To efficiently and economically decompose/remove nitrogenous compounds and/or chlorinated compounds from a decomposed oil of waste plastics to prepare a refined oil by treating the decomposed oil with steam in the presence of a catalyst.
A decomposed oil that is a decomposition product of waste plastics is treated with steam in the presence of a catalyst, so that at least either of nitrogenous compounds or chlorinated compounds contained in the oil are decomposed/removed to produce a refined oil. In the above treatment, it is preferred that the treating temperature is 200-600°C, the catalyst used is a catalyst in the catalytic cracking of petroleum (e.g. alumina), and the amount of steam is 0.1-50m3 (NTP) for each 1kg of the decomposed oil. The refined oil is produced efficiently and economically from the decomposed oil of waste plastics. Further, by subjecting the refined oil to a steam cracking treatment, 1-olefins such as ethylene and propylene and conjugated diolefins such as butadiene can be reclaimed in purities usable as petrochemical raw materials.
KAWAUCHI MASATOSHI
SHIMAMOTO KENJI
HIROWATARI NORIYUKI
