Thermodynamics of Processes in the Liquid-Metal Pyrolysis of Waste Car Tires

Abstract

Thermodynamic calculations to substantiate the new liquid-metal pyrolysis technology for waste car tires have been carried out. The possibility of using liquid lead as a coolant during the pyrolysis of tires has been investigated. It is calculated that the equilibrium oxygen pressure in the Pb–PbO system is significantly higher than the oxygen pressure in the pyrolysis products; therefore, during the interaction between the latter and lead, no solid phase of lead oxide will form. Depending on the sulfur content in the tires and temperature, the formation of condensed PbS and PbCl₂ phases is possible. In this case, the purification of molten lead from sulfur and chlorine can be carried out periodically or in a separate zone. It has been shown that under pyrolysis conditions it is difficult to expect lead oxidation with water vapor with the formation of a solid phase. Impurities of iron, zinc, copper, cadmium, and arsenic in the temperature range from 400 to 800°C do not form compounds with lead. There are no restrictions for using lead as a liquid-metal coolant during the pyrolysis of waste car tires.