Effects of the types of zeolites on catalytic upgrading of pyrolysis wax oil

Abstract

Because zeolites play an important role in an upgrading catalyst for heavy hydrocarbons in industrial refinery processes, the effects of the zeolite type on the upgrading of pyrolysis wax oil are investigated in this study. Raw pyrolysis wax oil was obtained from the pyrolysis of municipal plastic wastes in a commercial rotary kiln pyrolysis plant (Dongmyong RPF Co.). The catalystic experiments are performed for the three different types of commercial zeolites with different physicochemical properties in a continuous fixed bed reactor at 450°C for 1h as a MAT(micro-activity test) method: HZSM-5 (pure), zeolite Y (HY; pure or including 20% clay) and mordenite (HM; including 20% clay or alumina) catalysts. The highest conversion of pyrolysis wax oil into light hydrocarbons such as gas products and gasoline-range hydrocarbons is obtained for the HZSM-5 catalyst among them, and the composition of liquid products is found to become in the main aromatic components due to a shape selectivity. For the case of zeolite Y(HY), medium activity and the highest fraction of branched hydrocarbons with a high octane number, as well as a high fraction of aromatic products are shown. However, the mordenite (HM) with one-dimensional pore structure shows the lowest conversion of pyrolysis wax oil into light hydrocarbons and a very high fraction of paraffin product in the liquid product like the characteristics of raw pyrolysis wax oil.