High performance hydrophobic solvent, carbon dioxide capture

Patent metadata

Field	Value
Publication number	US-9643123-B2
Application number	US-201414525011-A
Country	US
Kind code	B2
Filing date	Oct 27, 2014
Priority date	Oct 28, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

Methods and compositions useful, for example, for physical solvent carbon capture. A method comprising: contacting at least one first composition comprising carbon dioxide with at least one second composition to at least partially dissolve the carbon dioxide of the first composition in the second composition, wherein the second composition comprises at least one siloxane compound which is covalently modified with at least one non-siloxane group comprising at least one heteroatom. Polydimethylsiloxane (PDMS) materials and ethylene-glycol based materials have high carbon dioxide solubility but suffer from various problems. PDMS is hydrophobic but suffers from low selectivity. Ethylene-glycol based systems have good solubility and selectivity, but suffer from high affinity to water. Solvents were developed which keep the desired combinations of properties, and result in a simplified, overall process for carbon dioxide removal from a mixed gas stream.

First claim

What is claimed is:

1. A method comprising:
contacting at least one first composition comprising carbon dioxide with at least one second composition to at least partially dissolve the carbon dioxide of the first composition in the second composition, wherein the second composition comprises at least one siloxane compound which is covalently modified with at least one non-siloxane group comprising at least one heteroatom.

2. The method of claim 1 , wherein the heteroatom is nitrogen or oxygen.

3. The method of claim 1 , wherein the heteroatom is oxygen.

4. The method of claim 1 , wherein the non-siloxane group comprising at least one heteroatom comprises an alkyleneoxy group, an amino group, an ester group, or a ketone group.

5. The method of claim 1 , wherein the non-siloxane group comprising at least one heteroatom comprises an alkyleneoxy group.

6. The method of claim 1 , wherein the compound has 3 or 4 Si atoms.

7. The method of claim 1 , wherein the compound has a molecular weight of 500 g/mol or less.

8. The method of claim 1 , wherein the compound is a liquid or oil when pure at 25° C.

9. The method of claim 1 , wherein the siloxane compound is represented by:
(A) x -(B) y
wherein A is a group comprising the siloxane moiety, and B is the non-siloxane group comprising the heteroatom, and A and B are covalently linked, and the values x and y, independently of each other, are integers, 1-10.

10. The method of claim 1 , wherein the siloxane compound is represented by (A) x -(B) y -(A) x , wherein B is the non-siloxane moiety and A is a siloxane moiety and y is 1 and x is 1.

11. The method of claim 1 , wherein the siloxane compound is represented by:
TSM-Si(R 4 )(R 5 )-TSM
wherein each TSM is independently a terminal siloxane moiety, wherein the TSM is represented by the monovalent group represented by R 1 R 2 R 3 —Si—O— wherein R 1 , R 2 , R 3 are monovalent alkyl moieties such as a C 1 -C 10 moiety such as methyl or ethyl; and wherein R 4 also is a monovalent alkyl moiety such as a C 1 -C 10 moiety such as methyl or ethyl; and R 5 is the non-siloxane group comprising the heteroatom such as oxygen or nitrogen.

12. The method of claim 1 , wherein the first composition further comprises hydrogen and water, and the water is present in the first composition in a saturation amount.

13. The method of claim 1 , wherein the contacting step is carried out at a temperature of about 0° C. to about 90° C.

14. The method of claim 1 , wherein after the contacting step, the second composition with its dissolved carbon dioxide is subjected to one or more carbon dioxide removal steps to form a third composition which is further contacted with a first composition comprising carbon dioxide.

15. A method comprising:
capturing carbon dioxide with use of a physical solvent of an ethylene oxide modified polydimethylsiloxane compound.

16. A method comprising capturing carbon dioxide by contacting a composition with a gaseous composition, wherein the composition comprises at least one siloxane compound which is covalently modified with at least one non-siloxane group comprising at least one heteroatom, wherein the compound has a molecular weight of 500 g/mol or less.

Assignees

• Univ Carnegie Mellon
• Us Dept Energy

Inventors

• Nulwala Hunaid
• Luebke David

Classifications

• B01D2252/204

  Amines · CPC title

• B01D2258/0283

  Flue gases · CPC title

• B01D2259/4533

  for medical purposes · CPC title

• B01D2252/502

  having two or more functionalities in the same molecule other than alkanolamine · CPC title

• Y02C10/06

  Cross-Sectional Technologies · mapped topic