Catalytic role of lignocellulosic materials in triacylglycerol cracking

Cracking of vegetable oils and animal fats carried out with a view to preparing fuels or fuel components for diesel engines is one of the options of reducing high molecular weight and viscosity of natural triacylglycerols (TAG). We have found out that lignocellulose shows a surprisingly high catalytic activity in TAG cracking comparable and equivalent to that achieved with zeolite catalysts NaY and clinoptilolite. This paper presents results obtained from cracking of rapeseed, sunflower, soybean and jatropha oils, lard and used cooking oils in the presence of woody sawdust, cereal straw and waste paper used as catalysts. The yield of liquid products in the feedstock was 80–90% relative to the feedstock TAG at temperatures of 350–440 °C applied for a period of 20–30 min. The yield of treated condensates having properties similar to those of fossil diesel reached, after water separation and evaporation of the volatile fraction up to 190 °C, 70–80% of the feedstock TAG. The type of the TAG and the lignocellulosic catalyst used had no significant effect on the product yield and its parameters. Liquid condensates obtained via catalysis with lignocellulosic catalysts had similar composition and properties as condensates produced by zeolite-catalyzed cracking. Blends of treated condensates of 5–10 vol.% with fossil diesel are compliant with the EN 590 standard and can thus be used as fuels for diesel engines.