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02430 Experimental study of grease flow in pipelines: wall slip and air entrainment effects
02 Liquid fuels (transport, refining, quality, storage) concentration range where ASTM D2158-02 is not applicable. The method is easier to operate and takes less time compared with ASTM D2158 02 method.
05/02428 Comparative studies of oil compositions produced from sawdust, rice husk, lignin and cellulose by hydrothermal treatment Karag6z, S. et al. Fuel, 2005, 84, (7 8), 875 884. The objective of this study is to investigate the distribution of products, i.e. liquid, gas and solid from wood (sawdust) and non-wood biomass (rice husk), and major biomass components, i.e. lignin, cellulose produced by hydrothermal treatment (280°C for 15 rain) and analysis of liquid hydrocarbons (oils) for the differences in the hydrocarbon composition with respect to feed material. Cellulose showed the highest conversion among the four samples investigated in the present study. Sawdust and rice husk has almost similar conversions. Liquid products were recovered with various solvents (ether, acetone, and ethyl acetate) and analysed by GC-MS. The oil (ether extract) from the hydrothermal treatment of cellulose consisted of furan derivatives whereas lignin-derived oil contained phenolic compounds. The compositions of oils (ether extract) from sawdust and rice husk contained both phenolic compounds and furans, however phenolic compounds were dominant. Rice husk derived oil consists of more benzenediols than sawdust derived oil. The volatility distribution of oxygenated hydrocarbons were carried out by C-NP gram and it showed that the majority of oxygenated hydrocarbons from sawdust, rice husk and lignin were distributed at n-Cl~, whereas they were distributed at n-Ca and n-C10 in cellulose-derived oil. The gaseous products were carbon dioxide, carbon monoxide, methane in sawdust, rice husk, lignin and cellulose. In addition to this, ethylene, ethane and propane were observed for sawdust, rice husk and lignin. The major gas product was carbon dioxide for all samples.
05/02429 Development of bimodal cobalt catalysts for Fischer-Tropsch synthesis Zhang, Y. et al. Catalysis Today, 2004, 93-95, 55-63. A new and simple method for preparing multi-functional nano-sized silica-silica or zirconia-silica bimodal pore catalyst support was developed by direct introduction of silica or zirconia sols into silica gel. The pores of the obtained bimodal pore supports distributed distinctly as two kinds of main pores. On the other hand, the increased BET surface area and decreased pore volume, compared to those of original silica gel, indicated that the obtained bimodal pore supports formed according to the designed route, and it is found that the zirconia-silica bimodal support improved catalyst activity significantly via not only spatial effect, the intrinsic property of the bimodal structure, but also chemically promotional effect of zirconia, when this kind of support was appiied in the liquid-phase Fischer-Tropsch synthesis (FTS) as a cobalt-loading catalyst.
05102430 Experimental study of grease flow in pipelines: wall slip and air entrainment effects Delgado, M. A. et al. Chemical Engineering and Processing, 2005, 44, (7), 805-817. Prediction of pressure drop gradient and evaluation of wall slip and air bubbles entrainment effects observed during the piping flow of lubricating greases were investigated. With this aim, viscous flow tests in rotational rheometers and pressure drop measurements in pipelines were carried out using different geometries with both smooth and rough surfaces. The Sisko model was applied in the experimental range of flow rates for predicting pressure drop gradient. Air entrainment occurring when the pumping system was primed with a highly viscous material as lubricating greases significantly decreases pressure drop gradient. This air entrainment effect can be corrected using a modified expression to evaluate the drag ratio defined for non-Newtonian liquid/ air intermittent flows. On the other hand, a new expression based on the internal relative roughness of pipelines was proposed to correct wall slip effect. Eliminating these two effects, the classical definition of the friction factor for a non-Newtonian fluid, f = 16/Rd, can be applied to predict pressure drop of grease flow in pipelines.
05102431 Flow modeling of a battery of industrial crude oil/gas separators using 113mln tracer experiments Constant-Machado, H. et al. Chemical Engineering and Processing, 2005, 44, (7), 760-765. The objective of this work was to study the flow behaviour of crude oil in a battery of industrial crude oil/gas separators in the oil industry. The battery was composed of three separators operating at different pressures. The residence time distribution (RTD) of the crude oil was determined by an impulse injection of l r 3 m In at the inlet of each separator and the concentration was continuously recorded at the outlet. The real volume occupied by the crude oil was determined by simple estimation of the first moments. The R T D of the crude oil was simulated by a model composed of few mixing cells in series representing the effect of the deflector located at the entrance and a
plug flow partly due to the high viscosity of the crude oil. The variation of the parameters of the model was been studied as a function of pressure conditions and they have been linked to the deposition of sediment. The tracer measurement in gas phase showed that this method can detect non-negligible malfunction but it is not sensitive enough to assume that the zero tolerance of oil concentration in gas phase requested by the exploitant is respected.
