Study on pyrolysis characteristics, kinetics and thermodynamics of waste tires catalytic pyrolysis with low-cost catalysts

Abstract

As a non-biodegradable solid waste, waste tires (WTs) have adverse effects on the ecological environment and human health. Waste tires are a good source of energy. In order to reduce the energy consumption of waste tires pyrolysis, this paper explores the influence of three low-cost catalysts on the catalytic effect of waste tires. The results of thermogravimetric experiments show that the use of spent FCC catalyst (FCC), red mud (Rm) and fly ash (Fa) during pyrolysis is beneficial to reducing the initial pyrolysis temperature of WTs. The kinetic calculation results show that compared with the direct pyrolysis of WTs, the average activation energy of WTs catalyzed by red mud and fly ash is reduced by about 9.5 kJ/mol and 7.8 kJ/mol, respectively. The average pre-exponential factor (lnA) decreased by about 1.3 min−1 and 1.4 min−1, respectively. The thermodynamic calculation results show that the endothermic reaction occurs in both the pyrolysis and catalytic pyrolysis of WTs, and the pyrolysis process cannot be carried out spontaneously. The pyrolysis reaction process of waste tires can be characterized by the combination of kinetics and thermodynamics, which provides parameters for determining the relevant process conditions for the industrialization of catalytic pyrolysis of waste tires.