Features:

Feeding the biofuels market

10th August January, 2007

Biofuels can be produced from a multitude of feedstocks, from traditional corn or rapeseed oil, to the more unconventional used cooking oil or cheese. But which feedstock provides the highest yield without detriment to the environment, together with the most cost effective processing solution is still subject to debate.

One biofuel pioneer is the Austrian University of Graz, which works in close cooperation with Austrian producer BioDiesel International (BDI). Together they have developed a multifeedstock technology to offer a new flexible process for the production of biodiesel from various vegetable oils, waste oils and animal fats.

In Europe, rapeseed oil methyl ester (RME) is the common feedstock but, according to BDI, non-edible oils (or seed oils), used cooking oils and animal fats are gaining ground due to their significantly lower emissions properties.

BDI research shows that when the chemical properties of various feedstocks are compared, the main difference between vegetable oils and animal fats is the diversity of fatty acids. While rapeseed and soybean oils have a high content of unsaturated fatty acids, animal fats like tallow or lard contain mainly saturated fatty acids - acids that have been proven to increase the oxidation stability of biodiesel. Consequently, tallow-derived biodiesel delivers not only reduced exhaust emissions but also higher diesel engine efficiency compared to conventional fossil-fuel diesel. Engine noise levels are also found to be lower.

BDI's single feedstock technology guarantees the highest yield (100%), while its multi-feedstock production technology has a 95-97% yield performance, depending on the quality of the feedstock.

Multi-feedstock technology

The technology involves a pre-treatment to rid the feedstock of impurities and water through a mechanical separation process. This precedes a chemical reaction in which a catalyst solution is added to the treated feedstock to convert it into methyl ester. This transesterification process transforms the fatty acids to produce biodiesel, although before it meets EN ISO 14 standards the liquid goes through further purification and drying. The process takes about 30 hours from raw material to final product.

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