Abstract A method of removing sulfur dioxide from waste gas mixtures comprising adsorbing sulfur dioxide onto activated carbon as sulfuric acid at a temperature between ambient temperature and 350* F., subsequently reacting the sulfuric acid laden activated carbon with the correct proportion of hydrogen sulfide at a temperature below 350* F., preferably 200*- 350* F., to homogeneously reduce all the hydrogen sulfide and a portion of the adsorbed sulfuric acid to elemental sulfur, then raising the temperature to between 350* to 1000* F. to react the elemental sulfur and remaining sulfuric acid to form concentrated sulfur dioxide without reaction with the activated carbon, recovering said sulfur dioxide from the activated carbon, and recycling the completely regenerated activated carbon. The recovered sulfur dioxide may be used in a variety of ways, for instance, it may be reacted with methane to produce hydrogen sulfide, it may be reacted with hydrogen sulfide as in a Claus unit to produce elemental sulfur, or it may be converted to sulfuric acid.
The process of claim 1 further comprising, d. recycling said activated carbon adsorbent to adsorb additional amounts of sulfur dioxide.
Claim 2
Dependent Claim
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The process of claim 1 wherein said activated carbon is a bituminous coal-based activated carbon.
Claim 3
Dependent Claim
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The process of claim 1 wherein step (a) is conducted by a fluidizing gas.
Claim 4
Dependent Claim
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The process of claim 1 further comprising (e) recycling at least a portion of said purged sulfur dioxide for use as a fluidizing gas in step (b).
Claim 5
Dependent Claim
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The process of claim 1 wherein at least a portion of said purged sulfur dioxide is reacted with a hydrocarbon to form hydrogen sulfide.
Claim 6
Dependent Claim
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The process of claim 6 wherein a portion of the hydrogen sulfide produced is used in step (a).
Claim 7
Dependent Claim
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The process of claim 1 wherein at least a portion of said purged sulfur dioxide is reacted with hydrogen sulfide to form elemental sulfur.
Claim 8
Dependent Claim
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A process for removing sulfur dioxide from a sulfur dioxide, oxygen and water vapor containing waste gas stream which comprises; a. contacting said sulfur dioxide, oxygen and water vapor containing gas stream with an activated carbon adsorbent at a temperature between ambient temperature and 350* F. to form sulfuric acid adsorbed onto said activated carbon, b. reacting the sulfuric acid laden activated carbon homogeneously with hydrogen sulfide at a mole ratio of up to one mole hydrogen sulfide per three moles sulfuric acid at a temperature between 200* and 350* F. to reduce all of said hydrogen sulfide and a portion of said sulfuric acid to elemental sulfur, c. heating said sulfuric acid-sulfur mixture to a temperature between 350* and 1,000* F. to form sulfur dioxide, and d. purging said sulfur dioxide from said activated carbon adsorbent.
Claim 9
Dependent Claim
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The process of claim 9 further comprising, reacting a portion of said waste gas stream with natural gas to form hydrogen sulfide for use in step (b).