Bk. Gullett et al., THE EFFECT OF COFIRING HIGH-SULFUR COAL WITH MUNICIPAL WASTE ON FORMATION OF POLYCHLORINATED DIBENZODIOXIN AND POLYCHLORINATED DIBENZOFURAN, ENVIRONMENTAL ENGINEERING SCIENCE, 15(1), 1998, pp. 59-70
The effect of cofiring minor amounts (5-10 wt %) of high-sulfur coal w
ith municipal refuse-derived fuel (RDF) on emissions of polychlorinate
d dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) was
studied under a range of operating conditions. Through use of a 2(x) f
actorial test matrix the program examined the effect of sulfur dioxide
(SO2) concentration on preventing PCDD/F formation while accounting f
or differences in hydrogen chloride concentration, sorbent slurry inje
ction, and various furnace operating conditions such as quench rate, r
esidence time, and RDF feed rate. An understanding of the effect of co
al- and operating-related parameters on the postcombustion formation o
f PCDD/F is expected to assist in developing strategies aimed at preve
nting PCDD/F formation. The test facility was a 0.6-MWt (2 x 10(6) Btu
/h) pilot scale, grate-fired combustor, designed to mimic the solid fu
el handling and combustion rates of field units. Results were analyzed
by examining comparative-run-averaged yields and through development
of a model based on regression methods with stepwise parameter selecti
on. The run-averaged yields and model show that higher SO2 concentrati
ons due to cofiring with coal result in significant suppression of PCD
D/F formation, even when controlling for changes in other operating pa
rameters.