NOVELTY - Waste plastic is separated to polyolefin-type plastic and plastic excluding polyolefin-type plastic. The separated polyolefin-type plastic is vaporized by thermal decomposition. Heating decomposition of gas obtained by decomposition is performed in presence of silicate catalyst, and specific gaseous and liquid phase components are produced using several catalyst decomposition tanks (6). Thus, waste plastic is chemically recycled.    USE - For chemical recycling of waste plastic and producing hydrogen used as fuel for fuel cells, and chemical and pharmaceutical raw material.    ADVANTAGE - The waste plastic is efficiently and economically recycled for a long period of time, and collection installation for halogen processing is not required.    DETAILED DESCRIPTION - Waste plastic is separated to polyolefin-type plastic and plastic excluding polyolefin-type plastic. The separated polyolefin-type plastic is vaporized by thermal decomposition. Heating decomposition of gas obtained by decomposition is carried out in the presence of silicate catalyst, and gaseous and liquid phase components are produced using several catalyst decomposition tanks (6). The gaseous phase component contains hydrogen and 2-4C lower hydrocarbon, and liquid phase component contains aromatic hydrocarbon as main component. Hydrogen is separated from gaseous phase component, and 2-4C lower hydrocarbon is produced. The liquid phase component is separated to aromatic hydrocarbon having benzene, toluene and xylene as main component. The catalyst is repeatedly decomposed and regenerated. Thus, chemical recycling of waste plastic is enabled.    An INDEPENDENT CLAIM is included for chemical recycle apparatus of waste plastic, which has a pre-processor (1) for separating waste plastic, a melting extruder (2) for heat-melting the separated polyolefin-type plastic, a thermal decomposition tank (3) for vaporizing the melted polyolefin-type plastic, several catalyst decomposition tanks (6), a reflux device (14) for separating high boiling point component from the gas ejected from catalyst decomposition tanks, a condenser (15) for cooling the gas free from high boiling point, a gas-separation apparatus for separating the gaseous phase component, and a fractional distillation apparatus for separating the liquid phase components.    DESCRIPTION OF DRAWING(S) - The figure shows a flowchart illustrating the chemical recycling of waste plastic. (Drawing includes non-English language text).    preprocessor (1)    melting extruder (2)    thermal decomposition tank (3)    catalytic reaction tank (6)    reflux device (14)    condenser (15)    gaseous phase (16)    liquid phase (17)