bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissolution reaction of potash fertilizer with moisture
Authors: Peng Shi‐Wen , Strathdee Graeme , Besant Robert W. 
Published: March 2009

AbstractThis paper presents the solubility analysis of potash fertilizer at thermodynamic equilibrium. The Pitzer equations applicable to a KCl‐NaCl‐MgCl2‐H2O system are developed to describe the interaction between the aqueous ions. The equilibrium constant method is used to analyze the dissolution reaction equilibrium. A critical relative humidity around 52% is obtained which characterizes the moisture‐potash interaction mechanism as adsorption or condensation. Three distinct stages of dissolution exist for typical potash products that depend on moisture and temperature, with surface brine saturated with three salts (sylvite, halite and carnallite), two salts (sylvite and halite), and single salt (sylvite), respectively. At high relative humidities (i.e., RH > 75%), dissolution depends on the temperature, and moisture content may exceed 3% and dissolution of sylvite can increase without a limit.
Pyrolysis of kraft lignin in the presence of molten ZnCl2‐KCl mixture
Authors: Kudsy Mahally , Kumazawa Hidehiro 
Published: March 2009

AbstractPyrolysis of kraft lignin was carried out using small reactors with an added ZnCl2‐KCl mixture at three levels of temperature, 500°C, 550°C and 600°C, and three levels of salt‐to‐lignin ratio (SR), 1, 2 and 3. Nineteen kinds of phenolic compound were identified and their quantitative determinations were made by gas chromatography. The yield of gaseous products determined gravimetrically exhibited a strong dependence on the added amount of salt mixture, and its lowest value was obtained at SR of 1. The formation of gaseous products, apparently stemming from decomposition of liquid products and tar, was observed at reaction times longer than 30 min. At SR of 1 and a temperature of 550°C, all phenolic compounds attained their maximum yields almost synchronously at a reaction time of 15 min. Cresol's formation was slightly increased with the amount of added salt mixture. At a temperature of 550°C, cresols and guaiacols decomposed according to a pseudo‐first‐order lumping model, while catechols did not follow the similar model.
Effect of sound on the fluidization of group B particles
Authors: Leu Lii‐Ping , Yen Yung Song 
Published: March 2009

AbstractThe behaviour of several kinds of group B particles ranging from 100 μm to 600 μm was studied in a sound wave vibrated fluidized bed (SVFB). The fluidized bed consists of a transparent Plexiglas tube that is 54 mm i.d. × 1 m high. A speaker mounted at the top of the bed was supplied by a function generator with square waves and was used to generate the sound as the source of vibration of the fluidized bed. The influence of the particle size, density of particles and sphericity of particles on the minimum fluidization velocity, pressure fluctuations and bubble rise velocity in the SVFB was investigated. The minimum fluidization velocity decreased as the sound energy increased. When the sound energy was strong enough and greater than the critical power, the minimum fluidization velocity would approach the same value regardless of the degree of resonance (DOR) value if the particles were in spherical shape. For non‐spherical shape particles the minimum fluidization velocity was the function of the DOR value if the power was greater than the critical power. For the middle particle size range, the standard deviation of pressure fluctuations in an SVFB became lower than the one without the effect of sound in high superficial gas velocity range, but the result was reverse for the low superficial velocity; for the large particle size range, the standard deviation of pressure fluctuations in an SVFB was larger than the one without the effect of sound. The sound could also reduce the bubble rise velocity in an SVFB.
Testing a mathematical model for initial chemical reaction fouling using a dilute protein solution
Authors: Rose Ian C. , Watkinson A. Paul , Epstein Norman 
Published: March 2009

AbstractA 1 wt% lysozyme solution was used as a model fluid to test a previously formulated mathematical model for the initial chemical reaction fouling rate of a heat transfer surface. The experimental results showed that, at a given wall temperature, a maximum initial fouling rate existed over a range of fluid velocities. The maximum rate and the fluid velocity at which it occurred both increased as the wall temperature increased. These observations were consistent with the model. Quantitatively, the average absolute percent deviation between the experimental results and the optimum model predictions was 23,3%. The decrease in initial fouling rate with increasing velocity at high fluid velocities was even greater than predicted by the model.
The effect of surface properties on CaSO4 scale formation during convective heat transfer and subcooled flow boiling
Authors: Müller‐Steinhagen Hans , Zhao Qi , Helali‐Zadeh Abbas , Ren Xiao‐Guang 
Published: March 2009

