عنوان

Palladium-coated high-flux tubular membranes for hydrogen separation at high temperatures and differential pressures, and, Mathematical modeling of a fluidized bed reformer with oxygen input

TLpq304341465

انگلیسی

Palladium-coated high-flux tubular membranes for hydrogen separation at high temperatures and differential pressures, and, Mathematical modeling of a fluidized bed reformer with oxygen input

[Thesis]

M. T. Islam

B. B. Pruden

University of Calgary (Canada)

1997

164

M.Sc.

University of Calgary (Canada)

1997

Part I. This study was carried out to evaluate composite metal membranes for a fluidized bed membrane reactor application for the production of hydrogen. The membrane of choice was a palladium coated niobium-tantalum alloy membrane made commercially by REB Research & Consulting. In this application the tubular membranes were spring reinforced to resist collapsing from outside pressure at high temperatures. Permeabilities of spring reinforced palladium coated niobium-tantalum alloy tubular membranes (High-flux membranes) with different palladium coating thicknesses were measured in a fluidized bed environment for differential pressures as high as 1380 kPa and temperatures up to usd700\sp\circusdC. The hydrogen permeability for a High-flux membrane with 5.4 mum palladium coat was usd2.03\times 10\sp{-9}usd mol/(m.s.Pa) at usd700\sp\circusdC. The membrane's high flux and ability to operate at high temperatures and differential pressures would make it suitable for competitive membrane reactor applications. Part II. A fluidized bed steam-methane reforming reactor model was developed, and used to demonstrate the effects of providing oxygen in the feed so that the in situ oxidation of methane provides heat for the endothermic reforming reactions. The model predicts the composition of the gas stream at different heights in the catalyst bed as well as in the freeboard region. Simulation showed that a significant amount of reaction can take place in the freeboard region. For reforming in the absence of oxygen, a good match between experimental results reported by Adris (1994) and the model predictions was obtained. The autothermal mode of operation, achieved for certain ranges of operating variables, would eliminate the requirement for radiant heat thus enabling the use of a single large diameter reactor with less expensive materials of construction. Experimental studies are necessary to evaluate the performance of the reactor for this mode of operation.

Applied sciences

Chemical engineering

B. B. Pruden

M. T. Islam

p

[Thesis]

276903

a

Y