Session: 08-01: Solar Chemistry: Thermochemical Fuel Production I

Paper Number: 138597

138597 - Development of the Solar Thermochemical Fuel Production Technology R2mx 

Abstract: 

Solar driven thermochemical redox cycles are a promising path to cost effective large-scale production of renewable hydrogen and other renewable fuels. Due to the direct conversion of heat into a chemical energy carrier and the full utilization of the solar spectrum, the theoretical process efficiency potential is very attractive. Significant progress has been made over the past decade, especially in the development and demonstration of receiver-reactors with fix redox beds operated in a batched temperature and pressure swing mode. Nevertheless, experimentally observed efficiencies still fall well short of the theoretical potential. The reasons for this are manifold and there is still significant room for improvement, but some of the challenges seem rather fundamental to the fixed bed concept. Based on these findings, an innovative receiver-reactor concept, R2Mx, has been proposed [1] applying a modular approach to find a sweet spot in the triangle of performance potential, technical feasibility and scalability. The R2Mx concept uses separate reactors for the two reactions – reduction and oxidation -and integrates several independently operating units of redox material that can be linearly moved between the reactors. These features increase the design and operation parameter space considerably and enable the implementation of new approaches to overcome the challenges of the state-of-the-art technology.

This presentation will describe the new R2Mx concept, its components and how the process differs from the state-of-the-art. The operation characteristics and performance potential will be assessed using a numerical model of a receiver-reactor at MW-scale. With this model, design and operational parameter sets with very promising performance values are identified. Apart from the numerical analysis, an experimental campaign under preparation will be introduced, which will provide the proof-of-concept for the R2Mx technology. The respective test rig showcases implementations of the characteristic features of the concept, in particular: separated reaction zones, transport of redox structures, and atmosphere separation between reactors. The basic design of the demonstrator will be presented as well as first results of component pre-tests. Several component models have been developed to support the design process and to optimize the system. The presentation will give an overview of the state of development and an outlook for this promising new solar thermochemical fuel production technology.

[1] Brendelberger, S., Holzemer-Zerhusen, P., Vega Puga, E., Roeb, M., Sattler, C., Study of a new receiver-reactor cavity system with multiple mobile redox units for solar thermochemical water splitting, Solar Energy 235 (2022), 118-128, https://doi.org/10.1016/j.solener.2022.02.013

Presenting Author: Stefan Brendelberger German Aerospace Center (DLR)

Presenting Author Biography: Stefan Brendelberger is leading the group of Fuel Production Technologies at the Institute of Future Fuels of DLR. He is working in the field of solar thermochemical cycles for more than 10 years, focusing on the simulation and demonstration of related components and processes.

Authors:

Stefan Brendelberger German Aerospace Center (DLR)
Paul Kant German Aerospace Center (DLR)
Fabio Pierno German Aerospace Center (DLR)
Estefanía Vega Puga German Aerospace Center (DLR)
Louis Thomas German Aerospace Center (DLR)
Vamshi Krishna Thanda German Aerospace Center (DLR)
Asmaa Eltayeb German Aerospace Center (DLR)
Martin Roeb German Aerospace Center (DLR)
Christian Sattler German Aerospace Center (DLR)