bluuebunny/crossref_metadata_2025_split huggingface dataset:
The relative hydrogen saturation factor and its use for material balance analysis of underground coal gasification
Authors: Edwards Wayne C. 
Published: March 2009

AbstractSteady oxygen and hydrogen conservation relationships for an underground coal gasification reactor were combined with a simple model for the evolution of oxygen and hydrogen within the gasifier to yield a relationship for the fraction of evolved carbon originating from char gasification. This relationship is independent of the flow terms due to injection and production of water, whether the gas which leaks from the gasifier is like injected gas or produced gas. The relationship is a function of a dimensionless parameter called the relative hydrogen saturation factor of the evolved gas. Equations based on the concept of the relative hydrogen saturation factor are given for the carbon recovery efficiency and the fraction of exploited coal which has been completely gasified.Data from two field experiments were analysed. Results indicate that the relative hydrogen saturation factor is a valuable monitor of the relative importance of char gasification. The carbon recovery efficiency predicted by the analysis compares fairly well with the value measured from an excavation of a gasification site. The fraction of evolved carbon originating from char gasification, the carbon recovery efficiency, and the fraction of exploited coal which has been completely gasified are given for each field test.
Hydrogen adsorption measurements by the dynamic pulse method
Authors: Wanke S. E. , Lotochinski B. K. , Sidwell H. C. 
Published: March 2009

AbstractHydrogen adsorption uptakes by supported metal catalysts are commonly measured by the dynamic pulse technique. The pulse technique has several experimental advantages over the conventional static method, but the hydrogen uptakes measured by the pulse method are not easily interpreted. The measured pulse adsorption uptakes are influenced by the desorption of weakly adsorbed hydrogen. We found that the desorption of hydrogen at room temperature depends on the metal and the metal dispersion. We also found that hydrogen uptake measurements by the dynamic pulse method under well defined conditions are very reproducible.
The thermal conductivity of oils sands
Authors: Karim G. A. , Hanafi A. 
Published: March 2009

AbstractMeasurements have been made of the effective thermal conductivity of some samples of Athabasca oil sands using a steady state method over the temperature range 20°C – 120°C. The bitumen content of the samples was altered from its natural value by mixing with additional sand and the resulting values of the thermal conductivity were found to increase with increasing the oil content. Moreover, the effective thermal conductivity values were found to decrease with increasing temperature.
Effect of surface roughness on the rate of mass transfer to a pipe wall in the mass transfer entry region
Authors: Sedahmed G. H. , Soliman M. Nagy , El‐Kholy N. S. 
Published: March 2009

AbstractRates of mass transfer between a turbulently flowing solution and the inner wall of a rough tube were measured using an electrochemical technique involving the measurement of the limiting current of the cathodic reduction of potassium ferricyanide in a large excess of sodium hydroxide. Roughness was made by cutting V‐threads in the inner surface of the pipe. Four degrees of surface roughness with peak to valley height ranging from 0.047 to 0.833 mm were used. Reynolds number ranged from 5000 to 40000. Under these conditions it was found that surface roughness increases the rate of mass transfer by an amount ranging from 10% to 115% depending on the degree of roughness and Reynolds number. The data were correlated in the mass transfer entry region by the equation:
Propriétés photocatalytiques de Ta2O5/SiO2
Authors: Kaliaguine S. , Gnakoury M. , Roberge P. C. 
Published: March 2009

AbstractThe photocatalytic properties of deposited tantalum oxide (Ta2O5) on silica, in the reaction of photocatalytic oxidation of cyclohexane by oxygen, have been studied. The properties of this catalyst were compared with those of the previously studied system V2O5/SiO2, and it was concluded that the mobilities of V+5 and Ta+5 ions on the surface of silica under radiation arc verymuch different. This study was completed by an analysis of the diffuse reflectance spectra and a thermogravimetric analysis of the used catalysts. The conclusion was that the site active in the photocatalytic reaction, is hydrated during the oxidation of cyclohexane.
Hydrogenation of carbon monoxide over nickel zeolite catalysts — effect of reduction and calcination
Authors: Bajpai Pramod K. , Bakhshi Narendra N. , Mathews Joseph F. 
Published: March 2009

