NOVELTY - A chemical recycle apparatus has pre-processing installation (1), extruder (2), thermal decomposition tank (3), catalyst decomposition tank (6), reflux device (14), condenser (15), gas separator, and distillation apparatus (18). The installation separates polyolefin-type plastic and other plastic. Tank (3) vaporizes polyolefin plastic, and tank (6) heat-decomposes the pyrolysis gas and produces hydrogen and hydrocarbons.    USE - For chemically recycling waste plastic, such as polyolefin-type plastic (polyethylene and polypropylene), contained in waste materials, such as municipal solid wastes, polyethylene-terephthalate bottles, and foam material containers, boards and bags, and using as raw material for petrochemistry.    ADVANTAGE - The chemical recycle apparatus enables efficient recovery of aromatic hydrocarbons, such as benzene, toluene and xylene, which can be recycled as chemical/pharmaceutical raw material, hydrogen which can be recycled as fuel for fuel cells and as raw material for hydrogenation and de-sulfurization, and 2-4C olefin gas which can be recycled as a plastic raw material. The residue produced in the thermal decomposition tank is safely ejected. The thermal decomposition tank can be driven continuously without stopping. The apparatus is effective in control, operativity and safety. The reaction in the catalyst layer is stabilized by regularly supplying pyrolysis gas while carrying out catalyst decomposition. The composition of the product is fixed, the yield is improved, and the catalyst durability is enhanced. The use of purge gas is eliminated.    DETAILED DESCRIPTION - A chemical recycle apparatus has a pre-processing installation (1), a melting extruder (2), a thermal decomposition tank (3), a catalyst decomposition tank (6), a reflux device (14), a condenser (15), a gas separator, and a fractional distillation apparatus (18). The pre-processing installation separates a polyolefin-type plastic and plastic other than that from waste plastic. The melting extruder heat-melts the separated polyolefin-type plastic and supplies to a heating decomposition installation. The thermal decomposition tank vaporizes the supplied melting polyolefin-type plastic by thermal decomposition. The catalyst decomposition tank carries out heating decomposition of the pyrolysis gas obtained by the thermal decomposition tank in the presence of a silicate catalyst, and produces hydrogen, 2-4C lower hydrocarbon, and an aromatic hydrocarbon. The reflux device separates a high-boiling-point component from the gas coming out of the catalyst decomposition tank. The condenser cools the gas from which the high-boiling-point component is removed, and separates a gaseous-phase component (16) containing hydrogen and 2-4C lower hydrocarbon, and a liquid-phase component (17) containing an aromatic hydrocarbon. The gas separator separates the gaseous-phase component to hydrogen and 2-4C lower hydrocarbon, and the fractional distillation apparatus separates the liquid-phase component to aromatic hydrocarbons, such as benzene, toluene and xylene.    DESCRIPTION OF DRAWING(S) - The figure shows the basic flow of the chemical recycle method of waste plastic. (Drawing includes non-English language text).    pre-processing installation (1)    melting extruder (2)    thermal decomposition tank (3)    catalyst decomposition tank (6)    heater (12)    reflux device (14)    condenser (15)    gaseous-phase component (16)    liquid-phase component (17)    fractional distillation apparatus (18)