Catalytic cracking of RP-3 jet fuel over wall-coated Pt/ZrO2–TiO2–Al2O3 catalysts with different Al2O3 ratios

Abstract

A series of Pt/ZrO2–TiO2–Al2O3 (PZTA) composite oxides with different Al2O3 mass ratio (ZrO2:TiO2:Al2O3=1:1:x, where x=1, 2, 3, 4, 5) were coated on the wall of stainless-steel microchannels by using a co-precipitation method. Catalytic cracking of RP-3 over such PZTA-coated catalysts were investigated under high temperature and pressure conditions. It was found that the gas yield and heat sink of catalytic cracking of RP-3 were evidently heightened compared with the thermal cracking. Furthermore, catalytic cracking activities and high-temperature stabilities of the catalysts were greatly depending on the mass ratio of Al2O3. PZTA (ZrO2:TiO2:Al2O3 with a mass ratio of 1:1:3) performed a better catalytic cracking activity and high-temperature stability, which is in accordance with its higher amount of strong acid, larger surface area and pore volume. Deactivation of the increasing rate of gas yield and heat sink over PZTA at 700°C was possibly caused by decrement of their amount of surface acid, the collapse of the catalysts pores partly and the crystallizations of ZTA above 650°C, and the quickly generation of carbon deposition at 700°C. Even so, PZTA (ZrO2:TiO2:Al2O3 in the mass ratio of 1:1:3) kept a better catalytic cracking activity and high-temperature stability.