Continuous Solar-Powered Syngas Production: Advancements and Insights from the EU SOMMER Project

Abstract

The EU-funded SOMMER (Solar Membrane Reactor for Syngas Production) project is developing a renewable, solar-driven method for producing syngas—a key chemical-industry feedstock traditionally derived from fossil fuels. Syngas (H₂ + CO) is used to make methanol, DME, formaldehyde, acetic acid, fuels, plastics, fertilizers, and other industrial materials. SOMMER aims to replace fossil-based production by converting water and captured CO₂ (from industrial emissions or direct air capture) into syngas using concentrated solar energy, supporting a climate-neutral chemical sector.

At the core of the project is a solar-powered catalytic membrane reactor that converts H₂O and CO₂ without external electricity. High-temperature ceramic membranes—CaO-FSZ and STF—were selected for their thermal stability (up to 1500 °C) and catalytic efficiency. They are produced via extrusion (porous tubes with dense functional layers) and 3D printing (optimized geometries for higher power density). New fast-kinetic redox catalysts and CFD-validated membrane models support the reactor design. After fabrication, membranes undergo extreme-temperature testing before integration and evaluation under on-sun and off-sun conditions at DLR’s High-Performance Solar Facility. Generated syngas is then upgraded into methanol, DME, and other green chemicals, with roadmap activities addressing the entire CO₂ value chain.

The project has made significant progress in optimizing solar membrane reactor operation. Key parameters—sweep-gas flow, molar ratios, temperature, and pressure—were analyzed for their effect on conversion. High sweep-gas flow rates enhance conversion during on-sun operation, while lowering permeate-side pressure reduces sweep-gas demand. In off-sun conditions, adding reducing agents improves the oxygen partial-pressure gradient and boosts efficiency. Parallel efforts led to advanced CaO-FSZ and STF membranes with high thermal stability and catalytic performance (CaO-FSZ stable at 1500 °C; STF active around 900 °C). Tailored-porosity tubular membranes were successfully fabricated, and a new lab-scale setup capable of reaching 1500 °C now enables kinetic studies of oxygen permeation and syngas formation—critical steps toward viable solar-powered syngas production.