bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some characteristics of a sparged agitated vessel under foaming — Mechanical control of foaming —
Authors: Ohkawa A. , Sugiyama K. , Sakai N. , Imai H. , Endoh K. 
Published: March 2009

AbstractFoam‐breaking with a rotating disk mechanical foam‐breaker (MFRD) was studied for a foaming system containing a diluted detergent solution in a laboratory sparged agitated vessel. The change of the foam‐breaking capacity of the MFRD by varying the air sparge rate, the working volume and the impeller speed or the disk diameter was measured. Based on these measurements, empirical equations are presented for predicting the critical foam‐breaking regions of the MFRD fitted with the agitated vessel. The operational range where foam‐breaking with the MFRD can be carried out effectively and economically is also discussed.
Process safety analysis for better reactor cooling system design in the ethylene oxide reactor
Authors: Piccinini Norberto , Levy Guido 
Published: March 2009

AbstractThe operating data for a plant producing 30,000 t/yr of ethylene oxide (EO) are presented, along with a detailed “process safety analysis” of the system used for reaction heat removal. Process safety analysis is a key point in the design procedure for typically critical plants, such as a E.O. reactor.The paper is primarily directed to identification of the coolant fluid most suitable for the requirements of the process in terms of safety and economy. The evaporating fluid cooling system adopted is examined analytically under both normal and emergency situations with reference to three fluids: dowtherm J, n‐octane and n‐nonane. Nonane was chosen as the coolant because it minimised the temperature gradient along the vertical axis of the reactor (<4°C on the shell side), circulation rate and evaporation pressure.
Extraction of uranium from sea water using biological origin adsorbents
Authors: Tsezos M. , Noh S. H. 
Published: March 2009

AbstractWaste microbial biomass has been shown to be a good adsorbent for uranium. A small scale pilot plant was operated at Woods Hole Oceanographic Institute in collaboration with the Department of Nuclear Engineering of MIT in order to assess the potential use of the two selected types of microbial biomass to sequester uranium from sea water effectively. The experimental results suggest that factors such as the presence of carbonates in the sea water, suppress substantially the uranium adsorptive uptake capacity of the biomass. The selectivity of the biomass for uranium, is not as good as that of other synthetic inorganic or organic adsorbents as, for example, hydrous titanium oxide.
Mass transfer in a reciprocating plate extraction column — effects of mass transfer direction and plate material
Authors: Shen Z. J. , Rama Rao N. V. , Baird M. H. I. 
Published: March 2009

AbstractThe mass transfer performance of 5 cm diameter reciprocating plate column has been measured with the system n‐butyric acid/kerosene (dispersed)/water (continuous). In most of the tests, the reciprocating plate stack was made of stainless steel which was preferentially wet by the continuous phase. During the mass transfer process the holdup and in some cases the Sauter mean droplet diameter were measured.The mass transfer effectiveness, expressed as the height of a transfer unit (Hax) corrected for axial mixing, depended on the phase flow rates, the agitation rate and the direction of mass transfer. For continuous to dispersed phase mass transfer (c → d), the mass transfer was more effective, i.e. Hax was lower than for d → c mass transfer under the same external conditions. Qualitative and quantitative observations indicated much larger drop sizes in the d → c case due to enhanced coalescence. Although mass transfer was less effective under d → c conditions, the column capacity was increased. The same effects were also observed when the plate stack was modified by inserting some Teflon plates which were partly wet by the dispersed phase.
Residence time distributions of power law fluids in motionless mixers
Authors: Nigam K. D. P. , Nauman E. B. 
Published: March 2009

AbstractMotionless mixers, which are also known as static mixers, can often be modeled as open, circular tubes with parabolic velocity distributions except at a few isolated planes where radial mixing occurs via an instantaneous coordinate transformation. The extension of this idea to the processing of non‐Newtonian fluids is straightforward. The parabolic velocity distribution is replaced by whatever fully developed velocity profile is appropriate for the fluid. Experimental confirmation is given for the flow of carboxymethylcellulose solutions through motionless mixers of the Kenics variety. A previous observation that four Kenics elements are equivalent to one plane of complete radial mixing holds for these power law fluids as well as for Newtonian fluids.
Oil blob populations and mobilization of trapped oil in unconsolidated packs
Authors: Wardlaw N. C. , Mckellar M. 
Published: March 2009

