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Methane Control Research: Summary of Results, 1964-80

Description: From Abstract: "This bulletin summarizes the work conducted under the Bureau of Mines methane control research program during the years 1964 to 1979. This bulletin provides a comprehensive source of information on the accomplishments of the Bureau's methane control research program, on the technology developed, and the direction of further research."
Date: 1986
Creator: Deul, Maurice & Kim, Ann G.
Partner: UNT Libraries Government Documents Department

Microbial ecology of thermophilic anaerobic digestion. Final report

Description: This grant supported research on methanogenic archaea. The two major areas that were supported were conversion of acetic acid to methane and nitrogen fixation by Methanosarcina. Among the achievements of this research were the isolation of novel methanogenic cultures, elucidation of the pathways from acetate to methane, description of a specific DNA-binding complex in nitrogen fixing methanogens, and demonstration of an alternative nitrogenase in Methanosarcina.
Date: April 15, 2000
Creator: Zinder, Stephen H.
Partner: UNT Libraries Government Documents Department

Manifold methods for methane combustion

Description: Objective is to develop a new method for studying realistic chemistry in turbulent methane combustion with NO{sub x} mechanism. The realistic chemistry is a simplification to a more detailed chemistry based on the manifold method; accuracy is determined by interaction between the transport process and the chemical reaction. In this new (tree) method, probability density function or partially stirred reactor calculations are performed. Compared with the reduced mechanism, manifold, and tabulation methods, the new method overcomes drawbacks of the reduced mechanism method and preserves the advantages of the manifold method. Accuracy is achieved by specifying the size of the cell.
Date: December 31, 1995
Creator: Yang, B. & Pope, S.B.
Partner: UNT Libraries Government Documents Department

Landfill Gas Conversion to LNG and LCO{sub 2}. Phase II Final Report for January 25, 1999 - April 30, 2000

Description: This report summarizes work on the development of a process to produce LNG (liquefied methane) for heavy vehicle use from landfill gas (LFG) using Acrion's CO{sub 2} wash process for contaminant removal and CO{sub 2} recovery.
Date: October 20, 2000
Creator: Brown, W. R.; Cook, W. J. & Siwajek, L. A.
Partner: UNT Libraries Government Documents Department

Effect of Carbon Dioxide on SAES(R) St909 Methane Cracking

Description: Methane/carbon dioxide cracking tests using a bench scale system have been performed using SAES(R) St909 getter. The report shows carbon dioxide reduced the St909 methane cracking efficiency under a variety of test conditions. These bench scale tests revealed the complex interactions between reactive species expected to be present in future plant operations.
Date: September 30, 2002
Creator: Klein, J.E.
Partner: UNT Libraries Government Documents Department

Soft Radiation From Pu²³⁹

Description: "The radiation from Pu²³⁹ have been studied in the region 5-25 keV. For this purpose, a proportional counter, filled with argon to a pressure of 53 cm Hg and with methane to a pressure of 6 cm Hg, was employed in combination with a single-channel pulse analyzer and associated amplifying and counting circuits."
Date: 1952
Creator: Israel, Harvey Ira
Partner: UNT Libraries Government Documents Department

Direct Aromaization of Methane

Description: The thermal decomposition of methane offers significant potential as a means of producing higher unsaturated and aromatic hydrocarbons when the extent of reaction is limited. Work in the literature previous to this project had shown that cooling the product and reacting gases as the reaction proceeds would significantly reduce or eliminate the formation of solid carbon or heavier (Clo+) materials. This project studied the effect and optimization of the quenching process as a means of increasing the amount of value added products during the pyrolysis of methane. A reactor was designed to rapidly quench the free-radical combustion reaction so as to maximize the yield of aromatics. The use of free-radical generators and catalysts were studied as a means of lowering the reaction temperature. A lower reaction temperature would have the benefits of more rapid quenching as well as a more feasible commercial process due to savings realized in energy and material of construction costs. It was the goal of the project to identify promising routes from methane to higher hydrocarbons based on the pyrolysis of methane.
Date: January 15, 1997
Creator: Marcelin, George
Partner: UNT Libraries Government Documents Department

Growing carbon nanotubes by chemical vapor deposition technique.

Description: Carbon nanotubes were synthesized in the laboratory using chemical vapor deposition at different methane concentration. I found that a methane concentration of 4 sccm was ideal for well recognizable carbon nanotubes. A higher concentration led to fewer nanotube growth and silicon carbide structure. Coating the sample first with Fe(NO3)3 created a catalyst base on the substrate for the nanotube to adhere and grow on.
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Date: May 2000
Creator: Rajan, Harihar V.
Partner: UNT Libraries

Theoretical Rocket Performance of Liquid Methane with Several Fluorine-Oxygen Mixtures Assuming Frozen Composition

