Hydrogen Production by Water Dissociation in Surface‐Modified BaCo_xFe_yZr_1−x−yO_3−δ Hollow‐Fiber Membrane Reactor with Improved Oxygen Permeation

Abstract

A porous perovskite BaCo(x)Fe(y)Zr(0.9-x-y)Pd(0.1)O(3-delta) (BCFZ-Pd) coating was deposited onto the outer surface of a BaCo(x)Fe(y)Zr(1-x-y)O(3-delta) (BCFZ) perovskite hollow-fiber membrane. The surface morphology of the modified BCFZ fiber was characterized by scanning electron microscopy (SEM), indicating the formation of a BCFZ-Pd porous layer on the outer surface of a dense BCFZ hollow-fiber membrane. The oxygen permeation flux of the BCFZ membrane with a BCFZ-Pd porous layer increased 3.5 times more than that of the blank BCFZ membrane when feeding reactive CH(4) onto the permeation side of the membrane. The blank BCFZ membrane and surface-modified BCFZ membrane were used as reactors to shift the equilibrium of thermal water dissociation for hydrogen production because they allow the selective removal of the produced oxygen from the water dissociation system. It was found that the hydrogen production rate increased from 0.7 to 2.1 mL H(2) min(-1) cm(-2) at 950 degrees C after depositing a BCFZ-Pd porous layer onto the BCFZ membrane.

Influence of the preparation methods on the microstructure and oxygen permeability of a CO2‐stable dual phase membrane

“…Similar results were reported in 75 wt % Ce 0. 8 Figure 10. Arrhenius plots of the oxygen permeation fluxes through 40NFO-60CGO dual phase membranes (for the experimental conditions see Figure 9).…”

Nitrogen Production by Efficiently Removing Oxygen From Air Using a Perovskite Hollow-Fiber Membrane With Porous Catalytic Layer

“…In addition, the oxygen permeation flux can be further improved if the permeated oxygen can be fast consumed on the permeate side of perovskite membrane. For example, Jiang et al (2010b) reported that, the oxygen permeation flux of a perovskite BaCo x Fe y Zr 1−x−y O 3−δ (BCFZ) hollow-fiber membrane increased from 3.3 to 8 cm 3 min −1 cm −2 when methane was fed on shell side at 875°C. Lobera et al (2012) further observed that when dilute methane was used as sweep gas in a perovskite Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ (BSCF) membrane reactor, the logarithm of oxygen partial pressure gradient increased from 1.16 to 4.02, resulting in a 2.5-fold increase of oxygen permeation flux.…”

Dense ceramic oxygen permeable membranes and catalytic membrane reactors

“…The advantages of this concept are: (i) the oxygen permeation flux can be increased by the decreased oxygen partial pressure on the permeate side; (ii) syngas can be produced in this operation, which can be applied in the production of oxygenates (methanol) and hydrocarbons (diesel), as well as the hydrogen production through CO + H 2 O ? H 2 + CO 2 , the water gas shift reaction operated at relatively low temperatures [202][203][204]. Fig.…”

“…At 950°C, 70% CH 4 conversion and 60% CO selectivity with the hydrogen rate of 3.5 ml/min cm 2 was obtained. In our recent work [203], a porous catalyst layer of BaCo x Fe y Zr 0.9ÀxÀy Pd 0.1-O 3Àd (BCFZ-Pd) was coated on the surface of BCFZ hollow fiber membrane. The production rate of hydrogen raised to 2.1 ml/ min cm 2 at 950°C, which was about three times of that with blank BCFZ membranes.…”