Characteristics of Metal Supported-Zeolite Catalysts for Hydrocracking of Polyethylene Terephthalat

Abstract

Characterization and modification of natural zeolite (ZA) produced in Sukabumi, West Java, Indonesia, as well as metal supported onto the zeolite for hydrocracking catalysts of polyethylene terephthalat (PET) have been conducted. The natural zeolite was refluxed in HCl 3M for 30 min., drying and heated in a microwave produced the ZAA sample. The transition metal such as Cu, Cr, Ni, or Pd was loaded into the ZAA sample under reflux in methanol using salt precursor of each metal, produced the Cu/ZAA, Cr/ZAA, Ni/ZAA, and Pd/ZAA catalysts. The zeolite based samples were characterized by means of determination of acidity by vapor adsorption of NH3 and pyridine, catalyst crystalinity by X-ray diffraction (XRD), surface area by surface area analyzer NOVA-1000 and TO4 (T= Si and Al) site by Infra Red Spectrophotometer (IR). The PET was pyrolyzed in 350 oC produced liquid fraction as a feed for hydrocracking process. The hydrocracking of the PET was carried out in a fixed bed reactor of stainless steel at temperature of 350 o C, H2 flow rate of 20 mL/min., feed/catalyst ratio of 10. Liquid products of the hydrocracking were analyzed using GC and GC-MS. The characterization results showed that the Indonesian natural zeolite produced in Sukabumi consisted mainly of mordenite crystalline. The HCl treatment towards the natural zeolite caused dealumination, increased its acidity and surface area. Loading of Ni, Cu, Cr, or Pd metal on to the zeolite did not affect the zeolite crystallinity. However, the metal loading decreased surface area of the zeolite. Products of the hydrocracking were liquid, coke, and gas fractions. The liquid products consisted mainly of gasoline fraction (C5-C12). The highest liquid product conversion was produced by the Pd/ZAA catalyst, i.e. 34.05 wt. %, with selectivity towards gasoline fractions was 97.99 wt. %.