Wink of Knowledge: Alternative Liquid Fuels – Similar but Not Quite the Same? – A Journal

We are reinventing ourselves and launching a journal on alternative fuels. The idea is to present a growing collection of measurement data on fuels and to investigate their identification using our key parameters—density, viscosity, and speed of sound. Collaborations, partners, customers, and other interested parties are very welcome to join this initiative.

Alternative fuels such as HVO, biodiesel, or SAF are often considered “drop-in” solutions—meaning they can directly replace conventional diesel or kerosene. Chemically and from a regulatory perspective, this is true to a certain extent. However, there is still a need for monitoring fuels to ensure quality, for example, or to control combustion processes efficiently.

Our hypothesis is: Alternative fuels do not behave like fossil fuels – they often only look like them…And the combination of our measurement parameters reveals these differences.

In our investigations, different liquid fuels have been—and will continue to be—systematically measured and compared. The goal is to make differences visible and thereby improve real processes and/or enable clear identification of fuel types.

Focus of the investigation

Three physical parameters are at the core:

• Density as a robust base parameter for identification, quality assurance, and volume-to-mass conversion
• Viscosity as a process-relevant parameter, e.g. for flow behavior, lubrication, and atomization, as well as compliance with regulatory limits for kerosene, measured at -20°C
• Speed of sound as a parameter that is still rarely used in the fuel sector but provides highly valuable insights

And most importantly:The combination of these parameters.
Only through their correlation does a significantly more complete picture of the medium emerge.

We will continue to test our hypothesis with new fuels and expand this journal continuously – as a growing data collection of real fluid properties.

As a first step, three diesel alternatives were analyzed: conventional B7 diesel compared with the widely used alternatives FAME (fatty acid methyl ester, also known as biodiesel) and HVO (Hydrotreated Vegetable Oil). The following plots show clear differences across all parameters (except speed of sound for two samples).

Here is the 3D space defined by our measurement parameters, which we plan to populate with additional measurements in the future: