REMOVAL OF VOLATILE METALS FROM HIGH TEMPERATURE COAL CONVERSION GASSTREAMS

DOE IS DEVELOPING A NUMBER OF ADVANCED COAL CONVERSION PROCESSES THAT OPERATE AT HIGH TEMPERATURES AND PRESSURES. THE COAL THAT IS CONVERTED IN THESE PROCESSES PRODUCES A VARIETY OF CONTAMINANTS. THESE CONTAMINANTS NEED TO BE REMOVED FROM THE HOTGAS STREAM IN ORDER FOR THEPROCESS TO OPERATE AT MAXIMUM EFFICIENCY. VOLATILE METALS CONSTITUTE A FAMILY OF COMPOUNDS FOUND IN THESE GAS STREAMS THAT WILL REQUIRE REMOVAL NOT ONLY TO PROTECT DOWNSTREAM EQUIPMENT FROM CORROSION, BUT IN ORDER TO MEET EXPECTED FUTURE ENVIRONMENTAL CONTROL REGULATIONS. THE DEVELOPMENT OF SORBENTS TO REMOVE VOLATILE METAL EMISSIONS AT HIGH TEMPERATURES FROM THESE SYSTEMS IS THE OBJECTIVE OF THIS PROJECT. TWELVE CANDIDATE SORBENTSWILL BE EVALUATED DURING PHASE I LABORATORY TESTING AT HIGH TEMPERATURE USING A GAS STREAM SIMULATING AN ACTUAL COAL CONVERSION STREAM. MERCURY WILL BE USED AS A SURROGATE VOLATILE METAL FOR THE TESTS. REACTED SORBENTS WILL BE SUBJECTED TO A COMPREHENSIVE SERIES OF ANALYTICAL TESTS TO DETERMINE THE FUNDAMENTAL MECHANISMS INVOLVED IN CAPTURING THE MERCURY. DATA TO BE OBTAINED INCLUDE ABSORPTIVE CAPACITIES, SORPTION CAPABILITIES AS A FUNCTION OF TEMPERATURE AND RESIDENCE TIME, REACTION PRODUCT COMPOSITION, REACTION SITES, AND REACTED SORBENT STABILITY. SELECTED SORBENTSWILL BE EVALUATED FURTHER DURING PHASE II TO EVALUATE PHYSICAL TREATMENTS (PELLETIZING), AND LONG TERM STABILTY.