TRACE METAL AEROSOL CONTROL IN INCINERATORS

INCINERATION OF MOST INDUSTRIAL WASTES, INCLUDING MUNICIPAL SOLID WASTE, RESULTS IN THE EMISSION OF POTENTIALLY TOXIC TRACE METAL AEROSOLS. MOST OF THE TRACE METAL SPECIES IN THE WASTE FEED, SUCH AS LEAD, CROMIUM, MERCURY AND ARSENIC, COMPLETELY VOLATILIZE IN THE COMBUSTION ZONE, AND SUBSEQUENTLY CONDENSE AND CONCENTRATE IN THE SUBMICRON-SIZEDASH PARTICLES (FUME). THIS SIZE FRACTION CANNOT BE REMOVED WITH HIGH EFFICIENCY BY EXISTING PARTICULATE CONTROL DEVICES, THUS RESULTING IN ITS PREFERENTIAL ESCAPE INTO THE ENVIRONMENT. EVEN THE PARTICLES THAT ARE CAPTURED MAY LEACHSOLUBLE METALS TO THE GROUNDWATER IF IMPROPERLY DISPOSED IN LANDFILLS. FURTHER, THESE VOLATILIZED SPECIES, PARTICULARLYWHEN COMBINED WITH CHLORINE, CAN LEAD TO CORROSION OF INCINERATOR SURFACES. PSI HAS IDENTIFIED SEVERAL SPECIFIC ADDITIVES THAT MAY REACTWITH THE TRACE METAL SPECIES AND INCORPORATE THEM INTO MATRICES THAT HAVE BOTH LOW VOLATILITY AND LOW LEACHABILITY. THEREFORE, NOT ONLY IS THERE A POTENTIAL TO MITIGATE THE FORMATION OF TRACE METALS AND CONDENSATION AEROSOLS, BUT THE RESULTING FLYASH MAY BE SAFELY LANDFILLED WITHOUT LEACHING TOXIC METALS TO THE ENVIRONMENT. PSI'S PHASE I PROGRAM WILL FOCUS ON THE TREATMENT OF LEAD (PB) SPECIES, AND WILL CONSIST OF IDEALIZED REACTOR EXPERIMENTS USING SEVERAL ADDITIVES THAT HAVE THE POTENTIAL OF REDUCING LEAD VAPOR SPECIES BY SEVERAL ORDERS OF MAGNITUDE. INITIAL EXPERIMENTS WILL DETERMINE THE PARTITIONING OF TRACE METAL SPECIES BETWEEN THE VAPOR AND SOLID FOR DIFFERENT TEMPERATURES AND LEVELS OF HC1 IN THE GAS. PSI WILL ALSO CHARACTERIZE THE ASH PRODUCTS AND THEIR THERMAL AND CHEMICAL STABILITY UPON DISPOSAL. PHASE II WILLADDRESS PROCESS DEVELOPMENT AND DEMONSTRATION FOR THE SPECIFIC APPROACH SELECTED IN PHASE I.