Biodegradation of gas-to-liquids synthetic diesel, biodiesel and their blends

Abstract

Sustainable renewable alternatives to petroleum fuels are being investigated because of the growing demand for transportation fuel. Synthetic fuels like diesel are produced from natural gas and coal feed stocks, via the Fischer-Tropsch synthesis process. Biodiesel can be an attractive alternative to petroleum-derived diesel because its physical properties are similar to those of petrodiesel and it can be transported by and stored in existing infrastructure. The biodegradability of synthetic diesel and biodiesel blends were determined, using respirometry to establish whether the biodiesel could enhance the biodegradability of the blends when compared to the synthetic petroleum diesel. In addition, a model was developed to estimate the biodegradability of the diesel and diesel/biodiesel blends using the molecular composition of the fuels and a prediction software program. The addition of biodiesel to synthetic diesel enhanced the biodegradability of the blends. Less than 1% biodiesel addition improved the degradability classification from inherently biodegradable to readily biodegradable. The addition of biodiesel to petroleumderived diesel could promote the use of renewable alternatives because the blends have superior biodegradability compared to petroleum diesel. The benefit of using biodiesel to enhance the remediation of hydrocarbon contamination was also confirmed.