Materials for separation membranes in hydrogen and oxygen production and future power generation

Abstract

Future fossil fuel power generation is likely to include technologies which increase process efficiency and reduce its impact on the environment, for example, CO 2 sequestration. Some of the key technologies identified for clean coal and natural gas combustion to produce power or hydrogen or both include O 2 generation/separation, H 2 and CO 2 separation. Hydrogen is considered as a potentially excellent substitute for transport fuels due to the concern over dwindling oil reserves and global warming. This paper discusses various separation processes that may be used in the industrial production of hydrogen from fossil fuels, with an emphasis on membrane separation technologies. Membrane separation has the advantage over other separation methods in that it is simple and potentially less energy intensive. Depending on the particular separation process utilised, however, the membrane materials can differ substantially. The materials used for H 2 , O 2 and CO 2 separation are discussed and the major similarities and differences between the membranes highlighted. Critical design aspects of the membrane such as multiple phase design, nano-structure control, the need for surface layers and fabrication processes are also reviewed as they represent the areas where most research and development effort is likely to be directed in the future. r

96Zr Tracer Diffusion in AZrO3 (A = Ca, Sr, Ba)

“…AZrO 3 perovskite materials are attractive due to their high proton conductivity, with potential applications in protonic ceramic fuel cells (PCFC), electrolyzers, gas sensors, and hydrogen membrane technology [1][2][3][4][5][6][7]. The majority of studies on AZrO 3 proton conductors have focused on the transport properties, but a recent study has also addressed the mobility of cations in the BaZrO 3 (BZ)-materials, revealing the challenges with solid state sintering of the ceramics and chemical instability in CO 2 at elevated temperature [8].…”

“…Knowledge of the difference in the cation mobility at the different cation sub-lattices is vital for the understanding of the long-term stability of the materials in chemical potential gradients [19]. Moreover, cation diffusion is also relevant for the reactivity of materials with e.g., CO 2 , as recently shown for BZ-materials [20]. Cation diffusion in oxides is important for the processing of dense ceramics, and AZrO 3 materials are known for their high melting temperatures and slow sintering rates [21][22][23].…”

Gas separation membranes made through thermal rearrangement of ortho-methoxypolyimides

“…In addition, membrane technology is a much more environmentally friendly process with low footprint than, for instance, traditional absorptive technologies. In this regard, some application examples of industrial interest can be mentioned: O2 or N2 enrichment [6,7], natural gas sweetening [8,9], air drying [10,11], recovering of H2 from the purges of ammonia synthesis or syngas production [12,13], recovering of toxic, volatile monomers as vinyl chloride [14], olefin/paraffin separation [15][16][17], recovering of CO2 and acid gases from flue gas mixtures [18,19], etc.…”

Developments in the Ni–Nb–Zr amorphous alloy membranes

“…In 2006, Phair and Donelson [16] reviewed developments in non-palladium alloy membranes related to design and preparation of alloys for hydrogen permeability, and critical performance features of Ti, Zr, Hf and V,Nb,Ta group of elements and alloys. Phair and Badwal [17] reviewed materials for separation of membranes for hydrogen and oxygen production, H2 and CO2 separation, and power generation. In 2006, Dolan et al [18] published a comprehensive review on hydrogen selective amorphous membranes.…”