Process for depolymerizing plastic material for the production of hydrocarbons, and a plant therefor

A process for depolymerizing waste plastic material, wherein said process comprises the following steps:

• i. charging a mixture comprising waste plastic materials in an oxygen-free atmosphere into a feeding system comprising at least one screw extruder, which is heated at such a temperature that the material exiting from the extruder is at a temperature ranging from 150 to 180° C.;
• ii. charging the plastic material coming from the extruder in the previous step directly into a reactor having a body and a base, in which a liquid bath of polymeric material is formed and the thermal depolymerization takes place, forming a gaseous effluent, wherein, in the reactor, the area available for said gaseous effluent above the liquid bath has a volume which is less than 20% of the total volume, in order to reduce the residence time of the gas produced inside the reactor, and said reactor is heated to 300-450° C. by means of a stream of molten salts in a jacket outside the body of the reactor and connected to a system for transporting, heating and storing the molten salts and is provided with a screw conveyor connected to the base of the reactor and having a discharge head positioned higher than the level of the liquid bath present inside the reactor.