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Development of a Gas-Promoted Oil Agglomeration Process

Description: Further agglomeration tests were conducted in a series of tests designed to determine the effects of various parameters on the size and structure of the agglomerates formed, the rate of agglomeration, coal recovery, and ash rejection. For this series of tests, finely ground Pittsburgh No. 8 coal has been agglomerated with i-octane in a closed mixing system with a controlled amount of air present to promote particle agglomeration. The present results provide further evidence of the role played by air. As the concentration of air in the system was increased from 4.5 to 18 v/w% based on the weight of coal, coal recovery and ash rejection both increased. The results also show that coal recovery and ash rejection were improved by increasing agitator speed. On the other hand, coal recovery was not affected by a change in solids concentration from 20 to 30 w/w%.
Date: October 30, 1998
Creator: Shen, M. & Wheelock, T. D.
Partner: UNT Libraries Government Documents Department

The Mercury-Sensitized Photo-Reactions of 2,3-Dimethyl Butane

Description: The work encompassed by this thesis is partially a reproduction of the results obtained by John A. Marcia in his work on the photo-chemical reactions of branched hydrocarbons. The previous work done on this particular problem was rendered partially valueless because of the loss of the liquid hydrocarbon product when a fractionation column at the Texas Company Laboratory, Beacon, New York, broke during the fractionation run.
Date: 1947
Creator: Sutton, Cecil C.
Partner: UNT Libraries

Review of market for octane enhancers: Final report

Description: Crude oil is easily separated into its principal products by simple distillation. However, neither the amounts nor the quality of these natural products matches demand. Today, octane requirements must be achieved by changing the chemical composition of the straight-run gasoline fraction.
Date: June 20, 2000
Creator: J. E. Sinor Consultants, Inc.
Partner: UNT Libraries Government Documents Department

The lean oxidation of iso-octane at elevated pressures

Description: Both spark-ignition and compression-ignition engines burn large molecular-weight blended fuels, a class to which the primary reference fuels (PRF), n-heptane and iso-octane belong. In this study experiments were performed using iso-octane in a high pressure flow reactor at a temperature of 925 K, at 3, 6 and 9 atm pressure and with a fuel/air equivalence ratio of approximately 0.05. Many hydrocarbon and oxygenated hydrocarbon intermediates were identified and quantified as a function of time. These experimental results provide a strin- gent test of the low temperature chemistry portion of a kinetic model as they emphasise the importance of alkyl radical addition to molecular oxygen and internal H-atom isomerization reactions relative to alkyl radical decomposition reactions. A detailed chemical kinetic mechanism is used to simulate these experiments. We provide comparisons of model predictions with experimentally measured species profiles and describe how each species is formed as predicted by the detailed model.
Date: October 30, 1998
Creator: Chen, J S; Curran, H J & Litzinger, T A
Partner: UNT Libraries Government Documents Department


Description: With growing interest in oxygenates as octane booster for automotive fuels, various synthesis routes for these chemicals are being investigated. Among others, alternative routes to isobutene, the C4-components in MTBE-synthesis are under investigation. A promising path to isobutene is the heterogeneously catalyzed CO-hydrogenation to isobutanol with following dehydration (Fig. 1). As shown by thermodynamical studies, the heterogeneously catalyzed CO-hydrogenation to isobutanol is not expected to experience any thermodynamic constraints. However, heterogeneous hydrogenation of CO is a very exothermic process, a problem which can only be partly solved when being conducted in a plug flow reactor. When carried out in reaction vessels with moving catalyst bed (e.g. three phase stirred tank), heat transfer problems can be resolved, along with additional benefits connected with this reactor type. Several heterogeneous catalytic systems have been under investigation for their capability of isobutanol synthesis from syngas. Most promising catalysts for an active and selective isobutanol synthesis from CO are modified high temperature methanol catalysts.
Date: December 29, 2002
Creator: Tijrn, Peter
Partner: UNT Libraries Government Documents Department

Development of a gas-promoted oil agglomeration process. Quarterly technical progress report, July 1, 1995--September 30, 1995