05102432 Hydrocracking Brazilian Marlim vacuum residue with natural limonite. Part 1: catalytic activity of natural limonite Matsumura, A. et al. Fuel, 2005, 84, (4), 411-416. An experimental study examined the catalytic effects of natural Australian (AL) and Brazilian (BL) limonites used in hydrocracking Brazilian Marlim vacuum residue (ML-VR). The catalytic behavior of the limonites was compared with a conventional NiO-MoO3-A1203 (NiMo) catalyst. Diphenylmethane (DPM) and 1-methylnaphthalene (1-MN) were used as standards. The order in which coke and gas formation were suppressed during hydrocracking of ML-VR was N i M o > B L > A L , which is the same order as for the hydrogenation activity observed with the standard compounds. By contrast, the limonite catalysts exhibited relatively higher conversions and distillate yields in ML-VR hydrocracking than did the NiMo catalyst with the order of conversion and distillate yield (yield of the fraction with boiling point of 540°C) being A L > BL> NiMo, which is the same order obtained for catalytic cracking of the two standards. Coke formation was effectively suppressed at high hydrogen pressures. The limonite catalysts showed lower activities for nitrogen and sulfur removal than did NiMo, but both proved to have a larger activity for nickel removal.
05/02433 Hydrocracking Marlim vacuum residue with natural limonite. Part 2: experimental cracking in a slurrytype continuous reactor Matsumura, A. et al. Fuel, 2005, 84, (4), 417-421. Disposable Australian iron-slurry (AL) and NiO-MoO3-AlzO3 (NiMo) catalysts were used in hydrocracking experiments to convert Martim vacuum residue (ML-VR) in a slurry-bed continuous flow reactor at temperatures of 440-460°C, under a hydrogen pressure of 14.7 MPa and an LHSV of 0.5. The degree of conversion ranged from 54 to 83%, depending on the reaction temperature and catalyst used, with AL giving more complete conversion than NiMo. A L also proved more active in the removal of nickel. Hydrogen consumption was linearly correlated with conversion regardless of the catalyst used.
05/02434
Hydrodynamics of the tank with a screw impeller
Kuncewicz, C. et al. Chemical Engineering and Processing, 2005, 44, (7), 766-774. Results of mathematical modelling of liquid flow in a tank with a screw imp.elier operating in the system equipped with a diffuser in a laminar regime are presented in this paper. A two-dimensional model describing liquid flow in the tank was used to determine velocity fields. Results obtained were compared with experimental data given by earlier studies. Satisfactory agreement of the experimental and model values was obtained which confirmed that the model could be used in practical calculations. An optimization criterion of the tankimpeller system regarding mixing time was proposed and screw impellers were optimized.
05/02435 Systematic characterization of petroleum residua based on SFEF Zhao, S. et al. Fuel, 2005, 84, (6), 635-645. Supercritical fluid extraction and fractionation (SFEF) has been used to separate a variety of petroleum residua and other heavy oils into narrow-cut fractions with total yields up to 75-90%. Any insoluble material, or end-cut, corresponds to the asphaltene fraction in the parent oil. The narrow-cut fractions were analysed comprehensively and separated into the solubility classes of saturate, aromatic, resin, and asphaltene fractions. The boiling points were measured up to 700°C and correlations were established with the key factors such as density and molecular weight. This allows "extrapolation of boiling points of residue fractions up to 1000°C. Unlike bulk property measurements, the narrow-cut characterization data show increasing concentrations of key contaminants as the fractions become heavier. The solubility parameter for each narrow-cut fraction was measured using high-pressure fluid phase equilibrium with propane. The corresponding values for the end-cuts were obtained by the conventional precipitation method. The distribution and reactivity of sulfur species were determined by XPS in the bitumen pitch fractions and the corresponding residua produced during thermo-cracking and hydrocracking. The average structures for the narrow-cuts were constructed from molecular weight and elemental analyses together with FTIR, 1HN M R and 13C-NMR data. The results were used to develop a generalized feedstock characteristic index, KR. This index shows good correlation with feedstock hydrocarbon constituents and can be used to assess feedstock reactivity and processability. Downstream refiners can
Fuel and Energy Abstracts November 2005 359
