Influence of Fuel Composition on Residue Formation During the Evaporation of Liquid Fuels in Porous Media

Due to climate policy goals of the German government, there will be significant changes for liquid energy sources. Fossil energy sources are increasingly being supplemented by alternative energy sources from various sources. Their compatibility with existing combustion technologies is not always guaranteed. This also affects the mixture formation area of existing plants, which serves to provide fuel for combustion. The evaporation behaviour of the different fuels plays an important role here. Among other things, pyrolysis reactions caused by high heat input on the fuel cause deposits to form on wetted surfaces in the mixture formation area. The extent and properties of the deposits depend, among other things, on the middle distillate compositions and properties, the evaporator geometry, and the operating conditions of the evaporator.
The aim of the research project is to enable the deposit-free provision of fuel, including alternative energy sources for the combustion process. The use of alternative liquid energy sources as well as multi-component fuels in heating devices for mobile and stationary applications is to be made possible.

In this research project, the chemical-physical causes for deposit formation during fuel evaporation are to be identified. On one hand, this requires a detailed characterisation of the fuels in order to identify possible differences in detail. On the other hand, application-technical investigations are carried out with a test rig, the core element of which is a fleece evaporator. The deposits generated in the application-technical investigations are also examined with gravimetric, imaging and detail-analytical methods to determine their characteristics and composition. Based on the results of these investigations, strategies for prevention and regeneration of the deposits will be developed. These can be on the one hand additive strategies and on the other hand an adjustment of the operating conditions. In addition, based on the analytical and application-oriented investigations, a model is being further developed to enable the prediction of the evaporation behaviour of multi-component fuels. The aim of the project is to enable the deposit-free use of alternative energy sources in heating appliances.

The project has been completed. The results are documented in DGMK Research Report 829.