AbstractIn this paper the effects of surface energy and surface roughness on the deposition of calcium sulphate during convective and subcooled flow boiling heat transfer to aqueous CaSO4 solutions are studied. The surfaces of several test heaters have been treated by Ion Beam Implantation, Unbalanced Magnetron Sputtering, Mixed Sputtering and Plasma Arc Deposition to reduce surface energy. One heater was electropolished to reduce surface roughness and one heater was etched by an electrochemical method to increase surface roughness. Fouling runs with these heaters, and with an untreated surface as control, were carried out at different heat fluxes, flow velocities and salt concentrations. The results show that heat transfer surfaces with low surface energy experienced significantly reduced fouling, while electropolishing did not have a notable beneficial effect. The combined effect of reduced surface energy and flow velocity on fouling reduction is considerably stronger than previously reported for pool boiling.
The control of biofilms in tubes using wire‐wound inserts
Authors: Wills Amanda , Bott T. Reg , Gibbard Ian J. 
Published: March 2009

AbstractAs a possible alternative to the use of biocides in industrial water systems, studies have been made on the effectiveness of wire‐wound tube inserts for biofilm control. Comparisons of data obtained at two different empty tube velocities of 0.86 m/s and 1.27 m/s and a Reynolds number of 14 000 with and without inserts, show that a biofilm accumulation reduction approaching 50% can be achieved by the use of inserts under certain circumstances. Further work is required to establish the optimum design of insert for maximum effectiveness.
Lateral mixing of shallow liquid pools by air bubbling
Authors: Baird Malcolm H. I. , Rao Nadella V. Rama 
Published: March 2009

AbstractThe lateral mixing of water in a shallow rectangular tank (length 225 cm, width 56.5 cm, depth 15 cm) under the action of bottom‐stir plugs has been studied. The process has been measured and video‐recorded, using an acid‐base reaction with indicator to show the flow patterns. It is concluded that in spite of the very low depth/width ratio in the tank, lateral mixing can be achieved quite efficiently using certain configurations of plugs which promote lateral circulation. With the best configuration, a mixing time of about 3.5 min could be achieved using either 4 or 6 plugs. The specific power dissipation rate was very low (0.0044 W/kg). The mixing time was essentially the same with 4 or 6 plugs provided the total gas flow to the plugs was the same in the two cases. Tests with intermittent blowing of the plugs did not show any improvements over steady operation.
Flow patterns and oil—water dispersion in a 0.38 m diameter oscillatory baffled column
Authors: Ni Xiongwei , Nelson Greig , Mustafa Imtiaz 
Published: March 2009

AbstractWe report our experimental flow visualization observations of flow patterns and experimental oil‐water dispersion measurements in an oscillatory baffled column (OBC) of an internal diameter 380 mm. Both types of experiments were carried out covering an identical range of oscillation frequencies, amplitudes, orifice diameters and baffle spacings. The flow visualization observations show that eddy mixing has been achieved in the pilot OBC and the intensity of which is largely dependent on the operational and geometrical parameters tested, which is similar to that in a smaller scale OBC. The scale‐up correlation was found to be linear. The oil‐water dispersion measurements show that the degree of the dispersion depends significantly on the oscillation frequency and amplitude with an increase in either leading to an increase in dispersion. The effect of the orifice diameter on the oil—water dispersion is also evident, but the effect of the baffle spacing is much weaker. Based on the experimental data we have established a correlation relating the degree of oil—water dispersion to the power input to the system. We have also compared the power requirement to achieve a complete dispersion in the pilot OBC with that in a bench scale OBC of 50 mm diameter and found that the energy dissipation is more economical in the large scale application.
Sorption of NaOH and NaOC6H5 on quaternary ammonium resin in a fixed‐bed adsorber
Authors: Wu Ho‐Shing , Wang Chih‐Ta 
Published: March 2009

