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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

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

DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

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

DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

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

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

HYBRID SULFUR RECOVERY PROCESS FOR NATURAL GAS UPGRADING

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

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

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

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

MECHANICAL ALLOYING AND THERMAL TREATMENT FOR PRODUCTION OF ZIRCONIUM IRON HYDROGEN ISOTOPE GETTERS

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

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

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

In situ measurement of volatile organic compounds in groundwater by methods coupled to the cone penetrometer

Description: The objective of this investigation is to interface an in situ, on-line sparging system with a cone penetrometer to provide direct analysis of volatile organic compounds (VOCS) in groundwater by on-site analysis. Transfer line materials (15 m {times} 0.160--0.216 cm ID) composed of stainless steel, nickel, aluminum and Teflon{reg_sign}PFA, PTFE, and FEP were evaluated for their ability to quantitatively transfer chloroform, 1,1,1-trichloroethane, carbon tetrachloride, tetrachloroethylene, n-hexane, benzene, toluene, and o-xylene in the gas phase. The water content of the gas stream had an insignificant effect on the quantitative transfer of VOCs through Teflon{reg_sign} tubing but was critical to quantitative transfer of the compounds through metal tubing, particularly for nickel. Transfer efficiencies for all 7 analytes in moist gas streams through stainless steel tubing were greater than 95%. Toluene, tetrachloroethylene, and o-xylene were transferred with 93, 81 and 80% efficiency, respectively when drawn through Teflon{reg_sign}PFA tubing at 25 C. The sorption of these VOCs by Teflon{reg_sign} tubing was reversible and their transfer efficiencies improved to 94% when the tubing was flushed with 16 equivalent volumes of air. In general, the retention of the VOCs by Teflon{reg_sign} increased with decreasing aqueous solubility of the analyte. The efficiency at which VOCs were sparged from aqueous standards in Teflon{reg_sign}PFA, Type 304 stainless steel, and glass vessels were similar.
Date: March 1, 1995
Creator: Doskey, P.V.; Aldstadt, J.H.; Kuo, J.M.; Costanza, M.S. & Erickson, M.D.
Partner: UNT Libraries Government Documents Department

A comparison of the costs of treating wastes from a radio analytical laboratory

Description: The Radiological and Environmental Sciences Laboratory (RESL) is a government-owned, government-operated facility at the Idaho National Engineering Laboratory (INEL). RESL`s traditional strengths are in precise radionuclide analysis and dosimetry measurements. RESL generates small quantities of various types of waste. This study identified potential waste management options for a solvent extraction process waste stream and the cost differences resulting from either process changes, improved technology usage, or material substitutions or changes at RESL. Where possible, this report identifies changes that have resulted or may result in waste reduction and cost savings. DOE P2 directs the lab to review processes, evaluate waste practices, and estimate potential reductions in waste volumes and waste management costs. This study focused on selected processes, but the processes are illustrative of potential waste volume reductions and cost minimizations that may be achieved elsewhere at the INEL and throughout the DOE complex. In analyzing a waste disposal process, the authors allocated component costs to functional categories. These categories included the following: (1) operational costs, included waste generation and collection into a storage area; (2) administrative costs, including worker training, routine inspections, and reporting; and (3) disposal costs, including preparing the waste for shipment and disposing of it.
Date: April 1, 1996
Creator: Moore, R. & Pole, S.B.
Partner: UNT Libraries Government Documents Department

Autoignition chemistry of the hexane isomers: An experimental and kinetic modeling study

Description: Autoignition of the five distinct isomers of hexane is studied experimentally under motored engine conditions and computationally using a detailed chemical kinetic reaction mechanism. Computed and experimental results are compared and used to help understand the chemical factors leading to engine knock in spark-ignited engines and the molecular structure factors contributing to octane rating for hydrocarbon fuels. The kinetic model reproduces observed variations in critical compression ratio with fuel structure, and it also provides intermediate and final product species concentrations in very dose agreement with observed results. In addition, the computed results provide insights into the kinetic origins of fuel octane sensitive.
Date: June 1, 1995
Creator: Curran, H.J.; Gaffuri, P.; Pitz, W.J.; Westbrook, C.K. & Leppard, W.R.
Partner: UNT Libraries Government Documents Department

Refining of fossil resin flotation concentrate from Western coal. Ninth quarterly report, January 1--March 31, 1995

Description: Heptane showed a consistently higher extraction than hexane even through heptane contains only one more methylene group in its molecular structure. However economic factors must also be considered in the overall evaluation of the process. In this regard a simple economic evaluation was carried out taking into consideration the operating costs for the resin concentrate refining process. First of all, the price of industrial grade heptane is about the same as hexane. Because the process operates in a recycle mode, the initial cost would be about the same for both solvents. But in order to obtain the final resin product, the extracted resin has to be recovered from solution using evaporation techniques, which consume energy. Due to the significant difference in boiling points between the two solvents, approximately 25--35% more energy will be required for resin recovery by evaporation if heptane is used as the solvent for extraction. This represents a very significant increase of the operating cost. Secondly, based on bench scale tests the same yield can be achieved with hexane if the average residence time is increased. Such an increase in retention time only increases the capital cost by a small amount. It appears then from an economic perspective that hexane is the most appropriate solvent.
Date: March 31, 1995
Creator: Jensen, G.F. & Miller, J.D.
Partner: UNT Libraries Government Documents Department

