Minimizing emissions from existing ESP equipped MWCs

A number of municipal waste combustors (MWCs) built before the mid-1980`s, when local permitting processes resulted in the application of acid gas control technology, were equipped with electrostatic precipitators to minimize particulate emissions and comply with the then applicable New Source Performance Standards for Municipal Waste Incinerators (40 CFR 60, Subpart C). Polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/F) emissions can be minimized from these facilities by improving combustion to minimize furnace carryover and flame formation. Unfortunately, this can do nothing about the gas and particle phase formation of PCDD/F when the products of combustion are held in the dioxin formation window--250 to 400 C or 482 to 752 F. A proof-of-concept demonstration test program to demonstrate that flue gas temperature entering existing ESPs can be practically reduced below 175 C (350 F) to minimize PCDD/F formation in the air pollution control system (APCS). At the same time, the performance of powdered activated carbon (PAC) and dry acid gas control reagent injection are demonstrated to establish the practicability of bringing existing ESP-equipped MWCs into compliance with the USEPA`s Emissions Guidelines without scrapping the sunk investment in functional, high efficiency ESPs.