Effect of Feed Forms on the Results of Melting of Fly Ash by a DC Plasma Arc Furnace

摘要

Fly ash from a municipal solid waste incinerator (MSWI) without preprocessing(original fly ash, OFA) was melted by a direct current (DC) plasma arc furnace to investigate howthe feed forms governed the results. Dioxins in flue gas from stack and bag-filter ash (BFA) weredetected. The distribution of heavy metals of Pb, Cd, As, and Cr along the flue gas process systemwas analyzed. Through a comparison of the results for dioxins and heavy metals in this studyand previous work, carrying-over of fly ash particles with the flue gas stream can be deduced.Based on the magnetic induction equation and Navier-Stokes equations, a magnetohydrodynamic(MHD) model for the plasma arc was developed to describe the particle-carrying effect. The resultsindicate that, a. when melted, the feed forms of MSWI fly ash affect the results significantly; b.it is not preferable to melt MSWI fly ash directly, and efforts should be made to limit the masstransfer of OFA from the plasma furnace.