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

The formation of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) in catalytic reforming, a petroleum refining 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 and PCDDs were studied. No PCDFs/PCDDs were produced by the reforming catalyst and potential precursors under any conditions studied. During treatment of the coked catalyst, dibenzofuran (DBF) was found in the flue gases. Chlorination experiments with flue gas concentrates and standard solutions in the presence of FeCl3 and HCl or Cl2 in the temperature 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.