Midyear Economic Report from the USSR. PDF Download

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Author: Владимир Семенович Высоцкий
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Languages : en
Pages : 380

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Languages : en
Pages : 597

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The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume (Sections 1 through 5).

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Languages : en
Pages : 190

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This project focuses on the compositional factors affecting jet fuel thermal stability at high temperatures. The chemical composition of the four jet fuel samples (JP-8C, JP-8P, JP-7P, Jet A-1) and Wilsonville middle distillates was characterized by using selective ion monitoring technique in GC-MS analysis. The thermal treatment tests have been performed on jet fuels and a series of model compounds including tetralin, decalin, ethylcyclohexane, butylcyclohexane, n-butylbenzene, t-butylbenzene, n-octane, n-decane, and n-tetradecane. Deposit samples from an actual aircraft fuel system as well as those produced from jet fuels and model compounds in microautoclaves were characterized by FTIR and polarized-light microscopy. Experiments were conducted to find the optimum amount of antioxidant 2,6-di-tert-butyl-4-methylphenol necessary to minimize the solid formation upon thermal stressing of JP8 neat and Jet A-1 fuel samples. The chemistry of thermal degradation of the fuel and antioxidant mixtures was studied by using FTIR to characterize the liquid products from thermal stressing.

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Languages : en
Pages : 131

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The Penn State program in advanced thermally stable coal-based jet fuels has five borad objectives: (1) development of mechanisms of degradation and solids formation; (2) quantitative measurement of growth of sub-micrometer and miocrometer-sized particles suspended in fuels during thermal stressing; (3) characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) elucidation of the role of additives in retarding the formation of carbonaceous solids; and (5) assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Pyrolysis of four isomers of butylbenzene was investigated in static microautoclave reactors at 450°C under 0.69 MPa of UHP N2. Thee rates of disappearance of substrates were found to depend upon the bonding energy of C[alpha]-C[beta] bond in the side chain in the initial period of pyrolysis reactions. Possible catalytic effects of metal surfaces on thermal degradation and deposit formation at temperatures>400°C have been studied. Carbon deposition depends on the composition of the metal surfaces, and also depends on the chemical compositions of the reactants. Thermal stressing of JP-8 was conducted in the presence of alumina, carbonaceous deposits recovered from earlier stressing experiments, activated carbon, carbon black, and graphite. The addition of different solid carbons during thermal stressing leads to different reaction mechanisms. 13C NMR spectroscopy, along with 13C-labeling techniques, have been used to examine the thermal stability of a jet fuel sample mixed with 5% benzyl alcohol. Several heterometallic complexes consisting of two transition metals and sulfur in a single molecule were synthesized and tested as precursors of bimetallic dispersed catalysts for liquefaction of a Montana subbituminous and Pittsburgh No. 8 bituminous coals.

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Languages : en
Pages : 197

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There are five tasks within this project on thermally stable coal-based jet fuels. Progress on each of the tasks is described. Task 1, Investigation of the quantitative degradation chemistry of fuels, has 5 subtasks which are described: Literature review on thermal stability of jet fuels; Pyrolytic and catalytic reactions of potential endothermic fuels: cis- and trans-decalin; Use of site specific 13C-labeling to examine the thermal stressing of 1-phenylhexane: A case study for the determination of reaction kinetics in complex fuel mixtures versus model compound studies; Estimation of critical temperatures of jet fuels; and Surface effects on deposit formation in a flow reactor system. Under Task 2, Investigation of incipient deposition, the subtask reported is Uncertainty analysis on growth and deposition of particles during heating of coal-derived aviation gas turbine fuels; under Task 3, Characterization of solid gums, sediments, and carbonaceous deposits, is subtask, Studies of surface chemistry of PX-21 activated carbon during thermal degradation of jet A-1 fuel and n-dodecane; under Task 4, Coal-based fuel stabilization studies, is subtask, Exploratory screening and development potential of jet fuel thermal stabilizers over 400 C; and under Task 5, Exploratory studies on the direct conversion of coal to high quality jet fuels, are 4 subtasks: Novel approaches to low-severity coal liquefaction and coal/resid co-processing using water and dispersed catalysts; Shape-selective naphthalene hydrogenation for production of thermally stable jet fuels; Design of a batch mode and a continuous mode three-phase reactor system for the liquefaction of coal and upgrading of coal liquids; and Exploratory studies on coal liquids upgrading using mesopores molecular sieve catalysts. 136 refs., 69 figs., 24 tabs.

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Languages : en
Pages : 40

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This report summarizes briefly the key results of a project for the development of coal-based jet fuel. The initial focus of the project was the development of a high heat sink fuel, JP-9OO, that could be used for thermal management as well as for propulsion energy. In the last year the focus shifted to development of a coal-based drop-in replacement for JP-8. Prototype fuel from hydrogenation of a mixture of light cycle oil and refined chemical oil met or exceeded all but four W-8 specifications. The fuel has excellent low-temperature viscosity behavior and 0-ring seal swell comparable to JP-8. Deposition from thermal stressing of the fuel in various reactors was invariably lower than JP-8 or JP-8+lOO. Mechanisms of oxidative deposit formation for both jet and diesel fuels are proposed to account for the fact that the chemistry involved in both storage and thermal oxidative deposit formation in middle distillates is similar. The fuel was successfully tested in a T63 turboshaft engine, with emissions only slightly greater than JP-8. Well over a hundred publications resulted from the seven-year project period.

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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.

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Languages : en
Pages : 176

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Quantitative structure-property relationships have been applied to study the thermal stability of pure hydrocarbons typical of jet fuel components. A simple method of chemical structure description in terms of Benson groups was tested in searching for structure-property relationships for the hydrocarbons tested experimentally in this program. Molecular connectivity as a structure-based approach to chemical structure-property relationship analysis was also tested. Further development of both the experimental data base and computational methods will be necessary. Thermal decomposition studies, using glass tube reactors, were extended to two additional model compounds: n-decane and n-dodecane. Efforts on refining the deposit growth measurement and characterization of suspended matter in stressed fuels have lead to improvements in the analysis of stressed fuels. Catalytic hydrogenation and dehydrogenation studies utilizing a molybdenum sulfide catalyst are also described.

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Languages : en
Pages : 111

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There are five tasks within this project on thermally stable coal-based jet fuels. Progress on each of the tasks is described. Task 1, Investigation of the quantitative degradation chemistry of fuels, has 3 subtasks which are described: Pyrolysis of n-alkylbenzenes; Thermal decomposition of n-tetradecane in near-critical region; and Re-examining the effects of reactant and inert gas pressure on tetradecane pyrolysis--Effect of cold volume in batch reactor. Under Task 2, Investigation of incipient deposition, the subtask reported is Uncertainty analysis on growth and deposition of particles during heating of coal-derived aviation gas turbine fuels; under Task 3, Investigation of the quantitative degradation chemistry of fuels, is subtask, Effects of high surface area activated carbon and decalin on thermal degradation of jet A-1 fuel and n-dodecane; under Task 4, Coal-based fuel stabilization studies, is subtask, Screening potential jet fuel stabilizers using the model compound dodecane; and under Task 5, Exploratory studies on the direct conversion of coal to high quality jet fuels, is subtask, Shape-selective naphthalene hydrogenation for production of thermally stable jet fuels. 25 refs., 64 figs., 22 tabs.