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Separation of Fischer-Tropsch Wax from Catalyst by Supercritical Extraction

Description: The proposed process of using supercritical fluid extraction in conjunction with the Fischer-Tropsch slurry bubble column reactor has been examined using the ASPEN Plus simulator by the research group at North Carolina State University. Qualitative results have been obtained for varying the following process parameters: solvent-to-wax ratio, solvent type (pentane or hexane), extraction temperature and pressure, and recovery unit temperature and pressure. The region of retrograde behavior was determined for pentane and hexane. Initial results show hexane to be the superior solvent; compared to pentane, hexane requires lower quantities of solvent makeup (the amount of solvent which needs to be added to account for solvent that cannot be recycled), and also results in a lower average molecular weight of slurry in the reactor. Studies indicate that increasing the extraction temperature, extraction pressure, recovery temperature, or solvent to wax ratio decreases the amount solvent makeup required. Decreasing the recovery pressure was found to decrease the makeup flowrate.
Date: January 31, 1997
Creator: Joyce, P.C. & Thies, M.C.
Partner: UNT Libraries Government Documents Department

Microwave processing improvements for methane conversion to ethylene

Description: This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project`s objective was to investigate microwave enhanced catalysis. Published work by others had demonstrated improved selectivity in microwave-driven catalytic conversion of 2-methylpentane to its isomers. We reproduced their experiment, discovering that there is no improvement in selectivity using microwaves. The selectivity at a given conversion was the same for both microwave heated and conventionally heated catalyst beds. Meetings with the authors of the previously published work led to the conjecture that their catalyst was not being prepared properly, leading to anomalously low selectivity for their conventional heating runs. An optical temperature diagnostic suitable for use on a microwave applicator was developed and characterized in this project. This pyrometer can measure the temperature of small scale features on the catalyst bed, and it has a fast response that can follow the rapid heating often encountered in a microwave processing system. The behavior of the microwave applicator system was studied, and theoretical models were developed to yield insight about the stability and control of the system.
Date: August 1, 1997
Creator: Stringfield, R.; Ott, K.; Nelson, E.; Anderson, G.; Chen, Dye-Zone; Dyer, T. et al.
Partner: UNT Libraries Government Documents Department


Description: The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing indicated that the growth, and the metal corrosion caused by pure cultures of sulfate reducing bacteria were inhibited by hexane extracts of some pepper plants. This quarter tests were performed to determine if chemical compounds other than pepper extracts could inhibit the growth of corrosion-associated microbes and to determine if pepper extracts and other compounds can inhibit corrosion when mature biofilms are present. Several chemical compounds were shown to be capable of inhibiting the growth of corrosion-associated microorganisms, and all of these compounds limited the amount of corrosion caused by mature biofilms to a similar extent. It is difficult to control corrosion caused by mature biofilms, but any compound that disrupts the metabolism of any of the major microbial groups present in corrosion-associated biofilms shows promise in limiting the amount/rate of corrosion.
Date: October 30, 2004
Creator: Bogan, Bill W.; Lamb, Brigid M. & II, John J. Kilbane
Partner: UNT Libraries Government Documents Department


Description: The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing indicated that the growth, and the metal corrosion caused by pure cultures of sulfate reducing bacteria were inhibited by hexane extracts of some pepper plants. This quarter tests were performed with mixed bacterial cultures obtained from natural gas pipelines. Treatment with the pepper extracts affected the growth and metabolic activity of the microbial consortia. Specifically, the growth and metabolism of sulfate reducing bacteria was inhibited. The demonstration that pepper extracts can inhibit the growth and metabolism of sulfate reducing bacteria in mixed cultures is a significant observation validating a key hypothesis of the project. Future tests to determine the effects of pepper extracts on mature/established biofilms will be performed next.
Date: July 30, 2004
Creator: Lowe, Kristine L.; Bogan, Bill W.; Sullivan, Wendy R.; Cruz, Kristine Mila H.; Lamb, Brigid M. & II, John J. Kilbane
Partner: UNT Libraries Government Documents Department

