Design and fabrication of large-sized planar oxygen transport membrane components for direct integration in oxy-combustion processes

Abstract

Membrane-based oxy-combustion is a promising technology for energy efficient combustion of carboncontaining fuels with the simultaneous opportunity to capture CO2 from the resulting exhaust gas.However, oxy-combustion conditions result in special demands on the design of the ceramic membrane components due to the high pressure and temperature applied. Therefore, we have developed a planar membrane design for 4-end operation using asymmetric membranes of La0.6Sr0.4Co0.2Fe0.8O3-δ. FEM and CFD simulations have been performed in order to develop an internal channel structure that allows withstanding pressures of 5 bar on the feed side while achieving the desired O2 concentrations of 27 % in the sweep gas, i.e. CO2, and an oxygen recovery rate from the feed gas of 86 % at the same time.Due to the symmetric design of the membrane components, they are scalable and adaptable in size. This design has been realized in a process chain from powder to the final component consisting of thin 20 µm Membrane layer, support with 38 % porosity, an inner channelled architecture and a thin (3-5 µm) porous activation layer. Particular emphasis was laid on scalable manufacturing processes in order to ensure transferability to industrial scale. The process chain is also applicable to other membrane materials suitable for any application of interest. Finally, the reproducible processing was successfully demonstrated by the fabrication of membrane components in lengths of 100 mm and widths of 70 mm.

Asymmetric LSCF Membranes Utilizing Commercial Powders

“…The microstructure of the sintered samples was compared with an asymmetric LSCF reference membrane manufactured by tape casting [26].…”

“…Table 1), densification starts at around 1100 • C, while the obtained relative density of the pellet is below 60% at 1300 • C without dwell time, when starting from a relative green density of 40%. To achieve a sufficiently high densification, it is necessary to increase the sintering temperature to at least 1300 • C, as reported in [26] and shown in the inset of Figure 4.…”

“…In the present work, five commercially available LSCF powders were characterized and compared with a custom powder, manufactured as Research&Development (R&D) Batch by Solvay, Belgium, specifically for tape casting and successfully used to manufacture asymmetric membranes by tape casting in the FP7 EU project GREEN-CC [26]. The most promising commercial powder was identified and used for slurry development.…”

“…The most promising commercial powder was identified and used for slurry development. The slurry composition was identified starting from an already published reference recipe for the manufacturing of asymmetric membranes [12,26]. The debinding process for tape cast membranes was optimized accordingly, and the microstructure of the sintered membranes was analyzed and compared to the LSCF membrane reported in literature.…”

Ceramic Membranes: Materials – Components – Potential Applications

“…Despite the fact that membrane modules for the supply of pure oxygen and hydrogen have already been developed on a pilot scale within various EU programs (HETMOC , GREEN‐CC , and ELECTRA ), and that industrial‐scale plants have now been established by the US companies Praxair and Air Products , there is still a pressing need for further development. In addition to module design and structure, another challenge yet to be fully met is the high‐temperature joining of thin supported membranes to assemble a reactor.…”