The effects of holdup on Sauter mean drop diameter, D₃₂, and dispersed phase mass transfer coefficient have been studied in the spray and packed extraction columns. For both columns, two well-defined regions for the dependence of D₃₂ on holdup were observed. D₃₂ increased and decreased with an increase in holdup at low and high levels of holdup, respectively. Changes in dispersed phase mass transfer coefficient against holdup were shown to be similar to D₃₂ for both columns. Moreover, empirical correlations have been derived to predict D₃₂ and dispersed phase mass transfer coefficient for both columns. It has been shown that the derived correlations are in a good agreement with the experimental data. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

In this study, the effects of particle size, type and concentration of acid solution on dissolution kinetics of ilmenite are investigated. The results showed that both oxalic and sulfuric acid and their concentrations had relatively high effects on the dissolution rate of titanium, which increased with an increase in acid concentration. About 86.4% of titanium could be leached in 10 h when using 4 M oxalic acid, 1 : 20 solid/liquid ratio, 90 °C temperature and particle size less than 45 µm. Under similar experimental conditions with the exception of sulfuric acid concentrations of 4, 8 and 12 M, the titanium solubilization was 16.1%, 48.2% and 52.0%, respectively. The experimental data followed reaction kinetics and indicated that the shrinking particle model controlled the chemical reaction. The observed titanium dissolution rates could be expressed as 1 − (1 − x)^1/3 = 0.0092C^1.2022t for oxalic acid for concentration varying between 1 and 4 M and 1 − (1 − x)^1/3 = 0.0006C^1.5977t for sulfuric acid for concentration varying between 2 and 12 M, respectively. The fitted models for estimating the titanium dissolution rate from the experimental data indicated good accuracy with coefficient of determination (R²) higher than 0.96. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Clinoptilolite, a natural zeolite, was proposed as a carrier for immobilized biocatalyst systems by polyethyleneimine and glutaraldehyde activation. Invertase (EC 3.2.1.26, beta-fructofuranosidase) as a model biocatalyst was covalently attached onto the particles by direct chemical reaction between aldehyde groups on the particles and amine groups of the enzyme. The effects of polyethyleneimine concentration, activation agent (glutaraldehyde) concentration, pH and invertase concentration on immobilization process were determined. Approximately 7 mg invertase was immobilized on a gram of clinoptilolite particles with 78% retained activity under optimum immobilization conditions. Immobilization did not affect optimum pH of the enzyme, but it brought out a wider pH–activity curve that was accepted as the indication of better pH stability. Immobilization resulted in an increase at the optimum temperature from 55 to 60 °C. The K_M value of immobilized invertase biosystem was found as approximately 1.5 times higher than that of the free enzyme. Immobilization provided improvement on the thermal stability of invertase, and activity half-life of the immobilized invertase was found as approximately four times longer than that of the free invertase. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

