Investigation on additives in paraffinic e-fuels and on the applicability of current no-harm test methods for middle distillate applications

The EU's Renewable Energy Directive II (RED II) stipulates that EU member states must become climate-neutral by 2050. To achieve this goal, CO2 emissions from energy demand must be significantly reduced. In 2019, the share of mineral oil in primary energy demand was 35.3 % (1256 TWh). Currently, mineral oil middle distillates are used as liquid energy sources in transport to a large extent and in space heating to a not insignificant extent. It has been shown that paraffinic Fischer-Tropsch (FT) fuels are excellently suited to replace EL heating oil and diesel fuel either completely or as an admixture component. With these liquid paraffinic energy sources, a greenhouse gas reduction can already be achieved at this point in time in the transport and heating sectors, provided they are produced with renewable energies. The advantage of this approach is that the infrastructure currently available for middle distillates nationwide is immediately available. The distribution structures and technologies can be used. Thus, in terms of CO2 reduction, an effect can be achieved immediately and with little investment. In the case of middle distillates, additives are usually added to optimise their application properties and ensure safety along the transport chain. Additives are usually offered mixed with a solubilizer, which ensures the optimum distribution of the additive in the middle distillate. Negative effects of an additive are detected or excluded before its introduction by means of no-harm test procedures specific to the respective middle distillate.
The objectives of the research project are to test different solvents for common additives in pure paraffinic fuels and to investigate the applicability of the no-harm test methods of middle distillates for paraffins and, if necessary, to develop alternative test methods.

The suitability of various commercially available additive formulations in paraffinic fuels is being tested. Possible additives include antioxidants, flow improvers, lubricity improvers and possibly other additives. Mixing and solubility behaviour will be investigated. In cooperation with additive manufacturers, active components are added to the paraffins in pure form and with various solubilizers, such as aromatics and alternatively, for example, naphthenes or alcohols. As part of these tests, additivated samples and non-additivated samples are stored for extended periods of time to investigate whether additives settle or precipitate over time, and how the fuels change over time with and without additives. The no-harm test methods that exist for middle distillates will be applied to pure paraffinic fuels. The focus is on the applicability of the methods.

The IGF application was approved by the AiF reviewers. The application for funding has been submitted.