TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Apparatus: In thermal conversion pyrolysis reactor apparatus, the heat source is electricity. The conveyer inlet is sealed by use of a cooling tube (17) around a portion (5) of the conveyer prior to entry of the conveyer into the reactor, where molten plastic and/or char in the reactor bottom enters the cooling tube and solidifies on or in the conveyer. The conveyer outlet is sealed by use of a cooling tube around a portion of the conveyer as the conveyer exits the reactor and where molten plastic and/or char in the reactor bottom enters the cooling tube and solidifies on or in the conveyer. The cooling tube abuts the reactor vessel. The coolant (18, 19, 22) used in the cooling tubes is water. The apparatus may be used in a two part process being: (a) formation of dense plastic pellets (9) by melting the raw plastic in the reactor at a low enough temperature to minimize decomposition but sufficient to melt the plastic in the reactor and then transport and harden the molten plastic into discrete pellets via the conveyer; and (b) subsequent pyrolysis of the discrete pellets, to decompose the pellets into gas and char. Conveyer is a chain. The condensing seal includes a cooling jacket (21) surrounding the outlet of the reactor through which decomposed gas is conveyed from the reactor. Condensing seal creates a layer of cool gas and gases of a higher density or molecular weight condense in the layer and return to the reactor. The coolant used in the condensing seal is water. The heat source is sufficient to heat plastic material in the bottom of the apparatus to a temperature from 100 degrees C to 800 degrees C. The decomposition gas includes hydrocarbon chains with a length of less than 25 carbon atoms. Decomposition gas includes hydrocarbon chains with a length of less than 15 carbon atoms. The apparatus processes plastic material as a batch process with plastic raw material being added to the reactor in one step. It processes plastic material as a semi-continuous process with plastic raw material being added in stages to the reactor. The apparatus processes plastic material as a continuous process with plastic raw material being added to the reactor as a continuous feed. The reactor vessel has a V-shaped bottom. It has an aspect ratio of 2:1 to 10:1 height to width. The decomposition gas is used to generate energy. The energy may be selected from electricity and/or heat. The apparatus is transportable. The plastic raw material is selected from thermoplastic wastes of polyolefinic and/or polyaromatic nature that does not have heteroatoms. Plastic includes heteroatoms and the apparatus includes an additional stage of low temperature pyrolysis to remove the heteroatoms prior to full decomposition. EXAMPLE - No suitable example given.