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Effects of minerals on the pyrolysis of Kern River 650 F{sup +} residuum

Description: Kern River 650 F{sup +} residuum (Kern Co, CA) and mixtures of Kern River 650 F{sup +} residuum with solids were examined by micropyrolysis at nominal constant heating rates from 1 to 50 C/min from temperatures of 100 to 700 C to establish evolution behavior, pyrolysate yields, and kinetics of evolution. The profiles for all samples generally exhibited two regimes of evolution: (1) low temperature (due to distillation), and (2) high temperature (due to cracking and distillation). The pyrolysate yields of the residuum alone and residuum with solids exhibited, with increasing sample size, a broad maximum at 0.005 to 0.010 g of {approximately} 1,000 mg pyrolysate/g residuum (relative to Green River oil shale Fischer Assay yield) as well as shifting of distribution from distillation to cracking regime. For kinetic parameters, because much of the low temperature evolving data was due to volatilization and not cracking, determinations were limited mostly to the discrete method. The best fits exhibited very similar parameters for all the samples have principal E{sub discrete} of 50 to 51 kcal/mol (accounting for {approximately}30% of total energy) and A{sub discrete} around 10{sup 12} to 10{sup 13} sec{sup {minus}1}. These results indicate the use of heat carriers, such as alumina or dolomite, in pyrolysis processing of heavy oils may effect the overall yields of the pyrolysate, but will probably not effect the pyrolysis cracking rates.
Date: April 1, 1995
Creator: Reynolds, J.G. & King, K.J.
Partner: UNT Libraries Government Documents Department

Destruction of 2,4,6-trinitrotoluene using ammonium peroxydisulfate

Description: TNT was destroyed in a small batch reactor, using uncatalyzed 4 N ammonium peroxydisulfate at 95 {degrees}C. The material was destroyed below limit of detection in less that 15 minutes, indicating a formal order rate constant of 0.06 min{sup -1}. A crude estimate of scaleup rates indicates a throughput of 1 tonne/m{sup 3}-day.
Date: July 1996
Creator: Cooper, J. F.; Wang, F.; Shell, T. & King, K.
Partner: UNT Libraries Government Documents Department

Effect of Nitrate on the Critical Potentials of Alloy 22 in Chloride Containing Environments

Description: The study of Alloy 22 has been undertaken in several selected nitrate/chloride (NO{sub 3}Cl{sup -}) electrolytes. These electrolytes include chloride concentrations [Cl{sup -}] of 1.0, 3.5 and 6.0 metal with NO{sub 3}/Cl{sup -} ratios of 0.05, 0.15 and 0.5 at various temperatures. Alloy 22 maintains is passivity in most industrial environments. As a result, it is highly desirable for numerous industrial applications including underground waste disposal systems. Alloy 22 possesses remarkably low general corrosion rates. It has exceptional resistance so localized corrosion including environmentally assisted cracking [1-7]. Alloy 22 (N06022) is a nickel(Ni)-alloy and contains 22% chromium (Cr), 13% molybdenum (Mo), 3% tungsten (W) and about 3% iron (Fe). The goal of this study was to determine the levels of NO{sub 3} required for effective inhibition of crevice corrosion at Alloy 22. To achieve this, carefully designed statistical cost matrices covering the selected range of CT compositions and temperatures were employed in carrying out the experiments. Specimens for three experiments were in the form of multiple crevice assemblies (MCA), optimized with 24 artificial crevice sites. Tests used in this investigation involved open circuit potential monitoring, polarization resistance, and cyclic polarization experiments. Potentiostatic polarization test were also employed.
Date: May 13, 2004
Creator: Ilevbare, G.; King, K.; Gordon, S.; Gdowski, G.; Elayat, H. & Summers, T.
Partner: UNT Libraries Government Documents Department

Effect of Nitrate on the Repassivation Potential of Alloy 22 in Chloride Containing Environment

Description: The study of Alloy 22 was undertaken in several selected nitrate/chloride (NO{sub 3}{sup -}/Cl{sup -}) electrolytes with chloride concentrations [Cl{sup -}] of 1.0, 3.5 and 6.0 molal with [NO{sub 3}{sup -}]/[Cl{sup -}] ratios of 0.05, 0.15 and 0.5 at temperatures up to 100 C. The repassivation potentials increased with increase in [NO{sub 3}{sup -}]/[Cl{sup -}] ratio and decreased with increase in temperature. The absolute [Cl{sup -}] was found to have less of an effect on the repassivation potential compared with temperature and the [NO{sub 3}{sup -}]/[Cl{sup -}]. Regression analyses were carried out to describe the relationship between the repassivation potential, temperature, [Cl{sup -}] and [NO{sub 3}{sup -}] for the conditions tested.
Date: September 21, 2004
Creator: Ilevbare, G.; King, K.; Gordon, S.; Elayat, H.; Gdowski, G. & Summers, T.
Partner: UNT Libraries Government Documents Department