Vapor space characterization of waste tank 241-TY-103: Results from samples collected on 4/11/95

Description: This report describes inorganic and organic analyses results from samples obtained from the headspace of the Hanford waste storage Tank 241-TY-103 (referred to as Tank TY-103). The results described here were obtained to support safety and toxicological evaluations. A summary of the results for inorganic and organic analytes is listed in Table 1. Detailed descriptions of the results appear in the text. Quantitative results were obtained for the inorganic compounds ammonia (NH{sub 3}), nitrogen dioxide (NO{sub 2}), nitric oxide (NO), and water (H{sub 2}O). Sampling for hydrogen cyanide (HCN) and sulfur oxides (SO{sub x}) was not requested. In addition, quantitative results were obtained for the 39 TO-14 compounds plus an additional 14 analytes. Of these, 16 were observed above the 5-ppbv reporting cutoff. Sixteen tentatively identified compounds (TICs) were observed above the reporting cutoff of (ca.) 10 ppbv and are reported with concentrations that are semiquantitative estimates based on internal-standard response factors. The 10 organic analytes with the highest estimated concentrations are listed in Table 1 and account for approximately 95% of the total organic components in Tank TY-103. Two permanent gases, carbon dioxide (CO{sub 2}) and nitrous oxide (N{sub 2}O), were also detected.
Date: October 1, 1995
Creator: Ligotke, M.W.; Clauss, T.W. & Pool, K.H.
Partner: UNT Libraries Government Documents Department

Recovery of semi-volatile organic compounds during sample preparation: Compilation for characterization of airborne particulate matter

Description: Semi-volatile compounds present special analytical challenges not met by conventional methods for analysis of ambient particulate matter (PM). Accurate quantification of PM-associated organic compounds requires validation of the laboratory procedures for recovery over a wide volatility and polarity range. To meet these challenges, solutions of n-alkanes (nC{sub 12} to nC{sub 40}) and polycyclic aromatic hydrocarbons PAHs (naphthalene to benzo[ghi]perylene) were reduced in volume from a solvent mixture (equal volumes of hexane, dichloromethane and methanol), to examine recovery after reduction in volume. When the extract solution volume reached 0.5 mL the solvent was entirely methanol, and the recovery averaged 60% for n-alkanes nC{sub 12} to nC{sub 25} and PAHs from naphthalene to chrysene. Recovery of higher MW compounds decreased with MW, because of their insolubility in methanol. When the walls of the flasks were washed with 1 mL of equal parts hexane and dichloromethane (to reconstruct the original solvent composition), the recovery of nC{sub 18} and higher MW compounds increased dramatically, up to 100% for nC{sub 22}-nC{sub 32} and then slowly decreasing with MW due to insolubility. To examine recovery during extraction of the components of the High Capacity Integrated Gas and Particle Sampler, the same standards were used to spike its denuders and filters. For XAD-4 coated denuders and filters, normalized recovery was > 95% after two extractions. Recovery from spiked quartz filters matched the recovery from the coated surfaces for alkanes nC{sub 18} and larger, and for fluoranthene and larger PAHs. Lower MW compounds evaporated from the quartz filter with the spiking solvent. This careful approach allowed quantification of organics by correcting for volatility- and solubility-related sample preparation losses. This method is illustrated for an ambient sample collected with this sampler during the Texas Air Quality Study 2000.
Date: May 1, 2002
Creator: Swartz, Erick; Stockburger, Leonard & Gundel, Lara
Partner: UNT Libraries Government Documents Department

SEPARATION OF FISCHER-TROPSCH WAX FROM CATALYST BY SUPERCRITICAL EXTRACTION

Description: The objective of this research project is to evaluate the potential of supercritical fluid (SCF) extraction for the recovery and fractionation of the wax product from the slurry bubble column (SBC) reactor of the Fischer-Tropsch (F-T) process. The wax, comprised mostly of branched and linear alkanes with a broad molecular weight distribution up to C{sub 100}, will be extracted with a hydrocarbon solvent that has a critical temperature near the operating temperature of the SBC reactor, i.e., 200-300 C. Initial work is being performed using n-hexane as the solvent. The success of the project depends on two factors. First, the supercritical solvent must be able to dissolve the F-T wax; furthermore, this must be accomplished at conditions that do not entrain the solid catalyst. Second, the extraction must be controlled so as not to favor the removal of the low molecular weight wax compounds. That is, a constant carbon-number distribution in the wax slurry must be maintained at steady-state column operation. Three major tasks are being undertaken to evaluate our proposed SCF extraction process. Task 1: Equilibrium solubility measurements for model F-T wax components in supercritical fluids at conditions representative of those in a SBC reactor. Task 2: Thermodynamic modeling of the measured VLE data for extending our results to real wax systems. Task 3: Process design studies of our proposed process. Additional details of the task structure are given.
Date: July 31, 1998
Creator: THIES, MARK C. & JOYCE, PATRICK C.
Partner: UNT Libraries Government Documents Department