Process and sorbent system for removing nitrogen and other oxides from gas streams
AssigneeNoxso Corporation
InventorJules Magder
Life of this patent
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Abstract
Novel sorbents comprising (a) an alumina component comprising alumina of the surface area of at least 20 and preferably 100 square meters per gram, and (b) a salt, or mixtures of salts, of an alkali or alkaline earth metal, especially oxides, hydroxides, carbonates, nitrates, acetates or aluminates of sodium and potassium, are outstandingly effective for the removal of nitrogen oxides and sulfur oxides from waste gas streams.
Claims62
A method for removing sulfur oxides and nitrogen oxides from a sorbent comprising alumina having a surface area of at least 20 square meters per gram and an alkaline component comprising an oxide, hydroxide or salt of a Group IA or IIA metal of atomic number not exceeding 56 which sorbent contains both sulfur oxides and nitrogen oxides which comprises:
- (a) contacting said sulfur oxide and nitrogen oxide-containing sorbent in a regeneration zone with a regenerant gas stream containing at least 0.01 atmosphere partial pressure of hydrogen sulfide at a temperature of about 350.degree. to about 750.degree. C. for a period of time sufficient to recover a substantial portion of the sorbent's capacity for nitrogen oxide and sulfur oxide sorption;
- (b) withdrawing nitrogen oxide formerly contained on said sorbent in the form of elemental nitrogen, or a non-polluting nitrogen compound;
- and
- (c) withdrawing sulfur oxides formerly contained on said sorbent in the form of elemental sulfur.
A method for removing sulfur oxides and nitrogen oxides from a sorbent containing both sulfur oxides and nitrogen oxides which consists essentially of:
- (a) Contacting said sulfur oxide and nitrogen oxide-containing sorbent in a regeneration zone with a regenerant gas stream containing at least 0.01 atmosphere partial pressure of hydrogen sulfide at a temperature of about 350.degree. to about 750.degree. C. for a period of time sufficient to recover a substantial portion of the sorbent's capacity for nitrogen oxide and sulfur oxide sorption;
- (b) Withdrawing nitrogen oxide formerly contained on said sorbent in the form of elemental nitrogen, or a non-polluting nitogen compound;
- and
- (c) Withdrawing sulfur oxides formerly contained on said sorbent in the form of elemental sulfur.
A method for the removal of sulfur oxides and nitrogen oxides from a gas-containing them which comprises contacting said gas at a temperature of 85.degree. C. to about 200.degree. C. with a sorbent, which sorbent comprises:
- (a) an alumina component comprising alumina having a surface area of at least about 20 square meters per gram;
- and
- (b) an alkaline component comprising at least one oxide, hydroxide or salt of a Group IA or Group IIA metal of atomic number not exceeeding 56 and, thereafter, removing nitrogen oxides and sulfur oxides from said sorbent by:
- (c) contacting the nitrogen oxide and sulfur oxide containing sorbent in a regeneration zone with a regenerant gas stream containing at least 0.01 atmosphere partial pressure hydrogen sulfide at a temperature of about 350.degree. to about 750.degree. C. for a period of time sufficient to recover a substantial portion of the sorbent's capacity for nitrogen oxide and sulfur oxide sorption;
- (d) withdrawing nitrogen oxides formerly contained on said sorbent in the form of elemental nitrogen;
- (e) withdrawing sulfur oxides formerly contained on said sorbent in the form of elemental sulfur.
Dependencies are inferred from the claim text.