Development of a Fast-Aging Method for Middle Distillates for Modelling the Longterm Aging Behaviour by Using Online-Measurement of Multiple Stability Parameters

Within the framework of the predecessor project DGMK-763, a rapid ageing method for alternative fuels was developed to simulate the long-term stability behaviour. The delta value analysis of stability parameters such as acid number, water content, total contamination and oxidation stability after certain running times showed a good correlation to conservative long-term storage with running times of mostly 2 years. The analytical evaluation of the fuel properties was carried out after the test runs. Due to the current test rig design, a continuous measurement data acquisition of analytical characteristics is not possible. A measurement data-based termination criterion cannot be determined at present. For a more precise prognosis of the long-term stability behaviour of the fuels/the ageing process, it is necessary to extend the method by integrating "in situ" measurement concepts to determine the stability characteristics.

The rapid ageing method for alternative fuels developed within the DGMK project 763 to simulate the long-term stability behaviour is modified by installing "in situ" measurements. The integration of the following sensor technology is conceivable in order to extend the method for a continuous evaluation of the fuel with regard to the ageing progress: acid formation by means of conductivity measurement, formation of suspended matter/sediments, density and viscosity, relative humidity, as well as infrared spectroscopy for the detection of ageing products/degradation of additives. The data acquisition of the online measured values enables a better understanding of the ageing reactions taking place and serves as a basis for the extrapolation-based prognosis of the long-term stability behaviour, through which more precise ageing functions / models can be created. The comparison with the standard analysis as well as the detailed analysis serves additionally for method validation. The fuel matrix from the DGMK 763 project is to be extended with alternative fuels such as UCOME and XtL.

DGMK Research Report 798 has been published.