Catalytic pyrolysis
of polymer waste is an attractive alternative
process for the conversion of large hydrocarbon compounds to useful
products for the most reliable fueling and valuable chemicals, growing
toward a circular economy and enhancing the reduction of waste materials.
In this study, catalytic pyrolysis of waste polyethylene wax (WPEW)
using a dual acid–acid catalyst and acid–base catalyst,
which had various pore size distributions and included a strong active
site, maximized the desirable yield and product distribution. The
effect of the process conditions and synergy of activated carbon (AC)
blended into both a spent fluid catalytic cracking catalyst (FCC)
and magnesium oxide (MgO) catalyst was examined in a 3000 cm
3
custom-built reactor at varying operating temperatures (400–470
°C), inert nitrogen gas flow rates (50 mL min
–1
), catalyst loading (1–5 wt %), and FCC-AC and MgO-AC ratios
in the catalytic conversion of WPEW to obtain the highest amount of
diesel-like oil. The results indicated that thermal cracking of WPEW
at 420 °C by a fixed inert N
2
flow rate of 50 mL min
–1
obtained the highest liquid yield of 81.64 wt % and
a diesel-like fraction of 35.51 wt %, while the catalytic conversion
of WPEW under optimum conditions (temperature: 420 °C; fixed
inert N
2
flow rate: 50 mL min
–1
; catalyst
load: 5 wt %; MgO-AC ratio: 0.5:0.5) achieved the highest liquid diesel-like
yield of 41.92 wt %. Physicochemical analyses showed that the highest
heating value of WPEW pyrolytic oil was 44.20 MJ kg
–1
, and the viscosity was 1.7 mm
2
s
–1
at
40 °C. The combination of MgO-AC as a dual catalyst illustrates
a positive synergistic effect on the catalytic activity performance
markedly, outstanding catalytic characteristics alongside high selectivity
in pyrolysis of WPEW to paraffinic hydrocarbons in the diesel-like
fraction.