Separation of gas from solvent by membrane technology

• US 4,995,888 A
• Filed: 07/05/1988
• Issued: 02/26/1991
• Est. Priority Date: 07/05/1988
• Status: Expired due to Fees

• Current Assignee: Texaco Development Corporation (Chevron Corp.), Texaco Incorporated (Chevron Corp.)
• Original Assignee: Texaco Incorporated (Chevron Corp.)
• Inventors: Beaupre, Richard F., Jung, Dick Y.
• Primary Examiner(s): SPITZER, ROBERT H
• Application Number:
  US07/214,983
• Time in Patent Office: 966 Days
• Field of Search: 55/16, 55/48, 55/68, 55/73, 55/158, 55/159, 55/70, 423/226, 423/228, 423/229
• US Class Current: 95/46
• CPC Class Codes: B01D 19/0031 by filtration
• CPC Class Codes: B01D 53/22 by diffusion manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 61/00 Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor separation of gases or vapours by diffusion B01D53/22
• CPC Class Codes: C07C 213/10 Separation; Purification; Stabilisation; Use of additives
• CPC Class Codes: C07C 41/36 by solid-liquid treatment; by chemisorption
• CPC Class Codes: C07C 43/11 Polyethers containing —O—(C—C—O—)n units with ≤ 2 n≤ 10
• CPC Class Codes: C07D 295/182 Radicals derived from carboxylic acids

Abstract

Hydrogen sulfide is separated from the dimethyl ether of tetraethylene glycol through a membrane of hydrolyzed cellulose.

Claims

1. The method of separating a charge rich liquid containing gas dissolved in solvent therefor which comprises

maintaining said charge rich liquid containing gas dissolved in solvent therefore in liquid phase in contact with a gas-permeable, essentially solvent impermeable membrane of pore size of less than about 1000 A and molecular weight cutoff of below about 1,000 selected from the group consisting of cellulose acetate membrane, hydrolyzed cellulose membrane, and polyethyleneimine membrane, and;

maintaining a pressure drop across said gas-permeable essentially solvent-impermeable membrane;

passing said gas from the charge rich liquid containing gas dissolved in solvent therefore at the higher pressure side of said membrane through said membrane thereby forming lean liquid containing decreased quantities of gas dissolved in solvent on the higher pressure side of said membrane and, on the lower pressure side of said membrane, gas containing decreased quantities of liquid;

recovering lean liquid containing decreased quantities of gas dissolved in solvent from the high pressure side of said membrane; and

recovering gas containing decreased quantities of liquid from the lower pressure side of said membrane.

2. The method of separating a charge rich liquid containing gas dissolved in solvent therefor as claimed in claim 1 wherein said gas is

carbon dioxide

hydrogen sulfide

carbon disulfide

hydrogen cyanide

carbonyl sulfide

methyl mercaptan

sulfur dioxide or

ammonia.

3. The method of separating a charge rich liquid containing gas dissolved in solvent therefor as claimed in claim 1 wherein said gas is hydrogen sulfide.

4. The method of separating a charge rich liquid containing gas dissolved in solvent therefor as claimed in claim 1 wherein said gas is carbon dioxide.

5. The method of separating a charge rich liquid containing gas dissolved in solvent therefor as claimed in claim 1 wherein said charge rich liquid is selected from the group consisting of alcohols, glycols, polyoxyalkylene polyols, glycol ethers, organic carbonates, nitrogen heterocycles, sulfur heterocycles, amines, and olamines.

6. The method of separating a charge rich liquid containing gas dissolved in solvent therefor as claimed in claim 1 wherein said solvent is methanol.

7. The method of separating a charge rich liquid containing gas dissolved in solvent therefor as claimed in claim 1 wherein said solvent is tetraethlene glycol dimethyl ether.

8. The method of separating a charge rich liquid containing gas dissolved in solvent therefor as claimed in claim 1 wherein said solvent is N-methyl diethanolamine.

9. The method of separating a charge rich liquid containing gas dissolved in solvent therefor as claimed in claim 1 wherein said solvent is N-formyl morpholine.

10. The method of separating a charge rich liquid containing hydrogen sulfide gas dissolved in dimethyl ether of tetraethylene glycol solvent which comprises

maintaining said charge rich liquid containing hydrogen sulfide gas dissolved in dimethyl ether of tetraethylene glycol solvent in contact with a gas-permeable, essentially solvent impermeable, hydrolyzed cellulose acetate membrane of pore size of about 0.1-1000 A and molecular weight cutoff of less than about 1000;

maintaining a pressure drop across said membrane of about 200-500 psig;

passing hydrogen sulfide from the charge rich liquid containing hydrogen sulfide dissolved therein at the higher pressure side of said membrane through said membrane thereby forming lean liquid containing decreased quantities of hydrogen sulfide on the higher pressure side of said membrane and on the lower pressure side of said membrane, gas containing decreased quantities of liquid;

recovering lean liquid containing decreased quantities of hydrogen sulfide from the high pressure side of said membrane; and

recovering hydrogen sulfide containing decreased quantities of liquid from the lower pressure side of said membrane.