In prescreening, a fuel is first chemically analyzed, then its properties are compared with those of other fuels and the specifications of the ASTM standardization authority.
Alternative fuels have become a major subject in energy supply and mobility in recent years and are more relevant today than ever before: as fuel in aircraft engines, as fuel for decentralised power plants and as a storage medium for the fluctuating energy supply from wind and solar plants. Alternative fuels stand out due to their high energy densities, simple handling and exceptional versatility in their use.
DLR is conducting research into the production, characterisation, evaluation and use of such fuels. The activities cover the spectrum from basic chemical principles to laboratory experiments and the development of prototypes in cooperation with industry. The methods used include chemical-kinetic modelling, numerical simulation methods, chemical-analytical and laser-based measurement techniques as well as validation experiments of varying complexity. Finally, alternative fuels are evaluated and optimised with regard to their energetic and economic properties.
DLR is working on various ways to produce alternative fuels. These include electrolysis and high-temperature processes using concentrating solar radiation to produce hydrogen, as well as processes for further processing into fuels.
Characterisation and evaluation
Like the source materials and production processes, the fuels are also diverse, for example bio-alcohols, hydrogen, fuels from gasification or fermentation processes or Fischer-Tropsch products. A fundamental goal in this field is therefore research into the properties of these fuels, whose technical use is not possible without knowledge of them. Aspects of efficiency and reliability are just as important as climate and environmental compatibility.
Fuel design
The 'design' of alternative fuels is playing an increasing role, in other words the optimisation of the composition with regard to physical and chemical properties such as specific energy density, combustion properties, environmental compatibility as well as aspects of production and storage. In terms of combustion properties in aircraft engines or stationary gas turbines, the focus of the investigation is on achieving high flame stability and low pollutant emissions.
Since the fuel composition plays a decisive role in all combustion properties, in view of the large variety of potential fuels, optimisation cannot be achieved by empirical methods, but only by methods based on a profound understanding of the underlying physical and chemical chains of action.
