The invention describes a process and a plant for pyrolyzing hydrocarbon-containing waste products, in particular used tires or biowaste, in which the material to be pyrolyzed is introduced into a pyrolysis furnace and is pyrolyzed at 500.degree. C. The significant factor is that the material is introduced as far as possible without being broken down, into a receiving device outside the furnace (1), which receiving device is introduced into the pyrolysis furnace, which is open at the bottom, from below, the device simultaneously closing the furnace (1) in a sealed manner. The significant advantage is that a plurality of different receiving devices for different materials can be provided, so that the pyrolysis plant can be used with a relatively quick changeover for different pyrolysis raw materials, without changeover measures on the furnace being required.