The Steam Jet Pump (SJP) is the most suitable pump for pumping radioactive and hazardous liquids because of its mechanical simplicity, no maintenance, low cost, easy construction, no leakage, simple control, and so on. The only problem with the SJP is the complexity in the transport phenomena involved in it. In this study, the void fraction in the mixing section has been measured experimentally through gamma-ray densitometry technique, and the flow through the SJP was simulated numerically. The reported numerical study of the SJP is very limited because of the complexity of the problem. In this work, three-dimensional steady state numerical simulations of the SJP were carried out using the Shah Direct-Contact Condensation (DCC) model developed previously. The experimental and Computational Fluid Dynamics (CFD) results of void fraction have been compared at different steam inlet pressure, and it was found that they match closely with each other. The transport phenomena in the SJP were explained using the CFD results of condensation heat transfer coefficient, steam plume shape, radial temperature distributions, and contours of static pressure and steam density. This study helps in validating the Shah direct-contact condensation model and providing valuable information about the transport phenomena occurring within the mixing section of the SJP. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Overall liquid side volumetric mass transfer coefficient k_La was determined experimentally for cocurrent Taylor flow moving upwards in a glass tube of an internal diameter of 3 mm. Experiments were performed for physical absorption of oxygen in 20% aqueous solution of ethanol. Shadowgraph technique was deployed for precise measurements of bubble lengths and velocities. Experimental values of volumetric mass transfer coefficient k_La were evaluated by use of oxygen sensor and contributions of two possible mass transfer mechanisms: bubble to liquid slug and bubble to liquid film were discussed. Effects of various hydrodynamic parameters such as superficial velocity, length of bubble and slug, and so forth on k_La have also been presented. A correlation has been proposed for the estimation of k_La for a wide range of bubble to slug lengths ratio and superficial velocities of gas and liquids. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Mixed block copolymers have been used as a template in the synthesis of new mesoporous silica particles, prepared from sol–gel method. The prominent effect of the block copolymers have been used to provide a new template that controls the surface area and porosity of the particles. Tetraethyl orthosilicate as silica source and two block copolymers, poly(propylene oxide)-b-poly(ethylene oxide)-b-poly(propylene oxide) and poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronics) as a surfactant, were used in water/n-octane co-solvent with citric acid catalyst to prepare new nanostructures of mesoporous silica (SPB₁ and SPB_1,2). The displacement of ethanol with cyclohexanol as a co-surfactant drastically changed the surface properties of the new mesoporous silica particles (SPB_1,2). The surface area, porosity, morphology, and microstructure of particles were characterized by X-ray diffraction, nitrogen adsorption–desorption, scanning electron microscopy), and transmission electron microscopy. The prepared particles have been specifically characterized for specific use and applications as supporting catalysts for the polymerization of vinyl acetate, drugs delivery, and in the membranes manufacturing based on polyurethanes. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

In this study, the performance of moving bed radial flow reactors in Olefex technology to produce isobutene from isobutane dehydrogenation is studied at steady state condition. The dehydrogenation reactors have been modeled heterogeneously on the basis of the mass and energy governing laws considering a two-dimensional model. In this system, isobutane dehydrogenation, hydrogenolysis, propane dehydrogenation, and coke formation reactions occur on the catalyst surface. The coke deposition on the catalyst surface and the catalyst velocity along the axial direction result to an activity profile along reactors that has been calculated from proper correlation. To prove the accuracy of the considered mathematical model and assumptions, simulation results are compared with the plant data at the same process condition. The isobutane conversion and isobutene selectivity have been obtained at about 38.53% and 90.76%, respectively, which have good agreement with the plant data. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

The incomplete regeneration of diesel particulate filter may cause a local build-up of the soot on the partially regenerated areas during next filtration cycle. This may be one of reasons causing the melting of the ceramic filter during regeneration. In this paper, we investigated several situations at which the particulate matter was partially regenerated. The simulations illustrated that at stationary feed conditions, the influence of nonuniformity of soot loading on the peak temperature rise was less important. When regeneration was conducted at transient feed conditions, the peak temperature attained under the condition of uneven soot distribution along the channel, especially more soot accumulated near the end of the diesel particulate filter, was much higher than that attained under the condition of even soot distribution inside the channel. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

The cyclic CO₂ capture activity of natural CaO–MgO sorbents derived from dolomite or limestone with different MgO contents has been investigated on a TGA, with the consideration of the influence of H₂O during the carbonation and calcination. The scanning electron microscopy (SEM) and the brunauer emmett teller (BET) were used to characterize the fresh and used CaO–MgO sorbents. The results have indicated that the natural CaO–MgO sorbent with MgO content of 31.5%–38.7% should be good to improve the cyclic capture activity of CaO. The CaO–MgO sorbent has the best cyclic activity when H₂O is present during both carbonation and calcination. H₂O changes the sorbent morphology producing bigger particles and pores for the sintering during calcination but makes the sorbent have more stable surface area for the taking palace of the fast kinetic carbonation reaction. Besides, H₂O decreases the product layer diffusion resistance and increases the reaction rate during the transition and the product layer diffusion control stage. After sorbent sinters during the reaction cycles, the H₂O-improving effect becomes more obvious as the MgO content increases. The results indicate the potential of the natural CaO–MgO sorbent with proper MgO content for cyclic CO₂ capture in the presence H₂O. Copyright © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Because of the limitation of accurate measurement of microscopic parameters in the dual-contact-flow absorption tower, the diameter, velocity, temperature of a single droplet, and the concentration of matter in it are difficult to be obtained through experimental methods. However, these data are of crucial importance to understand the behaviors of liquid phase in the absorber. In this paper, the microscopic motion, heat, and mass transfer characteristics of droplets in the dual-contact-flow absorption tower have been numerically simulated, and the results have been validated by experimental data. The motion trails of droplets under different initial jetting velocities and gas velocities are studied, and the fall-back characteristics have been obtained. The critical diameters of droplets increase remarkably with the increase of gas velocity but have limited relationship with the liquid initial jetting velocity. The heat and mass transfer capacities of droplets have also been investigated. It is found that because of the diversity between the concentration relaxation time and the temperature relaxation time, there may be considerable difference between heat and mass transfer behaviors. All the work above is a complement of the basic performance of droplets in the dual-contact-flow absorber and can supply guidance for estimating the practical application performance. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

