HIGH TEMPERATURE REMOVAL/RECOVERY OF TRACE SULFUR SPECIES FROM WESTERN COAL DERIVED FUEL GAS STREAMS

GASIFICATION OF WESTERN COAL RESULTS IN THE GAS LEAVING THE GASIFIER AT A MODERATE TEMPERATURE (300 DEGREES TO 500 DEGREES CENTIGRADE). CURRENT STATE-OF-THE-ART SORBENT-BASED PROCESSES, DEVELOPED FOR COAL GAS TEMPERATURES OF 600 DEGREES TO 750 DEGREES CENTIGRADE, ARE NOT SUITABLE FOR DESULFURIZATION OF WESTERN COAL-DERIVED GAS STREAMS. THEREFORE, THE SULFUR CONTENT OF THESE COAL GASES IS INCOMPATIBLE WITH MANY INTENDED USES, IN OPERATIONS SUCH AS INTEGRATED GASIFICATION COMBINED-CYCLE (IGCC) SYSTEMS, FUEL CELL POWERPLANTS, AND AS A FEEDSTOCK IN THE CHEMICAL PROCESS INDUSTRY. IN ADDITION, EMISSION OF SULFUR-CONTAINING COMPOUNDS IS ENVIRONMENTALLY OBJECTIONABLE. FURTHER, THE MOST DEVELOPED DESULFURIZATION TECHNOLOGY EMPLOYS BULKY CHEMICAL SORBENTS IN A BATCH-TYPE PROCESS AND PRODUCES A LARGE QUANTITY OF SPENT SORBENTS THAT ARE ENVIRONMENTALLY UNDESIRABLE. THIS PROJECT IS DEVELOPING A NOVEL TYPE OF REACTIVE MEMBRANE THAT ACCOMPLISHES EFFECTIVE MODERATE TEMPERATURE, HIGH PRESSURE GAS DESULFURIZATION BY AN EXTREMELY SELECTIVE FACILITATED TRANSPORT MECHANISM. THE SULFUR IS RELEASED AS ELEMENTAL SULFUR WITHOUT PRODUCING HAZARDOUS BYPRODUCTS. THE PHASE I EFFORT INVOLVES: (1) PREPARATION OF APPROPRIATE MEMBRANES; (2) CHARACTERIZATION WITH RESPECT TO FILM THICKNESS AND COMPOSITION, PERMEABILITY, AND CHEMICAL AND PHYSICAL STABILITY; AND (3) DEMONSTRATION OF THE CONCEPT IN A LABORATORY-SCALE SIMULATED COAL GAS DESULFURIZATION REACTOR.