05/02428 Comparative studies of oil compositions produced from sawdust, rice husk, lignin and cellulose by hydrothermal treatment Karag6z, S. et al. Fuel, 2005, 84, (7 8), 875 884. The objective of this study is to investigate the distribution of products, i.e. liquid, gas and solid from wood (sawdust) and non-wood biomass (rice husk), and major biomass components, i.e. lignin, cellulose produced by hydrothermal treatment (280°C for 15 rain) and analysis of liquid hydrocarbons (oils) for the differences in the hydrocarbon composition with respect to feed material. Cellulose showed the highest conversion among the four samples investigated in the present study. Sawdust and rice husk has almost similar conversions. Liquid products were recovered with various solvents (ether, acetone, and ethyl acetate) and analysed by GC-MS. The oil (ether extract) from the hydrothermal treatment of cellulose consisted of furan derivatives whereas lignin-derived oil contained phenolic compounds. The compositions of oils (ether extract) from sawdust and rice husk contained both phenolic compounds and furans, however phenolic compounds were dominant. Rice husk derived oil consists of more benzenediols than sawdust derived oil. The volatility distribution of oxygenated hydrocarbons were carried out by C-NP gram and it showed that the majority of oxygenated hydrocarbons from sawdust, rice husk and lignin were distributed at n-Cl~, whereas they were distributed at n-Ca and n-C10 in cellulose-derived oil. The gaseous products were carbon dioxide, carbon monoxide, methane in sawdust, rice husk, lignin and cellulose. In addition to this, ethylene, ethane and propane were observed for sawdust, rice husk and lignin. The major gas product was carbon dioxide for all samples.
05/02429 Development of bimodal cobalt catalysts for Fischer-Tropsch synthesis Zhang, Y. et al. Catalysis Today, 2004, 93-95, 55-63. A new and simple method for preparing multi-functional nano-sized silica-silica or zirconia-silica bimodal pore catalyst support was developed by direct introduction of silica or zirconia sols into silica gel. The pores of the obtained bimodal pore supports distributed distinctly as two kinds of main pores. On the other hand, the increased BET surface area and decreased pore volume, compared to those of original silica gel, indicated that the obtained bimodal pore supports formed according to the designed route, and it is found that the zirconia-silica bimodal support improved catalyst activity significantly via not only spatial effect, the intrinsic property of the bimodal structure, but also chemically promotional effect of zirconia, when this kind of support was appiied in the liquid-phase Fischer-Tropsch synthesis (FTS) as a cobalt-loading catalyst.
05102430 Experimental study of grease flow in pipelines: wall slip and air entrainment effects Delgado, M. A. et al. Chemical Engineering and Processing, 2005, 44, (7), 805-817. Prediction of pressure drop gradient and evaluation of wall slip and air bubbles entrainment effects observed during the piping flow of lubricating greases were investigated. With this aim, viscous flow tests in rotational rheometers and pressure drop measurements in pipelines were carried out using different geometries with both smooth and rough surfaces. The Sisko model was applied in the experimental range of flow rates for predicting pressure drop gradient. Air entrainment occurring when the pumping system was primed with a highly viscous material as lubricating greases significantly decreases pressure drop gradient. This air entrainment effect can be corrected using a modified expression to evaluate the drag ratio defined for non-Newtonian liquid/ air intermittent flows. On the other hand, a new expression based on the internal relative roughness of pipelines was proposed to correct wall slip effect. Eliminating these two effects, the classical definition of the friction factor for a non-Newtonian fluid, f = 16/Rd, can be applied to predict pressure drop of grease flow in pipelines.
05102431 Flow modeling of a battery of industrial crude oil/gas separators using 113mln tracer experiments Constant-Machado, H. et al. Chemical Engineering and Processing, 2005, 44, (7), 760-765. The objective of this work was to study the flow behaviour of crude oil in a battery of industrial crude oil/gas separators in the oil industry. The battery was composed of three separators operating at different pressures. The residence time distribution (RTD) of the crude oil was determined by an impulse injection of l r 3 m In at the inlet of each separator and the concentration was continuously recorded at the outlet. The real volume occupied by the crude oil was determined by simple estimation of the first moments. The R T D of the crude oil was simulated by a model composed of few mixing cells in series representing the effect of the deflector located at the entrance and a
plug flow partly due to the high viscosity of the crude oil. The variation of the parameters of the model was been studied as a function of pressure conditions and they have been linked to the deposition of sediment. The tracer measurement in gas phase showed that this method can detect non-negligible malfunction but it is not sensitive enough to assume that the zero tolerance of oil concentration in gas phase requested by the exploitant is respected.
