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The kinetics of the high-temperature (1070-1134 K), low and high-pressure gas-phase forward water-gas shift reaction were evaluated in an empty quartz reactor and a quartz reactor packed with quartz particles. The power law expression for the reaction rate was consistent with the Bradford mechanism and was invariant with respect to pressure. The(More)
The permeance of Pd–Cu alloys containing 40, 53, 60, and 80 wt.% Pd has been determined over the 623–1173 K temperature range for H 2 partial pressure differences as great as 2.6 MPa. Pure palladium and copper membranes were also evaluated. The Pd–Cu alloys exhibited predictable permeances that reflected the crystalline phase structures as shown in the(More)
The high-pressure (100-2500 kPa) hydrogen permeance of two membranes, each composed of a thin palladium film (~22 μm) deposited on the oxidized surface of a porous stainless steel tubular substrate (0.2 μm grade support) has been determined over the 623 – 723 K temperature range. The hydrogen flux was proportional to the H 2 partial pressure in the(More)
Metal membranes play a vital role in hydrogen purification. Defect-free membranes can exhibit effectively infinite selectivity but must also provide high fluxes, resistance to poisoning, long operational lifetimes, and low cost. Alloying offers one route to improve on membranes based on pure metals such as palladium. We show how ab initio calculations and(More)
The high-temperature rate of reaction of the homogeneous, reverse water-gas shift reaction, rWGSR, has been evaluated in quartz reactors with rapid feed pre-heating at low-pressure and high-pressure conditions. The form of the power-law rate expression was consistent with the Bradford mechanism. The Arrhenius expressions for the reaction rate constant(More)
14 The hydrogen permeability of bulk tantalum and tantalum coated with thin films of palladium was measured at temperatures from 623 to 1173 K and hydrogen partial pressures from 0.1 to 2.6 MPa in a flowing gas system. Palladium coatings were deposited by both electroless plating (1–2 ␮m thick Pd layer) and cold plasma-discharge sputtering with two(More)
Objectives • Evaluate water-gas shift (WGS) reaction kinetics and membrane flux using industrial gas mixtures and conditions • Test the feasibility of enhancing the WGS reaction at high temperature without added catalysts by using a membrane reactor Approach • Complete reverse kinetics and Computational Fluid Dynamics (CFD) modeling to optimize reactor(More)
Palladium-copper alloys continue to be of interest for hydrogen membrane applications because of their high catalytic activity for hydrogen dissociation, high hydrogen permeability, robustness, and degradation resistance in the presence of sulfur-containing compounds. This sulfur tolerance makes these alloys attractive for membrane applications where sulfur(More)
Hydrogen membranes have been identified as a promising technology for extracting pure hydrogen from processes such as coal gasification, hydrocarbon steam-reforming or any hydrogen producing process. Novel palladium-copper (Pd-Cu) alloys continue to be of interest due their highly catalytic surface, high performance, suppression of the hydride-phase(More)