Pyrolysis and gasification of landfilled plastic wastes with Ni-Mg-La/Al2O3 catalyst

Pyrolysis and gasification processes were utilized to study the feasibility of producing fuels from landfilled plastic wastes. These wastes were converted in a gasifier at 700-900 degrees C. The equivalence ratio (ER) was varied from 0.4-0.6 with or without addition of a Ni-Mg-La/Al2O3 catalyst. The pyrolysis and gasification of plastic wastes without catalyst resulted in relatively low H-2, CO and other fuel gas products with methane as the major gaseous species. The highest lower heating value (LHV) was obtained at 800 degrees C and for an ER of 0.4, while the maximum cold gas efficiency occurred at 700 degrees C and for an ER of 0.4. The presence of the Ni-Mg-La/Al2O3 catalyst significantly enhanced H2 and CO production as well as increasing the gas energy content to 15.76-19.26 MJ/m(3), which is suitable for further usage as quality fuel gas. A higher temperature resulted in more H-2 and CO and other product gas yields, while char and liquid (tars) decreased. The maximum gas yield, gas calorific value and cold gas efficiency were achieved when the Ni-Mg-La/Al2O3 catalyst was used at 900 degrees C. In general, addition of prepared catalyst resulted in greater H-2, CO and other light hydrocarbon yields from superior conversion of wastes to these gases. Thus, thermochemical treatment of these problematic wastes using pyrolysis and gasification processes is a very attractive alternative for sustainable waste management.