bluuebunny/crossref_metadata_2025_split huggingface dataset:
A heat transfer relation for swirl flow in a vortex tube
Authors: Lin Sui , Chen Jirui , Vatistas Georgios H. 
Published: March 2009

AbstractAn experimental investigation was made to study the heat transfer behavior of a water‐cooled vortex tube with air as the working medium. The vortex flow was generated by leading the compressed air to enter the vortex tube tangentially. The pressures of the inlet air were 300 to 500 kPa gauge. For each of these inlet pressures, the heat transfer performance of the vortex tube was studied at different cold mass flow ratios. New experimental data are presented. An empirical correlation for the prediction of the air‐side Nusselt number is established. It was shown that the air‐side Nusselt number for the swirl flow in this vortex tube can be up to 30 times higher than that for a flow without swirl in the same tube.
Interfacial area and mass transfer in gas‐liquid cocurrent upflow and countercurrent flow in reciprocating plate column
Authors: Sundaresan A. , Varma Y. B. G. 
Published: March 2009

AbstractThe volumetric mass transfer coefficient and the interfacial area were measured for carbon dioxide absorption into water using a reciprocating plate column of plate geometry different from a Karr column. The specific interfacial area was governed by a change in bubble size at low agitation rates and by a variation in gas holdup at high agitation rates. The liquid phase mass transfer coefficient was strongly influenced by the agitation rate, the phase velocities and the plate geometry.
Oil recovery from oil in water emulsions using a flotation column
Authors: Pal Rajinder , Masliyah Jacob 
Published: March 2009

AbstractA flotation column was used to recover oil from oil in water emulsions. The feed oil concentrations investigated were relatively high, in the range of 0.25 to 8 percent by volume. Previous studies using conventional flotation cells dealt with very dilute systems where the oil concentration was less than 0.1 percent by volume.The oil recovery was found to decrease with an increase in the feed oil concentration. The addition of wash water to the froth zone of the column had little effect on the oil recovery. The oil recovery decreased with increasing feed flow rate and surfactant concentration. The effect of increasing the gas flow rate was to initially increase the oil recovery. The oil recovery data were analyzed using a kinetic model. The order of the flotation kinetics was found to be 0.6.The gas hold‐up behaviour of the recovery and the froth zones of the flotation column is found to correlate well with the drift‐flux model.
The electrochemical oxidation of aqueous phenol at a glassy carbon electrode
Authors: Gattrell M. , Kirk D. W. 
Published: March 2009

AbstractThe electrooxidation of phenol is of interest as a model compound for the treatment of aqueous organic wastes. The effect of voltage, concentration and temperature on the electrochemical oxidation of acidic dilute aqueous solutions of phenol was studied. Electrolysis was carried out by recirculating phenol solutions through a flow‐by electrochemical reactor employing a reticulated glassy carbon anode. Concentrations of phenol and some breakdown products were monitored using HPLC analysis.Increased voltage was found to shift the product distribution to favour more oxidized products but also to increase electrode corrosion and decrease current efficiency. Higher phenol concentrations (over the range of 5‐20 mmol/L) showed a shift in product distribution to favour less oxidized, mostly insoluble products. Elevated temperatures (about 50°C and higher) showed a marked ability to reduce electrode passivation and increase the phenol oxidation rate.
Henry's law constants and thermodynamic properties of gases and vapours in bitumens
Authors: Xv Yuming , Hepler Loren G. 
Published: March 2009

AbstractSolubilities for 13 gases and vapours (CO2, alkanes from ethane to n‐octane, benzene, toluene, xylene, dichloromethane, and methanol) in two Alberta bitumens (Athabasca and Wolf Lake) have been measured at several temperatures (30‐150°C), using gas‐liquid chromatography (GLC). The GLC method yields accurate solubilities and Henry's law constants for moderately soluble gases, but is not applicable to less soluble gases such as CH4 and H2. Results have been used for calculations of ΔHo and ΔCop for processes of the type Solute Substance (gas) = Solute Substance (in bitumen).Correlations of Henry's law constants and ΔHo values with carbon number for alkanes have been observed and used for predictions of CH4 solubilities in bitumens.
A generalized correlation for the prediction of phase behaviour in supercritical systems
Authors: Trebble M. A. , Sigmund P. M. 
Published: March 2009

