Fuel, Vol.242, 794-803, 2019
Improvement of cold flow properties of a new biofuel derived from glycerol
One of the barriers for the extended use of fatty acid methyl esters (FAME) as a diesel fuel component is the yield of raw glycerol as a by-product of the transesterification process. In fact, glycerol is considered as one of the most abundant waste feedstock in the world. A new fuel denoted as FAGE (Fatty Acid Glycerol formal Esters) produced from glycerol and waste oil has been developed. FAME is concomitantly obtained during the manufacturing process of FAGE in different proportions depending of the reaction conditions. Since FAGE cold flow properties are in disadvantage when compared to FAME, the influence of some cold-flow improvers in FAGE/FAME blends has been investigated. In this work, the use of some acetals, co-products of the FAGE production process, are proposed as cold-flow improvers, giving extra value to this new fuel since all the co-products obtained from the production process would have a new industrial use. These two acetals are GF (Glycerol Formal) and GFOMOM (Methoxy-methyl glycerol formal). The results obtained show that cold flow properties become poorer when the amount of FAGE increases in the FAGE/FAME blend, but such effect is very slight up to 50% FAGE. The use of the acetals improves cold flow properties of the blends up to 2 degrees C, with minor effect of the GF content in the GF/GFOMOM acetal blend. In addition, a commercial cold flow improver was tested, improving the pour point and the cold filter plugging point with only small effect on cloud point and crystallization temperature. The results obtained from the acetals and the cold flow improver are compared, and the value of the acetals as cold flow improvers has been proved. A combination of both, acetals and cold-flow improver, is proposed as an optimal method to improve cold flow properties.