Fuel Oils

Application characteristics of fuels with biogenic components

In the German heating oil standard DIN SPEC 51603 – part 6 several limits regarding the fuel quality are defined. These limits have to be strictly observed in order to ensure operability. Formation of acids, high-molecular molecules and water as aging products during storage lead to changes in the physico-chemical characteristics of fuels. Those long term changes are not detected sufficiently by the analysis at the beginning. In this project, a test rig which can in short time age fuels close to reality was developed. Fuels are tested together with commercially available burner components regarding their long term behavior. One aim of the project was to reduce the required operation time below 1,000 h. Furthermore, the significance of different aging parameters like temperature, light, water and cycle of operation was evaluated. Increasing the temperature in the drum and at the preheater the operation time was halved. Stressing the fuel with light reduces the operation time about 30 %, while a change in the operation cycle led to another 10 % decrease. Despite applying different aging parameters, the same aging products were formed, although in different shares. The sediments mainly originate from the FAME. It could be shown that the tendency of fuel to form sediments is the main factor for operability. In laboratory tests influences on the fuel were investigated directly. They showed that copper has a great, but zinc has no measurable influence on the fuel. Light, however, showed the predominant influence compared to the others. Waterphases had only small influence. Only the fuels were sampled in the laboratory tests. In the test rig tests, however, it could be shown that the sediment is relevant for operability.