Description: "Theoretical rocket performance for frozen composition during expansion was calculated for liquid methane with several fluorine-oxygen mixtures for a range of pressure ratios and oxidant-fuel ratios. The parameters included are specific impulse, combustion-chamber temperature, nozzle-exit temperature molecular weight, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, isentropic exponent, viscosity, and thermal conductivity. The maximum calculated value of specific impulse for a chamber pressure of 600 pounds per square inch absolute (40.827atm) and an exit pressure of 1 atmosphere is 315.3 for 79.67 percent fluorine in the oxidant" (p. 1).
Date: May 20, 1958
Creator: Gordon, Sanford & Kastner, Michael E.
Partner: UNT Libraries Government Documents Department

The Mechanisms of Methane C–H Activation and Oxy-insertion Via Small Transition Metal Complexes: a DFT Computational Investigation

Description: Our country continues to demand clean renewable energy to meet the growing energy needs of our time. Thus, natural gas, which is 87% by volume of methane, has become a hot topic of discussion because it is a clean burning fuel. However, the transportation of methane is not easy because it is a gas at standard temperature and pressure. The usage of transition metals for the conversion of small organic species like methane into a liquid has been a longstanding practice in stoichiometric chemistry. Nonetheless, the current two-step process takes place at a high temperature and pressure for the conversion of methane and steam to methanol via CO + H2 (syngas). The direct oxidation of methane (CH4) into methanol (CH3OH) via homogeneous catalysis is of interest if the system can operate at standard pressure and a temperature less than 250 C. Methane is an inert gas due to the high C-H bond dissociation energy (BDE) of 105 kcal/mol. This dissertation discusses a series of computational investigations of oxy-insertion pathways to understand the essential chemistry behind the functionalization of methane via the use of homogeneous transition metal catalysis. The methane to methanol (MTM) catalytic cycle is made up of two key steps: (1) C-H activation by a metal-methoxy complex, (2) the insertion of oxygen into the metal−methyl bond (oxy-insertion). While, the first step (C-H activation) has been well studied, the second step has been less studied. Thus, this dissertation focuses on oxy-insertion via a two-step mechanism, oxygen-atom transfer (OAT) and methyl migration, utilizing transition metal complexes known to activate small organic species (e.g., PtII and PdII complexes). This research seeks to guide experimental investigations, and probe the role that metal charge and coordination number play.
Date: May 2014
Creator: Prince, Bruce M.
Partner: UNT Libraries

Computational Study of Small Molecule Activation via Low-Coordinate Late First-Row Transition Metal Complexes

Description: Methane and dinitrogen are abundant precursors to numerous valuable chemicals such as methanol and ammonia, respectively. However, given the robustness of these substrates, catalytically circumventing the high temperatures and pressures required for such transformations has been a challenging task for chemists. In this work, computational studies of various transition metal catalysts for methane C-H activation and N2 activation have been carried out. For methane C-H activation, catalysts of the form LnM=E are studied, where Ln is the supporting ligand (dihydrophosphinoethane or β-diketiminate), E the activating ligand (O, NCH3, NCF3) at which C-H activation takes place, and M the late transition metal (Fe,Co,Ni,Cu). A hydrogen atom abstraction (HAA) / radical rebound (RR) mechanism is assumed for methane functionalization (CH4 à CH3EH). Since the best energetics are found for (β-diket)Ni=O and (β-diket)Cu=O catalysts, with or without CF3 substituents around the supporting ligand periphery, complete methane-to-methanol cycles were studied for such systems, for which N2O was used as oxygen atom transfer (OAT) reagent. Both monometallic and bimetallic OAT pathways are addressed. Monometallic Fe-N2 complexes of various supporting ligands (LnFe-N2) are studied at the beginning of the N2 activation chapter, where the effect of ligand on N2 activation in end-on vs. side-on N2 isomers is discussed. For (β-diket)Fe-N2 complexes, the additional influence of diketiminate donor atom (N(H) vs. S) is briefly addressed. The remainder of the chapter expands upon the treatment of β-diketiminate complexes. First, the activation and relative stabilities of side-bound and end-bound N2 isomers in monometallic ((β-diket)M-N2) and bimetallic ((β-diket)M-N2-M(β-diket)) first row transition metal complexes are addressed. Second, the thermodynamics of H/H+/H- addition to (β-diket)Fe-bound N2, followed by subsequent H additions up to release of ammonia, is discussed, for which two mechanisms (distal and alternating) are considered. Finally, the chapter concludes with partial distal and alternating mechanisms for H addition to N2 ...
Date: May 2010
Creator: Pierpont, Aaron
Partner: UNT Libraries

An experimental and density functional theory study of the interactions of CH4 with H-ZSM-5

