New proton ceramic reactor stack for highly efficient hydrogen production and carbon capture in a single step
A team of researchers from CoorsTek Membrane Sciences and SINTEF in Norway, and Universitat Politècnica de València in Spain, has demonstrated a 36-cell well-balanced proton ceramic reactor stack enabled by a new interconnect that achieves complete conversion of methane with more than 99% recovery to pressurized hydrogen, leaving a concentrated stream of carbon dioxide. The team has also demonstrated that the process can be scaled up for commercial application.
A paper on the work is published in the journal Science.
Proton ceramic electrochemical reactors can extract pure hydrogen from gas mixtures by electrolytically pumping protons across the membrane at 800 °C. However, as the extraction proceeds, temperature gradients and entropic effects lead to efficiency drops. The new nickel-based glass-ceramic composite interconnect allowed for the design of a more complex reactor pathway. Counterflowing streams balanced heat flows and maintained stable operating conditions that enabled 99% efficiency of hydrogen recovery.
This figure shows the principles behind the new ceramic membrane used in the production of hydrogen. Figure courtesy of CoorsTek Membrane Sciences.
Currently established methods have energy efficiency ratings of between 70 and 75 percent, but our approach has a potential efficiency of 90 percent. The end product is compressed hydrogen with a high degree of purity. The ceramic membrane reactor also separates carbon dioxide more efficiently, enabling the greenhouse gas to be easily transported and sequestered.
This is an important step on the road to making hydrogen far more practical as a fuel. The process also has a low carbon footprint.—Harald Malerød-Fjeld at CoorsTek Membrane Sciences
The research is being carried out at SINTEF’s facilities and laboratories in Oslo, which are co-located with CoorsTek Membrane Sciences’ premises.
The steam reforming technology used for producing hydrogen from natural gas is well known. A major problem associated with steam reforming is that the process is energy-demanding and takes place in several stages. It also has CO2 as a by-product. The new technology, on the other hand, requires no external heat to drive the steam reforming process. A key to the new process is that heat is produced automatically when the hydrogen is being pumped through the ceramic membrane. In this way the heat is generated exactly where it is needed.
The smallest building block used in the new method is an electrochemical fuel cell that consists of a six-centimeter long ceramic cylinder. The scaled-up membrane reactor measures 4 by 40 centimeters. It is made up of 36 such cells that are connected to form a continuous electrical circuit.
The material that connects the cells consists of a glass-ceramic which, as the name suggests, is a composite of both glass and ceramic materials, such as porcelain.This material is then mixed with an electrically conductive metal powder.
According to CoorsTek Membrane Sciences, the development of this material has been key to making the scaling-up process possible. The reactor membrane is then placed in a steel tube that keeps the gases under high pressure.
On encountering methane (CH4), the proton ceramic membrane breaks the individual atoms down into their constituent protons and electrons. The positively-charged protons permeate through the membrane, while the electrons are captured on the electrodes and transported around the membrane via an external electrical circuit. When the protons and electrons are reunited on the other side of the membrane, the product is pure, compressed hydrogen.
The technology behind this new ceramic membrane reactor for hydrogen production has been developed by researchers at CoorsTek Membrane Sciences, the University of Oslo and Instituto de Tecnologica Quimica in Valencia, Spain. SINTEF’s role in the project has been to test the reactors and to look into how this new hydrogen production concept can be integrated into a larger energy system.
The next stage in the development of this technology is already well underway. A pilot facility has been established in Dhahran in Saudi Arabia. The generator installed at this facility, which is five times bigger than the one described in the Science paper, has also been shown to work.
We’re certain that this technology can be scaled up even further. Our hope is that the first industrial installation of a commercial hydrogen production system can take place in the next two to three years.—Harald Malerød-Fjeld
SINTEF is continuing to collaborate with CoorsTek Membrane Sciences on the development of larger membrane reactors, and both organizations are working on other projects related to materials technology.
The research is being financed by ENGIE, ExxonMobil, Equinor, Saudi Aramco, Shell and Total Energies. The project is also being funded by Gassnova as part of the CLIMIT CO2 management research program. The research is being carried out under the Open Innovation model, by which all project partners have full access to all data generated during the project.
Clark Daniel et al. (2022) “Single-step hydrogen production from NH3, CH4, and biogas in stacked proton ceramic reactors” Science doi: 10.1126/science.abj3951