METAL CAPTURE BY SORBENTS DURING FLUIDIZED-BED COMBUSTION

Metal capture experiments were performed in a 76 mm (3'') ID fluidized-bed combustor with limestone, sand and alumina serving as both the fluidized medium and metal capture sorbents. Wood pellets spiked with metal solutions were used to simulate the metal-containing combustible fuel. The tested metals were nitrate and chloride species of lead and cadmium. The experimental parameters included metal species and concentration, sorbent type and size, combustor temperature, air flow rate and combustion duration. Experimental results indicated that the technology is highly promising. In-furnace lead capture by limestone was observed to be as high as 95%. The capture efficiency, however, varied with experimental parameters and chemical additives. Most of the captured metals were observed to be TCLP nonleachable.