There are two main types of Solid Oxide Fuel Cells which can also be run in an electrolysis mode:
- Oxygen ion conducting Solid Oxide Fuel Cells (O=SOFC)
- Proton conducting Solid Oxide Fuel Cells (H+SOFC)
The working principles of both types of fuel cells are different what defines their influence on the steam cycle when integrated. O=SOFC generates hydrogen inside the steam flow by extracting oxygen, whereas H+SOFC will generate pure hydrogen and introducing oxygen into the steam at the same time. Both solutions have their pros and cons. Producing hydrogen inside a steam flow, gives certain difficulties with obtaining this gas at adequate purity afterwards. On the other hand, putting oxygen inside the steam cycle may cause with increase of corrosion processes, but amount of oxygen in steam flow is two times smaller than adequate amount of hydrogen.
Introducing of high temperature electrlysis into the steam cycle can dry a steam from moist by heating the steam up.
O=SOE
...
H+SOE