Reaction Engineering for Chemical Hydrogen Storage (INW-3)
The Reaction Engineering for Chemical Hydrogen Storage subinstitute (INW-3) is concerned with the scale of hydrogenation and dehydrogenation apparatus. By optimizing heat management and hydrodynamics, there is enormous potential here to increase volumetric productivity, which is of critical importance for all applications with high power density requirements. Optimization tools include reaction engineering and fluid mechanics models as well as reactor internals derived from them, catalytically activated structural elements for flow configuration, dosing concepts, approaches for removing hydrogen from the reactor (e.g. membrane reactors), and methods for improving heat input (e.g. condensation reactor, optimization of heat transfer from the heating elements to the reaction mixture).
Improving heat input (hydrogen release) and heat removal (hydrogen storage) also ensures that critical temperatures, above which the degradation of the catalyst or any organic storage molecules present increases sharply, are not exceeded in the reactor at any point. Optimizing heat management in the reactor therefore contributes considerably to substantially increasing the lifetime of the catalysts and storage molecules in the respective processes, which in turn would decrease the need for expensive regeneration, purification, and recycling.
The fabrication of the reactor elements that are optimized in terms of reaction engineering and fluid dynamics should preferably be carried out using additive processes since this allows maximum geometric and conceptual freedom. During the additive manufacturing of catalytically activated, structured reactors, however, the full reactor element is not manufactured from the expensive catalyst material, as the costs involved would be unrealistically high. Instead, good heat-conducting, low-cost metal structures are used, which are produced by means of additive manufacturing processes with a hydrodynamically optimized structure. The surface of these structures is then catalytically activated in several process steps. This is typically achieved by coating the metallic structure with a highly porous catalyst carrier layer (e.g. made of aluminium oxide). Impregnation processes are then used to precisely apply the catalytically active component to the carrier layer, exploiting the expensive noble metal components to the highest possible extent. Calcination and activation of the catalyst coating complete the fabrication of such additively manufactured, structured reactor elements.