Description: The preliminary laboratory-scale development of a gas-promoted, oil agglomeration process for cleaning coal advanced in three major research areas. One area of research resulted in the development of a method for measuring the rate of agglomeration of dilute particle suspensions and using the method to relate the rate of agglomeration of coal particles to various key parameters. A second area of research led to the development of a method for monitoring a batch agglomeration process by measuring changes in agitator torque. With this method it was possible to show that the agglomeration of a concentrated coal particle suspension is triggered by the introduction of a small amount of gas. The method was also used in conjunction with optical microscopy to study the mechanism of agglomeration. A third area of research led to the discovery that highly hydrophobic particles in an aqueous suspension can be agglomerated by air alone.
Date: December 31, 1995
Creator: Wheelock, T.D.
Partner: UNT Libraries Government Documents Department

Oxidation of automotive primary reference fuels in a high pressure flow reactor

Description: Automotive engine knock limits the maximum operating compression ratio and ultimate thermodynamic efficiency of spark-ignition (SI) engines. In compression-ignition (CI) or diesel cycle engines the premixed urn phase, which occurs shortly after injection, determines the time it takes for autoignition to occur. In order to improve engine efficiency and to recommend more efficient, cleaner-burning alternative fuels, we must understand the chemical kinetic processes which lead to autoignition in both SI and CI engines. These engines burn large molecular-weight blended fuels, a class to which the primary reference fuels (PRF), n-heptane and isooctane belong. In this study, experiments were performed under engine-like conditions in a high pressure flow reactor using both the pure PRF fuels and their mixtures in the temperature range 550-880 K and at 12.5 atm pressure. These experiments not only provide information on the reactivity of each fuel but also identify the major intermediate products formed during the oxidation process. A detailed chemical kinetic mechanism is used to simulate these experiments and comparisons of experimentally measures and model predicted profiles for O{sub 2}, CO, CO{sub 2}, H{sub 2}O and temperature rise are presented. Intermediates identified in the flow reactor are compared with those present in the computations, and the kinetic pathways leading to their formation are discussed. In addition, autoignition delay times measured in a shock tube over the temperature range 690- 1220 K and at 40 atm pressure were simulated. Good agreement between experiment and simulation was obtained for both the pure fuels and their mixtures. Finally, quantitative values of major intermediates measured in the exhaust gas of a cooperative fuels research engine operating under motored engine conditions are presented together with those predicted by the detailed method.
Date: January 1, 1998
Creator: Curran, H.J.; Pitz, W.J.; Westbrook, C.K.; Callahan, C.V. & Dryer, F.L.
Partner: UNT Libraries Government Documents Department

Ethanol Demand in United States Production of Oxygenate-limited Gasoline

Description: Ethanol competes with methyl tertiary butyl ether (MTBE) to satisfy oxygen, octane, and volume requirements of certain gasolines. However, MTBE has water quality problems that may create significant market opportunities for ethanol. Oak Ridge National Laboratory (ORNL) has used its Refinery Yield Model to estimate ethanol demand in gasolines with restricted use of MTBE. Reduction of the use of MTBE would increase the costs of gasoline production and possibly reduce the gasoline output of U.S. refineries. The potential gasoline supply problems of an MTBE ban could be mitigated by allowing a modest 3 vol percent MTBE in all gasoline. In the U.S. East and Gulf Coast gasoline producing regions, the 3 vol percent MTBE option results in costs that are 40 percent less than an MTBE ban. In the U.S. Midwest gasoline producing region, with already high use of ethanol, an MTBE ban has minimal effect on ethanol demand unless gasoline producers in other regions bid away the local supply of ethanol. The ethanol/MTBE issue gained momentum in March 2000 when the Clinton Administration announced that it would ask Congress to amend the Clean Air Act to provide the authority to significantly reduce or eliminate the use of MTBE; to ensure that air quality gains are not diminished as MTBE use is reduced; and to replace the existing oxygenate requirement in the Clean Air Act with a renewable fuel standard for all gasoline. Premises for the ORNL study are consistent with the Administration announcement, and the ethanol demand curve estimates of this study can be used to evaluate the impact of the Administration principles and related policy initiatives.
Date: August 16, 2000
Creator: Hadder, G.R.
Partner: UNT Libraries Government Documents Department

