Fuel Purpose Hydrotreating of Vegetable Oil on NiMo/γ-Al2O3 Catalyst

Abstract

The application of biofuels has become more important in the whole world since the last decades. Intensive research has been started for the production of biofuels which can be applied in Diesel engines and has different chemical composition from the previously used ones. Among these fuels the most important one is biogasoil (normal and iso-paraffins) produced from triglycerides with catalytic hydrotreating (special hydrocracking). The aim of present study was to investigate the applicability of commercial NiMo/γ-Al2O3 catalyst for conversion of specially pretreated Hungarian sunflower oil to produce motor fuel components. The change in the hydrotreating activity of applied catalyst, the pathways of hydrodeoxigenation reactions and the effect of process parameters (T=300–360 °C, p=20–60 bar, LHSV=0.5–2.0 h-1, H2/sunflower oil volume ratio: 400 Nm3/m3) on the yield and composition of the products were also investigated. It was concluded that on the investigated NiMo/γ-Al2O3 catalyst products with relatively high (>50%) paraffin content (T=360–380 °C, p=60 bar, LHSV=0.5–1.0 h-1) could be produced. The yield of the produced target fraction was 50.7–54.5% at these advantageous process parameters. So it is necessary to separate and recirculate the heavy fraction. In case of every investigated process parameter C18-, C17-, C16- and C15 normal paraffins were formed, i.e. both the HDO and the decarboxylation/ decarbonylation reactions took place. The cetane number of the target fractions, are very high (>80, EN standard: ≥51), but the cold flow properties of this fraction are disadvantageous. To improve this disadvantageous property it is necessary to carry out selective isomerization of the target fraction.