The increasing generation of waste plastics causes serious pollution problem. Since waste plastics is essentially nonbiodegradable, they are not suitable either for compost or landfill. Accordingly, thermal treatment by pyrolysis or incineration is attractive. The pyrolysis, which converts waste plastics to fuel or useful hydrocarbons, has been recognized as a useful approach. In this work, the characteristics of the pyrolytic heavy oils obtained from mixed waste plastics by kiln pyrolysis process have been studied to verify the effectiveness of the co-combustion with B-C oil. HCl concentration in flue gas for the co-combustion with B-C oil was estimated. And pH was predicted for B-C and pyrolytic oil mixture.