Detailed Chemical Kinetic Reaction Mechanisms for Primary Reference Fuels for Diesel Cetane Number and Spark-Ignition Octane Number

Description: For the first time, a detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reaction mechanism. Representative applications of this mechanism to two test problems are presented, one describing fuel/air autoignition variations with changes in fuel cetane numbers, and the other describing fuel combustion in a jet-stirred reactor environment with the fuel varying from pure 2,2,4,4,6,8,8-heptamethyl nonane (Cetane number of 15) to pure n-hexadecane (Cetane number of 100). The final reaction mechanism for the primary reference fuels for diesel fuel and gasoline is available on the web.
Date: March 3, 2010
Creator: Westbrook, C K; Pitz, W J; Mehl, M & Curran, H J
Partner: UNT Libraries Government Documents Department

Reforming petroleum-based fuels for fuel cell vehicles : composition-performance relationships.

Description: Onboard reforming of petroleum-based fuels, such as gasoline, may help ease the introduction of fuel cell vehicles to the marketplace. Although gasoline can be reformed, it is optimized to meet the demands of ICEs. This optimization includes blending to increase the octane number and addition of oxygenates and detergents to control emissions. The requirements for a fuel for onboard reforming to hydrogen are quite different than those for combustion. Factors such as octane number and flame speed are not important; however, factors such as hydrogen density, catalyst-fuel interactions, and possible catalyst poisoning become paramount. In order to identify what factors are important in a hydrocarbon fuel for reforming to hydrogen and what factors are detrimental, we have begun a program to test various components of gasoline and blends of components under autothermal reforming conditions. The results indicate that fuel composition can have a large effect on reforming behavior. Components which may be beneficial for ICEs for their octane enhancing value were detrimental to reforming. Fuels with high aromatic and naphthenic content were more difficult to reform. Aromatics were also found to have an impact on the kinetics for reforming of paraffins. The effects of sulfur impurities were dependent on the catalyst. Sulfur was detrimental for Ni, Co, and Ru catalysts. Sulfur was beneficial for reforming with Pt catalysts, however, the effect was dependent on the sulfur concentration.
Date: December 4, 2001
Creator: Kopasz, J. P.; Miller, L. E.; Ahmed, S.; Devlin, P. R. & Pacheco, M.
Partner: UNT Libraries Government Documents Department

Development of a gas-promoted oil agglomeration process. Quarterly report, October 1, 1996--December 31, 1996

Description: Further agglomeration tests were conducted in a series of tests designed to determine the effects of various parameters on the size and structure of the agglomerates formed, the rate of agglomeration, coal recovery, and ash rejection. For this series of tests, finely ground Pittsburgh No. 8 coal has been agglomerated with i-octane in a closed mixing system with a controlled amount of air present to promote particle agglomeration. The present results provide further evidence of the role played by air. As the concentration of air in the system was increased from 4.5 to 18 v/w% based on the weight of coal, coal recovery and ash rejection both increased. The results also show that coal recovery and ash rejection were improved by increasing agitator speed. On the other hand, coal recovery was not affected by a change in solids concentration from 20 to 30 w/w%.
Date: December 1, 1996
Creator: Wheelock, T.D.
Partner: UNT Libraries Government Documents Department


Description: A feasibility study for a proposed petroleum refinery for the Jicarilla Apache Indian Reservation was performed. The available crude oil production was identified and characterized. There is 6,000 barrels per day of crude oil production available for processing in the proposed refinery. The proposed refinery will utilize a lower temperature, smaller crude fractionation unit. It will have a Naphtha Hydrodesulfurizer and Reformer to produce high octane gasoline. The surplus hydrogen from the reformer will be used in a specialized hydrocracker to convert the heavier crude oil fractions to ultra low sulfur gasoline and diesel fuel products. The proposed refinery will produce gasoline, jet fuel, diesel fuel, and a minimal amount of lube oil. The refinery will require about $86,700,000 to construct. It will have net annual pre-tax profit of about $17,000,000. The estimated return on investment is 20%. The feasibility is positive subject to confirmation of long term crude supply. The study also identified procedures for evaluating processing options as a means for American Indian Tribes and Native American Corporations to maximize the value of their crude oil production.
Date: October 1, 2004
Creator: Jones, John D.
Partner: UNT Libraries Government Documents Department

