Effects of chlorides on hydrogen chloride (HCl) formation and heavy metal partitioning in waste incineration

This study investigates the effects of chlorides on the potential for hydrogen chloride (HCl) formation in a single heavy metal incineration system, using simulated municipal solid waste (MSW) with spiked organic and inorganic chlorides. The experiments were conducted at 900°C with the chlorine content varying from 0% to 1.6% (w/w as Cl). The spiked chlorides include ionic and molecular bond compounds, such as PVC, C₂Cl₄, NaCl, KCl, and FeCl₃. The results indicate that an increase in the chlorine content enhances the potential for HCl formation in the flue gas and this potential is mainly affected by the characteristics of the chlorides, the presence of alkaline metals (Na and K) and the hydrogen content in the wastes. In particular, to what extent the chlorine, alkaline metals and hydrogen may divide from their compounds in the wastes will govern the formation of HCl and the volatile metal chlorides. Furthermore, the HCl formation potential due to the presence of various organic and inorganic chlorides is found to be influenced in decreasing order as: PVC, C₂Cl₄, FeCl₃, NaCl, and KCl. The consistence between the above experimental results and model predictions based on thermodynamic equilibrium analysis are confirmed.