High temperature electrolyser with novel proton ceramic tubular modules of superior efficiency, robustness, and lifetime economy (ELECTRA) (completed)

About the project

High temperature electrolysers (HTEs) produce H₂ efficiently utilising electricity from renewable sources and steam from solar, geothermal, or nuclear plants. CO₂ can be co-electrolysed to produce syngas and fuels. The traditional solid oxide electrolyser cell (SOEC) leaves wet H₂ at the steam side. ELECTRA in contrast develops a proton ceramic electrolyser cell (PCEC) which pumps out and pressurises dry H₂ directly. Delamination of electrodes due to O₂ bubbles in SOECs is alleviated in PCECs. The proton conductor is based on state-of-the-art Y:BaZrO₃ (BZY) using reactive sintering for dense large-grained films, low grain boundary resistance, and high stability and mechanical strength. A PCEC can favourably reduce CO₂ to syngas in co-ionic mode. Existing HTEs utilise the high packing density of planar stacks, but the hot seal and vulnerability to single cell breakdown give high stack rejection rate and questionable durability and lifetime economy. ELECTRA uses instead tubular segmented cells, mounted in a novel module with cold seals that allows monitoring and replacement of individual tubes from the cold side. The tubes are developed along 3 design generations with increasing efforts and rewards towards electrochemical performance and sustainable mass scale production. Electrodes and electrolyte are applied using spraying/dipping and a novel solid state reactive sintering approach, facilitating sintering of BZY materials. ELECTRA emphasises development of H₂O-O₂ anode and its current collection. It will show a kW-size multi-tube module producing 250 L/h H₂ and CO₂ to syngas co-electrolysis with DME production. Partners excel in ceramic proton conductors, industry-scale ceramics, tubular electrochemical cells, and integration of these in renewable energy schemes including geothermal, wind and solar power.

Objectives

The main goal of ELECTRA is to design, build, and test a kW size multi-tubular proton ceramic high temperature electrolyser for production of hydrogen from steam and renewable energy.

Sub goals:

• Develop efficient and stable oxygen side electrodes with integrated current collection
• Develop segmented-in-series proton ceramic tubular cells
• Design and test a system for mounting, contacting, monitoring, closing, and replacing each tube in a single tube unit.
• Design and build a multi-tubular module with its necessary periphericals for heat, steam, gas, and electrical management.
• Test the multi-tubular unit for production of 250 L/h hydrogen.
• Test the single tube unit in co-ionic co-electrolysis mode for production syngas and DME from CO₂ and steam.
• Analyse the use of PCEC modules for hydrogen production and CO₂ co-electrolysis from sources of steam, CO₂, and renewable energy.

Financing

The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative and the Research Council of Norway.

Cooperation

The project counts 7 partners (4 SMEs/industry), is coordinated by University of Oslo, and runs for 3 years.