AbstractA generalized two parameter model is presented which uses molecular properties of pure fluids to predict interaction parameters in the attractive term of the Peng‐Robinson equation of state. The predictive method is based on a consideration of London (dispersive) forces and includes attractive forces between polar and non‐polar molecules that result from induction. Polar‐polar effects and quantum forces are omitted. A large body of experimental vapor‐liquid equilibrium data measured at near and supercritical conditions (that excludes quantum components and polar‐polar systems) was used to calibrate the generalized model. Overall bubble point pressure deviations calculated using the proposed generalization were 5.66% for 3240 data points which compares to average deviations of 3.27% obtained by using regressed binary interaction parameters. Average vapor mole fraction deviations were just under 0.01 using both the generalized and the regressed interaction parameters. The sensitivity of predicted phase envelopes to dispersive and inductive term in the generalized correlation is shown graphically for several systems. Comparisons are also made to another recent interaction parameter generalization presented by Nishiumi et al. (1988).
Multivariate statistical monitoring of process operating performance
Authors: Kresta James V. , Macgregor John F. , Marlin Thomas E. 
Published: March 2009

AbstractProcess computers routinely collect hundreds to thousands of pieces of data from a multitude of plant sensors every few seconds. This has caused a “data overload” and due to the lack of appropriate analyses very little is currently being done to utilize this wealth of information. Operating personnel typically use only a few variables to monitor the plant's performance. However, multivariate statistical methods such as PLS (Partial Least Squares or Projection to Latent Structures) and PCA (Principal Component Analysis) are capable of compressing the information down into low dimensional spaces which retain most of the information. Using this method of statistical data compression a multivariate monitoring procedure analogous to the univariate Shewart Chart has been developed to efficiently monitor the performance of large processes, and to rapidly detect and identify important process changes. This procedure is demonstrated using simulations of two processes, a fluidized bed reactor and an extractive distillation column.
An expert system for identifying separation processes
Authors: Garg Mahesh K. , Linders James G. , Douglas Peter L. 
Published: March 2009

AbstractThis paper presents the development of an expert system, called SIS (Separator Identification System), to generate near‐optimal separation sequences for any multicomponent mixture. SIS was designed based on a combination of heuristic and algorithmic approaches. Heuristics were used to select the location of the split. Algorithms were used to calculate physical properties of the multicomponent mixture. A fuzzy approach was used for the propagation of the truth function and uncertainty management. SIS was tested using four sample problems involving gas, liquid, and solid components. The separation sequences suggested by SIS were the same or similar to those found in process synthesis literature.
Extrudate swell of newtonian liquids from rectangular dies
Authors: Esmail M. N. 
Published: March 2009

AbstractExtrudate swell from square and rectangular dies was studied for glycerol solutions. Experiments were performed for a wide range of viscosities 75 < μ < 464 mPa · s, with small changes in surface tension and density. Dies with aspect ratios of 3:1 and 2.25:1 and a wide range of length to hydraulic diameter ratios, i.e., 24 < l/Dh < 62, were used. Results were obtained in the range of Reynolds number 1 < Re < 50. Swell ratios for the short and long faces of a die are below the swell ratio of a plane slit. Swell ratios for the short face are consistently higher than those for the long face for lower Reynolds numbers. Liquid contracted at the corners, while swelling along faces.
Simplified analytical prediction of distillation column startup time at total reflux
Authors: Iribarren Oscar A. , Chiotti Omar J. 
Published: March 2009

AbstractA short‐cut explicit expression is presented for distillation at total reflux that predicts the time it takes to shift the reboiler composition from an initial charge composition to the final steady state composition.The prediction is of interest when handling low relative volatility mixtures, as in isomeric or isotopic distillations, where the startups involve times in the order of a day or more.
Gas‐liquid mass transfer in the bubble column with viscoelastic liquid
Authors: Suh I.‐S. , Schumpe A. , Deckwer W.‐D. , Kulicke W.‐M. 
Published: March 2009

