Production of sulfur from gaseous mixtures containing hydrogen sulfide

Claim 1

IN A PROCESS FOR RECOVERING ELEMENTAL SULPHUR FROM A GASEOUS STREAM CONTAINING AT LEAST 50 VOLUME PER CENT HYDROGEN SULFIDE INVOLVING THE PARTIAL OXIDATION OF SAID HYDROGEN SULFIDE TO FREE SULFUR, THE STEPS WHICH COMPRISE ADDING TO SAID STREAM NOT MORE THAN ABOUT 75 VOLUME PER CENT OF THE OXYGEN REQUIRED TO OXIDIZE SAID HYDROGEN SULFIDE TO FREE SULFUR, INTRODUCING THE RESULTING MIXTURE INTO A HOLLOW REACTION ZONE, THE INTERIOR SURFACE OF WHICH CONSISTS ESSENTIALLY OF A CATALYTIC FERROUS METAL TO PARTIALLY CONVERT SAID HYDROGEN SULFIDE INTO FREE SULFUR AT A TEMPERATURE RANGING FROM ABOUT 600* TO ABOUT 750* F., WITHDRAWING A MIXTURE OF HOT GASEOUS PRODUCTS AND UNCONVERTED HYDROGEN SULFIDE FROM SAID ZONE AND ADDING TO SAID MIXTURE THE REMAINDER OF THE REQUIRED AMOUNT OF AIR FOR THE CONVERSION OF SAID UNCONVERTED HYDROGEN SULFIDE INTO FREE SULFUR WHEREBY THE TEMPERATURE OF THE RESULTING MIXTURE IS REDUCED TO A VALUE OF FROM SLIGHTLY ABOVE THE DEWPOINT OF SULFUR TO ABOUT 550* F., NEXT CONTACTING THE RESULTING MIXTURE WITH A FIXED BED TO CATALYST FOR SAID OXIDATION MAINTAINED AT A TEMPERATURE OF FROM ABOUT 400* TO ABOUT 1200* F., THEREAFTER COOLING THE RESULTING SULFUR CONTAINING VAPORS, AND SEPARATING LIQUID SULFUR THEREFROM.