AbstractThe sorption behaviours of NaOH and NaOC6H65 on quaternary ammonium resin with functional groups of ‐NMe+4CI− (hydrophilicity) and ‐NBu+4Cl− (lipophilicity) in an aqueous fixed‐bed adsorber were investigated. The types of resins and salts, salt concentration, and operating temperature were evaluated to achieve the optimum sorption conditions. The probability distribution function of the breakthrough curve was employed to describe the sorption system. The parameters of probability distribution function, sorption rate, exchange capability, height of mass‐transfer zone and degree of saturation were also obtained. The effective exchange capacities for hydrophilic resins were found to be smaller than those for lipophilic resins. The sorption capability of NaOC6H5 in the resin was larger than that of NaOH.
The role of the vapour phase in fluid coker cyclone fouling: Part 2. Liquid and vapour yields and compositions
Authors: Mallory Donald G. , Mehta S. A. (Raj) , Moore R. Gordon 
Published: March 2009

AbstractThe vapours derived from thermally cracked Athabasca bitumen were exposed to temperatures phase 490°C and 560°C in order to investigate the effects of vapour phase thermal cracking on product yields and campositiom. Raising the vapour phase temperature above the temperature at which the vapours were derived increased both the yield of non‐condensable vapours and the amount of olefins in the produced gas. In addition, the liquid yield decreased with increasing vapour phase temperature and changes in liquid product composition were also observed. The H/C ratio of the liquid product decreased with increasing vapour phase temperature.
Performance of symmetric polygonal fins with and without tip loss — A comparison of different methods of prediction
Authors: Kundu Balaram , Das Prasanta K. 
Published: March 2009

AbstractNo analytical solution exists for estimating the efficiency of symmetric polygonal fins (SPFs) circumscribing circular tubes. Performance of such fins is conventionally determined from either of the two approximate techniques, namely, the equivalent annulus method and the sector method. The present work aims to judge the relative merits and applicability of these two methods critically. To this end, the results obtained from the approximate techniques have compared with those obtained from a semi‐analytical technique. It has been noted that, with the increase of the tip heat loss, the accuracy of prediction from any of the approximate methods decreases. For the sector method, a modification has been suggested. The prediction from the modified version of the sector method is always more accurate than that from the equivalent annulus method. It has been further illustrated that though the approximate techniques can be employed for the prediction of efficiency, they cannot be used to predict the tip temperatures accurately.
Evaluation of an artificial neural network for NOX emission prediction from a transient diesel engine as a base for NOX control
Authors: Krijnsen H. C. , Van Kooten1 W. E. J. , Calis H. P. A. , Verbeek R. P. , Van Den Bleek C. M. 
Published: March 2009

AbstractFor an adequate control of the reductant flow in selective catalytic reduction of NOx in diesel exhaust, a tool has to be available to predict accurately and fast the engine's NOx emission. In this article the application of a neural network is proposed. Measurements were performed on a transient diesel engine. The average absolute deviation between the measured NOx emission and the emission predicted by the neural network is 6.7%. The high accuracy of the neural network predictions, combined with the short computation times (0.2 ms/data point), makes the neural network a very promising tool in automotive NOx control.
Transient multi gas—solid reactions in a bubbling fluidized bed
Authors: Hastaoglu M. A. , Hilal N. , Abdulkarim M. , El‐Naas M. 
Published: March 2009

AbstractA “multimodel” for gas‐solid reactions in a reacting particle has been applied to a bubbling fluidized bed reactor. The particle is tracked and bed and particle variables are determined continuously. The conservation equations of mass and heat with auxiliary relations are solved in an accelerating particle, which may rise or fall. The effects of bulk pressure, velocity and temperature, and particle diameter are studied. Heat and mass transfer coefficients may fluctuate up to 75% and 148% respectively. Doubling the pressure changes hc by 75% and kc by −45%. Increase in pellet diameter reduces both hc and kc.
Modélisation du traitement de purification de l'acide phosphorique de voie humide par la méthylisobutylcétone
Authors: Feki Mongi , Ayedi Hassine Ferid 
Published: March 2009

