Formation of Heavy Metal Species During PVC-Containing Simulated MSW Incineration

Abstract

The effect of PVC-derived chlorine on heavy metal emissions in MSW incineration was investigated using a tubular furnace and simulated MSW spiked with PVCs and heavy metals (Cd, Cr, Cu, and Zn). The molar ratio of the chlorine content to that of the heavy metal (Cl/M ratio) was varied from 3-200 as one parameter. The results indicated that the major species found in the fly ash were chlorides of alkaline and alkali-earth metals, whereas those identified in the bottom ash were MgSiO3, SiO2 and some complex aluminates and silicates. The emission of heavy metals and/or their compounds, with extreme and medium volatility, tended to be enhanced within the lower Cl/M range, whereas those with a refractory volatility were likely to be affected within the higher Cl/M range. However, those with an extremely refractory volatility were less affected by an increase of the Cl/M ratio. The variation of speciation and partitioning in MSW combustion as affected by the Cl/M ratio are discussed.

Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature

“…It is clear that highly volatile (Hg, Cd) and medium volatile (Pb, Zn, As) elements showed an increased distribution to fly ash with an increase of chlorine from 1% at Umeå to 2% at Söderenergi waste fuel. These results are in agreement with previously reported values (Wang et al, 1999;Chiang et al, 2007;Luan et al, 2013). The primary reason for an increased partition to fly ash could be the formation and vaporization of metal chlorides owing to high chlorine content in input waste of Söderenergi (Chiang et al, 1997).…”