TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Arrangement: The high-temperature condenser is arranged between the waste plastic thermal decomposition furnace (10) and a separator. Preferred Apparatus: The apparatus is equipped with a high-temperature condensation tank (40) and a low-temperature condensation tank (50). The separator has an outlet pipe for heavy oil products connected to the combustor through the high-temperature condensation tank and an outlet pipe for light oil products connected to the low-temperature condensation tank. The outlet pipeline of the low-temperature condenser is connected to the upstream of the high-temperature condensation tank through the low-temperature condensation tank. A directional control valve (25) for heavy oil products is arranged at the downstream of the outlet pipeline of separator and directional control valve (54) for light oil products is arranged downstream of low-temperature condensation tank outlet pipeline. Downstream of the directional control valve (54) is connected to the downstream of the directional control valve (25). The combustor is a gas turbine (60) driving a generator (90). The apparatus has a recuperator (70) partitioned into two narrow spaces (72,73) with a partition plate (71). The recuperator is equipped with i) the waste plastic thermal decomposition furnace which is heated with exhaust gas and thermolysis gas as heat source and ii) a stream generator which performs heat exchange. The thermolysis gas is heated by a combustion unit provided within the recaptuator to at least 900-1300degreesC more than thermolysis temperature of plastics. A dehalogenation reactor is provided in the upstream of the furnace for waste plastic containing halogens. Preferred Process: The recuperator burns thermolysis gas (51) not condensed with the low-temperature condenser and recovers heat from the combustion exhaust gas (65) ejected from the combustor. The heavy oil products are burnt during thermolysis of waste products, keeping the directional control valve (25) open and closing the valve (54). The light oil product subjected to low-temperature condensation is stored in low-temperature condensation tank. The heavy oil products from a high temperature condensation oil tank is used as fuel when simultaneously operating the generator and thermal decomposition furnace. When operating the generator independently, the directional control valve (25) is closed and the directional control valve (54) is opened. The gas turbine is run using oil of low-temperature condensation tank. The apparatus is stopped by terminating operation of the decomposition furnace prior to stopping the functioning of the gas turbine. Consequently, the directional control valve for heavy oil products is closed and light oil products is sent to the turbine, via valve (54). Subsequently, all high temperature condensation oil in the path to the gas turbine is displaced with low temperature condensation oil, stopping the generator.