The paper describes the results of incremental activities to create a planar membrane module for the efficient high-temperature separation of oxygen to be used for its production in industrial settings. Previous activities have highlighted the significance of having membrane modules available for the production of pure oxygen in various processes in the industrial sector, with potential, important benefits in terms of energy efficiency of the processes and their decarbonization.

Research efforts have been mainly focused on the joining system between the ceramic membrane and the metal material of the module, to ensure an adequate gas seal. Therefore, joint tests begun in an previous period were continued, using a laboratory-developed glass-ceramic material potentially suitable for coupling the metal material (Inconel 625) with the LSCF membrane and, in parallel, using a commercial glass-ceramic material.

Specifically, in the first case, the process of deposition of theglassyslurrywas automated, initiating the development of a 3D printing process using therobocastingtechnique. A glassy paste with suitable rheological characteristics was identified and initial tests were initiated to define the optimal parameters, for obtaining a joint with well-controlled thickness and morphology.

In the second case, homogeneous joints were created by coupling samples of the same material (membrane-membrane, metal-metal) using the commercial glass-ceramic sheet. In all tests performed, joint failure was observed caused by a crack in the sealant, parallel to the interfaces. The fracture is less evident when splicing materials with lower thermal expansion, thus suggesting that the crack forms due to the different expansion between the layers. A thermomechanical model was developed that supports this hypothesis. The metal and ceramic with the lowest expansion (ODS steel and 70CGO-30LSCF composite, respectively) were spliced, yielding a promising glass-ceramic morphology.

In parallel, a literature review was begun on innovative materials for the development of ceramic membranes for oxygen separation, with the aim of improving their thermomechanical behavior. This study revealed that dual-phase composites enable a combination of sufficient oxygen permeation flux and dilatometric behavior compatible with metals and glass-ceramic sealants. With some ceramic powders of various morphologies, some tests were also carried out onmanufacturingasymmetric membranes using sequential tape casting, showing that the process can be applied for powders with specific surface area up to 10 m2/g and thus lends itself to being extended to innovative materials for which powders with low specific surface area are not available.