Process for recovering sulfur by removal of sulfur dioxide from gaseous mixtures

Patent · Tue Apr 13 04:00:00 EST 1982

OSTI ID:5058903

Tung, S E

A process is claimed for removing sulfur dioxide from a mixture of gases and recovery of sulfur dioxide. The sulfur dioxide is first contacted in a scrubbing zone with an aqueous solution of a salt, M/sub 2/B, where M is an alkali metal cation, and B is a divalent anion derived from a weak acid which has an ionization constant (Pka) value of at least 3.0. The pregnant scrubbing solution is then contacted with an amine acid salt, ahb, where a is an amine cationic group containing a hydrophobic subgroup of 8-45 carbons, and hb is a monovalent proton containing anion of a weak acid, to form by ion exchange, an amine hydrogen sulfite and an aqueous solution of alkali metal salt containing the anion hb. The sulfur bearing amine is heated to decompose the sulfite, releasing sulfur dioxide and a reduced sulfur content amine phase. The reduced sulfur content amine phase is contacted with the aqueous solution of alkali metal hb salt to regenerate the scrubbing salt solution of M/sub 2/B and the amine acid salt ahb. The heating of the sulfur bearing amine can be conducted separate from the aqueous alkali metal salt solution, or in the presence thereof. When the sulfur bearing amine is heated in the presence of the alkali metal salt solution, sulfur dioxide release and regeneration occur in situ and simultaneously. The regenerated salt solution is recycled to the scrubber and the amine acid salt is recycled to the anion exchange step. Citrate and phosphate salts are preferred for the scrubbing salt and the amine acid salt.

• Assignee: EDB-82-145432
• Patent Number(s): US 4324775
• OSTI ID: 5058903
• Country of Publication: United States
• Language: English

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AIR POLLUTION CONTROL
ALKALI METALS
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CHEMICAL REACTIONS
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DESULFURIZATION
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ION EXCHANGE
METALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
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SCRUBBING
SULFUR
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
WASTES