FORMATION OF POLYCHLORINATED DIBENZOFURANS BY CHLORINATION AND DE-NOVO REACTIONS WITH FECL3 IN PETROLEUM REFINING PROCESSES

The formation of polychlorinated dibenzofurans (PCDFs) and polychlorin ated dibenzo-p-dioxins (PCDDs) in catalytic reforming, a petroleum ref ining process, was studied using a laboratory apparatus. Conditions in the catalyst regeneration step in catalytic reforming were simulated, and the reactions of precursor compounds for the formation of PCDFs a nd PCDDs were studied. No PCDFs/PCDDs were produced by the reforming c atalyst and potential precursors under any conditions studied. During treatment of the coked catalyst, dibenzofuran (DBF) was found in the f lue gases. Chlorination experiments with flue gas concentrates and sta ndard solutions in the presence of FeCl3 and HCl or Cl2 in the tempera ture range of 220-540-degrees-C indicated that DBF can be chlorinated to PCDFs. A precursor mixture of 1,1,1-trichloroethane (TCE) and CCl4 in hexane also produced PCDFs by de novo formation.