AbstractNiNaY zeolite catalysts were prepared by successive ion exchange of NaY. The catalysts were characterized for BET surface area, nickel metal area, nickel crystallite size and crystallinity. The methanation of carbon monoxide was studied in a fixed bed reactor in the temperature range of 523–673 K. Specific activities for methanation were found to vary with nickel concentration and crystallite size. The values of nickel metal area and specific methanation activity for the uncalcined catalysts were found to be higher compared to those of calcined catalysts. The effect of reduction at 723 K on the zeolite base structure and the effects of calcining the catalyst on metal area, crystallite size and activity are discussed.
Hydrogen production by the catalytic steam reforming of methanol part 1: The thermodynamics
Authors: Amphlett J. C. , Evans M. J. , Jones R. A. , Mann R. F. , Weir R. D. 
Published: March 2009

AbstractThe thermodynamic equilibria involved in the catalytic steam reformation of methanol to produce hydrogen have been examined over the ranges of pressure 101–3040 kPa, temperature 400–700K and water to methanol feed ratio 1.5–0.67. Four models have been considered based upon possible reaction products and the equilibrium composition of each model calculated.The presence of methane and carbon reduce the quantity and quality of hydrogen produced. The best condition for hydrogen production occurs at 500K in the model in which carbon (soot) and methane gas are excluded and where pressures are low, and water is in excess in the feed. To achieve these conditions in practice the reactions for methane formation, which is thermodynamically favoured, and the appearance of carbon (soot) must be inhibited.
Solubility of acetylene in several polar and non‐polar solvents and solvent mixtures
Authors: Miyano Y. , Hayduk W. 
Published: March 2009

AbstractSolubilities of acetylene in pure solvents, hexane, cyclohexane, hexadecane, benzene, carbon disulfide, carbon tetrachloride, methanol, butanol and ethylene glycol, and mixtures, hexane‐hexadecane and butanol‐ethylene glycol, are reported at atmospheric pressure and temperatures ranging from 0 C to 50 C. Hydrogen bonding (H‐bonding) factors expressed by a simplified Margules equation were found useful to correlate the solubilities of gases in the pure solvents as well as the solvent mixtures.
Deactivation studies of nickel catalysts used in the methanation of carbon monoxide
Authors: Bajpai P. K. , Bakhshi N. N. , Mathews J. F. 
Published: March 2009

AbstractFour laboratory prepared catalysts (Ni/Al2O3, NiNaY‐uncalcined, NiNaY‐calcined, NiCaY‐calcined) and a commercially available catalyst G‐87 were studied for their deactivation behavior over a period of 24 h at 573 k for various H2/CO ratios (3.1, 3.8, 6.4 and 24.5). The results indicated that the activities did not change much with time at H2/CO ratios of 3.8 and higher. Detailed measurement of catalytic activities, crystallite sizes, metal areas and carbon depositions were made at an H2/CO ratio of 3.1. These measurements indicated that sintering and carbon depositions occurred on all the catalysts thus deactivating the catalysts. An attempt has been made to explain the catalytic behavior in terms of crystallite size changes and carbon depositions. Limited regeneration studies of G‐87 and NiNaY‐calcinated catalysts have also been done.
The effect of surfactant on terminal velocity of and mass transfer from a fluid sphere in a non‐newtonian fluid
Authors: Kawase Y. , Ulbrecht J.J. 
Published: March 2009

AbstractThe effect of interfacial tension gradients on creeping flow past a fluid sphere (bubble or drop) in a non‐Newtonian fluid is investigated. The drag force and the Sherwood number for contaminated fluid spheres moving in a non‐Newtonian fluid are obtained by an approximate solution of equations of motion in the creeping flow regime. It has been found that surface‐active agents decrease both the terminal velocity and the mass transfer rate. The influence of the flow index of the power‐law on both the drag coefficient and the Sherwood number is superimposed over the influence of the interfacial tension gradient.Comparisons between the present analysis and the available experimental data in the literature show reasonable agreement for the terminal velocity and the Sherwood number.
Separation of nitrocellulose fine particles from industrial effluent with organic polymers
Authors: Wang Lawrence K. , Pressman Maurice , Shuster William W. , Shade Ray W. , Bilgen Fusun , Lynch Thomas 
Published: March 2009

