HIGH TEMPERATURE HYDROGEN SULFIDE REMOVAL

REGENERABLE HOT GAS ABSORBENTS (E.G., ZINC FERRITE) ARE BEING DEVELOPED TO REMOVE H2S FOR COAL SYNTHESIS GASES. THEREGENERATION PROCESS PRODUCES A STREAM OF SO2 WITH IS THEN REACTED WITH LIMESTONE. WHILE THIS APPROACH SHOWS MUCH PROMISE, THE EXPENDABLE SO2 ABSORBENT AND DISPOSAL OF THAT SPEND LIMESTONE INCREASES THE TOTAL COST OF SULFUR REMOVAL. TDA RESEARCH, INC. (TDA) PROPOSES A SYSTEM WHICH COULD FURTHER REDUCE THE COST FOR SULFUR REMOVAL. THE SYSTEM USESTWO REGENERABLE ABSORBENTS TO REMOVE SULFUR FROM THE HOT GASSTREAM AND PRODUCE ELEMENTAL SULFUR AS A PRODUCT FOR SALE. ZINC FERRITE REMOVES HALF OF THE SULFUR. THE SECOND, PROPRIETARY ABSORBENT REMOVES THE OTHER HALF OF THE SULFUR FROM THE HOT GAS STREAM. AFTER ABSORPTION OF H2S, THE PROPRIETARY ABSORBENT IS REGENERATED BY THE SO2 PRODUCED FROM ZINC FERRITE REGENERATION. THE PROPRIETARY ABSORBENT REACTS WITH THE SO2 LIBERATING ELEMENTAL SULFUR IN THE VAPORSTATE. CONDENSING THAT SULFUR PRODUCES A HIGH PURITY PRODUCT. TDA HAS EVALUATED THE THERMODYNAMICS OF THE REACTIONS IN THESYSTEM AT THE CONDITIONS EXPECTED IN A HOT GAS STREAM AND DURING REGENERATION. MORE THAN HALF OF THE H2S COULD BE REMOVED BY OUR PROPRIETARY ABSORBENT. THE REACTION OF THE PROPRIETARY ABSORBENT WITH SO2 WAS SHOWN TO OCCUR AT LOW SO2 CONCENTRATIONS. IN PHASE I THE REACTION OF THE ABSORBENT WITH LOW CONCENTRATIONS OF H2S IN THE PRESENCE OF HYDROGEN AND WATER WILL BE DEMONSTRATED. THE REGENERATION OF THE ABSORBENT WITH SIMULATED ZINC FERRITE REGENERATION GAS WILL ALSO BE DEMONSTRATED. AN ECONOMIC ANALYSIS WILL COMPARE OUR NEW SYSTEM WITH CURRENT HOT GAS DESULFURIZATION TECHNOLOGY.