Modellierung, Energieflussanalyse und Prozessoptimierung eines solarthermischen Reaktors zur regenerativen Erzeugung von Wasserstoff

The focus of this work is on the investigation and improvement of an alternative process for regenerative hydrogen production via two-step thermochemical redox cycles using metal oxides in combination with concentrated solar power. Due to the small number of process steps, highly attractive thermodynamic efficiencies in the range of 50% to 60% can be theoretically achieved. Up to date, maximum practical effi-ciencies of around 5% have been demonstrated with a technology readiness level (TRL) of 5 to 6. Thus, ongoing research and development for further technological development up to a desired economic industrial application is required. In an international consortium with the participation of the German Aerospace Center (DLR), a pilot plant has been developed using a large scale 250 kW thermochemical reactor which has been investigated and further developed in detail within the framework of the research projects ASTOR and ASTOR_ST.
In this work, a flexible and accurate simulation model of the entire pilot plant has been developed and used for the analysis and optimization of energy flow, reactor design and operational strategy. To ensure accurate simulation results, the model is validated using experimental measurement data of the current pilot plant. By use of the validated model, first the complex physical system behavior is analyzed to gain new and detailed insights into the dynamic process conditions. Based on the process analysis, several possibilities for potential efficiency improvement are developed. To qualify and quantify possible ap-proaches for efficiency improvement, a holistic energy flow analysis of the entire system is carried out, by taking various operating strategies into account. Furthermore, the interactions of the operational strategy and system efficiency is examined in more detail. The aim here is to maximize the system efficiency by determining optimal operational process parameters, considering various plant concepts.
In addition, the simulation model is intended to be used for ongoing techno-economic analysis to determine the hydrogen production costs and for the development of a realtime system control in field test operation. The necessary requirements were success-fully created in this work, but not explained in detail.