Hydroconversion of Vegetable Oils Isomerized over ZSM-5: Composition and Properties of Hydroraffinates

摘要

Three vegetable oils (rapeseed oil, palm oil, and soybean oil) were isomerized (the so-called zeoforming process) using two different ZSM-5 catalysts (A or B) at a constant temperature (300 degrees C) and liquid hourly space velocity (LHSV) (1.0 h(-1)) and variable pressure (1.7, 2.5, or 4.0 MPa). The obtained isomerized zeoformates were hydrotreated under constant conditions (temperature, 340 degrees C; LHSV, 0.5 h(-1); pressure, 4.5 MPa; and hydrogen/feed ratio, 1500 Nm(3)/m(3)). The obtained hydroraffinates exhibited diverse contents of n-paraffins (24-83 wt %), isoparaffins (reaching greater than 50 wt %), aromatics (up to 15.1 wt %), and possibly compounds with alkyl naphthene structures. Hydroraffinates containing high aromatic contents also showed increased final boiling points (FBPs) of distillation, which was most likely related to the oligomerization reactions of fatty acids. The increase in pressure during the zeoforming process reduces the formation of aromatics and isoparaffins. Moreover, under the same temperature and pressure conditions, the zeoforming reactions of saturated fatty acids were more difficult, resulting in smaller yields of isoparaffins and aromatics in the hydroraffinates.