Hydrogen permeation characteristics and stability of Ni-doped silica membranes in steam at high temperature

Kanezashi, Masakoto; Asaeda, Masashi

doi:10.1016/j.memsci.2005.07.011

Cited by 246 publications

(142 citation statements)

References 23 publications

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“…The reduction kinetics also needs high temperature preferentially ≥ 500 ºC as reported elsewhere for metal oxide silica membranes [1,15].…”

Section: Fig 1 the Volumetric Adsorption Systemmentioning

confidence: 84%

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Improved pore connectivity by the reduction of cobalt oxide silica membranes

Ji¹,

Smart²,

Bhatia³

et al. 2015

Separation and Purification Technology

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This work investigated the permeation of binary gas mixtures in non-reducing (He/CO 2 ) and reducing (H 2 /Ar) conditions at temperatures ranging from 200 to 500 ºC. A common performance aspect under both non-reducing and reducing conditions was that the He and H 2 purity in the permeate stream was independent of temperature for the tested binary gas mixtures, except at very high He/CO 2 or H 2 /Ar concentrations (≥90/10) in the retentate stream. Under non-reducing conditions, the transport of gases was consistent with molecular sieving properties of silica derived membranes, and He permeance was constant irrespective of the He/CO 2 binary concentration tested.An anomalous H 2 transport was observed under reduced conditions, as unexpectedly the H 2 permeance was higher for gas mixtures instead of single gas. Further tests showed that H 2 permeance increased 170% as the gas mixture changed from single H 2 gas to H 2 /Ar gas mixtures.This was attributed to the experimental procedure, as the membranes were partially reduced each day and tested for gas permeation from pure H 2 to lower H 2 concentration in gas mixtures. Under these partial reducing conditions, H 2 slowly reacts with the surface of the dense Co 3 O 4 particle, thus 2 forming a porous CoO region. The increase in H 2 permeance was therefore attributed to improved pore connectivity between the silica structure and the porous CoO region.

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“…The reduction kinetics also needs high temperature preferentially ≥ 500 ºC as reported elsewhere for metal oxide silica membranes [1,15].…”

Section: Fig 1 the Volumetric Adsorption Systemmentioning

confidence: 84%

“…Since then a variety of metal oxides have been investigated including Ni [1], Co [2], Nb [3], Pd [4] and binary metal oxides including FeCo [5].…”

Section: Introductionmentioning

confidence: 99%

Improved pore connectivity by the reduction of cobalt oxide silica membranes

Ji¹,

Smart²,

Bhatia³

et al. 2015

Separation and Purification Technology

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“…To address this problem, several groups have developed metal/alloys [15][16][17][18] or microporous ceramic membranes based on silica [19][20][21][22] and zeolites [23][24][25] for H 2 separation at high temperatures. In addition, membrane reactor configurations have been investigated, where WGSR catalysts and membranes are integrated into a single process unit for H 2 separation and the subsequent WGSR shifting, overcoming equilibrium limitations at the same time [25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Ultra-microporous membrane separation using toluene to simulate tar-containing gases

Deonarine

Smart

et al. 2017

Fuel Processing Technology

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This study investigates the performance of ultra-microporous cobalt oxide silica membranes for processing simulated gas streams containing toluene as a model tar compound in gasification. The performance of the membranes was initially investigated for He (simulating H 2 ), CO 2 , N 2 and Ar in a range of temperatures. Subsequently, toluene was added to a gas mixture containing He and tested to 2 simulate the effect of toluene as a tar compound in gasification. The membranes delivered molecular sieving features, showing activated transport as the permeation of the smaller molecular gas He increased with temperature whilst the permeation decreased for the other larger molecular gases. Prior to toluene exposure, He permeance increased by almost twofold from 3.6 × 10 -8 to 7.1 × 10 -8 mol m -2 s -1 Pa -1 as the temperature was raised from 50 to 200 °C. Under a feed gas containing 0.24 mol% toluene, He permeance decreased by an average value of 17%. Upon regeneration of the membrane by heat, He permeance was not fully recovered, a clear indication of tar fouling. A toluene balance calculation showed toluene being retained by the membrane.

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“…A possible approach to improve the gas permselectivity of these hybrid silica membranes is the incorporation of metal ions in the hybrid silica matrix. This approach was successfully implemented by doping the silica network with metal ions, such as aluminum and magnesium [16], zirconium [17,18], niobium [19,20], nickel [21] and cobalt [22,23]. For hybrid silica (i.e., BTESE), only the incorporation of niobia has been reported to date [24,25], where it is claimed that the introduction of niobia created surface active sites resulting in a reduced CO 2 permeance.…”

Section: Introductionmentioning

confidence: 99%

Doped microporous hybrid silica membranes for gas separation

Qureshi

Besselink

Elshof

et al. 2015

J Sol-Gel Sci Technol

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Hybrid silica (i.e., bis-triethoxysilylethane: BTESE) membranes doped with B, Ta or Nb were made through a sol-gel process. Triethyl borate, tantalum (V) ethoxide (TPE) and niobium (V) ethoxide (NPE) were selected as doping precursors. The doping concentration was optimized to produce sols, suitable for membrane fabrication. Thermal stability, structural analysis, crosssectional micrographs and single gas permeation experiments were performed on these membranes, and results are compared with an undoped BTESE membrane. It was observed that the synthesized doped BTESE materials and membranes resulted into a more open (and, in one occurrence, SF 6 permeable) pore microstructure, showing high permeances of larger gas molecules, while having a crosssectional thickness comparable to undoped BTESE membranes. Graphical Abstract& Louis Winnubst a.j.a.winnubst@utwente.nl;

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Hydrogen permeation characteristics and stability of Ni-doped silica membranes in steam at high temperature

Cited by 246 publications

References 23 publications

Improved pore connectivity by the reduction of cobalt oxide silica membranes

Improved pore connectivity by the reduction of cobalt oxide silica membranes

Ultra-microporous membrane separation using toluene to simulate tar-containing gases

Doped microporous hybrid silica membranes for gas separation

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