Pittsburgh Environmental and Energy Systems, Inc.

Pittsburgh Environmental Systems Incorporated

Edward Shapiro

Henry C Bramer

Hubert Lloyd Barnes

A process for removing SO.sub.2 and NO.sub.x from waste gas and recovering sulfur comprising scrubbing the waste gases with a water slurry of FeS in the presence of FeSO.sub.4 and Na.sub.2 SO.sub.4. SO.sub.2 is captured by the formation of FeS.sub.2 and FeSO.sub.4 in the scrubber. By thermal regeneration in a reducing atmosphere the FeS.sub.2 is converted to FeS and Na.sub.2 SO.sub.4 to Na.sub.2 S. The FeS is recycled to the scrubber. The Na.sub.2 S is returned to the system reacting with FeSO.sub.4 to form Na.sub.2 SO.sub.4 and FeS. The last reaction reduces the amount of FeSO.sub.4 entering the regenerator where by an undesirable side reaction, it may be partially converted to SO.sub.2 and Fe.sub.3 O.sub.4.

Process for removing SO.sub.2 and NO.sub.x from gases

A process and apparatus are provided whereby sulfur and nitrogen oxides as well as carbon monoxides and unburned hydrocarbons are removed from internal combustion engine exhaust gases. The gases are passed through a chamber containing a sulfide and an oxide of iron, copper or zinc. The system is partially self-regenerating and can be used in conjunction with present catalytic converter units or in lieu thereof. In certain embodiments the present invention can also replace muffler units in exhaust systems.

Method and apparatus for purification of exhaust gases

A method is disclosed for scrubbing SO.sub.2 and NO.sub.x containing gases with iron sulfide. The reaction proceeds only to the formation of FeS.sub.2 and FeSO.sub.4 without significant formation of sulfur or iron oxide. The reaction products are subsequently regenerated to FeS by heating and can be recycled for further scrubbing operations; elemental sulfur is recovered as a by-product.

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Pittsburgh, PA, United States of America

Edward Shapiro