The oxidation of isobutane was investigated over various complex vanadium oxide catalysts. Mg₂V₂O₇, MgV₂O₆, and Mg₃V₂O₈ are effective catalysis for isobutene formation at >300°C. Cu₂V₂O₇ and CaV₂O₆ showed intermediate activity and BiVO₄ and Ca₇V₄O₁₇ were slightly active. The active catalysts had relatively strong acidic sites, and H abstraction from the t-carbon of isobutane by acidic site was considered to be the initial and rate-determining step because a linear relationship was observed between the amount of acidic sites and the catalytic activity of the catalysts. The introduction of transition metals into the Mg sites of the Mg₂V₂O₇ crystal lattice formed Mg_1.8V₂M_0.2O₇ (M = Mn, Cr, Fe, Co, Ni) catalysts. This substitution significantly promoted the catalytic activity without changing the selectivity for isobutene. Introduction of these transition metals increased the reactivity of lattice oxygen in Mg_1.8V₂M_0.2O₇ catalysts. Decreased W/F, increased the selectivity for isobutene to approaching 100%, suggesting that the initial reaction is the oxidative dehydrogenation of isobutane without parallel CO_x formation.

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The application of the membrane reactor to steam reforming of methanol was studied as a hydrogen producing reaction. The activities, stabilities and selectivities of Cu/ZnO, Ni/Al₂O₃ and Ru/Al₂O₃ catalysts were tested using a conventional fixed-bed flow reactor. Ni/Al₂O₃ catalyst showed the most stable activity at 723 K but relatively low hydrogen yield because of methanation. However, the hydrogen-permeable membrane reactor suppressed methanation and hydrogen yield was enhanced compared with the conventional reactor. The membrane reactor was more effective at higher temperatures and higher W/F.

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Carbon deposited on spent vacuum gas oil (VGO) hydrotreating catalysts from a commercial plant was investigated by elemental analysis and Raman spectroscopy. The samples of spent catalysts were separately recovered from the catalyst bed at several depths in the reactor after one year of commercial operation at 8 MPa, 360-400°C and LHSV 2 h^-1. The amount of coke deposited increased with depth in the catalyst bed, whereas volatile components in the spent catalyst decreased. The Raman spectrum of the carbon deposits on all catalyst samples showed bands at 1600 cm^-1 and 1350 cm^-1, which became more pronounced at greater depths in the catalyst bed. Calcination of the catalyst at 500°C for 2 h under a nitrogen gas stream caused marked enhancement of the bands of coke on the catalysts recovered from the upper part of the bed, but had no effect on the bands of coke on the catalysts recovered from the lower part of the bed. The asphaltene fraction contaminated with VGO was adsorbed on the catalyst in the upper parts of catalyst bed and condensed at the designed reaction temperature. In contrast, the higher temperatures at the lower parts of the catalyst bed due to the heat released by the hydrogenation reaction had extensively carbonized the adsorbed VGO to form partially graphitized carbon on the catalyst surface. Raman spectroscopy indicated the reaction temperature at each location of the catalyst bed and the progress of exothermic reactions.

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Friedel-Crafts acylation of toluene with benzoic anhydride to produce phenyl tolyl ketone was studied over various ion exchanged heteropoly acids (HPA). Metal chloride such as AlCl₃ was not used as a catalyst. Acid chloride was not used as an acylating agent. Therefore, this reaction could provide a halogen-free fine chemical synthesis process. The effect of partial ion exchange with Na, Rb, K, Cs, Ca, Mg and Fe on HPA was tested at atmospheric pressure. Insoluble H_0.5Cs_2.5PW₁₂O₄₀ catalyst showed the highest yield of 60%. The limited value of maximum yield was attributed to the side reaction. The effect of temperature showed that higher temperatures above the boiling point of toluene were desirable to reduce the side reaction. Then, the reaction was conducted in a sealed stainless autoclave reactor under pressurized conditions. Almost complete conversion without the side reaction was observed with this system above 410 K. The distribution of isomers of phenyl tolyl ketone at high temperatures was the same as that at low temperatures, suggesting that the reaction mechanism was independent of temperature. After washing the used catalyst with toluene, the catalyst was active for the second run but the activity gradually decreased after the third run.

