Conversion of Palm Fatty Acid Distillate to Biojet Fuel over Ni/HY-PdiTiOz Core-shell Catalyst

Abstract

Generally, jet fuel is obtained from the refining of petroleum feedstock in order to powering the aircrafts, hence the world is more confronting a problem with increasing air pollution emission. Therefore, biojet fuel is introduced as an alternative way to solve the problem. Biojet fuel can be derived from bio-based feedstock such as palm fatty acid distillate or PFAD. Which is converted via the deoxygenation reaction in order to remove oxygenated compounds, carboxylic and carbonyl groups in the fatty acid molecules then followed by hydrocracking and hydroisomerization reaction. The heterogeneous catalyst is used to convert PFAD into saturated paraffins in the range of jet fuels using the design of core-shell catalyst model to do both steps of deoxygenation and hydroprocessing reaction. In terms of catalyst supports, TiO2 is used as the support in deoxygenation process to produce long chain hydrocarbon. In addition, zeolite is considered as support for hydrocracking process because of its suitable structure and acidity properties. The active metals such as Pd and Ni are also used to develop the efficiency of jet fuel production. In this work, the conversion of PFAD to biojet fuel will be investigated in a continuous flow fixed-bed reactor. The Ni/HYcore-Pd/TiO2shell catalyst will be prepared. During the catalytic activity testing at 425 °C, pressure 30 bar, H2/feed molar ratio of 10, and LHSV of 1.5 h-1 exhibited highest selectivity 48% towards biojet fuel. The effect of increasing space velocity did not give higher selective biojet fuel production due to shorter residence time. The formation of hydrocarbons from fatty acid over core-shell catalyst occurs through an aldehyde and alcohol intermediates further transform to heavier hydrocarbon then subsequently hydrocracking/hydroisomerization to biojet fuel.