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# c12) United States Patent Ouimet et al. 

# (54) PROCESS FOR CAPTURING SULFUR DIOXIDE FROM A GAS STREAM 

(71) Applicant: CANSOLV TECHNOLOGIES INC., Montreal, Quebec (CA) 

(72) Inventors: Michel Ouimet, Mirabel (CA); Melina Infantino, Montreal (CA) 

(73) Assignee: SHELL OIL COMPANY, Houston, TX (US) 

( *) Notice: Subject to any disclaimer, the term ofthis patent is extended or adjusted under 35 U.S.C. 154(b) by 122 days. 

(21) Appl. No.: 15/034,360 

(22) PCT Filed: Nov. 5, 2014 

(86) PCT No.: PCT /CA2014/051059 § 371 (c)(l), (2) Date: May 4, 2016 

(87) PCT Pub. No.: WO2015/066807 PCT Pub. Date: May 14, 2015 

## (65) Prior Publication Data 

US 2016/0263519 Al Sep. 15, 2016 

## (30) Foreign Application Priority Data 

Nov. 7, 2013 (EP) ..................................... 13191903 

(51) Int. Cl. 

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(52) U.S. Cl. CPC ..... BOID 53/1481 (2013.01); BOID 53/1425 (2013.01); BOID 5311475 (2013.01); 

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# (IO) Patent No.: US 9,919,262 B2 

# (45) Date of Patent: Mar.20,2018 

(58) Field of Classification Search CPC ............ BOID 53/1425; BOID 53/1475; BOID 53/1481; BOID 53/1493; BOID 2252/20; 

## (56) References Cited 

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Fogg, P.G.T., et al.: Solubility of Gases in Liquids, A Critical Evaluation of Gas/Liquid Systems in Theory and Practice, Chapter 5, Solubility of Sulfur Diolide, pp. 39-85, 1991. 

Primary Examiner - Frank Lawrence 

## (57) ABSTRACT 

A process for removing sulfur dioxide from a feed gas stream, which comprises (i) contacting the feed gas stream with an aqueous lean absorbing medium comprising a chemical solvent comprising a regenerable absorbent, a physical solvent, and one or more heat stable salts. The regenerable absorbent is an amine. The ratio of the wt % of the physical solvent over that of the regenerable absorbent is 0.5 to 2.5. The ratio of the wt% of heat stable salts over that of the regenerable absorbent is 0.29 to 0.37. The pH of the lean absorbing medium is 6 or less. With the process SO2 can be selectively removed. When the absorbing medium is stripped, a reduced amount of energy is required as com› pared to known processes. 

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US009919262B2 

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## U.S. PATENT DOCUMENTS 

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## FOREIGN PATENT DOCUMENTS 

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## OTHER PUBLICATIONS 

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## 15 Claims, 6 Drawing Sheets 