AbstractResidual oil was obtained by waterflooding, under water‐wet conditions, in unconsolidated packs of glass spheres at low capillary numbers. Trapped oil blobs were mobilized in a sequence of decreasing size with subsequent increases in capillary number. The larger blobs, which extend over many adjacent pores, fission repeatedly upon mobilization and the smaller daughter blobs are restranded. There is negligible oil production until the blob population has been reduced to single pore blobs (singlets).Thus, the critical capillary number for mobilization of significant amounts of oil in unconsolidated bead packs is not related to the original blob size population, but rather to the conditions necessary for mobilization of singlets.
Flow pattern boundaries during condensation: New experimental data
Authors: Rahman M. M. , Fathi A. M. , Soliman H. M. 
Published: March 2009

AbstractNew experimental data on the flow patterns of condensing steam inside horizontal tubes of 13.4 and 25.3‐mm i.d. are presented and discussed. Comparisons with flow pattern maps of adiabatic (gas‐liquid) and condensing flows, as well as individual transition correlations, resulted in good agreements at the mist‐annular and annular‐wavy transitions. All of the horizontal flow pattern correlations tested failed in reasonably predicting the wavy‐slug transition while the results of gas‐liquid flow in upwardly inclined tubes appear to provide some explanation of the trend at this transition.
Kinetics of coke deposition in naphtha pyrolysis
Authors: Kumar P. , Kunzru D. 
Published: March 2009

AbstractThe effect of run time, surface area, reaction temperature and inlet naphtha partial pressure on the rate of coke formation during naphtha pyrolysis has been investigated in a jet‐stirred reactor. The pyrolysis products could be predicted by a model developed earlier for naphtha pyrolysis. Various simplified models for the coke formation involving either the reactant or products were postulated and the kinetic parameters determined by a statistical analysis. The rate of coke formation was best modelled by an approximately second order reaction involving the aromatics.
An empirical method for calculating vapor‐liquid critical points of multicomponent mixtures
Authors: Peng Ding‐Yu 
Published: March 2009

AbstractThe critical temperatures and critical pressures of binary mixtures involving nitrogen, carbon dioxide, hydrogen sulfide, and paraffinic hydrocarbons ranging from methane through n‐heptane as calculated from the Peng—Robinson equation of state have been correlated using a modified compositional function of the Wilson equation in conjunction with the pseudo‐critical properties. The resulting parameters have been used to predict the critical properties of sixty‐one multicomponent systems. The empirically calculated critical temperatures and critical pressures deviate from the rigorously calculated values by an average of less than 1 K and 100 kPa, respectively.
Aggregate behaviour of liquid fluidised beds
Authors: Gibilaro L.G. , Hossain I. , Foscolo P.U. 
Published: March 2009

AbstractNew and long published experimental observations of the onset of aggregate (bubbling) behaviour in liquid fluidised beds are shown to be in agreement with the predictions of a recently published model of the fluidisation process. For a given liquid, the transition from particulate to aggregate fluidisation depends on both the density and size of the suspended particles: the lower the particle density the larger is the size necessary for a transition to occur: thus for fluidisation by ambient water, lead particles larger than 200 μm and soda glass particles larger than 2000 μm will exhibit aggregate behaviour; below a critical particle density no such transition is possible.
Measurement of voidage in the fountain of a spouted bed
Authors: Waldie B. , Wilkinson D. , Mchugh T.G.P. 
Published: March 2009

AbstractA γ‐ray technique is described for measuring the distribution of fractional voidage in the fountain of an air spouted bed. What appear to be the first experimental data on fountain voidage are presented. For the relatively shallow, 160 mm diameter, conical spouted bed studied, fountain fractional voidage is quite high, 0.88 and upwards. Generally voidage increases with height up the fountain, apart from a plateau or slight fall part way up. This trend differs from that proposed by Grace and Mathur in a theoretical model for a deeper cylindrical spouted bed. Fountain voidage is shown to depend on air flow rate and on particle size distribution.
Hydropyrolysis of kraft hardwood and softwood black liquor
Authors: Gilbert Allan F. , Cooper Dave F. 
Published: March 2009