This paper presents a control strategy based on stage temperature measurements to control composition of the products in a Petlyuk-type distillation column. This column is formed by a prefractionator in which feed is introduced and a main column from which three product streams are extracted. Prefractionator and main-column modules are connected through the exchange of liquid and vapor streams resulting in a strong interaction that can result in operating problems, poor control performance, and instability due to their complex structure. Different steady-state methods for the selection of appropriate control structures were analyzed. The control structure comprises four controllers implemented as follows: three Proportional-Integral (PI) controllers to regulate the temperature of three stages along the main column and a cascade controller to regulate temperature at a stage in the main column manipulating temperature in a prefractionator stage. Controllers were designed using internal model control guidelines for traditional PI compensation. Feed composition disturbances were introduced in order to observe the response of the control system. The obtained results show that the control structure maintains the purity of the final products within acceptable ranges despite the existence of disturbance. Copyright © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

A laboratory-scale batch reactor is built and operated to study the kinetic of formation of carbon dioxide hydrate in deionized water and sodium dodecyl sulfate (SDS) solutions. In this experimental work, the formation of carbon dioxide hydrate in deionized water (18 Ω) is investigated at fixed temperature of 273.65 K and different pressures of 20, 25, 30, and 35 bar, respectively. The formation of carbon dioxide hydrate in SDS solutions is investigated by using various concentrations of SDS up to 3000 ppm at temperature of 273.65 K and 35 bar. For carbon dioxide hydrate, the induction time decreases with the increase of initial carbon dioxide pressure because of the increase of subcooling and driving force in the system. Moreover, experimental results show that the addition of SDS reduces the induction time required for hydrate formation and significantly increases the carbon dioxide uptake, and these effects are concentration dependent. Furthermore, the addition of SDS in the hydrate-forming systems has been shown to improve the apparent rate constant of the system. These results show that SDS shows a good promise to be used as low-dosage hydrate promoter to improve the efficiency of gas hydrate-based processes. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Wax formation is a serious problem in the gas and oil industry because it can block oil production facilities and transportation pipelines. It is, therefore, of great importance to have a reliable tool to predict wax formation under various operational conditions. The hydrocarbon plus fractions that comprise a significant portion of naturally occurring hydrocarbon fluids create major problems when determining the thermodynamic properties and the volumetric behavior of these fluids by equations of state. In this work, an effort has been made to further improve the characterization of the plus fraction, splitting the plus fraction into a single carbon number (SCN) and generating the mole fraction, on the basis of the relationship between the three-parameter gamma distribution, experimental molar fraction, molecular weight, and SCN data obtained from literature and industrial contact. The three-parameter gamma distribution is used to fit the trend of the computational analysis. The method has been used to predict wax appearance temperatures (WATs) for a great number of systems and to compare with some methods generated previously. The average deviation of the calculated WAT is 1.47 K for the system with the experimental data. There are some correlations generated to calculate the physical–chemical properties as a function of SCN. Those correlations have been originally developed to work with light oil. The developed approach, along with some of the correlations, is tested for calculating WAT to identify the applicability in this work. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