AbstractPolymers were used in the experiments to determine optimum type and dosage requited for effective treatment of an industrial effluent containing nitrocellulose fine particles. It was found that (a) contact flocculation filtration was not effective for treating the nitrocellulose‐manufacturing wastewater due to the high initial turbidity; (b) mixing, flocculation, and settling of the wastewater with cationic polyelectrolyte and bentonite clay gave greater than 95% turbidity removal; (c) with the same optimum chemical dosages, mixing, flocculation and centrifugation also gave about 97% turbidity removal; and (d) with the same optimum chemical dosages, mixing, flocculation, sedimentation and filtration removed 99.9% of the wastewater turbidity.
Reactions and residence time distributions in motionless mixers
Authors: Nauman E.B. 
Published: March 2009

AbstractMotionless mixers are modeled as open, circular tubes with parabolic velocity distributions except at a few isolated planes where radial mixing occurs via an instantaneous coordinate transformation. Possible transformations are constrained by continuity of volumetric flow. Complete flow inversion appears the theoretically optimal transformation, being superior to complete mixing.A model consisting of intermediate planes of complete mixing approximates existing experimental data on the Kenics Static Mixer when four Kenics elements are made equivalent to a single plane of complete mixing. This model preserves the essential nature of a laminar flow residence time distribution while providing a relatively simple means of estimating mixer performance.
Laminar flow past a permeable sphere
Authors: Nandakumar K. , Masliyah Jacob H. 
Published: March 2009

AbstractFlow past an isolated permeable sphere has been studied. The complete Navier‐Stokes equation governs the fluid motion outside the sphere, while Brinkman's extension of Darcy's Law is assumed to hold within the porous sphere. The Navier‐Stokes equation is solved using a finite difference scheme. The flow within the porous sphere is solved in two different ways, each being efficient over a particular range of Reynolds number. Drag Coefficients are presented for dimensionless permeability, β, of 5, 10, 15, and 30 and for Reynolds numbers up to 50. The computed drag coefficients are within 10% of the experimental values observed by Masliyah and Polikar for 15 < β > 33, the range covered in their work. Separation was observed only for β > 10. The onset of separation is delayed considerably in porous spheres.
Modeling of Shallow Fluidized Bed Reactors: I. analytic solution of a simplified model
Authors: Chang C. C. , Fan L. T. , Rong S. X. 
Published: March 2009

AbstractA fairly general dynamic model for shallow fluidized bed reactors is developed, and analytic solutions for the governing equations of the model are obtained after some simplification. The bubble size, the lateral dispersion coefficient of solids, the level of the excess fluid reactant and the structure of the bed are examined to determine their effects on the conversion of solids. It has been shown that the conversion of solids is influenced profoundly by the bubble size and that it is advantageous to employ a shallow fluidized bed reactor if a high conversion of solids is required.
Liquefaction of aspen poplar wood
Authors: Eager R. L. , Mathews J. F. , Pepper J. M. 
Published: March 2009

AbstractDried and green aspen poplar wood suspended in water containing alkaline catalysts has been converted completely to an oil, water‐soluble chemicals and gases if heated for one hour in the presence of carbon monoxide in a rocking batch reactor. Within the ranges of parameters studied: temperature (593—633 K), nominal reaction times (0—1 h), water‐to‐wood ratio (0.5:1—5:1), catalyst (Na2CO3, K2CO3, NaOH), amount of catalyst (7.0—12.5 wt %) and initial hydrogen to carbon monoxide ratios (2:1—0:1), the water‐to‐wood ratio was most important. Oil yields of ˜50% with a carbon plus hydrogen content of ˜80% and representing a carbon recovery of ˜66% were obtained. The higher heats of combustion ranged from 32.2 to 36.0 MJ/kg.
Correlations for prediction of molecular diffusivities in liquids
Authors: Hayduk W. , Minhas B. S. 
Published: March 2009

AbstractNew correlations have been developed for diffusivities in liquids at infinite dilution for normal paraffin solutions, for aqueous solutions, as well as generally for polar and non‐polar solutions. The molar volume, parachor and radius of gyration for both solute and solvent were used as correlating parameters. The new correlations represent a significant improvement in accuracy for predicted diffusivities.
UNIFAC and infinite dilution activity coefficients
Authors: Alessi P. , Kikic I. , Fredenslund Aa. , Rasmussen P. 
Published: March 2009

