# US 9,751,044 B2 · Aqueous solutions of amine functionalized ionic compounds for carbon capture processes

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- Number: US 9,751,044 B2
- Document ID: US9751044B2
- Status: Granted
- Kind: B2
- Application number: 14/870,318
- Filed: 2015-09-30
- Published: 2016-01-21
- Granted: 2017-09-05
- Earliest claimed: 2010-12-30
- Assignees: Chevron U.S.A. Inc.; University of South Alabama
- Applicants: Chevron U.S.A. Inc.; University of South Alabama
- Inventors: Daniel Chinn; Rusell Evan Cooper; Zunqing He; James H. Davis, Jr.; Kevin N. West; Hye Kyung Timken; Michael S. Driver
- Web page: https://patentgrep.com/patent/US9751044B2

## CPC

- B01D 53/62: Carbon oxides
- B01D 53/1475: {Removing carbon dioxide}
- B01D 53/1493: {Selection of liquid materials for use as absorbents}
- B01D 53/78: with gas-liquid contact
- B01D 2252/204: Amines
- B01D 2252/2056: Sulfur compounds, e.g. Sulfolane, thiols
- B01D 2252/30: Ionic liquids and zwitter-ions
- B01D 2252/502: having two or more functionalities in the same molecule other than alkanolamine
- B01D 2258/0283: Flue gases
- Y02C 20/40: of CO2
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]

## Abstract

An aqueous ionic absorbent solution is disclosed containing (a) about 15 wt. % to about 80 wt. % of one or more diluents, based on the total weight of the aqueous ionic absorbent solution; and (b) an ionic absorbent containing a cation and an anion comprising an amine moiety.

## Claims

### Claim 1

A process for separating carbon dioxide (CO2) from a carbon dioxide-containing gas stream, the process comprising:
(a) contacting the carbon dioxide-containing gas stream with an aqueous ionic absorbent solution under absorption conditions to absorb at least a portion of the CO2 from the carbon dioxide-containing gas stream and form a CO2-absorbent complex; wherein the aqueous ionic absorbent solution has a viscosity of about 0.1 to about 100 centistokes (cSt) and further wherein the aqueous ionic absorbent solution comprises (i) about 40 wt. % to about 80 wt. % of one or more diluents, based on the total weight of the aqueous ionic absorbent solution; and (ii) an ionic absorbent selected from the group consisting of tetrabutylammonium N-propyl-N-(3-sulfopropyl)amine, tetrabutylphosphonium N-isopropyl-N-(3-sulfopropyl)amine, tetraethylammonium N-isopropyl-N-(3-sulfopropyl)amine and mixtures thereof; and
(b) recovering a gaseous product having a reduced CO2.

### Claim 2 (depends on 1)

The process of claim 1, wherein the carbon dioxide-containing gas stream is flue gas and the aqueous ionic absorbent solution absorbs higher than about 0.5 mol CO2 per mol ionic absorbent at 40° C. with a CO2 partial pressure in the range of 1 to 20 psia.

### Claim 3 (depends on 1)

The process of claim 1, wherein the one or more diluents comprise water.

### Claim 4 (depends on 1)

The process of claim 1, wherein the one or more diluents comprise a diluent selected from the group consisting of a monohydric alcohol, a polyol and mixtures thereof.

### Claim 5 (depends on 1)

The process of claim 1, wherein the amount of the one or more diluents is from about 40 wt. % to about 70 wt. % diluent, based on the total weight of the aqueous ionic absorbent solution.

### Claim 6 (depends on 1)

The process of claim 1, wherein the amount of the one or more diluents is from about 40 wt. % to about 60 wt. % diluent, based on the total weight of the aqueous ionic absorbent solution.

### Claim 7 (depends on 1)

The process of claim 1, further comprising (i) pressurizing the CO2-absorbent complex to a pressure of greater than about 1.9 bar to about 10 bar and (ii) heating the pressurized CO2-absorbent complex to recover an ionic absorbent stream depleted in CO2.

### Claim 8 (depends on 7)

The process of claim 7, wherein the pressurized CO2-absorbent complex is heated to a temperature ranging from greater than 60° C. to about 80° C.

### Claim 9 (depends on 7)

The process of claim 7, wherein the pressurized CO2-absorbent complex is heated to a temperature ranging from greater than 100° C. to about 120° C. under atmospheric conditions.

### Claim 10 (depends on 7)

The process of claim 7, wherein the pressurized CO2-absorbent complex is heated to a temperature ranging from about 120° C. to about 200° C. under high-pressure conditions including a pressure of greater than about 1.9 bar to about 10 bar.