Raman Scattering Sensor for Control of the Acid Alkylation Process in Gasoline Production

Description: Gasoline refineries utilize a process called acid alkylation to increase the octane rating of blended gasoline, and this is the single most expensive process in the refinery. For process efficiency and safety reasons, the sulfuric acid can only be used while it is in the concentration range of 98 to 86 %. The conventional technique to monitor the acid concentration is time consuming and is typically conducted only a few times per day. This results in running higher acid concentrations than they would like to ensure that the process proceeds uninterrupted. Maintaining an excessively high acid concentration costs the refineries millions of dollars each year. Using SBIR funding, Process Instruments Inc. has developed an inline sensor for real time monitoring of acid concentrations in gasoline refinery alkylation units. Real time data was then collected over time from the instrument and its responses were matched up with the laboratory analysis. A model was then developed to correlate the laboratory acid values to the Raman signal that is transmitted back to the instrument from the process stream. The instrument was then used to demonstrate that it could create real-time predictions of the acid concentrations. The results from this test showed that the instrument could accurately predict the acid concentrations to within ~0.15% acid strength, and this level of prediction proved to be similar or better then the laboratory analysis. By utilizing a sensor for process monitoring the most economic acid concentrations can be maintained. A single smaller refinery (50,000 barrels/day) estimates that they should save over $120,000/year, with larger refineries saving considerably more.
Date: April 19, 2006
Creator: Uibel, Rory, H.; Smith, Lee M. & Benner, Robert, E.
Partner: UNT Libraries Government Documents Department

Refinery Integration of By-Products from Coal-Derived Jet Fuels

Description: This report summarizes the accomplishments toward project goals during the first six months of the third year of the project to assess the properties and performance of coal based products. These products are in the gasoline, diesel and fuel oil range and result from coal based jet fuel production from an Air Force funded program. Specific areas of progress include generation of coal based material that has been fractionated into the desired refinery cuts, acquisition and installation of a research gasoline engine, and modification of diesel engines for use in evaluating diesel produced in the project. Characterization of the gasoline fuel indicates a dominance of single ring alkylcycloalkanes that have a low octane rating; however, blends containing these compounds do not have a negative effect upon gasoline when blended in refinery gasoline streams. Characterization of the diesel fuel indicates a dominance of 3-ring aromatics that have a low cetane value; however, these compounds do not have a negative effect upon diesel when blended in refinery diesel streams. The desulfurization of sulfur containing components of coal and petroleum is being studied so that effective conversion of blended coal and petroleum streams can be efficiently converted to useful refinery products. Equipment is now in place to begin fuel oil evaluations to assess the quality of coal based fuel oil. Combustion and characterization of fuel oil indicates that the fuel is somewhere in between a No. 4 and a No. 6 fuel oil. Emission testing indicates the fuel burns similarly to these two fuels, but trace metals for the coal-based material are different than petroleum-based fuel oils. Co-coking studies using cleaned coal are highly reproducible in the pilot-scale delayed coker. Evaluation of the coke by Alcoa, Inc. indicated that while the coke produced is of very good quality, the metals content of the ...
Date: May 17, 2006
Creator: Clifford, Caroline E. Burgess; Boehman, Andre; Song, Chunshan; Miller, Bruce & Mitchell, Gareth
Partner: UNT Libraries Government Documents Department

E85 Optimized Engine through Boosting, Spray-Optimized DIG, VCR and Variable Valvetrain

