Preparation of fuel from co-pyrolysis of waste vegetable oil and waste polyethylene plastics

The production of high quality renewable hydrocarbon fuels through catalytic pyrolysis of waste vegetable oil and polyethylene with the ZrO₂/Al₂O₃/TiO₂ polycrystalline ceramic foam as catalyst in the high-pressure reaction kettle was carried out. The effects of reaction temperature, time, catalyst amount and material feeding ratio were investigated on the production of renewable hydrocarbon fuels through catalytic pyrolysis of waste vegetable oil and polyethylene. The optimal condition was achieved that the reaction temperature was 430℃, the reaction time was 40 min, the dosage of the catalyst was 15%, the quality ratio of waste vegetable oil and waste polyethylene plastic was 1:1, and liquid product yield was 65.9%. The GC-MS analysis indicated saturated hydrocarbon percentage of TIC peak areas in pyrolysis liquid product was close to 100%, 97.85% of which were straight-chain alkanes. The pyrolysis gas and liquid products were precisely analyzed to deduce co-pyrolysis with ZrO₂/Al₂O₃/TiO₂ polycrystalline ceramic foam catalyst mechanism. Pyrolysis oil properties were determined. Compared with biodiesel and 0^# diesel, pyrolysis oil heat value was higher, and the density and viscosity were similar to 0^# diesel. Freezing point and cold filter plugging point were better than those of biodiesel. The low temperature fluidity was good. It proved the feasibility to derive renewable hydrocarbon fuel from co-pyrolysis of waste vegetable oil and waste polyethylene plastics with ZrO₂/Al₂O₃/TiO₂ polycrystalline ceramic foam catalyst.