Use of Pd membranes in catalytic reactors for steam methane reforming for pure hydrogen production

Design concepts of a scaled-down autothermal membrane reformer for on board hydrogen production

“…A m pre-exponential factor of membrane permeance ½mol=m 2 s ffiffiffiffiffiffiffi ffi bar p A Ox pre-exponential factor of CH 4 (2) implies that for adiabatic system the maximal molar ratio of H 2 generated/CH 4 consumed is 3.3, as opposed to stoichiometrically 4. Recuperation of heat, at least in part, will require arranging the streams in either reversed-flow or counter-current mode, as we do here.…”

“…The Cu based catalysts are not used at the high temperature stage due to sintering. These steps are followed by pressure swing adsorption (PSA) for CO 2 reforming) for clearing any residual CO [1]. Clearly this production scheme, which is adopted in large scale production ($10 5 Nm 3 /h) and in an efficient way, is too complicated for a scale down process aimed at producing small on demand amounts of H 2 (0.1-10 Nm 3 /h).…”

“…The use of highly selective Pd based membranes for pure H 2 -production in integrated membrane reactors has been investigated in the last two decades; see recent reviews by Shigarov et al [2] and Gallucci et al [3]. Recent advances in Pd membranes production techniques have led to higher H 2 fluxes, and along with the increasing demand for clean H 2 production, either on board or in decentralized fueling stations, serve as the main incentive for optimizing process design of these complex systems.…”

Computational study of Pd-membrane CH4 steam reformer with fixed catalyst bed: Searching for a way to increase membrane efficiency

“…Turning back to MRs with a fixed bed catalyst, the authors [22] believe, that the potential of such membrane reformers has not yet been completely realized. The suggested in that paper way to overcome concentration polarization and heat transfer limitations is the usage of specially structured catalyst bed with enhanced radial mixing properties.…”

“…In principle the relations (22)(23) are approximate in nature and are derived analytically from rigorous 2D-model solution only for parabolic temperature and concentration radial/ transversal profiles (with additional assumption that axial gradient is only weekly dependent on the radial coordinate). But the relations (22-23) may also be used as good approximation in general case.…”