Description: The use of biofuels for internal combustion engines has several well published advantages. The biofuels, made from biological sources such as corn or sugar cane, are renewable resources that reduce the dependence on fossil fuels. Fuels from agricultural sources can therefore reduce a countries energy dependency on other nations. Biofuels also have been shown to reduce CO2 emissions into the atmosphere compared to traditional fossil based fuels. Because of these benefits several countries have set targets for the use of biofuels, especially ethanol, in their transportation fuels. Small percentages of ethanol are common place in gasoline but are typically limited to 5 to 8% by volume. Greater benefits are possible from higher concentrations and some countries such as the US and Sweden have encouraged the production of vehicles capable of operating on E85 (85% denatured ethanol and 15% gasoline). E85 capable vehicles are normally equipped to run the higher levels of ethanol by employing modified fuel delivery systems that can withstand the highly corrosive nature of the alcohol. These vehicles are not however equipped to take full advantage of ethanol's properties during the combustion process. Ethanol has a much higher blend research octane number than gasoline. This allows the use of higher engine compression ratios and spark advance which result in more efficient engine operation. Ethanol's latent heat of vaporization is also much higher that gasoline. This higher heat of vaporization cools the engine intake charge which also allows the engine compression ratio to be increased even further. An engine that is optimized for operation on high concentrations of ethanol therefore will have compression ratios that are too high to avoid spark knock (pre-ignition) if run on gasoline or a gasoline/ethanol blend that has a low percentage alcohol. An engine was developed during this project to leverage the improved evaporative ...
Date: May 31, 2011
Creator: Confer, Keith & Husted, Harry
Partner: UNT Libraries Government Documents Department

High Temperature Chemical Kinetic Combustion Modeling of Lightly Methylated Alkanes

Description: Conventional petroleum jet and diesel fuels, as well as alternative Fischer-Tropsch (FT) fuels and hydrotreated renewable jet (HRJ) fuels, contain high molecular weight lightly branched alkanes (i.e., methylalkanes) and straight chain alkanes (n-alkanes). Improving the combustion of these fuels in practical applications requires a fundamental understanding of large hydrocarbon combustion chemistry. This research project presents a detailed high temperature chemical kinetic mechanism for n-octane and three lightly branched isomers octane (i.e., 2-methylheptane, 3-methylheptane, and 2,5-dimethylhexane). The model is validated against experimental data from a variety of fundamental combustion devices. This new model is used to show how the location and number of methyl branches affects fuel reactivity including laminar flame speed and species formation.
Date: March 1, 2011
Creator: Sarathy, S M; Westbrook, C K; Pitz, W J & Mehl, M
Partner: UNT Libraries Government Documents Department

Propane vehicles : status, challenges, and opportunities.

Description: Propane as an auto fuel has a high octane value and has key properties required for spark-ignited internal combustion engines. To operate a vehicle on propane as either a dedicated fuel or bi-fuel (i.e., switching between gasoline and propane) vehicle, only a few modifications must be made to the engine. Until recently propane vehicles have commonly used a vapor pressure system that was somewhat similar to a carburetion system, wherein the propane would be vaporized and mixed with combustion air in the intake plenum of the engine. This leads to lower efficiency as more air, rather than fuel, is inducted into the cylinder for combustion (Myers 2009). A newer liquid injection system has become available that injects propane directly into the cylinder, resulting in no mixing penalty because air is not diluted with the gaseous fuel in the intake manifold. Use of a direct propane injection system will improve engine efficiency (Gupta 2009). Other systems include the sequential multi-port fuel injection system and a bi-fuel 'hybrid' sequential propane injection system. Carbureted systems remain in use but mostly for non-road applications. In the United States a closed-loop system is used in after-market conversions. This system incorporates an electronic sensor that provides constant feedback to the fuel controller to allow it to measure precisely the proper air/fuel ratio. A complete conversion system includes a fuel controller, pressure regulator valves, fuel injectors, electronics, fuel tank, and software. A slight power loss is expected in conversion to a vapor pressure system, but power can still be optimized with vehicle modifications of such items as the air/fuel mixture and compression ratios. Cold start issues are eliminated for vapor pressure systems since the air/fuel mixture is gaseous. In light-duty propane vehicles, the fuel tank is typically mounted in the trunk; for medium- and heavy-duty vans and ...
Date: June 17, 2010
Creator: Rood Werpy, M.; Burnham, A.; Bertram, K. & Systems, Energy
Partner: UNT Libraries Government Documents Department

