DEVELOPMENT OF REGENERABLE HOT-GAS DESULFURIZATION SORBENTS WITH IMPROVED POLLUTANT CAPTURE PROPERTIES

CURRENTLY, COAL AND RESIDUAL OIL-FIRED, STEAM-ELECTRIC STATIONS ARE THE LARGEST SOURCE OF ATMOSPHERIC SULFUR DIOXIDE POLLUTANTS. THE FRACTIONAL CONTRIBUTION OF SULFUR OXIDE EMISSIONS FROM COAL IS GREATER THAN ITS FRACTION FROM OIL USED IN POWER GENERATION SINCE THE SULFUR CONTENT OF MOST OF THE COAL IS HIGHER. AMONG THE VARIOUS ALTERNATIVES THAT MAY BE USED TO REDUCE THE SULFUR OXIDE POLLUTION CAUSEDBY COAL-FIRED POWER GENERATION PLANTS, THE ADVANCED POWER GENERATION SYSTEMS BASED ON THE INTEGRATED COMBINED CYCLE GENERATORS AND THE MOLTEN CARBONATE FUEL CELLS APPEAR TO HAVE GREAT POTENTIAL. CURRENTLY THE MOST ADVANCED HOT GAS DESULFURIZATION PROCESS IS BASED ON THE ZINC FERRITE SORBENT. RECENT STUDIES WITH THE ZINC TITANATE SORBENT HAVEINDICATED THAT IT HAS A HIGHER OPERATING TEMPERATURE AND LIMITS THE SULFATE FORMATION. IT IS BELIEVED THAT THE PERFORMANCE OF ZINC TITANATE SORBENTS CAN BE IMPROVED BY THE ADDITION OF SOME PROMOTERS TO (1) DECREASE THE EFFLUENT SULFUR LEVELS BELOW 1 PPM, (2) INCREASE ELEMENTAL SULFUR FORMATION DURING REGENERATION, (3) FACILITATE THE REMOVAL OF OTHER CONTAMINANTS SUCH AS ORGANIC SULFUR COMPOUNDS AND AMMONIA, AND (4) INCREASE THE SULFUR CAPTURE CAPACITY. THE MAIN OBJECTIVE OF THE PROPOSED RESEARCH IS TO STUDY IN DETAIL THE EFFECT OF PROMOTERS SUCH AS COBALT ON ZINC-TITANIUM OXIDE SORBENTS, NAMELY ON THEIR REACTIVITY, STABILITY, AND REGENERABILITY OVER THE TEMPERATURE RANGE OF 538-870 DEGREES CENTIGRADE. ANOTHER FACTOR THAT WILL BE INVESTIGATED IS THE ABILITY OF PROMOTERS TO ENHANCE ELEMENTAL SULFUR FORMATION DURING REGENERATION. THE RESULTSOF THE PROPOSED INVESTIGATION WILL CONTRIBUTE TO THE COMMERCIALIZATION OF ADVANCED POWER GENERATION SYSTEMS BASED ON THE INTEGRATED COMBINED CYCLE GENERATORS AND THE MOLTEN CARBONATE FUEL CELLS WHICH ARE SHOWN TO HAVE THERMAL EFFICIENCIES 15-30% HIGHER THAN THOSE OF CURRENT COAL-FIRED POWER GENERATORS.