Acid rain abatement
Patent 5176888 Issued on January 5, 1993. Estimated Expiration Date: 
May 1, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
May 1, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesProcess for the treatment of sulfur and nitrogen oxides formed during power generation Sulfur dioxide reduction process utilizing catalysts with spinel structure Removal of sulfur from process streams Process for removing sulfur oxide and nitrogen oxide Patent #: 4830840 InventorAssigneeApplicationNo. 694085 filed on 05/01/1991US Classes:423/239.1, Utilizing solid sorbent, catalyst, or reactant423/244.09, Catalyst423/576Utilizing promotor containing silica or aluminumExaminersPrimary: Heller, Gregory A.Attorney, Agent or FirmInternational ClassesB01J 008/00C01B 021/00 C01B 017/00 C01B 017/02 AbstractThe process of this invention will remove acid rain precursors, sulfur oxides (SOX) and nitrogen oxides (NOX) by catalytically reducing the NOX to water and elemental nitrogen and the SOX to either H2 S or elemental sulfur as desired. The process employs specific catalysts in the heteropoly acid or salt group and the spinel or inverse spinel group. The process conditions achieve an oxygen-free environment and reduction is effected with stoichiometric to 100% excess above stoichiometric H2 or H2 and CO as reducing gas. Temperatures can be 200° to 900° C. with the lower temperature range being favored space velocity can be 2000 to 20,000 and still achieve 95+% abatement. The only product of the reaction which must be disposed of is saleable elemental sulfur. |
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