Desulfurization and low temperature regeneration of carbonaceous adsorbent
AssigneeFoster Wheeler Energy Corporation
InventorPeter Steiner
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Abstract
A gas desulfurization process is disclosed wherein a particulate, partially oxidized coal is used as an adsorbent for gaseous sulfur oxides and is regenerated by contact with a low temperature recycled stream of its own desorbed off-gas containing at least 40% steam and 15% SO.sub.2. A bleed stream of the desorbed off-gas may be reacted with coal at 1150.degree. F. to 1550.degree. F. to partially oxidize the coal and transform it into an adsorbent suitable for use in the adsorber.
Claims15
A process for desulfurizing a flue gas with a carbonaceous adsorbent and reactivating the spent carbonaceous adsorbent, comprising:
- (1) using a partially oxidized coal as the carbonaceous adsorbent and continuously passing the spent adsorbent through a regeneration zone as a non-static bed;
- (2) passing an initial charge of an inert gas into a regenerating gas loop and through the regeneration zone in a direction countercurrent to the flow of the spent adsorbent for contact with the spent adsorbent to desorb adsorbed volatiles including sulfur oxides and water vapor from the spent adsorbent;
- (3) maintaining the temperature of the regeneration zone at the gas inlet within the range of 800.degree.-1000.degree. F. by externally heating and recycling the desorbed volatiles through the regeneration zone whereby a water vapor concentration of at least 40 mole percent and an SO.sub.2 concentration of at least 15 mole % in the regeneration gas loop are maintained and whereby the spent adsorbent is continuously regenerated;
- (4) continuously removing a portion of the gas from the regenerating gas loop at the rate at which volatiles are desorbed to maintain steady-state operation;
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- (5) processing the gas removed from the regenerating gas loop to recover the sulfur value contained therein.
A process for desulfurizing a flue gas with a carbonaceous adsorbent and reactivating the spent carbonaceous adsorbent, comprising:
- (1) using a partially oxidized coal as the carbonaceous adsorbent and continuously passing the spent adsorbent through a regeneration zone as a non-static bed;
- (2) passing an initial charge of an inert gas into a regenerating gas loop and through the regeneration zone in a direction countercurrent to the flow of the spent adsorbent for contact with the spent adsorbent to desorb adsorbed volatiles including sulfur oxides and water vapor from the spent adsorbent;
- (3) maintaining the temperature of the regeneration zone at the gas inlet within the range of 800.degree.-1000.degree. F. by externally heating and recycling the desorbed volatiles through the regeneration zone whereby a water vapor concentration of at least 40 mole % and an SO.sub.2 concentration of at least 15 mole % is maintained in the regeneration gas loop and whereby the spent adsorbent is continuously regenerated;
- (4) continuously removing a bleed portion of the gas from the regenerating gas loop at the rate the volatiles are desorbed to maintain steady-state operation;
- (5) continuously feeding said bleed gas portion to a reaction zone containing coal and maintained at a temperature of from 1150.degree. F. to 1550.degree. F. to convert the sulfur dioxide to gaseous elemental sulfur and to partially oxidize the coal;
- (6) continuously removing and condensing said gaseous sulfur from the reaction zone;
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- (7) continuously removing the partially oxidized coal from the reaction zone.
Dependencies are inferred from the claim text.