A study of competitive adsorption of organic molecules onto mineral oxides using DRIFTS

Description: Analysis of DRIFTS spectra was used for a quantitative study of competitive adsorption of myristic and salicylic acids onto kaolinite or {gamma}-alumina. Peaks unique to the ring or the chain were selected and single molecule studies used as calibration. Samples were exposed to hexane solution containing equal molecular quantities of each acid. The surface loading of salicylic acid was not influenced by the presence of myristic acid on either mineral but the maximum loading of myristic acid was decreased (46-50%) by salicylic acid. Displacement of myristic acid from {gamma}-alumina, but not kaolinite, was observed when excess salicylic acid remained in solution. A 25% increase in the maximum loading was observed for kaolinite, but not for{gamma}-alumina. On {gamma}-alumina, after a loading of 1 molecule per nm{sup 2}, increased exposure resulted in salicylic acid adsorption only, this value is approximately the same for salicylic acid adsorption from aqueous solution or for water washed hexane treated samples. Thus a set of sites for adsorption of either acid is indicated together with other energetically less favorable sites, which can be occupied by salicylic, but not by myristic, acid.
Date: February 1, 2010
Creator: Joan E. Thomas, Michael J. Kelley
Partner: UNT Libraries Government Documents Department


Description: The objective of this task was to demonstrate that metal hydrides could be produced by mechanical alloying in the quantities needed to support production-scale hydrogen isotope separations. Three starting compositions (ratios of elemental Zr and Fe powders) were selected and attritor milled under argon for times of 8 to 60 hours. In general, milling times of at least 24 hours were required to form the desired Zr{sub 2}Fe and Zr{sub 3}Fe phases, although a considerable amount of unalloyed Zr and Fe remained. Milling in liquid nitrogen does not appear to provide any advantages over milling in hexane, particularly due to the formation of ZrN after longer milling times. Carbides of Zr formed during some of the milling experiments in hexane. Elemental Zr was present in the as-milled material but not detected after annealing for milling times of 48 and 60 hours. It may be that after intimate mixing of the powders in the attritor mill the annealing temperature was sufficient to allow for the formation of a Zr-Fe alloy. Further investigation of this conversion is necessary, and could provide an opportunity for reducing the amount of unreacted metal powder after milling.
Date: February 20, 2008
Creator: Fox, K.
Partner: UNT Libraries Government Documents Department

A Low-Temperature Calorimetric Cryostat

Description: A low temperature adiabatic cryostat for determining precise calorimetric data has been described. The accuracy of the data produced by this apparatus has been established by measuring the thermal properties of n-hexane up to 300 deg K. These data agree with available precise data, in general, to within 0.2%. The precision of the heat capacity measurements is, for the most part, better than 0.1%. (auth)
Date: January 20, 1950
Creator: Oliver, G.D.; Grisard, J.W. & Anderson, V.E.
Partner: UNT Libraries Government Documents Department

Room-temperature Formation of Hollow Cu2O Nanoparticles

Description: Monodisperse Cu and Cu2O nanoparticles (NPs) are synthesized using tetradecylphosphonic acid as a capping agent. Dispersing the NPs in chloroform and hexane at room temperature results in the formation of hollow Cu2O NPs and Cu@Cu2O core/shell NPs, respectively. The monodisperse Cu2O NPs are used to fabricate hybrid solar cells with efficiency of 0.14percent under AM 1.5 and 1 Sun illumination.
Date: January 18, 2010
Creator: Hung, Ling-I; Tsung, Chia-Kuang; Huang, Wenyu & Yang, Peidong
Partner: UNT Libraries Government Documents Department

Hexone Extraction-Coulometric Titration of Uranium

Description: Samples containing 5 to 10 mg of uranium were extracted with hexone (methyl isobutyl ketone) and titrated coulometrically in sulfate media. Relative standard deviations of 0.43% for samples containing 5 mg and 0.56% for 10 mg were determined by precision studies. (auth)
Date: June 22, 1959
Creator: Blevins, E. L.
Partner: UNT Libraries Government Documents Department

