Q2. What is the main transport mechanism in the support pores?
Since molecular diffusion is the main transport mechanism in the support pores, the structure of the porous support is crucial for the oxygen permeability in the supported thinfilm membranes.
Q3. What is the driving force for oxygen transport through a MIEC membrane?
The thermodynamic driving force for oxygen transport through a MIEC membrane is the oxygen chemical potential gradient along the thickness of the membrane, which is given by the operating conditions.
Q4. What was used as the sweep gas on the permeate side?
Synthetic air (21% v/v O2 in the feed stream) or pure oxygen was fed into the oxygen-rich chamber, while argon was used as the sweep gas on the permeate side.
Q5. What is the effect of concentration polarization on the oxygen activation layer?
In the feed gas, concentration polarization can occur especially at high permeation rates due to oxygen depletion in the gas phase above the support (RCP1).
Q6. What is the main reason for the high fluxes of the supported perovskite?
In relation to their potential application in oxyfuel processes, new highly permeable and stable materials must be developed to achieve high fluxes using recirculated flue gas as the sweep.
Q7. What is the effect of the RS2 limitation on the oxygen fluxes?
The oxygen fluxes obtained proved that it is possible to achieve extremely high electronic and oxide ion currents through the crystalline oxide when the other “external limitations” are removed or at least partially mitigated.
Q8. What is the effect of the resistances RCP1 and RSUPPORT on the flow?
As the resistances RCP1 and RSUPPORT were negligible and RS19/16was minimized, surface exchange (RS2) and bulk transport (RSOLID) became more important.
Q9. What is the likely cause of surface deposits?
These surface deposits are most likely caused by fouling, i.e. the deposition of particles (SiO2, CrOx, FeOx, etc.) from the piping, the quartz reactor or the sealing material.
Q10. What is the effect of surface modification on the JO2?
Several studies have shown that surface modification leads to an improved surface exchange rate and a corresponding increase in the JO2.
Q11. How large was the pore size of the membrane layer?
The pore size of the substrates ranged from 5 to 25 µm while the closed pores of the dense membrane layer had an average pore size of approx.
Q12. What is the effect of the increase in the gas flow rate on the oxygen permeation flux?
It can be ascertained that the increase in the sweep flow rate is very beneficial for the oxygen permeation, especially at the highest temperatures when the highest oxygen fluxes are reached.
Q13. What is the main reason for the low resistances in the support?
there is an engineering challenge in designing membrane module concepts with minimized resistances due to concentration polarization in the gas phases as well as in the support.
Q14. How can the oxygen permeation flux be adjusted?
In summary, the oxygen permeation flux can be adjusted by controlling the temperature, oxygen partial pressure gradient, and gas flow rates.
Q15. What is the effect of the gas concentration on the permeate side?
In this case, the gas concentration polarization effects on the permeate side (RCP2) may be very severe due to the very high oxygen flux achieved under these conditions.
Q16. What is the way to capture CO2 in a dry flue gas?
The CO2 can then be captured more easily than when air is used in the combustion process, which leads to 10-14% CO2 in the dried flue gas. [1]
Q17. What is the sintering shrinkage of the two tapes?
The sintering shrinkage of the two tapes has been adapted in such a way that a maximum match existed, leading to low bending of the co-sintered sample tracked by laser topography.
Q18. What is the effect of the deposition of a catalytic layer?
the effect of the deposition of a catalytic layer becomes more important with increasing sweep gas flow rates, as can be seen in Figure 6.