AbstractThe effects of liquid‐phase viscosity, pseudoplasticity, and viscoelasticity on gas‐liquid mass transfer in a bubble column have been investigated using aqueous solutions of sucrose, xanthan, polyacrylamide, and mixtures of xanthan and polyacrylamide. The elastic properties, considered in the form of the Weissenberg number, decreased the volumetric mass transfer coefficient by a factor of up to 5. The effect was strong even at low Weissenberg numbers encountered in many liquids, the elasticity of which is usually neglected.
Experimental simulation of large‐scale bioreaetor environments using a Monte Carlo method
Authors: Namdev Pradyumna K. , Yegneswaran Pallavur K. , Gray Murray R. , Thompson B. G. 
Published: March 2009

AbstractCells grown in production‐scale stirred bioreactors experience fluctuating concentrations due to local variations in supply and consumption of oxygen and nutrients. A new method for studying the effects of fluctuations in local conditions on growth and productivity of cells was developed using a Monte Carlo approach to simulate circulation within a fermenter. A small fermenter was driven through cycles of aeration and feeding, with the time of each cycle controlled by a Monte Carlo method to give a log‐normal distribution. Experiments with Monte Carlo supply of air to batch and fed‐batch cultures of Saccharomyces cerevisiae showed that the method gave reproducible results which were different from both periodic cycling and continuous supply. When substrate was provided to a fed‐batch culture of S. cerevisiae according to the Monte Carlo method, the yields of biomass were higher than experiments with continuous feeding or periodic feeding.
Desulfurization of benzothiophene with molybdenum naphthenate. Application of statistical analysis to evaluate the role of donor solvent
Authors: Ng F. T. T. , Walker G. R. 
Published: March 2009

AbstractThe activities of molybdenum naphthenate and cobalt naphthenate for benzothiophene desulfurization are studied at 350 to 400°C and 6.9 to 13.8 MPa pressure. Molybdenum is found to be more active than cobalt naphthenate for desulfurization. At 400°C, using 104 mg/kg Mo on benzothiophene in tetralin under 6.9 MPa H2, over 90 mol % conversion of benzothiophene to ethylbenzene is observed. No styrene is detected. The dominant pathway for desulfurization is proposed to be via the initial hydrogenation to dihydrobenzothiophene, followed by elimination of H2S to generate ethylbenzene.The relative roles of donor solvent and molecular hydrogen in desulfurization are evaluated using a novel application of statistical analysis and fractional factorial design. At 4000 mg/kg Mo on benzothiophene, statistical analysis clearly isolates hydrogen atmosphere as the dominant factor affecting benzothiophene conversion. This result is also in agreement with thermodynamic predictions where benzothiophene conversion proceeds more favorably with hydrogen relative to tetralin.
Thermodynamic analysis of the thermochemical decomposition of H2S in the presence of iron sulphide
Authors: Berk Dimitrios , Heidemann Robert A. , Svrcek William Y. , Behie Leo A. 
Published: March 2009

AbstractThe decomposition of H2S by a two‐step closed loop thermochemical decomposition process was investigated. In the first step, H2S decomposes by reacting with iron sulphide to produce hydrogen and a solid solution consisting of FeS and S2. In the second step, the solid solution is decomposed at high temperature to recover sulphur and the iron sulphide which is reused in the first step. The thermodynamics of the first reaction were studied in detail by taking into account 12 gas phase chemical reactions and the phase equilibrium that is established between the sulphur in the gas and in the solid solution. The non‐linear system of 13 equations, which relate the fugacities of the components at equilibrium to the equilibrium constants, were numerically solved by the Newton‐Raphson iteration technique. The calculation results showed that the gas phase at equilibrium contains predominantly H2S, H2, and H2S2. The equilibrium conversion was found to decrease with increasing temperature; however, when the sulphur content of the solid solution was small, high hydrogen yields were possible even at high temperatures.
Kinetic studies of the pyrolysis of sewage sludge by tga and comparison with fluidized beds
Authors: Dümpelmann Ralf , Richarz Werner , Stammbach Marc R. 
Published: March 2009