Stress Corrosion Cracking Behavior of Alloy 22 in Multi-Ionic Aqueous Environments

Description: The US Department of Energy is characterizing a potential repository site for nuclear waste in Yucca Mountain (NV). In its current design, the nuclear waste containers consist of a double metallic layer. The external layer would be made of NO6022 or Alloy 22 (Ni-22Cr-13Mo-3W-3Fe). Since over their lifetime, the containers may be exposed to multi-ionic aqueous environments, a potential degradation mode of the outer layer could be environmentally assisted cracking (EAC) or stress corrosion cracking (SCC). In general, Alloy 22 is extremely resistant to SCC, especially in concentrated chloride solutions. Current results obtained through slow strain rate testing (SSRT) shows that Alloy 22 may suffer SCC in simulated concentrated water (SCW) at applied potentials approximately 400 mV more anodic than the corrosion potential (E{sub rr}).
Date: July 15, 2002
Creator: King, K.J.; Estill, J.C. & Rebak, R.B.
Partner: UNT Libraries Government Documents Department

Methods of Calculation of Resistance to Polarization (Corrosion Rate) Using ASTM G 59

Description: The corrosion rate of a metal (alloy) can be measured using: (1) Immersion tests or weight loss such as in ASTM G 1 and G 31 or (2) Electrochemical techniques such as in ASTM G 59. In the polarization resistance (PR) or linear polarization method (G 59), the resistance to polarization (Rp) of a metal is measured in the electrolyte of interest in the vicinity of the corrosion potential (E{sub corr}). This polarization resistance can be mathematically converted into corrosion rates (CR). A plot of E vs. I in the vicinity of E{sub corr} is generated by increasing the potential at a fixed rate of 0.1667 mV/s and measuring the output current. The polarization resistance (Rp) is defined as the slope of a potential (E) (Y axis) vs. Current (I) (X axis) plot in the vicinity of the corrosion potential (E{sub corr}). When the potential is ramped and the current is measured, E is the independent variable and I is the dependent variable. In a proper mathematical plot, E should be represented in the X axis and I in the Y axis. However, in the conventions of the corrosion community, E is always plotted in the Y axis and I in the X axis. Therefore, how this plot of Delta E/Delta I is analyzed is a matter of current debate.
Date: February 5, 2006
Creator: Wong, L L; King, K J; Martin, S I & Rebak, R B
Partner: UNT Libraries Government Documents Department

Corrosion Rate of Alloy 22 as a Function of Immersion Time

Description: Alloy 22 (N06022) is a nickel (Ni) based alloy containing nominally 22% Chromium (Cr), 13% Molybdenum (Mo) and 3% tungsten (W). Alloy 22 is highly resistant to general and localized corrosion such as pitting corrosion and stress corrosion cracking. Due to the formation of a stable passive film, when Alloy 22 is immersed in certain electrolytes, its corrosion potential (E{sub corr}) increases and its corrosion rate (CR) decreases as a function of the immersion time. This paper discusses the evolution of E{sub corr} and corrosion rate (CR) of creviced Alloy 22 specimens in six different mixtures of sodium chloride (NaCl) and potassium nitrate (KNO{sub 3}) at 100 C. Two types of specimens were used, polished as-welded (ASW) and as-welded solution plus heat-treated (ASW+SHT). The latter contained the black annealing oxide film on the surface. Results show that, for the two type of materials, as the immersion time increases, E{sub corr} increased and the CR decreased. Even for concentrated brine solutions at 100 C the CR was < 50 nm/year after more than 100 days immersion.
Date: March 21, 2005
Creator: Estill, J C; Hust, G A; King, K J & Rebak, R B
Partner: UNT Libraries Government Documents Department

Destruction of organic wastes by ammonium peroxydisulfate with electrolytic regeneration of the oxidant

