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MECHANISTIC STEPS IN THE PRODUCTION OF PCDD AND PCDF DURING WASTE COMBUSTION
Citation:
Gullett, B., K. Bruce, L. Beach, AND A. Drago. MECHANISTIC STEPS IN THE PRODUCTION OF PCDD AND PCDF DURING WASTE COMBUSTION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/056.
Description:
The paper discusses work involving a reactor that simulates the down-stream flue gas conditions of a waste combustor and an analytical laboratory to investigate the formation mechanisms of polychlorinated dibenzo-p-dioxins (PCDDS) and polychlorinated dibenzofurans (PCDFS) to develop pollution prevention and control technologies in support of EPA's air emission regulations. esearch has shown that synthesis of PCDDs and PCDFs during municipal waste combustion can proceed through a three-step mechanism: 1) production of C12 from a metal-catalyzed reaction of HCl and O2, 2) C12 chlorination of aromatic rings through substitution reactions, and 3) formation of duel-ring structures by a second metal-catalyzed reaction Formation of the dual-ring PCDD and PCDF structures, likely through condensation reactions of chlorophenols, is enhanced up to 3 orders of magnitude in the presence of metal catalysts, such as Cu(II), reaching a maximum at around 400 C.