Cold flow properties and oxidation stability of blends of near zero sulfur diesel from Ural crude oil and FAME from different origin

Abstract

Cold flow properties and oxidation stability of near zero sulfur diesel from Ural crude oil and fatty methyl esters (FAME) from different origin and their blends were studied in this work. It was found that undercutting the petroleum diesel to obtain arctic diesel deteriorates its oxidation stability and anti-oxidant addition is required to keep the oxidation stability within acceptable limits. The addition of commercially available FAMEs, produced from 100% rape seed oil; 70% soya and 30% palm oil; 50% rape seed oil and 50% sunflower oil, to the petroleum diesel depresses the cold filter plugging point (CFPP). The depressing effect on the conventional diesel CFPP of the FAME depends on the petroleum diesel and the FAME properties. The Honeywell software RPMS model used to predict cloud points (CP) of blends of different conventional middle distillates was found to be capable of predicting cloud points of blends of petroleum diesel and FAME. The highest class 4 of arctic diesel according to EN 590 (CP=−34°C; CFPP=−44°C) can be produced by blending petroleum diesel with the 100% rape seed FAME treated with cold flow improver in concentration up to 10%. The addition of the synthetic anti-oxidant ionol (BHT) to petroleum diesel with high unsaturated hydrocarbon level and to the blends petroleum diesel/FAME seems to inhibit the secondary reactions of peroxides decomposition to acids to a greater extent than the oxidative polymerization.