AbstractLes performances de l'étape d'extraction du procédé de purification de l'acide phosphorique de voie humide par extraction liquide—liquide avec la méthyl isobutyl cétone ont été déterminées en faisant appel à la méthodologie des plans d'expériences. Pour ce faire, un plan factoriel complet 24 avec comme variables, la concentration de l'acide d'alimentation, le taux de solvant, la température et le nombre d'étages théoriques d'extraction a été réalisé. Les modèles obtenus ont permis de prédire les performances de l'extraction en terme aussi bien de rendement en P2O5 que de facteur de décontamination de l'acide produit et ce quelle que soit la teneur en eau du solvant recyclé. Le recours à la fonction désirabilité a permis de déterminer l'optimum multiréponse réalisant le meilleur compromis entre aussi bien un rendement en P2O5 de l'extraction élevé que des facteurs de décontamination de l'acide désextrait acceptables.
Estimation of diffusivity of alkaline metals in graphite lattice from oxidation rate measurements
Authors: Shimizu Akira , Akuzawa Noboru 
Published: March 2009

AbstractA reaction model has been developed for the estimation of diffusivity of the intercalated species in graphite on the basis of a material balance expressed in terms of cylindrical coordinates, where the species in the layered structural cylinder diffuse radially from the center to the surface and react with gas. The resultant kinetic equations are used to analyze the experimental data for the oxidation rate of potassium atoms intercalated in natural graphite powder of initially different sizes intercalated at the first stage.
Turbulence decay behind expanded metal screens
Authors: Oshinowo Lanre , Kuhn David C. S. 
Published: March 2009

AbstractAn experiment study of the turbulent flow behind expanded metal screens has been carried out in a low‐turbulence wind tunnel using an X‐probe hot‐wire anemometer system. The expanded metal screens turn flow due to a complex array of vaned elements. The flow turning was found to vary accordingly with the dimensions of the strands that make up the screen. The turbulence generated by the screens decays at a rate proportional to the downstream distance to the power ‐ 5/7, consistent with studies in the literature of conventional screens types, and was found to scale with the thickness of the screen strands. The mean velocity, pressure drop and turbulence characteristics of expanded metal screens are presented.
Hydrodynamics and mass transfer in a pulsed packed column
Authors: Jie Yu , Weiyang Fei 
Published: March 2009

AbstractThe hydrodynamics and mass transfer characteristics of a pulsed packed column (PPC) filled with a stainless steel super mini ring (SMR), ceramic and stainless steel Raschig rings have been studied using a 30% tributyl phosphate‐kerosene (dispersed phase)/acetic acid/water (continuous phase) system. Experiments were performed in a 100 mm internal diameter column with 1.0 m height of packing. The mass transfer and axial mixing parameters were estimated simultaneously from the measured concentration profiles of two‐phase based on the backflow model. It was found that pulsation has great influence on hydrodynamics and mass transfer characteristics of PPC with the SMR. Hoxp and Hox decrease significantly with pulsation, whereas flooding velocity decreases only slightly. Comparison among the three types of packing showed that the SMR has superior characteristics both in terms of capacity and mass transfer efficiency. The influence of mass transfer on characteristics of PPC was also studied. New empirical equations of characteristic velocity, Hoxand Hoxd were proposed and good agreement between calculated and experimental data was obtained.
Heat transfer in a reciprocating plate column
Authors: Rao Nadella V. Rama , Baird Malcolm H. I. 
Published: March 2009

AbstractA pilot‐scale (5.08 cm internal diameter) reciprocating plate column has been modified by the insertion of a brass test section for heat transfer measurements. Heat is supplied to liquid (water or a glucose solution) in the column from an electrical heating tape wound round the brass section, the walls of which contain thermocouples. Reciprocation of the plates in the column results in up to a seven‐fold improvement In heat transfer coefficient, to single phase liquids. Conditions are turbulent with oscillatory Reynolds numbers up to 20000. The effect of plate reciprocation is much less pronounced when the liquids are agitated by a stream of gas bubbles. The single‐phase heat transfer coefficients have been correlated for 5 different types of plates using approaches already available in the literature for turbulent systems in steady flow. The best‐fit oscillatory flow correlation differs slightly from the existing correlations for steady flow.
Removal of trace quantities of co from H2 using temperature‐swing‐adsorption
Authors: Sadhankar Ramakant R. , Aelick Christopher R. , Burns Deborah L. , Marcinkowska Krystyna 
Published: March 2009