AbstractThe hydropyrolysis of hardwood and softwood derived black liquor was studied to develop material balance data and to investigate the potential yield of phenolic oils that might be obtained as chemical by‐products of a kraft pulp mill. Hydropyrolysis reactions on softwood liquors were found to be more efficient in char formation than those on hardwood liquors. The yield of extractible phenolic oils was low, around 20–30 percent of black liquor organics, but the yields of simple phenols determined by gas chromatography were found to be even lower at 1–5 percent on black liquor organics.
Structural changes in catalytic hydroprocessing of syncrude coker gas oil
Authors: Khorasheh Farhad , Gray Murray R. , Dalla Lana Ivo G. 
Published: March 2009

AbstractA method of Structural Group Analysis (SGA) was used to characterize feed and liquid products from catalytic hydroprocessing using a commercial Ni‐Mo catalyst. Comparison of the structural profiles revealed significant changes in the concentration of various structural groups. SGA is a promising tool for investigating chemical changes in complex reacting systems.
Breakup of non‐newtonian emulsion jets
Authors: Kitamura Yoshiro , Shigeta Hiromoto , Kawata Toshio , Takahashi Teruo 
Published: March 2009

AbstractThe breakup of non‐Newtonian emulsion jets into drops was experimentally studied by ejecting both O/W and W/O emulsions vertically downward into stagnant air through nozzles. Breakup lengths of non‐Newtonian emulsion jets were found to be almost equivalent to those of Newtonian jets. Experimental breakup data establish that the static surface tension of the oil phase can be used as the surface tension of W/O emulsion jets, whereas the dynamic surface tension of aqueous surfactant solutions is used as that of O/W emulsion jets. Diameters of drops formed from non‐Newtonian emulsion jets are in good agreement with the prediction from the stability theory previously developed by the authors. When the rheological index in a power law model is appreciably smaller than unity and the Ohnesorge number is significantly large, however, drop sizes are larger than the prediction because of the profile relaxation in jets. The critical velocity of emulsion jets, either O/W or W/O emulsion, is significantly lower than that of homogeneous Newtonian jets.
Mass transfer between solid particles and liquid in a three phase fluidized bed
Authors: Prakash A. , Briens C. L. , Bergougnou M. A. 
Published: March 2009

AbstractParticle‐liquid mass transfer in a co‐current three‐phase fluidized bed of glass beads, water and air was studied with two measurement techniques. Both techniques measured the weight loss of a few particles coated with benzoic acid in a bed of inert glass beads. The effects of liquid and gas velocities, gas distribution and surface active agents on particle‐liquid mass transfer in a three‐phase fluidized bed were thus determined. In the absence of surface active agents in the liquid, particle‐liquid mass transfer rates in a three‐phase fluidized bed were up to 30% higher than in the corresponding liquid fluidized bed. When surface active agents were added to the liquid, the particle‐liquid mass transfer rate was increased by up to about 100% in the three‐phase fluidized bed, relative to the liquid fluidized bed. The particle‐liquid mass transfer coefficient was found to be inversely proportional to the liquid hold‐up in the three‐phase fluidized bed.
Coke formation during naphtha pyrolysis in a tubular reactor
Authors: Kumar P. , Kunzru D. 
Published: March 2009

AbstractThe effect of run time, temperature, conversion and inlet steam‐to‐naphtha ratio on the rate of coke deposition during naphtha pyrolysis in an annular tubular reactor has been investigated. Rates of coke deposition increased with increasing temperature, conversion and inlet naphtha partial pressure. Pyrolysis and coking models available for naphtha cracking were used to calculate the total coke deposited by treating the temperature difference between the reacting fluid and the outer reactor wall as a parameter. For all the runs, the experimental and calculated coking rates were in close agreement for an assumed temperature difference of 35‐45°C.
Flow through porous media of a shear‐thinning liquid with yield stress
Authors: Al‐Fariss T. , Pinder K. L. 
Published: March 2009

