Reactor design for oxygen-conducting separation membranes

The success of the energy transition depends on the global energy sector switching from fossil fuels to carbon-free energy sources by the second half of this century. And by reducing energy-related CO₂ emissions in order to mitigate climate change and limit global temperatures. The production of green hydrogen using membrane reactors, for example, can help to achieve this goal.

The ceramic membrane of the reactor enables power-to-X processes such as the decomposition of water vapour by removing oxygen. The membrane is therefore the centrepiece of the system. In order for the membrane to work optimally, it is important that the temperature is as high as possible, the gas flow is homogeneous and sufficient, the membrane is highly impermeable and can be used cyclically in the reactor without components failing. These requirements apply not only to the membrane and its connection, but also to the gas-conducting housing, which consists of several layers for reasons of scalability. Until now, the layers, like the membrane, have been joined by soldering processes in order to fulfil the requirements. However, as soon as a membrane cell or a membrane connection fails, the reactor can no longer be used.

The soldering processes make analysing a tested prototype costly and there is a risk of components being destroyed when the stack is opened. A new concept for the design of a housing for the use of flat membranes should make it possible to separate the reactor to replace membrane layers. It is possible that the content of high-alloy steels and the number of brazing layers will be reduced, which may have a positive effect on the cost structure and manufacturing time of the reactor. Last but not least, the scrap of membrane layers can also be reduced, which is in line with the original sustainability concept.