AbstractThe pyrolysis of sewage sludge was examined by thermogravimetric analysis using different heating rates, particle sizes and final temperatures. A semi‐empirical model was developed with four global consecutive/competitive reactions to volatile and solid products including also a heat balance. This model was extrapolated to isothermal reactor conditions and compared to experimental data on fluidized bed pyrolysis. Depending on the particle size and reactor temperature, about 90% of the maximum conversion in a fluidized bed takes place under external heat transfer control, the rest under kinetic control. Incomplete conversion occurs at short particle residence times, which were calculated approximately by the model.
Vapor phase reaction of cyclohexanone oxime over boria modified HSZM‐5 zeolites
Authors: Takahashi Takeshige , Ueno Kazuhiko , Kai Takami 
Published: March 2009

AbstractThe vapor phase Beckmann rearrangement of cyclohexanone oxime has been carried out over zeolites and boria modified HZSM‐5 zeolites to elucidate the effects of acidity and acid strength distribution on the conversion and ε‐caprolactam selectivity. Although ε‐caprolactam selectivity was increased with the SiO2Al2O3 ratio in a HZSM‐5 zeolite, the highest selectivity in the study was accomplished over a boria modified HZSM‐5. The selectivity was dependent on the ratio of weak acid sites to strong acid sites. The boria played an important role in controlling the acid strength distribution of the zeolites.It was found that the production of a polymer over strong acid sites caused a decrease in ε‐caprolactam selectivity during the reaction.
Boundary layer model for char combustion and gasification
Authors: Özüm B. , Chambers A. , Kovacik G. , Oǧuztöreli M. 
Published: March 2009

AbstractA non‐steady boundary layer model is developed for numerical simulation of combustion and gasification of a single shrinking char particle. The model considers mass and energy conservation coupled with heterogeneous char reactions producing CO and homogeneous oxidation of CO to CO2 in the boundary layer surrounding the char particle. Mass conservation includes accumulation, molecular diffusion, Stefan flow and generation by chemical reaction. Energy conservation includes radiation transfer at the particle surface and heat accumulation within the particle. Simulation results predict experimentally measured conversion and temperature profiles of a burning Spherocarb particle in a laminar flow reactor. Effects of bulk oxygen concentration and particle size on the combustion process are addressed. Predicted particle temperature is significantly affected by boundary layer combustion of CO to CO2. With increasing particle size, char gasification to char combustion ratio increases, resulting in decreasing particle temperature and increasing peak boundary layer temperature.
Constrained chemical equilibrium and incompletely specified elemental abundance data
Authors: Norval G. W. , Phillips M. J. , Missen R. W. , Smith W. R. 
Published: March 2009

AbstractA general method for the computation of equilibrium composition in the presence of linear equilibrium constraints on chemical potentials is described for use in a standard general‐purpose algorithm. The existence of constraints, implied by product specifications or measured product distribution, is related to incomplete specification of elemental abundances and has implications for feed composition. The method is illustrated by two examples: SO2 removal from stack gas and catalytic reforming. The distinction between equilibrium subject to equilibrium constraints on chemical potentials and that subject to stoichiometric restrictions is emphasized.
Mass transfer in structured corrugated packing
Authors: Nawrocki P. A. , Xu Z. P. , Chuang K. T. 
Published: March 2009

AbstractThe performance of structured corrugated packing has been simulated by establishing mechanistic models for liquid distribution, liquid flow on the packing surface and mass transfer. The models were used to investigate the effect of packing height, liquid load, initial maldistribution as well as differing initial distribution and solid‐liquid contact angle on the packed column performance.Wetted surface area is the primary value of interest and the simulated results compare very well with those predicted by Onda (1968). The results clearly demonstrate that the wetted surface area is a strong function of the solid‐liquid contact angle. Other predicted values such as mass transfer coefficients and overall height of a transfer unit show reasonable agreement with published data.
Phase equilibria calculations for ill‐defined mixtures using the prsv equation of state
Authors: Cheluget E. L. , Vera J. H. 
Published: March 2009

