Modeling the Steady-State and Transient Response of Polarized and Non-Polarized Proton-Conducting Doped-Perovskite Membranes

Abstract

This paper develops and demonstrates a model representing radial defect transport through proton-conducting ceramic membranes, such as might be used in shell-and-tube type membrane reactors. The model uses a Nernst–Planck–Poisson (NPP) formulation and is designed to represent both steady-state and transient responses within mixed-conducting membranes with multiple charge-carrying defects. The partial differential equations, representing defect and charge conservation, are solved computationally using the method-of-lines in a differential-algebraic setting. Several example problems are solved and discussed, illustrating important aspects of the model.

Fabrication and Performance of Tubular, Electrode‐Supported BaCe0.2Zr0.7Y0.1O3–δ Fuel Cells

“…The highly oxidizing conditions at the cathode result in a large concentration of holes on the cathode-side of the membrane and consumption of vacancies. The counterdiffusion of these charge carriers through the thin membrane enables charge transport in the absence of an external circuit [18], and open-circuit measurements that are below the theoretical Nernst potential [12]. The magnitude of this internal short could be considerable across thin membranes like those described here.…”

“…Such a straightforward measurement can provide insight into the roles of the different charge carriers in BCZY, and serve as a useful experimental data set for validation of computational models [12,21,22]. However, the result is limited to quantification of an integrated transference number, that is the sum of the transference numbers of the multiple charge carriers.…”

Process intensification in the catalytic conversion of natural gas to fuels and chemicals

“…One is based on palladium or palladium alloys [200] . The other is based on dense ceramic perovskites such as doped barium zirconates (e.g., BaZr 0.9 Y 0.1 O 3 −δ , BZY10), which are mixed ionic-electronic conductors [201][202][203][204] .…”

“…Because the electronic conductivity is also very low, it is possible to establish an electrostatic potential across the membrane, which can increase the proton flux by increasing the protonic migration. Although the electrode fabrication and attachment can be challenging, it is possible to control the hydrogen flux via electrical polarization [201] .…”

“…Thus, the net oxygen flux depends greatly on the operating temperature. Details for modeling the incorporation chemistry and the defect transport within the membrane may be found in previous publications [201][202][203][204] .…”