• Shi Wei
• Thompson Robert L
• Tiwari Surya P
• Resnik Kevin P
• Hong Lei
• Steckel Janice A
• Hopkinson David
• Siefert Nicholas

Classifications

• Y02C20/40

  of CO2 · CPC title

• B01D2252/205

  Other organic compounds not covered by B01D2252/00 - B01D2252/20494 · CPC title

• B01D2256/16

  Hydrogen · CPC title

• B01D2257/504

  Carbon dioxide · CPC title

• B01D2256/20

  Carbon monoxide · CPC title