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Description: 9 > ? ( ing schedule included MTR, ETR, and other aluminum-type fuels that were processed through the TBP headend at 75 to 100% of flowsheet rates and through the Hexone second and third cycle extraction system at up to l5O% of flowsheet values, achieving an over-all recovery of 99.60%. In carrying out basic studies on aqueous zirconium processing, results obtained during the potentiometric titration of zirconium-fluoride-nitric acid solutions with sodium hydroxide were explained by a mechanism in which the untitrated zirconium fluoride species is converted to a fluozirconate and further hydrolysis proceeds via a fluozirconate route. A modified Zirflex flowsheet for processing 2.5% U-Zr alloy fuels is proposed as a result of bench scale dissolution studies on unirradiated PWR plates that showed that dissolver solutions could be stabilized by adding aluminum nitrate and nitric acid. that higher ammonium fluoride concentrations increased the dissolution rate, that higher hydrogen peroxide concentrations lowered the dissolution rate and decreased solution stability, and that ammonia removal by boiling with or without air sparging had little effect on the reaction. Density curves for Zirflex solutions are reported. First tests of the pilot plant for continuous dissolution of zirconium-type elements have indicated that the dissolution rate is approximately four times as great as predicted on the basis of batch dissolution rates and comparison with the rate ratio for batch vs. continuous dissolution of aluminum, which was used to establish the dissolver size. The continuous dissolution rate for a 2% zirconium- 98% uranium element was approximately proportional to the acid feed rate and reached l9O kg/day at an acid feed rate of 36 l/hr (11M nitric acid, 0.30M hydrofluoric acid, and 0.35M aluminum nitrate). Development of new waste treatment methods is influenced by waste volumes and the associated storage costs involved. A survey of current and proposed ...
Date: July 13, 1960
Creator: Slansky, C.M.; Warzel, F.M. & Bower, J.R. Jr. ed.
Partner: UNT Libraries Government Documents Department

Pentan isomers compound flame front structure

Description: The fuels (hexane, pentane, diethyl ether) and conditions investigated in this study are relevant to engine knock in spark- ignition engines. A review is provided of the field of low temperature hydrocarbon oxidation. Studies were made of radical and stable intermediate distribution in the front of cool flames: Maximum concentrations of H atoms and peroxy radicals were observed in the luminous zone of the cool flame front. Peroxy radicals appear before the luminous zone at 430 K due to diffusion. H atoms were found in cool flames of butane and hexane. H atoms diffuses from the luminous zone to the side of the fresh mixture, and they penetrate into the fresh mixture to a small depth. Extension of action sphear of peroxy radicals in the fresh mixture is much greater than that of H atoms due to their small activity and high concentrations.
Date: August 13, 1995
Creator: Mansurov, Z. A.; Mironenko, A. W.; Bodikov, D. U. & Rachmetkaliev, K. N.
Partner: UNT Libraries Government Documents Department

Enhancing low severity coal liquefaction reactivity using mild chemical pretreatment. Quarterly technical progress report, December 1991--February 1992

Description: In this paper, we describe results from a study in which mild chemical pretreatment of coal has been used to enhance low severity liquefaction reactivity. We have found that ambient pretreatment of eight Argonne coals using methanol and a trace amount of hydrochloric acid improves THF-soluble conversions 24.5 wt% (maf basis) for Wyodak subbituminous coal and 28.4 wt% for Beulah-Zap lignite with an average increase of 14.9 wt% for liquefaction of the eight coals at 623 K (350{degree}C) reaction temperature and 30 min. reaction time. Similar enhancement results occurred using, hexane or acetone in place of methanol. Pretreatment with methanol and HCI separately indicated that both reagents were necessary to achieve maximum liquefaction improvement. Acid concentration was the most important pretreatment variable studied; liquefaction reactivity increased with increasing acid concentration up to 2 vol%. No appreciable effect on reactivity was observed at higher acid concentrations. Although vapor phase alcohol/HCI mixtures have been shown to partially alkylate bituminous coals, analysis of Wyodak and Illinois {number_sign}6 coal samples indicated that no organic phase alteration occurred during pretreatment; however, over 90 wt% of the calcium was removed from each coal. Calcium is thought to catalyze retrogressive reactions during coal pyrolysis, and thus calcium removal prior to low severity liquefaction minimizes the rate of THF-insoluble product formation.
Date: July 13, 1992
Creator: Shams, K. G.; Miller, R. L. & Baldwin, R. M.
Partner: UNT Libraries Government Documents Department