Extents of alkane combustion during rapid compression leading to single and two stage ignition

Description: Extents of reactant consumption have been measured during the course of spontaneous ignition following rapid compression of N-pentane and N-heptane and also of PRF 60 (N-heptane = i-octane, 2.2.4 trimethylpentane) in stoichiometric mixtures with air. Compressed gas temperatures of 720-750 K and 845-875 K were studied at reactant densities of 131 mol m{sup minus 3}. At the lower gas temperature there was no evidence of reactant consumption during the course of the compression stroke. Two-stage ignition occurred at these temperatures, but only modest proportions of n-pentane were consumed during the first stage (< 15%) whereas about 40% of proportions of n- heptane reacted under the same conditions. At the higher compressed gas temperature the oxidation of n-pentane began only after the piston had stopped, whereas more than 30% of the n-heptane had already been consumed in the final stage of the compression stroke. The behavior of the PRF 60 mixture differed somewhat from that of N- pentane despite the similarly of the research octane numbers. Although there was a preferential oxidation of n-heptane at T{sub c} = 850K, which persisted throughout the early development of spontaneous ignition during the post-compression period, oxidation of both components of the PRF 60 mixture began before the piston had stopped. Numerical simulations of the spontaneous ignition under conditions resembling those of the rapid compression experiments show that the predicted reactivity from detailed kinetics are consistent with the observed features. Insights into the kinetic interactions that give rise to the relative reactivities of the primary reference fuel components are established
Date: February 1, 1996
Creator: Cox, A.; Griffiths, J.F.; Mohamed, C.; Curran, H.; Pitz, W.J. & Westbrook, C.K.
Partner: UNT Libraries Government Documents Department

Advanced thermally stable jet fuels. Technical progress report, April 1994--June 1994

Description: Research continued on coal-based, thermally stable, jet fuels. Significant progress has been made on the detection of polycyclic aromatic hydrocarbons present in highly stressed fuels, using high-performance liquid chromatography (HPLC) with diode-array detection. Gas chromatography is not able to detect compounds with {>=}6 fused aromatic rings, but such compounds can be identified using the HPLC method. The concentration of such compounds is low in comparison to aromatics of 1-3 rings, but the role of the large compounds in the formation of solid deposits may be crucial in determining the thermal stability of a fuel. The unusual properties of fluid fuels in the near-critical region appear to have significant effects on their thermal decomposition reactions. This issue has been investigated in the present reporting period using n-tetradecane as a model compound for fuel decomposition. Temperature-programmed retention indices are very useful for gas chromatographic and gas chromatography/mass spectrometric analysis of coal and petroleum derived jet fuels. We have demonstrated this in the identification of components in two JP-8 fuels and their liquid chromatographic fractions. The role of activated carbon surfaces as catalysts in the thermal stressing of jet fuel was investigated using n-dodecane and n-octane as model compounds. In some cases the reactions were spiked with addition of 5% decalin to test the ability of the carbon to catalyze the transformation of decalin to naphthalene. We have previously shown that benzyl alcohol and 1,4-benzenedimethanol are effective stabilizers at temperatures {>=}400{degrees}C for jet fuels and the model compound dodecane. The addition of ethanol to hydrocarbon/benzyl alcohol mixtures has a significant effect on the thermal stabilization of jet fuels above 400{degrees}C. Ethanol appears to function by reducing the benzaldehyde formed during the degradation of the benzyl alcohol. This reduction regenerates the benzyl alcohol.
Date: July 1, 1994
Creator: Schobert, H.H.; Eser, S. & Song, C.
Partner: UNT Libraries Government Documents Department

[News Clip: Gas blending]

Description: Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story. This story aired at 5 P.M.
Date: November 14, 1980
Creator: KXAS-TV (Television station : Fort Worth, Tex.)
Partner: UNT Libraries Special Collections