COORSTEK Membrane Sciences is working with independent European research organisation SINTEF to scale up its novel electrochemical cell technology for efficient hydrogen production and simultaneous carbon capture. The technology has progressed to pilot scale, and industrial installations are expected in 2–3 years.
Currently, hydrogen is primarily produced from natural gas using steam methane reform, in an energy-demanding process that takes place in several stages, and produces carbon dioxide as a byproduct. Harald Malerød-Fjeld, Project Manager at CoorsTek, said that current hydrogen production methods are between 70–75% energy efficient, while the novel approach developed by CoorsTek has a potential efficiency of 90%. In 2017, the researchers successfully demonstrated the fundamental principles behind the approach and have now confirmed it works and begun scaling it up.
Malerød-Fjeld said: “This is an important step on the road to making hydrogen far more practical as a fuel.”
CoorsTek’s method relies on electrochemical cells, consisting of 6 cm long proton-conducting ceramic cylinders which can be scaled up into proton ceramic electrochemical reactor (PCER) stacks. In research published in April, the researchers created 36-cell stacks comprising a series of six barrels containing six single cells connected electrically by newly-developed metal/glass-ceramic composite washers.
Daniel Clark, Senior Scientist/Project Manager at CoorsTek, said that the composites which the researchers made are key to scaleup because “to scale proton-conducting membranes, it’s crucial that the cells can be connected together both electrically [and] maintain a strong, robust bond”. The researchers developed glass-ceramic and metal/glass-ceramic composites that can be shaped like glass during fabrication, and have the high-temperature robustness of a ceramic and the electronic conductivity of a metal. “This allows the ceramic membrane technology to go from small cells that are joined into stacks and further combined into bigger modules,” said Clark.
Clark also explained how the reactors are used to generate hydrogen. He said that a hydrogen-containing molecule – methane, biogas, or ammonia – enters the inlet of the 36-cell PCER operating at high temperature (650–750°C) and pressure (1–3 MPa). The reactor is kept in a steel tube, which keeps the gases under pressure. When the hydrogen containing molecule encounters the membranes, electricity separates the hydrogen atoms into their constituent protons and electrons.
The protons permeate the membrane, while electrons are captured by electrodes and transported around the membrane via an external electrical circuit. The protons and electrons are reunited on the other side of the membrane, generating pure (up to 99.995%), pressurised hydrogen (1–5 MPa).
When biogas or methane is used as the hydrogen carrier, carbon dioxide formed in the process becomes concentrated in the retentate stream which exits the stack. When ammonia is used, nitrogen is left in the retentate.
Thijs Peters, Senior Research Scientist at SINTEF, said: “What is interesting about this technology is that it has both short- and long-term relevance. It can be used not only for the production of blue hydrogen from natural gas, but also for green hydrogen from biogas or ammonia as part of a ‘more sustainable future’.”
Also, the process does not require external heat input because the electricity supplied to the ceramic membrane generates heat, which can be coupled with the heat requirements of the steam methane reforming or ammonia decomposition reactions. Clark said this allows for higher efficiencies versus comparable technologies.
CoorsTek was able to scale up its technology working closely with SINTEF, which tested the novel reactors and investigated how to integrate the hydrogen production concept into larger energy systems.
The partners continue to collaborate and have already taken the technology to the next stage, with pilot facilities five-times larger than the devices used in the April study installed in Dhahran, Saudi Arabia and Oslo, Norway. CoorsTek expects to install its first industrial installation for commercial production in the next 2–3 years.
Project financers include oil and energy companies ENGIE, ExxonMobil, Equinor, Saudi Aramco, Shell, and Total Energies, as well as Norwegian state-owned CCUS promotor Gassnova.
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