PCT No. PCT / JP97 / 00572 Sec. 371 Date Jan. 8, 1998 Sec. 102(e) Date Jan. 8, 1998 PCT Filed Feb. 27, 1997 PCT Pub. No. WO97 / 31990 PCT Pub. Date Sep. 4, 1997This invention provides a method for reclaiming oil from waste plastic in such a way that thermosetting resins and
solid foreign matter in the plastic will not
pose a problem. This method greatly reduces the burden of presorting the garbage or
industrial waste. To achieve this objective when oil is to be reclaimed from a waste plastic containing
chlorine compounds, such as
vinyl chloride, the plastic must first be stripped of
chlorine. Prior to
pyrolysis, while being conveyed forward in a continuous
stream, the plastic is mixed with heated sand and / or an additive agent to raise its temperature to 250-350 DEG C. This creates a product which is comprised of a mixture of sand and substantially dechlorinated plastic. The product is mixed with heated sand to heat it directly to a temperature of 350-500 DEG C. It is maintained at this temperature until
pyrolysis occurs. In order to obtain high-quality oil with a low
boiling point, a first gas / liquid
separation process separates the product obtained from the aforesaid
pyrolysis into liquid high-
boiling point oil, gaseous low-
boiling point oil and low molecular-weight gases, and recirculates the liquid high-boiling point oil to the pyrolysis process, and a second gas / liquid
separation process separates the gaseous low-boiling point oil and low molecular-weight gases into liquid low-boiling point oil and low molecular-weight gases. The first and second gas / liquid
separation process are connected in sequence.