TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The non-decomposed solid residue from the first stage retort is conveyed to a second stage retort for pyrolysis at 390-400degreesC. The non-decomposed solid residue from the second stage retort is conveyed to a third stage retort for pyrolysis at 500-900degreesC. The gas-vapor mixture purified from the tar composition from the first retort is conveyed to a first dephlegmator, and the tar composition is conveyed to the second stage retort. The gas-vapor mixture purified from the tar composition from the second and third stage retorts is directed to a second dephlegmator, and the tar composition is conveyed to the third stage retort. The purified gas-vapor mixture from the second dephlegmator is conveyed to the first dephlegmator, and the tar composition is conveyed to the second stage retort. The gas-vapor mixture of second stage retort is purified on dephlegmatic lattices of the retort, and the tar composition is conveyed to the third stage retort. The gas-vapor mixture of first stage retort is conveyed to dephlegmatic lattices of first stage retort, and the tar composition obtained is returned to the second stage retort. From liquid fraction, distributor gas is conveyed to a reservoir for collection used for retort heating burners. The liquid fraction is transferred to reservoirs and the solid residue from the last retort is conveyed for cooling to a packing shop through a discharging device. Combustion gases are directed for heat recovery and for purification outside an aggregate.    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: Dephlegmatic lattices (24-26) for primary purification are installed inside each retorts behind the movable pulley across the retort cylinder from the elevated side of the retort. The dephlegmatic lattices comprise 4-5 metal membranes provided with through apertures. Gas burners (34) and burners for fuel oil are installed under an outer casing of each retort. The gas burners have block units provided with a slide automatic power control to set temperature in each retort. The burners for fuel oil have three-stage power control. Cavities between the retorts and outer casings are connected with pipes and a smoke tube (37) diverted from the first stage retort casing. Each retort is provided with ribbing formed on the outer side along the entire area of the retort's cylinder generatrix. The apparatus comprises three retorts installed on a frame and two dephlegmators attached by pipes to the retort's cavities and connected between them. A first dephlegmator is connected to second and first stage retorts by a pipe which conveys gas-vapor mixture to a cooler (43). The pipe is diverted from the lowest place to the second stage retort's cavity. A second dephlegmator is connected to the second and third stage retorts by a pipe for gas-vapor mixture. The pipe is diverted from the lowest place of dephlegmator to the third stage retort cavity. The first and second stage retorts and their saturation are made of ordinary boiler steel.