Catalytic degradation of polyethylene using thermal gravimetric analysis and a cycled-spheres-reactor

Commercial samples of pure polyethylene were decomposed over H-ZSM-5 and Y-type zeolites using thermal gravimetric analysis (TGA) and a laboratory-scale-plant, so-called the cycled-spheres-reactor. By the TGA measurements, the activity and the deactivation behavior of the zeolite catalysts were determined. The plastic to catalyst ratio was varied to find out the optimal value for catalyst screening and for the operation of the cycled-spheres-reactor. In addition, the deactivation behavior of the zeolite catalysts was investigated. Y-type zeolites revealed lower activity and faster deactivation behavior than H-ZSM-5. Higher module of H-ZSM-5 and Y-type zeolite showed slower deactivation, but lower activity than lower module of those. Experiments in the cycled-spheres-reactor proved the results of the TGA measurements in terms of activity. The main products in the non-catalytic degradation were waxes, and when catalysts were applied, a high yield of oils was obtained at the expense of waxes. The product spectra of product oils obtained with catalysts lay mainly in the range C₄-C₁₀.