AbstractThis paper deals with the possibility of estimating UNIFAC parameters from infinite dilution activity coefficients. Such activity coefficients can be obtained from gas chromatographic measurements (GLC).In some cases the original UNIFAC equations do not represent very well the variations of the activity coefficients with the concentration in the very dilute regions. It is then not possible to estimate reliable parameters from infinite dilution activity coefficients alone.It is shown that a recent modification of the combinatorial part of the UNIFAC equations allows for the estimation of UNIFAC parameters from infinite dilution activity coefficients for alkane—‐ketone, alkane—‐alcohol, and other mixtures.
Dynamics of adsorption columns with bacterial growth outside adsorbents
Authors: Tien Chi , Wang Shu‐Chieh 
Published: March 2009

AbstractThe dynamics of adsorption columns with the presence of bacterial activity was studied analytically and experimentally. The bacterial activity results in the formation of growing microbial films outside adsorbents. Equations describing the interaction between adsorption and bacterial growth were formulated and algorithms for their solutions developed. Experiments relating to the removal of valeric acid from aqueous solutions with granular carbon in the presence of denitrifying bacteria were performed to substantiate the analysis.
Coupling of mixing and microbial kinetics for evaluating the performance of bioreactors
Authors: Bajpai R. K. , Reuss M. 
Published: March 2009

AbstractThe effect of the dynamics of the mixing process in mechanically stirred bioreactors upon their performance has been investigated by using a circulation‐model for flow of fluid and a two‐environment‐model to account for the extent of micromixing in the vessel. With the help of an empirical kinetic model to depict the oxidative and the fermentative growth of bakers' yeast, experimentally observed effects of initial sugar concentrations upon critical dilution rates in continuous cultures of this system could be explained. Effect of different scales of operation upon productivities of fed‐batch cultures of bakers' yeast could also be satisfactorily predicted. A discrete simulation procedure was found to be a convenient tool in coupling the two‐environment circulation‐model of mixing with kinetics of microbial reactions.
Transformation of propene into acrylonitrile with nitric oxide over nickel oxide alumina catalyst in a continuous stirred tank reactor
Authors: Agbebavi James Thomas , Rouleau Denis , Pajonk Gerard 
Published: March 2009

AbstractCatalytic transformation of propene (C3H6) with nitric oxide (NO) over nickel oxide alumina catalyst (2NiO, Al2O3) has been investigated using a continuous stirred tank reactor at temperatures varying from 270 to 400°C, under atmospheric pressure. The main products found were acrylonitrile (C3H3N) and carbon dioxide (CO2). The rate of formation of C3H3N and the rate of disappearance of C3H6 were both correlated by the same model based on a redox mechanism:ri = kiokirPNOPHC/(kioPNO + kirPHC)The constants in the rate equation were expressed as a function of temperature.
Elutriation characteristics of solids from liquid fluidized bed systems Part I: Onset of elutriation
Authors: Ganguly V. P. 
Published: March 2009

AbstractExperimental data for the minimum elutriation velocity ume of solids for 134 different systems have been correlated by

The ranges of the different groups investigated were as follows:

For all of the experiments, the fluidizing liquid was water and the tube had an inside diameter of 4.92 cm. The standard deviation for the above correlation is 21.6 per cent.
Elutriation characteristics of solids from liquid fluidized bed systems Part II: Prediction of equilibrium bed concentration
Authors: Ganguly U. P. 
Published: March 2009

AbstractDuring elutriation of binary mixtures of solids differing in size and/or density, it has been found that the rate of decrease in concentration of the finer/lighter component is very fast at the beginning, falls off gradually and assumes an asymptotic value towards the end. The bed at this latter condition seems to have attained a retentive capacity for finer/lighter particles and this concentration has been termed the equilibrium bed concentration, CE. For all practical purposes, this sets the lower limit which the concentration of the elutriating component in the bed can attain, i.e. the maximum degree of removal of the particles from the system under a given set of operating conditions. Based on the experimental values of CE obtained from concentration versus time plots, an empirical correlation has been proposed as follows:

The correlation coefficient and the per cent standard deviation have been calculated to be 0.943 and 20.0, respectively.
On the annular‐to‐wavy flow pattern transition during condensation inside horizontal tubes
Authors: Soliman H. M. 
Published: March 2009

AbstractThe annular to wavy and intermittent flow pattern transition during condensation inside horizontal tubes was investigated. Eight data sets corresponding to different tube diameters and different test fluids were used to test the predictions of several diabatic and adiabatic correlations. Deficiencies were found in these correlations which prevented consistent agreement with the data base. An improved correlation is proposed and shown to have a good deal of generality and accuracy in predicting this transition.
A chromatographic study of diffusion of single components and binary mixtures of gases in 4A and 5A zeolites
Authors: Kumar Ravi , Duncan Robert C. , Ruthven Douglas M. 
Published: March 2009

AbstractResults of a chromatographic study of diffusion of light hydrocarbons and other permanent gases in 4A and 5A zeolites are reported. The data for CF4 and iC4Hm, on 4A sieve (no penetration of the zeolite lattice) suggest that micropore diffusion occurs primarily by a Knudsen mechanism. The majority of the measurements were made with small particles of crushed commercial pelleted zeolites under conditions of intracrystalline diffusion control. The dominance of intracrystalline resistance is shown by the similarity in the time constants obtained with different sizes of particle and the results are generally consistent with earlier gravimetric data. The data for the binary systems containing two adsorbed species are consistent with the simple hypothesis that each species in the mixture diffuses independently with the same intrinsic mobility as for single component diffusion at the same temperature. However, the actual diffusivity of a species in the binary mixture may differ from the pure component diffusivity due to differences in the form of the quilibrium isotherms.
Mass transfer modelling for GS heavy water plants: Part II: Tray efficiency on GS sieve trays
Authors: Neuburg H. J. , Chuang K. T. 
Published: March 2009

AbstractA mass transfer model to predict tray efficiency on industrial GS process sieve trays is presented. Tray efficiencies are predicted from point efficiencies on large trays up to 8.5 m in diameter, by taking into account effects of liquid flow distribution, weeping, entrainment, gas mixing and liquid mixing in the downcomers. Predictions by the model agree with tray efficiencies measured at the heavy water plants.
Microscopic structure of athabasca oil sand
Authors: Takamura Koichi 
Published: March 2009

AbstractA refined structural model for in situ oil sands is proposed in terms of the mutual arrangement of sand grains, fines, water and bitumen. In the Athabasca deposit, the sand grains consist mainly of quartz and their packing is such that the porosity is about 35%. In rich oil sand, 10–15% of the pore space is occupied by connate water whereas the remainder is occupied by bitumen. For lower grade oil sands, a direct correlation exists between the water content and the amount of fines (particles smaller than 44 μm) and an inverse correlation exists between the bitumen content and the amount of fines. These relationships are successfully explained in terms of the irreducible water saturation in a porous medium and the double layer interaction between sand and bitumen surfaces.
Methanation of carbon monoxide over alumina supported ni‐cu catalysts
Authors: Bajpai P. K. , Bakhshi N. N. , Dan‐Chu Liu , Mathews J. F. 
Published: March 2009

AbstractCopper has been added as a second metal to a nickel‐dispersed‐on‐alumina methanation catalyst. Compared with the nickel catalysts without copper, the initial methanation activity was reduced drastically but the tendency to deactivate with time‐on‐stream was much less. There were also less carbon deposition and less sintering of metal particles with the copper‐added catalysts.
Species grouping in multicomponent adsorption calculations
Authors: Calligaris Mary Beth , Tien Chi 
Published: March 2009

AbstractThe validity of the assumption of species grouping, which combines several adsorbable species into a fewer number of pseudo‐species in adsorption calculations, was examined by comparing the equilibrium concentrations obtained from exact calculations with those obtained with the use of the assumption. It was found that if the adsorption affinities of the individual species exhibited by their single‐species isotherms are of the same order of magnitude, the use of the species grouping assumption yields acceptable results. This procedure applies to three situations, including those in which (a) all the species are grouped into a single pseudo‐species; (b) the various species are combined into several (but fewer) pseudo‐species; and (c) only some of the species are grouped, while the others remain individual species.