Description: Research is reported concerning a new aqueous process for oxidative destruction of solid- and liquid organic wastes. This process uses acidified ammonium peroxydisulfate and operates at ambient pressure and at 80- to 100 {degrees}C. The oxidant may be efficiently regenerated by electrolysis of the sulfate by-product at Pt anodes, even in the presence of organic and inorganic contaminants expected to be entrained in the cycle. Integral rate constants were determined for the oxidation of 25 diverse organic compounds at low (50 ppm) concentrations through fixed-time experiments with excess oxidant and a Pt wire catalyst. For high initial concentrations, uncatalyzed mineralization rates were measured for waste surrogates including kerosene, triethylamine, ion exchange resin, oxalic acid, trinitrotoluene, and cellulose. A packed bed reactor was tested with ethylene glycol, with offgas analysis by mass spectroscopy. Rate data extrapolate to throughputs of approximately 200 kg/m{sub 3}-day. The process may benefit the destruction of highly toxic or specialized industrial wastes as well as the organic fraction of mixed wastes.
Date: July 1, 1997
Creator: Cooper, J.F.; Wang, J.F.; Krueger, R. & King, K.
Partner: UNT Libraries Government Documents Department

Demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation using peroxydisulfate. Progress report SF2-3-MW-35, October--December 1995

Description: Direct Chemical Oxidation is an emerging ``omnivorous`` waste destruction technique which uses one of the strongest known oxidants (ammonium peroxydisulfate) to convert organic solids or liquids to carbon dioxide and their mineral constituents. The process operates at ambient pressure and at moderate temperatures (80--100 C) where organic destruction is rapid without catalysts. The byproduct (ammonium sulfate) is benign and may be recycled using commercial electrolysis equipment. The authors have constructed and initially tested a bench-scale facility (batch prereactor and plug-flow reactor) which allows treatability tests on any solid or liquid organic waste surrogate, with off-gas analysis by mass spectroscopy. Shake-down tests of the plug flow reactor on model chemical ethylene glycol confirmed earlier predictive models. Pre-reactor tests on water-immiscible substances confirmed destruction of cotton rags (cellulose), kerosene, tributyl phosphate and triethylamine. The process is intended to provide an all-aqueous, ambient pressure destruction technique for difficult materials not suitable or fully accepted for conventional incineration. Such wastes include solid and liquid mixed wastes containing incinerator chars, halogenated and nitrogenated wastes, oils and greases, and chemical or biological warfare agents.
Date: January 27, 1996
Creator: Cooper, J.F.; Wang, F.; Krueger, R.; King, K.; Shell, T.; Farmer, J.C. et al.
Partner: UNT Libraries Government Documents Department

Distribution of soluble and precipitated iron and chromium products generated by anodic dissolution of 316L stainless steel and alloy C-22: final report

Description: At near neutral pH and at applied potentials above the threshold potential for localized breakdown of the passive film, virtually all of the dissolved chromium appeared to be in the hexavalent oxidation state (Cr(VI)). In acidic environments, such as crevice solutions formed during the crevice corrosion of 316L and C-22 samples in 4 M NaCl, virtually all of the dissolved chromium appeared to be in the trivalent oxidation state (Cr(III)). These general observations appear to be consistent with the Pourbaix diagram for chromium (Pourbaix 1974), pp. 307-321. At high pH and high anodic polarization (pH {approximately} 8 and 800 mV vs. SHE), the predominate species is believed to be the soluble chromate anion (CrO{sub 4}{sup 2{minus}}). At the same pH, but lower polarization (pH {approximately} 8 and 0 mV vs. SHE), the predominate species are believed to be precipitates such as trivalent Cr(OH){sub 3} {center_dot} n(H{sub 2}O) and hexavalent Cr{sub 2}O{sub 3}. In acidified environments such as those found in crevices (pH < 3), soluble Cr{sup 3+} is expected to form over a wide range of potential extending from 400 mV vs. SHE to approximately 1200 mV vs. SHE. Again, this is consistent with the observations from the creviced samples. In earlier studies by the principal investigator, it has been found that low-level chromium contamination in ground water is usually in the hexavalent oxidation state (Farmer et al. 1996). In general, dissolved iron measured during the crevice experiments appears to be Fe(II) in acidic media and Fe(III) in near-neutral and alkaline solutions (table 3). In the case of cyclic polarization measurements, the dissolved iron measured at the end of some cyclic polarization measurements with C-22 appeared to be in the Fe(III) state. This is probably due to the high electrochemical potential at which these species were generated during the potential ...
Date: August 11, 1999
Creator: Estill, J; Farmer, J; Gordon, S; King, K; Logotetta, L & Silberman, D
Partner: UNT Libraries Government Documents Department