AbstractDarcy's law for the laminar flow of Newtonian fluids through porous media has been modified to a more general form which will describe the flow through porous media of fluids whose flow behavior can be characterized by the Herschel‐Bulkley model. The model covers the flow of homogeneous fluids with a yield value and a power law flow behavior.Experiments in packed beds of sand were carried out with solutions of paraffin wax in two oils and with a crude oil from the Peace River area of Canada. The model fitted the data well.A sensitivity analysis of the fitting parameters showed that the model fit was very sensitive to errors in the flow behavior index, n, of the Herschel‐Bulkley model. A comparison of the “n” values calculated from viscometer measurements and from flow measurements agreed well.A more general Reynolds number for flow through porous media, which includes a fluid yield value, was developed. The data were fitted to a Kozeny‐Carman type equation using this Reynolds number. The constant in the Kozeny‐Carman equation was determined for the two packed beds studied using Newtonian oils.The data could all be represented, within the experimental error, by the relationship f* = 150/Re*. Since the mean volume to surface diameter of the packing was determined by the measurement of its permeability to a Newtonian oil, assuming C' = 150, the new definition of the Reynolds number allows the direct use of the Kozeny‐Carman equation with Herschel‐Bulkley type fluids.
Simultaneous Absorption of Hydrogen Sulfide and Carbon Dioxide into di‐isopropanolamine Solution
Authors: Yih Siu‐Ming , Sun Chi‐Chun 
Published: March 2009

AbstractThe simultaneous absorption of hydrogen sulfide and carbon dioxide into di‐isopropanolamine (DIPA) solution was investigated in a 183 cm long, 2.72 cm OD wetted‐wall column at atmospheric pressure. The influence of liquid flow rate, gas flow rate, temperature and liquid concentration on the absorption rate, overall gas‐phase mass transfer coefficient and selectivity factor were studied at a constant gas feed ratio. The results show that the absorption rate of CO2 increases rapidly with increasing liquid flow rate (the Reynolds number of the turbulent liquid film ranges from 2600 to 4350) but increases moderately with increasing gas flow rate (G = 18‐91 L/min), indicating that it is liquid‐phase mass transfer controlled. In contrast, the absorption rate of H2S increases very slowly with increasing liquid flow rate but increases rapidly with increasing gas flow rate, indicating that it is gas‐phase mass transfer controlled. The absorption rate of CO2 also increases with increasing temperature (26‐80°C) but H2S absorption rate decreases with increasing temperature. When the concentration of DIPA solution increases from 0.2 to 2.6 mol/L, the absorption rate of both CO2 and H2S increases but with a larger rate of increase for CO2 For selective H2S removal, it is preferable to operate at low liquid and high gas flow rates, low temperatures and low DIPA concentrations.
Kinetics of growth and lactic acid production from whey permeate by Lactobacillus helveticus
Authors: Roy Denis , Leduy Anh , Goulet Jacques 
Published: March 2009

AbstractBatch fermentation kinetics of Lactobacillus helveticus were examined in detail. The nature of the culture medium had a significant effect on the product synthesis mechanism. In a glucose synthetic medium, lactic acid produced by the non‐growth‐associated mechanism was less than that by the growth‐associated mechanism. In a lactose synthetic medium, the contribution of both mechanisms was approximately equal at the end of fermentation. In the whey‐yeast extract permeate medium, the contribution by the non‐growth‐associated mechanism was superior to that of the growth‐associated mechanism. Temperature and pH also influenced the relative contribution of the two mechanisms on the total production of lactic acid in whey‐yeast extract permeate medium. Under optimal conditions for temperature and pH, the contribution of non‐growth‐associated product formation was the highest among all temperatures, and the lowest among all pH's. The ATP concentration‐biomass concentration relationship in the batch fermentation process could be roughly approximated by a Luedeking‐Piret‐like equation.
A group‐contribution, continuous‐thermodynamics framework for calculation of vapor‐liquid equilibria
Authors: Wang Shao‐Hwa , Whiting Wallace B. 
Published: March 2009

AbstractContinuous thermodynamics is extended to the calculation of vapor‐liquid equilibria with UNIFAC. For many mixtures of discrete compounds, the UNIFAC model is an efficient method for calculating vapor‐liquid equilibria of systems when experimental data are scarce or non‐existent. Such constraints are especially important in continuous mixtures.The continuous distribution is characterized by model compounds chosen to reproduce the TBP analysis. The UNIFAC model is extended to systems including several gases, and the new parameters for several light gases are given.The new algorithm is described in detail. Sample calculations are shown for several semi‐continuous systems.
Gas holdup and gas entrainment of a plunging water jet with a constant entrainment guide
Authors: Funatsu Kazumori , Hsu Yung‐Chien , Kamogawa Takemi 
Published: March 2009