Description: The interactions of methane with Bronsted acid sites in H-ZSM-5 were investigated both experimentally and theoretically. Diffuse reflectance infrared spectroscopy was used to acquire spectra for methane adsorbed on H-ZSM-5 at room temperature and at 77 K. Upon adsorption, the v1 and v3 vibrational bands of methane shift by -15 and -23 cm-1, respectively, and the vibrational band for OH groups associated with Bronsted acid sites shifts by -93 cm-1. Quantum chemical calculations conducted at the DFT level of theory with a 6-31g**++ basis set show that the observed shifts for methane are attributable to the effects of the electrostatic field created by the atoms of the zeolite. To represent the influence of the zeolite on the adsorbed methane correctly, it is essential to take into account the effects of the Madelung field, as well as the local effects of the acid center. The calculated shift in the vibrational frequency of the bridging OH group lies within the range observed experimentally. However, the quantitative agreement of the calculated and observed shift is not as good as that seen for the bands of CH4.
Date: August 25, 2001
Creator: Khaliullin, Rustam Z.; Bell, Alexis T. & Kazansky, Vladimir B.
Partner: UNT Libraries Government Documents Department

Final Report

Description: The aim of this project was to determine phase equilibrium and PVT properties of fluids in the water-methane system using synthetic fluid inclusions. This information is critical to understanding the behavior of natural fluid inclusions trapped in hydrocarbon-bearing environments such as sedimentary basins, oil and gas fields, methane hydrate occurrences and Mississippi Valley type Pb-Zn deposits.
Date: June 15, 2005
Creator: Bodnar, R. J.
Partner: UNT Libraries Government Documents Department

Raman spectroscopic and mass spectrometric investigations of the hydrogen isotopes and isotopically labelled methane

Description: Suitable analytical methods must be tested and developed for monitoring the individual process steps within the fuel cycle of a fusion reactor and for tritium accountability. The utility of laser-Raman spectroscopy accompanied by mass spectrometry with an Omegatron was investigated using the analysis of all hydrogen isotopes and isotopically labeled methanes as an example. The Omegatron is useful for analyzing all hydrogen isotopes mixed with the stable helium isotopes. The application of this mass spectrometer were demonstrated by analyzing mixtures of deuterated methanes. In addition, it was employed to study the radiochemical Witzbach exchange reaction between tritium and methanes. A laser-Raman spectrometer was designed for analysis of tritium-containing gases and was built from individual components. A tritium-compatible, metal-sealed Raman cuvette having windows with good optical properties and additional means for measuring the stray light was first used successfully in this work. The Raman spectra of the hydrogen isotopes were acquired in the pure rotation mode and in the rotation-vibration mode and were used for on. The deuterated methanes were measured by Raman spectroscopy, the wavenumbers determined were assigned to the corresponding vibrations, and the wavenumbers for the rotational fine-structure were summarized in tables. The fundamental Vibrations of the deuterated methanes produced Witzbach reactions were detected and assigned. The fundamental vibrations of the molecules were obtained with Raman spectroscopy for the first time in this work. The @-Raman spectrometer assembled is well suited for the analysis of tritium- containing gases and is practical in combination with mass spectrometry using an Omegatron, for studying gases used in fusion.
Date: February 24, 1997
Creator: Jewett, J.R., Fluor Daniel Hanford
Partner: UNT Libraries Government Documents Department

Methane Capture: Options for Greenhouse Gas Emission Reduction

Description: This report discusses legislative alternatives for addressing methane capture, sources of methane, opportunities and challenges for methane capture, and current federal programs that support methane recovery.
Date: September 17, 2009
Creator: Bracmort, Kelsi; Ramseur, Jonathan L.; McCarthy, James E.; Folger, Peter & Marples, Donald J.
Partner: UNT Libraries Government Documents Department

Correlation of flame speed with stretch in turbulent premixed methane/air flames

Description: In the flamelet approach of turbulent premixed combustion, the flames are modeled as a wrinkled surface whose propagation speed, termed the {open_quotes}displacement speed,{close_quotes} is prescribed in terms of the local flow field and flame geometry. Theoretical studies suggest a linear relation between the flame speed and stretch for small values of stretch, S{sub L}/S{sub L}{sup 0} = 1 - MaKa, where S{sub L}{sup 0} is the laminar flame speed, Ka = {kappa}{delta}{sub F}/S{sub L}{sup 0} is the nondimensional stretch or the Karlovitz number, and Ma = L/{delta}{sub F} is the Markstein number. The nominal flame thickness, {delta}{sub F}, is determined as the ratio of the mass diffusivity of the unburnt mixture to the laminar flame speed. Thus, the turbulent flame model relies on an accurate estimate of the Markstein number in specific flame configurations. Experimental measurement of flame speed and stretch in turbulent flames, however, is extremely difficult. As a result, measurement of flame speeds under strained flow fields has been made in simpler geometries, in which the effect of flame curvature is often omitted. In this study we present results of direct numerical simulations of unsteady turbulent flames with detailed methane/air chemistry, thereby providing an alternative method of obtaining flame structure and propagation statistics. The objective is to determine the correlation between the displacement speed and stretch over a broad range of Karlovitz numbers. The observed response of the displacement speed is then interpreted in terms of local tangential strain rate and curvature effects. 13 refs., 3 figs.
Date: November 1, 1997
Creator: Chen, J.H. & Im, Hong G.
Partner: UNT Libraries Government Documents Department