Biodegradability and life cycle analysis of biodiesel-to-diesel fuel mixtures (B10)

Abstract

The enzyme-catalyzed in situ transesterification process was used to produce biodiesel-todiesel (B10) fuel mixtures. Biodiesel has been synthesized from rapeseed, the oil of which is high in free fatty acids, and is therefore known as poor quality. The biocatalyst used for the reaction, lipase – lipozyme TL IM (Thermomyces lanuginosus). Three fuel mixtures were made, consisting of 90 % of diesel, and 10 % of rapeseed oil methyl, ethyl, or butyl esters. The basic conditions of the production process of these fuel mixtures were optimized. The purpose of the study was to determine how the biodegradability of fuel mixtures is improved compared to the degree of biodegradation of diesel. Biodegradation was assessed according to the OECD 301 F methodology “Manometric Respirometry” (assessment of oxygen consumption). After 28 days, pure diesel biodegrades to 20.64 %. The results showed that almost 2 times faster biodegradable are fuel mixtures containing rapeseed oil methyl esters (37.27 %). Fuel mixtures containing of 10 % of rapeseed oil ethyl esters and rapeseed oil butyl esters improved biodegradations by 2.94 % and 2.27 %, respectively. This is due to the shorter methanol radical chain compared to ethanol and butanol esters. All fuel mixtures were evaluated according to the life cycle assessment using the CML-IA baseline V 3.02/EU 25 method at SimaPro software. 10 environmental impact categories have been assessed, such as: global warming, eutrophication, acidification, ozone layer depletion, and so on. The environmental impact was compared to that of pure diesel impacts. Fuel mixtures containing of 10 % of biodiesel have possitive effect and reduced these negative environmental impacts.