Fuels

Description

Fuels are chemical substances that release energy during combustion and thus usually drive combustion engines. Petrol and diesel, but also bioethanol, natural gas or even vegetable oils are used as fuels. Methods used in archaeometry can be used to study fuels. The main question here depends on the type of carbon source from which a fuel was produced – biogenic or petrochemical (from natural gas or petroleum). Fuels can be produced from petrochemical or natural sources or a mixture of both. Natural fuels are also called “biogenic” if their starting materials consist of esterified (mixture of alcohol and fatty acids in oil) vegetable oils and methanol – e.g. biodiesel – or of bioethanol produced from fruits containing sugar and starch. Using the ¹⁴C method, we can distinguish biogenic from petrochemical material and mixtures thereof. Due to its age (the age of the crude oil from which the raw material originates is several million years old), petrochemical material contains carbon that does not contain ¹⁴C. Biogenic material has the ¹⁴C carbon signature of the corresponding growth year of the corresponding plant. In our ¹⁴C laboratory the biogenic fraction is determined according to ASTM-D 6866 and EN 16640:2017, respectively.

Sample properties

For the determination of the biogenic portion:

Liquids: 0.1 ml (typically sample quantities of a few ml are sent to us)

Powder, solids: approx. 5-10 mg, depending on carbon content.

Suspensions, creamy solutions: approx 1 ml, depending on carbon content

If the material to be tested consists of a mixture of biogenic and petrochemical starting materials, it must be ensured that the sample is representative of the material to be tested. It may need to be homogenised. Ideally, the carbon content of the sample is known and can be reported to the laboratory.