Process for regenerative sorption of CO.sub.2

• US 3,865,924 A
• Filed: 03/03/1972
• Issued: 02/11/1975
• Est. Priority Date: 03/03/1972
• Status: Expired due to Term

• Current Assignee: Dimitri Gidaspow, Michael Onischak
• Original Assignee: Dimitri Gidaspow, Michael Onischak
• Inventors: Gidaspow, Dimitri, Onischak, Michael
• Primary Examiner(s): Thomas, Earl C.
• Application Number:
  US05/231,530
• Time in Patent Office: 1,075 Days
• Field of Search: 423/230-233,244,535 55/68,74
• US Class Current: 423/230
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: F24F 2203/1036 Details
• CPC Class Codes: H01M 8/0662 Treatment of gaseous reactants or gaseous residues, e.g. cleaning
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A process and apparatus for the removal of carbon dioxide from a gaseous stream, wherein the CO2 content ranges from trace amounts up to 50 mole percent, and for subsequent transfer to another gas stream by thermal regeneration. A special composition comprising a finely ground mixture of potassium carbonate and alumina, which has synergistic properties, is used as the absorbent. In a preferred apparatus embodiment, the mixture is incorporated into a rotary regenerative wheel.

Claims

1. A METHOD OF REMOVING CO2 FROM AGASES STREAM COMPRISING THE STEPS OF:

A. PASSING A CO2-CONTAINING INLET GAS STREAM INTO CONTACT WITH A SYNERGISTIC SORBENT COMPOSITION OF FINELY DIVIDED, PARTICULATE ALKALI METAL CARBONATE AND ALUMINA, SAID ALUMINA AND CARBONATE BEING SEPARATE DISCRETE PARTICLES AND HAVING BEEN GROUND TOGETHER TO PROVIDE SUCH SORBENT, TO SORB CO2 THEREINTO AND CONVERT SAID CARBONATE TO BICARBONATE, B. MAINTAINING SAID SORBENT COMPOSITION IN HYDRATED FROM, THEREBY TO REMOVE CO2 FROM SAID GASES STREAM;

AND C. REGENERATING SAID SORBENT COMPOSITION BY SUPPLYING HEAT TO RECONVERT SAID BICARBONATE TO SAID CARBONATE FROM WHILE EVOLVING CO2 THEREFROM, WITHOUT FORMING A CRUST OVER SAID SORBENT.

2. A method of CO2 removal as in claim 1 which includes the added steps of:

a. passing a an exhaust gas stream into contact with said sorbent when said sorbent is substantially in the bicarbonate form, b. maintaining said heat until said bicarbonate is regenerated to carbonate and said evolved CO2 is delivered to said exhaust gas stream.

3. A method of CO2 removal as in claim 2 wherein said process is maintained in a continuous cyclic fashion, said passing of inlet gases being in the sorption half of said cycle and said passing of exhaust gases being in the desorption regeneration half of said cycle.

4. A method of cO2 removal as in claim 3 wherein said sorption half of said cycle is maintained at a temperature of up to about 60*C, and said regeneration half of said cycle is maintained at a temperature of up to about 165*C.

5. A method of CO2 removal as in claim 1 wherein the inlet gas stream contains up to about 50 percent, by volume, CO2.

6. A method of CO2 removal as in claim 1 wherein said carbonate comprises from 5-75 percent, by weight of the total composition, and said alumina comprises from 95-25 percent, by weight of said total composition.

7. A method of CO2 removal as in claim 1 wherein said alkali metal corabonate is selected from potassium, sodium, rubidium, and cesium carbonate, and mixtures thereof.

8. A method of CO2 removal as in claim 7 wherein said alkali metal carbonate is potassium carbonate.

9. A method of CO2 removal as in claim 8 wherein said carbonate is admixed, in powdered form, in a size ranging from 20 to 1 U.S. mesh with said alumina, and said alumina has a specific surface area of more than 25 square meters/gram.

10. A method of CO2 removal as in claim 8 wherein said sorbent is supported on a filamentous carrier in an amount ranging from 5-300 percent by weight of said carrier.

11. A method of CO2 removal as in claim 10 wherein said filamentous carrier is selected from wire mesh or fibrous materials capable of withstanding temperatures of over 165* C.

12. A method of CO2 removal as in claim 11 wherein said carrier is a fibrous material selected from asbestos, cellulose, plastic, and mixtures thereof.