(628b) High CO2 Separation Performance of Hydroxide-Ceramic Dual-Phase Membrane

High CO₂ separation performance of hydroxide-ceramic
dual-phase membrane

Azadeh Amiri¹, Li Sze Lai¹, Maira
R. Cerón², Matthew Merrill³, Patrick G. Campbell²,
Sangil Kim^1†

¹Department
of Chemical Engineering, University of
Illinois at Chicago, Chicago, IL 60607, USA

²Lawrence
Livermore National Laboratory, Livermore, CA 94550, USA

³Luna Innovations Inc., Charlottesville,
VA 22903, USA

^†-sikim@uic.edu

Dual-phase membrane based on molten electrolyte
has been proposed as a solution to
efficient CO₂ capture from flue gas because of their high CO₂
selectivity/permeance at high temperature (> 600 ^oC).
There is, however, no existing CO₂ separation membrane technology
which can operate in the 300 to 600 °C temperature range of incipient flue gas
(in between the combustion turbine and the primary heat exchanger). It has been recently reported that CO₂
absorption by alkali hydroxides (e.g.,
KOH) is reversible in the presence of H₂O due to a phase change near
250 ^oC. This reaction can be used as a basis for developing highly CO₂
selective dual-phase membranes.

To validate this concept, we have developed
a novel dual phase membrane consisting of molten hydroxide phase and a ceramic solid oxide phase. We investigated the gas separation performance of molten
hydroxide separation phase loaded in the Y₂O₃-ZrO₂
(YSZ) membrane supports. Single and binary gas permeation results showed that
hydroxides loaded YSZ membranes have high CO₂/N₂
selectivity (>1000) and CO₂ permeance is an order of magnitude
higher than the best values of other carbonate-based dual-phase membranes. Besides, the membrane is stable for more than
80 hours and the results are repeatable by
switching testing condition between dry and wet sweep condition. The
hydroxide-based dual-phase membrane can operate temperature ranges of 500^oC to650 ^oC which is close to the temperature range of the flue gas.