Thermo-catalytic two-step pyrolysis of real waste plastics from end of life vehicle

摘要

This work focuses to the thermo-catalytic pyrolysis of real plastic waste from End of Life Vehicle. Two-step batch reactor fitted with electric heating was used for pyrolysis. Zeolite catalysts (ZSM-5, beta-zeolite and y-zeolite) was used in the first reactor at 425 degrees C and 485 degrees C, while the product yield and composition were further modified by the using of structured Ni/Mo-Al2O3 catalyst in the 2nd reactor at 380 degrees C. No water/steam was feed into the 2nd reactor. Gas-chromatography, high-pressure liquid chromatography, size exclusion chromatography and Fourier transformed infrared spectroscopy were used for identification of pyrolysis products, while the catalyst morphology was investigated by scanning electron microscopy. Catalysts in the 1st reactor had a significant effect to the product yields and decreased the time required for pyrolysis. ZSM-5 and y-zeolite catalysts had high activity in carbon frame isomerization. beta-zeolite catalyst could crack the polymer main chain with high efficiency; however, its deactivation was the fastest. Structured Ni/Mo-Al2O3 in the 2nd reactor affected the gas/pyrolysis oil ratio, increased the hydrogen yield in gases, monoaromatic yield in pyrolysis oil and owing to the coke formation, its surface was fully covered by coke depositions after the pyrolysis. The hydrocarbon compositions of pyrolysis oils were favourable for further separation and refinery application.