Synthesis of Compounds for Los Alamos National Laboratory

Description: As part of contract 6709U0015-3C, the compounds listed were synthesized and transferred to LANL for evaluation. Work on these has resulted in several papers, manuscripts and talks bearing LANL and UTD co-authorship. The detailed synthetic procedures are described and the chemical structure of the mentioned compounds are shown in a table. Synthetic procedures: (1) 2-Methoxy-5-(2{prime}-ethyl hexyloxy)-1,4-distyrylbenzene--see synthesis of compound V in the reference [1]. (2) MEHPPV : 1.000 g 1,4-methoxyethylhexyloxy-2,5-dibromomethylbenzene + 0.0042 g (1 mol %) anthracene were dissolved in 35 ml dry THF and 1.0 M solution of t-BuOK in THF was added slowly during 60 min and stirred at room temperature for 20 hours. The red suspension was precipitated in 200 ml cold MeOH, the solid was filtered, washed by MeOH and dried in vacuum. The red-orange solid was extracted by boiling hexane for 24 hours. Insoluble in hexane red polymer was extracted by boiling xylene for 24 hours, soluble in xylene fraction was dissolved in THF and precipitated in MeOH. After filtration and drying in vacuum 0.220 g(36% yield) of red polymer with M{sub W}=357000 and absorption maximum at 496 nm (chloroform) was obtained. (3)1,4-distyrylbenzene - see synthesis of compound 1 in the reference [1]. (4)1,4-Bis-(2{prime},5{prime}-dimethoxystyryl)-2-methoxy-5-(2{prime}-ethylhexyloxy)benzene: This compound was obtained in 51% yield according the general procedure for the Wittig reaction described in the reference [1] from 2- methoxy-5(2{prime}-ethylhexyloxy)-1,4-xylylene-bis(triphenylphosphonium chloride) and 2,5-dimethoxybenzaldehyde, m.p.49-51 C. (5) Films of aromatic copolyamides with fragments of 9,10-bis(p-carboxyphenyl) anthracene and bis(m-aminophenyl)-9,10-anthracene--see synthesis of copolyamides XXI and XXII in the reference [2]. (6,7) Films of the solid solution of 9,10-diphenylanthracene in poly(m- phenyleneisophtalamide) (PMPI) were obtained from the 5.0% solution of mixture 0.231 g PMPI and 0.0319 g 9.10-diphenylanthracene in N-MP at conditions described in the reference [2]. (8) 2,5-Didodecyloxy-1,4-distyrylbenzene--see synthesis of compound IV in the reference [1]. (9) 2,5- Dioctyloxy-1,4-distyrylbenzene--see synthesis of ...
Date: July 20, 1999
Creator: Ferraris, J.P.
Partner: UNT Libraries Government Documents Department

Preflame zone structure and main features of fuel conversion in atmospheric pressure premixed laminar hydrocarbon flames

Description: This report describes the structure study of the premixed hydrocarbon-oxidizer Bunsen flames burning at the atmospheric pressure and also the ones with some inhibitors added. Studies were performed on hexane, propane, methane, acetylene, and hexene flames.
Date: August 25, 1995
Creator: Ksandopulo, G.I.
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


Description: This first quarter report of 2002 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf{sup SM} (service mark of CrystaTech, Inc.) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane and other hydrocarbons without oxidation of the hydrocarbons. The project involves the development of a catalyst using laboratory/bench-scale catalyst testing, and then demonstration of the catalyst at CrystaTech's pilot plant in west Texas. In a previous reporting period tests were done to determine the effect of hydrocarbons such as n-hexane on catalyst performance with and without H{sub 2}S present. The experiments showed that hexane oxidation is suppressed when H{sub 2}S is present. Hexane represents the most reactive of the C1 to C6 series of alkanes. Since hexane exhibits low reactivity under H{sub 2}S oxidation ...
Date: April 1, 2002
Creator: Srinivas, Girish; Gebhard, Steven C. & DeBerry, David W.
Partner: UNT Libraries Government Documents Department

