Additive-manufactured MIEC ceramic membranes for solar-driven green fuels generation – MEMBRASOL

The production of renewable and dispatchable synthetic fuels using green processes constitutes a major challenge of the next decade for the decarbonation of the transport and energy sectors. This project aims to develop a novel groundbreaking approach that bypasses the use of electricity while being flexible and leading to the same net outputs of electrolysis. Thermochemical processes provide a thermodynamically favourable route for solar energy harvesting and decarbonized fuel production, converting the entire solar spectrum into high-temperature process heat without using expensive catalysts or intermediate electricity production, thus enabling high efficiencies. The proposed thermochemical pathway directly produces a variety of key solar fuels including hydrogen, syngas with the desired CO:H2 ratio for liquid fuel synthesis, or ammonia, solely from water, CO2, air, and concentrated solar energy as the only inputs to the process.
The considered approach is based on direct isothermal thermolysis via redox MIEC membranes with oxygen partial pressure gradient to spatially separate the gas products. It further achieves continuous and simultaneous production of O2 and H2/CO (or NH3) respectively, on both sides of the membrane. Relevant membrane structures with high thermo-mechanical and chemical stability need to be designed. Suitable formulations and stacks of MIEC materials have to be developed to increase oxygen ion diffusion rates and decrease the operating temperature, as well as efficient & robust shaping methods for materials integration in solar reactors. The intensified process integrating a solar membrane reactor for the in-situ separation of products will allow the production of sustainable energy carriers (H2, NH3) while operating CO2 valorization and solar energy harvesting, without the need for electricity or additional carbonaceous feedstocks. The expected innovations and outcomes concern: i) the design & characterization of novel membrane formulations and architectures with relevant redox activity and oxygen transport properties, ii) the development of a robust and scalable strategy for the synthesis & shaping of tubular MIEC ceramic membranes by 3D-printing techniques, and iii) the demonstration & performance assessment of the integrated solar membrane process under concentrated solar flux for the flexible production of renewable fuels.
Regarding the methodology, the design of MIEC membranes for optimized oxygen transport properties will be achieved at lab-scale by IEM, for proposing novel membrane configurations/architectures with detailed knowledge of oxygen permeability in comparison with ceria as benchmark. The best performing membranes will be shaped by additive manufacturing in the form of tubular prototypes by Marion Technologies. Such tubular membranes will be tested at PROMES for solar fuel production under high flux irradiation in a prototype solar reactor. The durability of the membrane performance will be evaluated on-sun to demonstrate the long-term stability, reliability, and robustness of the solar process. In addition, process simulations will be carried out to assess the process scalability and its potential for industrial scale solar fuel production.
The main positive impact of the project is the demonstration of a carbon-neutral green pathway to produce renewable fuels, directly compatible with current infrastructure and combustion engines, in an economically viable way. The project will demonstrate at lab-scale (TRL 4) a membrane process that combines concentrated sunlight with CO2 and H2O (+N2) as sole inputs, to produce strategic fuels. These outcomes of the project can contribute to achieving global net zero carbon emissions and sustainable development goals (in particular SDGs 7, 12 & 13). The 3 partners (PROMES coordinator, IEM, Marion Technologies) bring together the complementary expertise required in the different scientific and technical areas of the project.