REDUCTION OF COAL-BASED METAL EMISSIONS BY FURNACE SORBENT INJECTION

The ability of sorbent injection technology to reduce the potential fo r trace metal emissions from coal combustion was researched. Pilot sca le tests of high-temperature furnace sorbent injection were accompanie d by stack sampling for coal-based, metallic air toxics. Tested sorben ts included hydrated lime, limestone, kaolinite, and bauxite injected at 1000, 1150, and 1300 degrees C, and through the burner at several f eed rates. Continuous gas monitoring and solids sampling by particle s ize determined changes in metal concentrations from baseline measureme nts. The impact of sorbent injection on trace metal emissions is a fun ction of metal type, sorbent type, and injection mode. Reductions in s ubmicrometer concentrations of antimony, arsenic, mercury, and seleniu m were observed when hydrated lime and limestone were injected. The to tal amount of captured arsenic, cadmium, and lead increased when using , variously, hydrated lime, limestone, and kaolinite.