Abstract
Combustion experiments of model wastes using hydrogen chloride (HCl) gas in a laboratory-scale fluidized-bed reactor were performed to elucidate the role of each section of the incinerator in the formation of PCDDs and PCDFs. At first, homologue profiles of PCDDs and PCDFs are compared between the experiments of the model waste containing poly(vinyl chloride) (PVC) and that containing no PVC with HCl injected to the reactor. The similarity of the homologue profiles shows no difference between PVC in the waste and HCl injected in the role as a chlorine source in their formation. Then, combustion experiments of the waste containing no PVC were conducted supplying HCl at the different positions of the incinerator to investigate the PCDD/F formation in each section of the incinerator separately. The amounts of PCDDs and PCDFs formed largely decreased when HCl was not supplied to the main combustion section even though HCl was injected after it. The presence of HCl in the main combustion section is essential for their formation in the downstream sections. This indicates that the compounds that lead to PCDD/Fs in the downstream sections are formed in the main combustion section in the presence of HCl.
