Within this project, a forced test method was developed to determine the resistance of metallic materials to middle distillate fuels and mixtures of middle distillate and paraffinic hydrocarbons both with fatty acid methyl ester (FAME) as a biogenic component. In the method, specimens of the material are immersed in special test media. The compositions of two test media were developed within the project. These test media include the influence of aging of the FAME which is to be expected after a storage of the fuel exceeding 2 years in the field. They cover a range of up to 20 % (v/v) FAME content. The exposure test can be carried out at ambient pressure with little effort.
The suitability of a selection of metallic and polymeric materials relevant to middle distillate supply plants was determined by segregation in the following non-aged fuels: Fuel oil EL low sulphur (B0), fuel oil EL low sulphur with 20 % (V/V) FAME (B20), FAME (B100) and hydrogenated vegetable oil (HVO). The materials were also aged in a 1 year aged B20 and an 8 year aged B10. The temperature during ageing was 50 °C for the metallic materials and 40 °C and 70 °C for the polymer materials. The results of the resistance evaluation were summarised in resistance lists. The evaluations obtained with B20 generally apply to mixtures of fuel oil EL low-sulphur and FAME with a FAME content of up to 20 % (V/V). They are also transferable to mixtures of diesel fuel and FAME with a FAME content of up to 20 %(V/V).