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Experimental and model studies were performed on two-phase flow behavior at high-pressure conditions. The experiments were conducted using nitrogen and water in a test loop of 106.4 mm diameter pipe with inclination angles of 0°, 1°, and 3° at 2060 kPa. The liquid holdup data of 81 runs for each inclination angle were analyzed to identify the flow pattern.
The mechanistic model developed for low pressures was modified for high-pressure conditions. The model first detects the flow pattern, and then calculates liquid holdup and pressure drop based on the flow pattern. For dispersed-bubble flow, the critical bubble size mechanisms were also applicable at high pressures to predict a flow region in the flow pattern map, and the slip model of liquid holdup showed better matches with the experimental data than the non-slip model. For stratified flow, the flow region in the flow pattern map extended to higher liquid flow rates than at low pressures. Sequential application of the Taitel-Dukler and Bendiksen-Espedal criteria could correctly identify the stratified and non-stratified flow transition, and the Lockhart-Martinelli correlation based on the shear stresses could evaluate the liquid holdup much better than the common correlation based on the material balance. Elongated-bubble flow changed directly into dispersed-bubble flow as the liquid flow rate increases. Excellent performance of the model was demonstrated by error analyses of liquid holdup and pressure drop calculations.

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A quantitative procedure based on the magnetic flux leakage technique was proposed to evaluate the size of metal-loss type flaws such as corrosion pits in oil storage tank bottom floors. The approach considers both experimental findings and theoretical modeling of the simplified model flaws of local corrosion or pitting. Experiments were carried out on steel plate specimens, which contained artificial flaws with various depths and widths, such as flat-bottomed cylindrical holes and rectangular grooves in the backside of the specimen plates. The experimental results suggested that the depth of the flaw or residual plate thickness could be estimated by measurements of the strength and distribution of the vertical component of the magnetic leakage flux density, which is affected by far-side flaws. Analytical model calculations confirmed these findings. Moreover, a practical evaluation procedure for sizing flaws or the residual thickness of metal loss area by this technique was developed. The far-side magnetic leakage flux density distributions for conical holes were also measured and calculated using the theoretical model to confirm the procedure, which corrects the amplitude of the calculated far-side magnetic leakage flux density distribution. The far-side magnetic leakage flux density distributions for conical holes could be reproduced using the procedure.

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A high throughput screening (HTS) method for identifying supported nickel catalysts for the decomposition of methane was developed. Porous materials such as H-beta(SiO₂/Al₂O₃ = 150), H-beta(25), and H-ZSM-5(90) were highly effective supports for methane decomposition. The total time to find 3 active catalysts among 18 catalysts could be reduced to about one-third of that required with the conventional method. A Ni content of 5-10 mmol g-support^-1 was adequate. The HTS results were consistent with the results obtained using a conventional reactor.

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Decomposition of 1, 2-dichloroethane was examined over Ru, Rh, Pd, Pt, Cu, and Cr catalysts supported on TiO₂-SiO₂ in air. A large amount of Cl₂ was formed over Ru/TiO₂-SiO₂ catalyst at 400°C, whereas Rh, Pd, and Pt catalysts did not produce Cl₂ even at 450°C. Although Cu and Cr catalysts also produced Cl₂ effectively, the maximum activity observed at 650°C was still lower than that of Ru at 400°C.

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Diesel fuels having poor ignition properties would induce problems such as diesel knock and engine starting problems in cold weather. Diesel fuels in such cases need to have improved ignition properties. The addition of cetane number improving agents to diesel fuels is one method to improve the ignition properties of diesel fuels. However, addition of cetane number improving agents is not always an economically practical solution to improve the ignition properties of diesel fuels. Our previous study showed that the cetane numbers of autoxidized fuels in which hydroperoxides were produced increased. It is important for the development of cetane number improving systems by autoxidation to investigate the effects of molecular structures of hydrocarbons on the formation of hydroperoxides and the cetane number improvement. In this study, effects of carbon numbers and branching of alkanes on the formation of hydroperoxides were investigated. As a result, smaller carbon numbers produced more hydroperoxides. Also, effects of the molecular structures of the hydrocarbons on cetane number improvement by produced hydroperoxides have been investigated. The result suggests that the hydroperoxide produced from alkanes having a lower carbon number increases cetane number more. Furthermore, polynuclear aromatic hydrocarbons such as naphthalene and 1-methyl naphthalene had inhibition effects on the hydroperoxide production by autoxidation. From above results, the autoxidation could be a good method for improving diesel fuels such as city diesel and kerosene having low aromatic compounds and low distillation ranges because these fuels have to add cetane number improving agents to increase its number.

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The parachor method (PM) is widely used to predict interfacial tension (IFT) but may yield incorrect IFT values, and, thus, adjustment of the PM parameters may be necessary. The sensitivities of IFT predictions to the PM parameters were investigated by examining the Weinaug and Katz method (WKM) and the Lee and Chien method (LCM). Parameter adjustment of only the scaling exponent does not always yield good regression results, and including parachors (or related variables) in a set of regression parameters is recommended. The WKM may result in unrealistic parameter adjustment due to the absence of interrelation between the scaling exponent and the parachor. In contrast, the LCM honors the correct definition of the parachor and tends to yield acceptable IFT predictions within the limits of realistic parameter adjustment.

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