Abstract: Process water is formed when pyrolysis gas obtained in the pyrolytic decomposition of a starting material is cooled. Due to its content of chemical compounds, it is very costly to dispose of or eliminate the process water. A process for reducing the quantity of by-products in the generation of pyrolysis gas recycles the process water to a pyrolysis reactor operating with a fluidized bed. As a result, the process water is reduced in quantity and purified in a simple manner, and the yield of pyrolysis gas is increased.

Abstract: In the treatment of hydrocarbon-containing waste material, in particular plastic-containing waste material, by pyrolysis, gases containing hydrogen halide compounds which are formed are neutralized by the addition of basic additive material. Since the reacted additive material increases the pyrolysis residue, it is desirable to monitor the controlled feed of the additive material. Therefore, the pH value is measured in the low-boiling pyrolysis oil, which additionally also contains water vapor condensate, and the controlled feed of the additive material is automatically varied as a function of the measurement. The result is that the pollutants are largely, or at least adequately, bound with low consumption of additive material.