AbstractA method for the calculation of vapor‐liquid equilibria (VLE) for multicomponent systems using continuous thermodynamics is presented. The Extended Spline Fit Technique (ESFT) is used to represent the molar distribution curve of petroleum fluids. A continuous version of the Peng‐Robinson‐Stryjek‐Vera (PRSV) equation of state (EOS) with Generalized Single Carbon Number Properties (GSCNP) is utilized. For continuously distributed components, following the suggestion of Hendriks (1987), the number of equations solved is reduced through integration over the range of the distributing variable using Legendre‐Gauss quadrature. Integrated equations are solved using accelerated successive substitution. Flash, dew and bubble point calculations for an imaginary and a real system yield satisfactory results.
Interaction between bubbles and fibre optic probes in a bubble column
Authors: Chabot J. , Lee S. L. P. , Soria A. , de Lasa H. I. 
Published: March 2009

AbstractSpherical bulb fibre optic probes, developed and applied for bubble characterization in a bubble column and a slurry bubble column at high temperature, were investigated. The principle of operation of these new optical fibre probes is based on the difference in refractive indices between the gas and the liquid phases. The interaction between the gas bubbles and the fibre optic probes in a bubble column was studied using photographic techniques. The first objective of these experiments was to study the response of the sensors upon contact with gas bubbles of various sizes. The second objective of this study was to establish, under controlled situations, the optical probe bubble detection performance and ability for local quantitative measurements of the bubble rise velocity and the gas hold‐up.
Prediction of axial mixing coefficients in rotating disc and asymmetric rotating disc extraction columns
Authors: Kumar Arun , Hartland Stanley 
Published: March 2009

AbstractThe correlation of axial mixing in the continuous and dispersed phases of rotating disc and asymmetric rotating disc columns is presented. Published experimental results on continuous‐phase axial mixing for both single‐ and two‐phase flows, obtained with tracer injection methods and by solute concentration profiles, are considered. The correlation developed is based on 1055 data points for 32 liquid systems obtained by 19 different investigators. The axial mixing in rotating disc columns is found to be up to 20% larger than in asymmetric rotating disc columns.Data for the dispersed phase are harder to correlate than those for the continuous phase. Since the available results are often contradictory, the correlation for the dispersed‐phase coefficient is thus less accurate than that for the continuousphase coefficient.
Modelling of mass transfer in extraction columns with drop forward‐mixing and coalescence‐redispersion
Authors: Qian Yu , Wang Jiading 
Published: March 2009

AbstractThe objective of this work is to model the effect of simultaneous drop forward‐mixing and coalescence‐redispersion on the hydrodynamics and mass transfer efficiency of a two phase countercurrent extraction process. Based on the flow mechanism and drop size distribution in extraction columns, a novel model with a simplified sequential algorithm is developed. It is much easier to use, and computationally less expensive, than a direct simulation technique which would typically be a tedious boundary‐value iteration method. A new concept of Effective Mass Transfer Coefficient is presented, from which the effect of drop forward‐mixing and coalescence‐dispersion on extraction performance is directly evaluated from an analytical expression. The results calculated from the model are satisfactorily compared to experimental results obtained from three actual extraction system in two pulsed sieve‐plate extraction columns. The relationship between the present model and the diffusion model is discussed and a parameter transformation equation for the two models is given.
Gas‐liquid mass transfer in taylor flow through a capillary
Authors: Irandoust Said , Ertlé Sylvie , Andersson Bengt 
Published: March 2009

AbstractThe gas‐liquid mass transfer in two‐phase flow through a capillary has been measured for water‐air, ethanol‐air and ethylene glycol‐air systems. A semi‐theoretical model has been developed and compared with experimental results. and a full computer simulations of the flow pattern and mass transfer using a flow simulation program have been made. The measured values are about 30% less than the calculated values.