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Theses/Dissertations

Chemical engineering

1986

Articles 1 - 5 of 5

Full-Text Articles in Engineering

An Integrated Study Of The Ceramic Processing Of Yttria , James Alan Voigt Jan 1986

An Integrated Study Of The Ceramic Processing Of Yttria , James Alan Voigt

Retrospective Theses and Dissertations

The preparation of a yttria ceramic, beginning with the continuous precipitation of a yttrium hydroxynitrate precursor by the reaction between yttrium nitrate and ammonium hydroxide, was studied to find the interrelationships among the various processing steps. Emphasis was placed on the effect of precipitation conditions on the characteristics of the precursor powder; the effect of these initial powder properties on the product from the subsequent calcination, pressing, and sintering operations was then examined;The precipitation process was modeled using a population balance approach which included the competitive kinetic rate effects of nucleation, crystal growth, agglomeration, and agglomerate break-up. Physically reasonable ...


Carbochlorination Of Metal Oxides Using A Fused Salt Slurry Reactor , Michael Sean Dobbins Jan 1986

Carbochlorination Of Metal Oxides Using A Fused Salt Slurry Reactor , Michael Sean Dobbins

Retrospective Theses and Dissertations

The carbochlorination of alumina and fly ash slurried with carbon in a NaCl-AlCl(,3) fused salt using chlorine was investigated at temper- atures between 530 and 800(DEGREES)C. The chlorination rates for up to 85g of alumina or 25g of fly ash in 375g of fused salt containing as much as 45g carbon were determined. Alumina chlorination rates ranging from 2.1(10('-4)) to 1.7(10('-3)) g-moles min('-1) were observed at tempera- tures between 530 and 800(DEGREES)C using a carbon loading of 12.86g. Recoveries of 73% Al(,2)O(,3), 83% Fe ...


Model Vanadium-Phosphorous-Oxygen Catalysts For The Selective Oxidation Of C4 Hydrocarbons To Maleic Anhydride , Thomas Patrick Moser Jan 1986

Model Vanadium-Phosphorous-Oxygen Catalysts For The Selective Oxidation Of C4 Hydrocarbons To Maleic Anhydride , Thomas Patrick Moser

Retrospective Theses and Dissertations

Two model vanadium-phosphorus-oxygen catalysts, (beta)-VOPO(,4) and (VO)(,2)P(,2)O(,7), were investigated for the selective oxidation of C(,4) hydrocarbons to maleic anhydride. Particular emphasis was given to the characterization of the functioning model catalysts using in situ laser Raman spectroscopy. Complementary techniques including X-ray powder diffraction and X-ray photoelectron spectroscopy were used for characterization of the fresh and used catalytic materials. The in situ Raman technique was particularly valuable since it made possible the characterization of catalyst features during C(,4) hydrocarbon oxidation which were otherwise undetectable by post-catalytic characterization. The direct observation of phase ...


Reversion Reactions Catalyzed By Glucoamylases I And Ii From Aspergillus Niger: Product Analysis, Kinetics Equilibria, And Modeling , Zivko Nikolov Jan 1986

Reversion Reactions Catalyzed By Glucoamylases I And Ii From Aspergillus Niger: Product Analysis, Kinetics Equilibria, And Modeling , Zivko Nikolov

Retrospective Theses and Dissertations

High performance liquid chromatography (HPLC) of carbohydrates and glucoamylase-catalyzed reversion reactions were studied in this work. The HPLC of twenty different disaccharides on prepacked amine-bonded silica columns using acetonitrile-water eluents was described in Section I. Glucopyranosyl-glucoses had increasing retention times in the order of linkage (1(--->)3), (1(--->)4), (1(--->)2) and (1(--->)1), and (1(--->)6). Replacement of one of the glucosyl residues by galactose led to longer retention times, while substitution by fructosyl residue yielded shorter ones. Replacement with two xylosyl residues or forced assumption of the furanose ring form by the fructosyl residue, as in sucrose and ...


Vanadium-Phosphorous-Oxygen Industrial Catalysts For C4 Hydrocarbon Selective Oxidation To Maleic Anhydride , Robert Wayne Wenig Jan 1986

Vanadium-Phosphorous-Oxygen Industrial Catalysts For C4 Hydrocarbon Selective Oxidation To Maleic Anhydride , Robert Wayne Wenig

Retrospective Theses and Dissertations

The selective oxidation of n-butane to maleic anhydride by vanadium-phosphorus-oxygen (V-P-O) industrial catalysts varying in P-to-V ratio has been studied. V-P-O catalysts have been synthesized, characterized, and the reactivity of these catalysts has been studied in a fixed bed integral reactor system. Catalyst characterization studies including X-ray diffraction, laser Raman spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray energy dispersive spectroscopy, and BET surface area measurements were used. A strong effect of P-to-V synthesis ratio on catalyst structure, catalyst morphology, vanadium oxidation state, and reactivity in n-butane selective oxidation was observed. A slight "excess" of catalyst phosphorus (P ...