Solar-Based Membrane Reactor For Syngas Production

Project Information

SOMMER

Grant agreement ID: 101118293

DOI

10.3030/101118293

EC signature date 26 June 2023

Start date 1 November 2023

End date 31 October 2027

Funded under

• Climate, Energy and Mobility

Total cost

€ 4 711 516,25

EU contribution

€ 4 711 516,25

Coordinated by

DEUTSCHES ZENTRUM FUR LUFT - UND RAUMFAHRT EV
Germany

Periodic Reporting for period 1 - SOMMER (Solar-Based Membrane Reactor For Syngas Production)

Reporting period: 2023-11-01 to 2025-04-30

Summary of the context and overall objectives of the project

Syngas, a mixture of H2 and CO, is an important intermediate product in the chemical industry, widely used for producing methanol, fuels, and other chemicals. Traditionally, syngas is derived from natural gas via methane reforming, a process that emits 1.5 to 1.8 kg CO2 per kg of syngas, significantly contributing to global warming. Around 70% of these emissions stem from process-related CO2 released during reforming, while an additional 25% of natural gas consumption is used to fuel the endothermic reaction. SOMMER aims to tackle the required transition by developing and demonstrating a novel carbon-neutral syngas production path that integrates concentrated solar energy directly into the process. At the core of SOMMER’s approach lies a solar-powered catalytic membrane reactor that converts H2O and CO2, e.g. captured from high-emission industries or direct air capture, into syngas in a one-step thermochemical process. This eliminates the need for fossil-based energy and replaces natural gas feedstock with renewable CO2. Key outcomes include the experimental demonstration of this innovative technology, the development of high-performance, cost-effective catalytic membranes, and advancements in membrane manufacturing through slip-casting and additive manufacturing. Additionally, SOMMER aims to enhance operational flexibility by enabling two modes: (I) a purely solar-driven process at 1500°C and (II) a biogas-supported approach at 900°C to ensure continuous, round-the-clock operation regardless of sunlight availability. Beyond technology demonstration, SOMMER will assess the technological, ecological, and economic potential of solar syngas production, contributing to a detailed roadmap for commercialization. By bridging cutting-edge research with industrial application, SOMMER aims to set the foundation for a sustainable, scalable, and economically viable alternative to conventional syngas production, significantly reducing carbon emissions in the chemical industry. It approaches supports the EU’s climate mitigation targets and fosters a circular carbon economy, making it a practical solution especially in regions with high solar availability and industrial CO2 emissions.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

As part of the SOMMER project, significant technical and scientific progress was made towards developing a solar-driven membrane reactor for sustainable syngas production. The project focused on two main operation cases:

1. CASE I (1500 °C, solar-driven): Various ceramic membrane materials were evaluated, with Yttria-Stabilized Zirconia (YSZ) and Gadolinium-Doped Ceria (GDC) emerging as the most suitable due to their thermochemical stability. YSZ was found compatible with both conventional processing methods and manufacturability via both slip casting and additive manufacturing (3D printing), while 3D printing of GDC was not feasible. Corrugated membrane geometries were successfully printed and tested; however, scalability remains a challenge, this prompted the exploration of hybrid assembly solutions.

2. CASE II (900 °C, biogas-supported): Strontium Titanium Ferrite (STF) and GDC were selected for their excellent oxygen permeation and catalytic potential. STF-based asymmetric membranes were fabricated using slip casting and extrusion methods, with extrusion being further developed for the required reactor-scale geometries.

High-temperature electrical conductivity measurements and mechanical creep behavior tests were performed on candidate materials, addressing long-term stability and mechanical integrity under extreme conditions.
New membrane reactor components and sealing techniques were validated. A custom-built test rig was developed for kinetic and performance evaluations, supporting both membrane disc and tube formats under simulated CASE I and CASE II conditions.
Significant progress was made in defining the operating conditions for the solar membrane reactor and outlining the downstream process for methanol synthesis. Efforts included optimizing the reactor for converting H2O and CO2 into syngas and designing the downstream process based on the expected syngas composition.

Advanced multi-physics simulations, including thermodynamic and CFD models, guided reactor design and material selection. Simulation work identified the importance of low oxygen partial pressures, sweep gas flow optimization, and membrane geometry in achieving high conversion rates. Reactor design iterations ensured compatibility with membrane properties and thermal constraints.

Optical and thermal simulations of solar flux distribution informed the design of the cavity receiver for solar irradiation, optimizing temperature homogeneity along the membrane.
Initial reactor designs have been completed and optimized for both operational cases, ensuring high-efficiency performance under solar and biogas-assisted conditions.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The SOMMER project demonstrated several state-of-the-art breakthroughs that advance the current state of solar-thermochemical syngas production:

- Identification and experimental validation of doped YSZ and STF as leading candidates for high-temperature membrane reactors.
- Development of printable ceramic structures and hybrid joining techniques for scalable reactor integration.
- Unique experimental data on high-temperature conductivity (up to 1500 °C) and mechanical creep in doped ceramics, which are scarce in current literature.
- Creation of a robust test infrastructure for evaluating mixed-conducting membranes under realistic conditions to identify rate-limiting or synergistic effects. Commissioning of the test unit is currently underway.
- Coupled reactor-process modelling linking upstream membrane performance with downstream syngas-to-methanol conversion, supporting full system integration.
- Optical and thermal validation of cavity receiver concepts for concentrated solar input, enabling uniform heating critical for CASE I.
- Development of uniquely scaled-up solar membrane reactor designs to achieve optimal conversion.

Full-System Schematic of the SOMMER Project Scope