Steffen Schirrmeister

Hydrogen Production by Water Dissociation in Surface‐Modified BaCoxFeyZr1−x−yO3−δ Hollow‐Fiber Membrane Reactor with Improved Oxygen Permeation

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.

Olefin Production by a Multistep Oxidative Dehydrogenation in a Perovskite Hollow-Fiber Membrane Reactor

A multistep permeating hollow‐fiber membrane reactor is introduced with successive parts of permeable and passivated surface segments. This geometry allows a controlled oxygen insertion into the reactor over an extended length in order to overcome the equilibrium conversion. At the same time, it provides a lower oxygen concentration, which yields higher ethene selectivity by selectively burning off in situ the hydrogen formed by conventional catalytic dehydrogenation. In the range of low and moderate ethane conversions, this membrane reactor, by using a standard commercial catalyst, can compete with the best catalysts used in the cofeed mode of the oxidative dehydrogenation of ethane (ODE). Reaction conditions with long‐term stability could be established that have a comparable ethene yield to those in the industrial steam‐cracking process, but at a temperature that is approximately 100 °C lower.