TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: Successive pairs of stations may each represent materially- and energetically-separate systems in which the transition from one pair to another requires gas-tight (on both sides) decoupling from the line system concerned by means of a rapid closure device, after which the decoupled pyrolysis container is transferred to the next station; for each double line there are two containers in the drying phase, two in the prepyrolysis phase, two in the actual pyrolysis phase, two in the cooling phase and two in the further-cooling phase, and the containers are transferred from the stationary phases in parallel but in opposite directions in the lines. Or there may only be one process line, in which the furnace consists of two heating furnaces, the pyrolysis containers spend only half the usual time in each station and the containers are put in and taken out in opposite directions in such a way that, after the container leaves the second station, the container in the first station is moved (at right angles to the direction of input/output) to the second station and a new container is brought in; the outgoing container for cooling and the container from the prepyrolysis stage also form a station pair, as do the two containers in the further-cooling and drying phases, with two container pairs together forming a materially- and energetically-separate system; decoupling and inter-station transfer is as described above, except that in each half of the double line there is one container in the drying phase, one in prepyrolysis, one in the cooling phase, one in further-cooling and two in the actual pyrolysis phase, with container transport taking place outside the furnace in opposite directions. Containers in prepyrolysis are energetically and materially coupled (at least temporarily) with those in the first cooling phase, as are those in the drying phase with those in the second post-cooling phase, in such a way as to enable both heat transfer and gas transfer through the pyrolysis container and also a material and energetic connection between the surrounding spaces within the insulated space; this connection only lasts until the space to be heated between container and insulation has reached the temperature of the container to be cooled and is broken at the latest when supplementary heating is used to assist drying or prepyrolysis. Dry nitrogen from an air separator is passed through, first to cool the pyrolysis container in the post-cooling phase and then to assist the heating of the freshly-filled container, and also to provide an inert atmosphere with simultaneous drying (supplementary heating may be used as necessary to reach the required final temperature). Nitrogen preheated by off-gas from the pyrolysis furnace is further heated by passing it through the container in the first cooling phase and is then passed through the container in the prepyrolysis phase (with assistance from external burners if required). Residence times in each station are set by supplementary heaters to be of the same length so that transfer from one station to others can take place simultaneously, with transporter trollies moving along the lines quasi-continuously in a push-pull manner. Off gas from the drying phase, and that from prepyrolysis, is released to the atmosphere after suitable purification, but the actual pyrolysis products are heated to a temperature about 20-50 degrees C above the peak pyrolysis temperature and then separated in two condensation stages into a heavy oil fraction, a diesel-like light and medium oil fraction and a fraction containing energy-rich pyrolysis gases which do not condense at atmospheric pressure; these gases are used for heating the pyrolysis furnace and for the supplementary heaters. The bottom product from further heating (heavy oil, tar and carbon black) is heated up again and injected into the pyrolysis furnace. Uniform temperature distribution in the cylindrical pyrolysis containers in all stations is achieved by uniform rotation of the container about its long axis during the residence time in each station. High product purity for selected products can be achieved by presorting and prepurification of the material (I) into fractions which are then separately pyrolysed in at least one container and collected in separate tanks via the previously cleaned gas lines. EXAMPLE - A mixture of rubber scrap and plastic (polypropylene and polystyrene) was processed with the aid of a catalyst in a double-line pyrolysis unit comprising successive stages according to the invention, with the material in cylindrical containers moving between 10 tunnel-like insulated stations arranged in two parallel lines of 5 stations (running in opposite directions) with quick-seal flaps. The waste material was (a) first dried and freed from water-soluble harmful gases by heating to 220 degrees C with nitrogen from an air separator (preheated by passing through the further cooling stage), (b) prepyrolysed at 340 degrees C by further heating with nitrogen (preheated in two heat exchangers with the counter-current off-gas from the pyrolysis furnace and then by passing through the cooling container), (c) pyrolysed at 420 degrees C in the absence of air, with pyrolysis gas take-off, (d) cooled to 340 degrees C with nitrogen (preheated by the hot flue gas from the furnace burners) and (e) further cooled to 100 degrees C with cold (room temperature) nitrogen. This process gave good-quality, yellowish-brown pyrolysis oil with a boiling range of 73-385 degrees C and a density of 825 kg/m3 at 15 degrees C. Yields of products from the material used were 51 wt.% light pyrolysis oil, 3 wt.% heavy oil, 31 wt.% carbon black and 12 wt.% pyrolysis gas; the water content was low.