AbstractThe gas holdup and gas entrainment of a plunging liquid jet with a gas entrainment guide in an air‐water system was investigated. The measurement of the gas holdup was performed using an over‐flow method. The turbulent jet velocity calculated on an inside nozzle diameter in the range from 4.4‐26.5 m/s for this system has been used in our correlations. The gas holdup has been well correlated in terms of 1/H(v02 + 2gH1), H1 d0 and the gas entrainment in terms of 1/Hw(v02 + 2gH1), H1, d0. The jet power requirement was also obtained from experimental data.
Dispersed phase holdup and drop size distribution in pulsed plate columns
Authors: Prabhakar A. , Sriniketan G. , Varma Y. B. G. 
Published: March 2009

AbstractDispersed phase holdup was measured in a pulsed plate column for the kerosene‐water system under binary conditions and under solute transfer from dispersed to continuous and continuous to dispersed phases. The experimental data were satisfactorily modelled through a recirculation regime model.The drop size distribution, measured by a photographic technique, exhibited a multinodal character at low agitation rates and high dispersed phase flow rate. Sauter mean drop diameter was found to depend on the agitation rate, the dispersed phase flow rate, the mass transfer direction and the plate free area. Correlations for d32 and the interfacial area were presented using Kolmogoroff's isotropic turbulence model.
Effect of zeta potentials of oil droplets and bubbles on flotation of oil‐in‐water mixtures
Authors: Okada Kenji , Akagi Yasuharu , Yoshioka Naoya 
Published: March 2009

AbstractThe effects of surface charges of oil droplets and bubbles in the oil‐in‐water flotation process were studied by a zeta potential apparatus which was specially designed to measure the zeta potential of bubbles. To measure the electrophoretic velocity of bubbles accurately, small bubbles whose rising velocities were less than 1 mm/s were introduced into an electrophoresis cell by a method of pressure reduction of a solution containing dissolved air, and the movement of the bubble in the cell was followed by moving the cell vertically at the same velocity as that of the rising bubble. It was found that the separation efficiency, n, for the flotation was strongly dependent on the zeta potentials of both the oil droplets and the bubbles. n increased as the zeta potentials of both the oil droplets and the bubbles decreased. Also n became the largest when the oil droplets were negatively charged and the bubbles were positively charged. Furthermore, a critical adhesion parameter, m=4πϵζpζb/kA, between oil droplets and bubbles was calculated by the heterocoagulation theory, using the value of the experimentally determined Hamaker constant, A=3.38x 10−20J, and the dependence of n on m was examined.
Flow pattern of the phases and liquid saturation in gas‐liquid concurrent downflow through packed beds
Authors: Sai P. S. T. , Varma Y. B. G. 
Published: March 2009

AbstractFlow pattern was visually observed for non‐foaming and foaming Newtonian and non‐Newtonian liquids under concurrent downflow with air in packed beds using different configurations of column geometry and packins. Flow maps delineating the different flow regions were presented based on the present study as well as that of earlier investigations. The total and dynamic liquid saturation were experimentally measured and correlations were presented in terms of (i) the Lockhart‐Martinelli parameter, χ, and (ii) the flow variables.
Solubilities of propene, butane, isobutane and isobutene gases in n‐Octane, Chlorobenzene and n‐Butanol solvents
Authors: Hayduk W. , Asatani H. , Miyano Y. 
Published: March 2009

AbstractSolubilities are reported for atmospheric pressure and temperatures of 298.15, 323.15 and 343.15 K for the gases propene, butane, isobutane and isobutene in the solvents n‐octane, chlorobenzene and n‐butanol. The solvents were chosen to investigate the effect of the nature of the solvent on gas solubility. The solvents range from the non‐polar (octane) to slightly polar (chlorobenzene) and to polar and associating (butanol). The order of gas solubilities in the slightly polar chlorobenzene is found to be closely related to the normal boiling points of the dissolving gases. A method for relating solubilities at various temperatures in similar polar and associating solvents is examined.