AbstractA method for the removal of trace quantities (0.2 to 10 ppm) of carbon monoxide in commercial hydrogen using a temperature‐swing‐adsorption system with 0.5 wt% Pt/Al2O3, adsorbent has been investigated. The adsorbent could be regenerated by treatment with air at 200°C to 250°C or by treatment with hydrogen at 270°C. The breakthrough curves have been described by a model which considers both the external‐film resistance and the intraparticle diffusion resistance. The model has been validated at the high gas velocities expected in a commercial plant.
Liquid‐solid mass transfer from horizontal woven screen packing in bubble column reactors
Authors: Zaki M. M. , Nirdosh I. , Sedahmed G. H. 
Published: March 2009

AbstractThe effect of gas sparging on the rate of mass transfer at horizontal single screen and stacks of closely packed horizontal screens was studied by an electrochemical technique which involved measuring the limiting current of the cathodic reduction of potassium ferricyanide. Variables studied were: distance between the sparger and the screen, screen characteristics, e.g., mesh number and wire diameter, physical properties of the solution and superficial gas velocity. Screen characteristics were found to have little effect on the rate of mass transfer.The mass transfer measurement at beds of closely packed screens revealed that the mass transfer coefficient decreased below the single screen value with increasing the number of screens per bed. Comparison of the present data with previous results showed that screens produce higher rates of mass transfer than other geometries under otherwise the same conditions. The importance of the present work to the design and operation of catalytic and electrochemical reactors was highlighted.
A theoretical investigation of enhancement of mass transfer from a packed bed using acoustic oscillations
Authors: Sujith Raman I. , Zinn Ben T. 
Published: March 2009

AbstractThis paper describes a theoretical investigation of the possibility of improving the performance of packed bed dryers using acoustic oscillations. It was motivated by the increasing interest in the use of acoustic oscillations to improve the performance of energy‐intensive, industrial processes. Sound propagation in a packed bed was modelled as propagation through a porous medium. The effect of acoustic oscillations on the drying rate was then investigated by numerically integrating the heat and mass transfer equations. The model used quasi‐steady correlations for heat and mass transfer. The results show that threshold values for void fractions and sound pressure levels exist, above which significant increase in drying rate can be obtained. The increase in mass transfer decreases with effective particle diameter.
Solubilities of anthracene, fluoranthene and pyrene in organic solvents: Comparison of calculated values using UNIFAC and modified UNIFAC (Dortmund) models with experimental data and values using the mobile order theory
Authors: Hansen Henrik K. , Riverol Carmen , Acree William E. 
Published: March 2009

AbstractThe solubility of anthracene in 43 organic solvents, fluoranthene (45 solvents) and pyrene (30 solvents) has been calculated using UNIFAC and Modified UNIFAC (Dortmund) models to estimate the activity coefficient of the solute. It was found that both UNIFAC and Modified UNIFAC described better the solubilities in polar solvents like alcohols, ketones, esters and ethers than in nonpolar solvents like alkanes and aromatic hydrocarbons. UNIFAC and the Mobile Order Theory supplement each other well in calculating the solubilities, which means that one can choose the right model depending on the solvent one is using.
An experimental investigation of the cross‐flow of power law liquids past a bundle of cylinders and in a bed of stacked screens
Authors: Prasad D. V. N. , Chhabra R. P. 
Published: March 2009

AbstractThe steady flow of power‐law polymer solutions normal to arrays of cylinders and in a bed of screens has been investigated experimentally. Extensive pressure drop measurements have been made for three different test cells (two tube bundles and one bed made of screens) of different voidages for a series of inelastic carboxymethyl cellulose and sodium alginate aqueous solutions. The resulting values of friction factor correlate well with a modified definition of the Reynolds number based on the capillary bundle representation of the bed. The new data extend considerably the range of voidage values from ∼0.6 to ∼0.87. Extensive comparisons have also been made between the present experimental data and our previous calculations based on the use of simple cell models. The close correspondence between the two demonstrates the utility of such idealized analyses. All in all, the present results embrace the following ranges of physical and kinematic conditions: Reynolds number: 0.01 to ∼1200; power‐law flow behaviour index: 0.38 to 1; and three values of voidage, namely, 0.74, 0.78 and 0.87.