Production of biojet from hydrogenated biodiesel over Pt/HY catalysts: effect of zeolite crystal size

Abstract

The use of bio jet fuel in commercial aviation has received considerable attention in recent years because it can solve the problems associated with petroleum- based fuels such as unstable prices and environmental issues. In this research, the effect of different crystallite sizes of Pt/HY catalysts were studied for producing hydro treated renewable jet (HRJ) fuel. The smaller Y zeolite of catalyst results in shorter pore length, thus reducing the diffusion limitation. HY zeolite and Pt/HY catalysts were prepared by using microwave-hydrothermal (M-H) and incipient wetness impregnation (IWI) method, respectively. In order to prepare the different crystallite sizes, aging time, crystallization temperature, and alkalinity were adjusted. The catalysts were tested in a continuous flow packed-bed reactor at 450 ℃, 500 psig, liquid hourly space velocity of 1.0 h-1, and H2/feed molar ratio of 30. The XRD results showed that NaY zeolite was successfully synthesized after hydrothermal reaction at 100 ℃ for 2 h by using the microwave technique. The lower crystallization temperature, longer aging time, and higher Na2O contents resulted in small crystal size zeolite because the conditions allow an increase in number of nuclei precursors and reduce the growth rate of crystallization. In comparison with the three different crystal sizes, the results showed a good correlation between the crystal size of zeolites and conversion in which the smaller crystal size of synthesized Y zeolite exhibited higher catalytic activity and higher selectivity of jet fuel.