Pyrolysis of municipal waste: Effect of waste type and co-pyrolysis on the formation of products and coke over zeolite catalyst

Abstract

Thermal pyrolysis of different types of wastes including LDPE, carton, tire and poplar wood was conducted to investigate the effect of feedstock on the properties of products. The co-pyrolysis of single feedstocks was also the next trial. Zeolite (A4) was the catalyst. The reason for this was to study the influence of the catalyst on the products and also the effect of feedstock type on the structure of coke. The results showed that the type of feedstock could change the quantity and quality of the products significantly. Considering the average of the properties of the products obtained from the single feedstocks pyrolysis, the specification of the products obtained from the pyrolysis of mixture feedstock showed nonlinear changes. This indicated the cross-interaction of volatiles and non-volatiles through the secondary reactions during the co-pyrolysis process. Depending on the feedstock type, zeolite (A4) had different effects on the pyrolysis process. Zeolite (A4) increased the rate of cracking of large species and also their polymerization, but differently for different feedstocks. The nonlinearity of the change of the properties during the catalytic co-pyrolysis was observed. No coke/little amount formed on the surface of the catalyst after the pyrolysis of all types of the feedstocks used. However, the slight deactivation of the catalyst due to the change of the catalyst structure was seen.