EMISSIONS REDUCTION AND PYROLYSIS-GAS DESTRUCTION IN AN ACOUSTICALLY DRIVEN DUMP COMBUSTOR

The research described here focuses on the enhancement of hazardous wa ste and pyrolysis gas surrogate destruction and the reduction in nitri c oxide and unburned hydrocarbon emissions in an acoustically resonant dump combustor. While several prior studies have focused on flowfield interrogation and hazardous waste surrogate destruction under conditi ons of natural acoustic excitation, the present study focuses on the d evice's behavior under externally forced acoustic excitation. The effe ct of external forcing on hazardous waste surrogate destruction in the device was recently found to be significant, yielding destruction rat es for the surrogate SF6 that increased by as much as four orders of m agnitude with acoustic forcing at specific resonant modes [1]. The pre sent study also indicates a significant improvement in performance wit h external forcing at the same acoustic modes as those explored earlie r. Emissions of NO are seen to decrease by nearly 60%, unburned hydroc arbons are seen to drop by over two orders of magnitude, and waste and pyrolysis gas surrogate destruction is seen to increase by nearly thr ee orders of magnitude, all with external forcing at a specific acoust ic mode of the device. The present observations further support the id ea that acoustically resonant conditions can render the dump combustor device extremely efficient as well as highly controllable as a small- scale thermal treatment system. (C) 1998 by The Combustion Institute.