Emissions of hydrochloric acid, PCDD and PCDF from the combustion of chlorine-containing kraft pulp mill bleach plant waste

The objective of this work was to determine if combustion of chlorine-containing bleach plant waste causes emissions of hydrochloric acid, polychlorinated dibenzo-p-dioxins, (PCDD) and polychlorinated dibenzo-furans (PCDF). Small additions of chlorine-containing bleach plant waste to normal black liquor feed stock did not result in detectable increases HCl emissions during incineration. Large additions (≥ 10% by weight of solids) increased HCl emissions, possibly as a direct result of organochlorine combustion. The total PCDD/F in flue gas increased by a factor of ten with a 1% addition of bleach plant concentrate to black liquor. Comparisons of emitted PCDD/F and feed liquor PCDD/F indicated a net formation of PCDD/F during combustion. The emissions of PCDD/F may be a significant factor detracting from thermal destruction of mixtures of chlorine-containing bleach plant waste and black liquor in a standard recovery furnace.