Process and analytical studies of enhanced low severity co-processing using selective coal pretreatment. Quarterly technical progress report, June--August 1990

Description: This report describes progress on research during the seventh quarter of this contract dealing with applications of coal pretreatment techniques in coal hydroliquefaction. The objectives of the project are to investigate various coal pretreatment techniques and to determine the effect of these pretreatment procedures on the reactivity of the coal. Reactivity enhancement will be evaluated under both direct hydroliquefaction and co-processing conditions. Coal conversion utilizing low rank coals and low severity conditions (reaction temperatures generally less than 350 {degrees}C) are the primary focus of the liquefaction experiments, as it is expected that the effect of pretreatment conditions and the attendant reactivity enhancement will be greatest for these coals at these conditions.
Date: December 31, 1990
Creator: Baldwin, R. M. & Miller, R. L.
Partner: UNT Libraries Government Documents Department

Fischer-tropsch synthesis in supercritical fluids. Quarterly technical progress report, April 1, 1993--June 30, 1993

Description: We have completed modifications of the Taylor Dispersion Apparatus so that propane can be used as a solvent. Problems were encountered initially compressing propane to the necessary pressures because of cavitation in the liquid pump. This problem was overcome by placing a check valve in the line after the pump and pressures of 2500 psi have been achieved. The system has been pressure tested by using a soap solution on exposed joints and performing a mass balance (leak test). The mass balance was made by reading the volumetric flow rate of liquid in the syringe pump and converting this to expected gas flow rate. The liquid was then vaporized and a dry gas meter measured the amount of gas at the exit of the apparatus. The expected and measured gas flow rates were in excellent agreement, indicating that there are no significant leaks in the system. Presently, we are having problems with the use of UV detection for the dim using compounds. The detector is successfully auto-zeroing with a blank cell and with Co{sub 2}. With the use of instrument grade propane, however, the detector is unable to auto-zero because of absorption of unknown impurity. We believe this problem is caused by a sulfur compound in the propane gas cylinder and we plan to install an active carbon guard bed to remove a sulfur containing compounds.
Date: July 29, 1993
Creator: Akgerman, A. & Bukur, D. B.
Partner: UNT Libraries Government Documents Department


Description: A laboratory study of a gelatin headend process for feed from silicon- containing aluminum fuels and plant salvage solutions is described. The optimum conditions for the gelatin treatment of fuel solutions were to boil a 0.1 to 0.5N nitric acid solution with 100 milligrams of gelatin per liter for 30 minutes. This treatment improved filtration rates and decreased the surface activity of the filtrate for TBP extraction. A number of possible flowsheets for fuel solutions are presented using gelatin treatment and filtration. An adequate treatment was not found for salvage solutions of unknown composition because a gelatin dosage which was satisfactory for all solutions could not be selected. The optimum treatment for a salvage solution which was grossly contaminated with zirconium, soluble and colloidal silica, and dibutyl phosphate was to boil a 1N acid deficient solution with 600 milligrams of gelatin per liter, filter, and use a Hexone extraction system. A silicic colloid in fuel processing solutions was characterized as a surface active material by this study. (auth)
Date: February 1, 1959
Creator: Newby, B.J. & Paige, B.E.
Partner: UNT Libraries Government Documents Department


Description: A study was made of the performance of an orifice plate pulse column which is essentially a spray column containing internal constrictions in the form of orifices. The chemical system studied was acetic acid-waterhexone, and the variables considered were pulse frequency, throughput, phase continuity, and direction of solute transfer. For comparison purposes, several runs were made with a conventional spray column. Curves are presented showing the effect of the column variables on the column efficiency (HTU). The trends observed are explained as being due principally to the competing effects of the area for mass transfer and back-mixing. Photographs of a typical column section show qualitatively the effect of the important column variables. (auth)
Date: August 23, 1954
Creator: O'Brien, D.C.
Partner: UNT Libraries Government Documents Department