Evaluation of biodegradability and stability of biodiesel fuel and its mixtures

Abstract

Global warming has forced humanity to care for greenhouse gas emission reductions, at the same time the production and use of biofuels. One of the positive environmental properties of biofuels is fast biological degradation. Biological degradability of pure rapeseed oil fatty acid butyl esters (RBE) within 28 days is 70% and such product meets the requirements for biofuel. During the same period, only 26% of mineral diesel fuel (D) is decomposed. Multi-component fuel containing up to 30% biofuel is less biodegradable and specified as a partially biodegradable material. The peroxide and acid number of pure biodiesel is growing rapidly when aging compared to that of mineral diesel and multicomponent fuel mixtures. The acid number of pure rapeseed oil fatty acid methyl esters (RME) was higher than the standard requirements after 3 weeks of storage. The acid number of mixtures containing 15% RME (RME15B15D70) and RBE (RBE15B15D70 and RBE25B25D50) was less than 0.5 mg KOH/g^–1 after 8 weeks of storage. Multi-component fuel is more resistant to oxidation than pure biodiesel fuel.