Performance Of Catalytic Membrane Reactor Research Articles

Effect of Asymmetric Membrane Structure on Hydrogen Transport Resistance and Performance of a Catalytic Membrane Reactor for Ethanol Steam Reforming.

The performance of catalytic membrane reactors (CMRs) depends on the specific details of interactions at different levels between catalytic and separation parts. A clear understanding of decisive factors affecting their operational parameters can be provided via mathematical simulations. In the present paper, main results of numerical studies of ethanol steam reforming, followed by downstream hydrogen permeation through an asymmetric supported membrane, are reported. The membrane module consists of a thin selective layer supported on a substrate with graded porous structure. One-dimensional isothermal reaction–transport model for the CMR has been developed, and its validation has been carried out by using performance data from a lab-scale reactor with a disk-shaped membrane. Simulations demonstrate the model’s capabilities to analyze local concentrations gradients, as required to provide accurate estimates of the relationship between structure–property–performance. It was shown that transport properties of multilayer asymmetric membranes are highly related to the structural properties of each single layer.

Simulation and design of catalytic membrane reactor for hydrogen production via methylcyclohexane dehydrogenation

In this study, we sought to optimize the performance of catalytic membrane reactors for the production of hydrogen through the dehydrogenation of methylcyclohexane. Finite element method was used to simulate the radial and axial distributions of velocity, temperature, and concentrations. We examined a number of design parameters and their effects on reactor performance, including the feed flow rate of methylcyclohexane, the mass of catalysts, and pressure on the permeation side of the hydrogen-selective membrane. Dimensionless analysis using the Damköhler number and Péclet number was also employed in the optimization of the reactor. The catalytic membrane reactor optimized in this work achieved a hydrogen production rate more than five times higher than that of existing systems based on the same reactor volume. Simulations at the microscopic scale were also performed to investigate the effects of the pore size and the porosity of the catalytic layer on hydrogen production.

Comparative study of propane steam reforming in vanadium based catalytic membrane reactor with nickel-based catalysts

The performance of catalytic membrane reactor with Pd-coated V membrane was examined for steam reforming of propane. The long term reforming experiment confirmed the stability of the V membrane with high hydrogen selectivity and permeability. The effect of types of hydrogen permeable membranes on the performance of the catalytic membrane reactor was studied by comparing Pd-coated V, Pd–23Ag, and Pd–10Ag membranes. The types of hydrogen separation membranes (i.e. hydrogen removal rates) did not have a marked effect on the propane conversion rates, while the product compositions were largely influenced by the hydrogen removal rate. Varying metal oxide supports of Ni-catalysts resulted in significant differences in the product compositions. Further, the evaluation of various catalyst-support systems (9wt%Ni–1wt%M/CeO2, M = Co, Pt, Ag, Ru) revealed that hydrogen yield was the highest when 1wt%Ag was added to Ni/CeO2. However, it was also found that excessive secondary metal additions can have negative impact on the catalytic behaviour of parent catalysts.

ChemInform Abstract: Dense Ceramic Catalytic Membranes and Membrane Reactors for Energy and Environmental Applications

AbstractReview: 132 refs.

Dense ceramic catalytic membranes and membrane reactors for energy and environmental applications

Catalytic membrane reactors which carry out separation and reaction in a single unit are expected to be a promising approach to achieve green and sustainable chemistry with less energy consumption and lower pollution. This article presents a review of the recent progress of dense ceramic catalytic membranes and membrane reactors, and their potential applications in energy and environmental areas. A basic knowledge of catalytic membranes and membrane reactors is first introduced briefly, followed by a short discussion on the membrane materials including their structures, composition and strategies for material development. The configuration of catalytic membranes, the design of membrane reaction processes and the high temperature sealing are also discussed. The performance of catalytic membrane reactors for energy and environmental applications are summarized and typical catalytic membrane reaction processes are presented and discussed. Finally, current challenges and difficulties related to the industrialization of dense ceramic membrane reactors are addressed and possible future research is also outlined.

Fabrication of multilayer ceramic membranes

AbstractThe development of multilayer mixed conducting oxide membranes on macroporous dead‐end tubular composite glass/ceramic substrates is presented. Sol modification of glass/ceramic substrate enhances the performance of catalytic membrane reactor (CMR) with reduced thickness of ceramic layers. The shrinkage misfit between support and ceramic layers can be regulated by different processing steps including sol modification of substrate and preliminary annealing of ceramic powders. Nanopowders of compatible complex perovskites as membrane materials were obtained by mechanochemical synthesis. Porous and dense ceramic layers were supported onto the internal wall of substrate by slip casting of slurries comprised of the narrow fractions of agglomerated powders dispersed in organic media with addition of surfactants. For SrFeO3‐based dense perovskite ceramics, both dynamics of oxygen loss at high temperatures and mechanical properties were found to be affected by the presence of SrSO4 surface inclusions formed due to sulfur admixture in starting reactants. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.

Performance of catalytic membrane reactor in multiphase reactions

Single-channel catalytic membranes were prepared using an evaporation-crystallization Pt deposition method and characterized by employing SEM, EDX and EPMA techniques. Their activity was tested by conducting liquid-phase formic acid oxidation, and effects of trans-membrane pressure difference, catalyst loading and re-circulation rate on their performance is reported. The results obtained have revealed that the measured conversions are preferentially determined by diffusion of formic acid through the top and intermediate layers to the reaction zone on one hand, and by concentration gradient of gaseous reactant on the other hand. Which effect prevails, depends on the position of gas–liquid interface and the instantaneous molar ratio of reactants. Finally, thickness and reactants' concentrations in the reaction zone established within the membrane wall were calculated.