05102432 Hydrocracking Brazilian Marlim vacuum residue with natural limonite. Part 1: catalytic activity of natural limonite Matsumura, A. et al. Fuel, 2005, 84, (4), 411-416. An experimental study examined the catalytic effects of natural Australian (AL) and Brazilian (BL) limonites used in hydrocracking Brazilian Marlim vacuum residue (ML-VR). The catalytic behavior of the limonites was compared with a conventional NiO-MoO3-A1203 (NiMo) catalyst. Diphenylmethane (DPM) and 1-methylnaphthalene (1-MN) were used as standards. The order in which coke and gas formation were suppressed during hydrocracking of ML-VR was N i M o > B L > A L , which is the same order as for the hydrogenation activity observed with the standard compounds. By contrast, the limonite catalysts exhibited relatively higher conversions and distillate yields in ML-VR hydrocracking than did the NiMo catalyst with the order of conversion and distillate yield (yield of the fraction with boiling point of 540°C) being A L > BL> NiMo, which is the same order obtained for catalytic cracking of the two standards. Coke formation was effectively suppressed at high hydrogen pressures. The limonite catalysts showed lower activities for nitrogen and sulfur removal than did NiMo, but both proved to have a larger activity for nickel removal.
05/02433 Hydrocracking Marlim vacuum residue with natural limonite. Part 2: experimental cracking in a slurrytype continuous reactor Matsumura, A. et al. Fuel, 2005, 84, (4), 417-421. Disposable Australian iron-slurry (AL) and NiO-MoO3-AlzO3 (NiMo) catalysts were used in hydrocracking experiments to convert Martim vacuum residue (ML-VR) in a slurry-bed continuous flow reactor at temperatures of 440-460°C, under a hydrogen pressure of 14.7 MPa and an LHSV of 0.5. The degree of conversion ranged from 54 to 83%, depending on the reaction temperature and catalyst used, with AL giving more complete conversion than NiMo. A L also proved more active in the removal of nickel. Hydrogen consumption was linearly correlated with conversion regardless of the catalyst used.
05/02434
Hydrodynamics of the tank with a screw impeller
Kuncewicz, C. et al. Chemical Engineering and Processing, 2005, 44, (7), 766-774. Results of mathematical modelling of liquid flow in a tank with a screw imp.elier operating in the system equipped with a diffuser in a laminar regime are presented in this paper. A two-dimensional model describing liquid flow in the tank was used to determine velocity fields. Results obtained were compared with experimental data given by earlier studies. Satisfactory agreement of the experimental and model values was obtained which confirmed that the model could be used in practical calculations. An optimization criterion of the tankimpeller system regarding mixing time was proposed and screw impellers were optimized.
05/02435 Systematic characterization of petroleum residua based on SFEF Zhao, S. et al. Fuel, 2005, 84, (6), 635-645. Supercritical fluid extraction and fractionation (SFEF) has been used to separate a variety of petroleum residua and other heavy oils into narrow-cut fractions with total yields up to 75-90%. Any insoluble material, or end-cut, corresponds to the asphaltene fraction in the parent oil. The narrow-cut fractions were analysed comprehensively and separated into the solubility classes of saturate, aromatic, resin, and asphaltene fractions. The boiling points were measured up to 700°C and correlations were established with the key factors such as density and molecular weight. This allows "extrapolation of boiling points of residue fractions up to 1000°C. Unlike bulk property measurements, the narrow-cut characterization data show increasing concentrations of key contaminants as the fractions become heavier. The solubility parameter for each narrow-cut fraction was measured using high-pressure fluid phase equilibrium with propane. The corresponding values for the end-cuts were obtained by the conventional precipitation method. The distribution and reactivity of sulfur species were determined by XPS in the bitumen pitch fractions and the corresponding residua produced during thermo-cracking and hydrocracking. The average structures for the narrow-cuts were constructed from molecular weight and elemental analyses together with FTIR, 1HN M R and 13C-NMR data. The results were used to develop a generalized feedstock characteristic index, KR. This index shows good correlation with feedstock hydrocarbon constituents and can be used to assess feedstock reactivity and processability. Downstream refiners can
Fuel and Energy Abstracts November 2005 359