In recent years, various modular micro channel reactors have been developed to overcome limitations in challenging chemical reactions. Direct synthesis of hydrogen peroxide from hydrogen and oxygen is a very interesting process in this regard. However, the complex triphasic process (gaseous reactants, reaction in liquid solvent, solid catalyst) still holds challenges regarding safety, selectivity and productivity. The membrane micro reactor system for continuous liquid phase H₂O₂ direct synthesis was designed to reduce safety issues by separate dosing of the gaseous reactants via a membrane into a liquid-flow channel filled with a catalyst. Productivity is increased by enhanced mass transport, attainable in micro channels and by multiple re-saturation of the liquid with the reactants over the length of the reaction channel. Lastly, selectivity is optimized by controlling the reactant distribution. The influence of crucial technical features of the design, such as micro channel geometry, were studied experimentally in relationship with varying reaction conditions such as residence time, pressure, reactant ratio and solvent flow rate. Successful continuous operation of the reactor at pressures up to 50 bars showed the feasibility of this system. During the experiments, control over the reactant ratio was found to be crucial in order to maximize product yield. Thereby, yields above 80% were achieved. The results obtained are the key elements for future development and optimization of this reactor system, which will hopefully lead to a breakthrough in decentralized H₂O₂ production.

In today’s pressing quest of emission and pollution reduction in all energy sectors, research on renewable and sustainable fuels is a key component. The Institute of Combustion Technology at the German Aerospace Center strives to assess new, renewable fuel in a gear wheel approach of interdependent linked experiments, database comparison and model-based assessment, allowing for a fast iterative feedback to the fuel producer and giving a detailed valuation of fuels as well as a distinguished preselection when presented with numerous fuel samples. Synthetic fuels as a substitute for fossil fuels are becoming increasingly important within the framework global climate protection goals. Power-to-X technologies such as Fischer-Tropsch synthesis can be used to produce carbon-neutral fuels using carbon dioxide from air (direct air capture) and hydrogen obtained by water electrolysis using green electricity. This fuel assessment has been iteratively performed for the post-processing of a Fischer-Tropsch fuel, produced in the module-based, compact and highly innovative PtL plant erected by INERATEC GmbH. The aim of the present work was to evaluate the postprocessing steps hydration and distillation of the crude Fischer-Tropsch products with hindsight to “fit-for-purpose” properties of the resulting products for aviation. The chemical composition was determined using comprehensive two-dimensional GCxGC chromatography. Numerical blending analysis was performed utilizing the DLR SimFuel platform to evaluate the range of blending ratios of the Fischer-Tropsch fuels with conventional jet fuels. It could be demonstrated that the post-processed Fischer-Tropsch fuels display a beneficially high blending potential with conventional jet fuels considering the chemical composition and combustion behavior.