In this paper, liquid–liquid equilibrium in decanter of heterogeneous azeotropic distillation is solved by minimizing Gibbs free energy, by using global optimization technique. The azeotropic distillation column is modeled by solving material balance, equilibrium and summation equations, and repulsive particle swarm optimization (RPSO), a stochastic global optimization formalism, is employed to predict stable steady state solution in decanter. To verify the performance of the RPSO algorithm, it is compared with equation solving method for liquid–liquid equilibria by considering two azeotropic systems, namely (1) benzene–ethanol–water and (2) furfural–water. The proposed methodology shows feasibility of the RPSO algorithm in predicting liquid–liquid equilibrium in decanter of heterogeneous azeotropic distillation. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Thermophoresis particle deposition and mass transfer effects of a chemically reacting micropolar fluid past a continuously moving porous plate with heat generation/absorption and variable viscosity is investigated numerically. The fluid viscosity is considered to vary linearly with temperature. The radiative heat flux, heat generation/absorption, and the viscous dissipation are taken into account in the energy equation. The partial differential equations governing the flow have been transformed into system of nonlinear ordinary differential equation using similarity transformation and are solved numerically by fourth-order Runge–Kutta method with shooting technique. Effect of thermophoresis and suction/injection parameters on the velocity, micro-rotation, temperature, and concentration of the micropolar fluid is discussed and presented graphically. Effect of increasing chemical reaction parameter as well as Schmidt number on the concentration profiles are shown graphically. The result shows that the effect of chemical reaction parameter influences highly the concentration of the fluid within the boundary layer. Temperature of the fluid was also found increased due to increase in heat generation/absorption parameter. The rate of heat transfer from the wall for different values of Prantal number is plotted. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

In this study, Garcinia mangostana shell was used to prepare phosphoric acid activated carbon (GMAC). The adsorption studies of the GMAC were carried out using methylene blue as a model dye adsorbate and textile industry effluent. Adsorption studies were conducted in batch mode. Multiple variables affecting adsorption such as contact time, temperature and pH were studied. The optimum conditions for adsorption were found to be contact time of 60 min, temperature 323 K and pH 12. The resultant data were fitted into the Langmuir, Freundlich and Temkin isotherm. The data best fitted the Freundlich model indicating multilayer adsorption onto heterogeneous surface with irregular distribution of adsorption energy and affinity. The rate of adsorption has good correlation with pseudo-second-order kinetics, and diffusion models demonstrate that both film and intraparticle diffusion mechanisms are not the sole rate-limiting step in this particular adsorption. An evaluation of thermodynamic parameters, namely ΔH°, ΔS° and ΔG°, indicates that the adsorption was feasible, spontaneous and endothermic in nature. The low values of ΔH° and ΔG° correspond to physical adsorption. The results reveal that GMAC can be successfully used to remove various types of dye from aqueous solution. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Carbon nanotubes (CNTs) with a carbon content of 3% were synthesized via the disproportionation of CO over a CoMo/SiO₂ catalyst. The proposed purification technique consisted of four sequential steps: oxidative treatment, acid leaching, silica dissolution, and froth flotation. The as-synthesized CNTs were oxidized at 250 °C before being treated with a 5-m HCl solution at 80 °C and a sonication time of 6 h, resulting in a catalyst removal of 90% and an increase in carbon content to 4%. For the silica dissolution, the CNTs were treated with a 0.5-m NaOH solution at 70 °C and a sonication time of 12 h, leading to a silica removal of 70% and an increase in carbon content to 35%. The froth flotation technique was employed to separate the CNTs from the remaining silica using two types of surfactants: linear ethoxylated alcohol with an average degree of polymerization of 7 and a linear alkyl chain of 12–14 carbon number (Surfonic L24-7) and sodium dodecyl benzene sulfonate (SDBS). The separation performance was maximized at a Surfonic L24-7-to-SDBS molar ratio of 1 : 12 with a total surfactant concentration of 230 mg/L, yielding a carbon content of 76%. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

To achieve the goal of implementation of low-energy and low-chemical usage for trace organic compound removal, the hybrid oxidation/adsorption purification system using nitrogen-doped titanium dioxide catalytic oxidation followed by activated carbon adsorption was proposed in this paper. When isopropyl alcohol, ethylene glycol, and urea were selected as model components, superior oxidation effects were achieved by combination of nitrogen-doped titanium dioxide with 254 nm UV unit than by traditional high-energy-consumed 185 nm UV unit, which indicated such configuration would be an ideal candidate to replace the current high-energy-consumed UV unit. By incorporating this new configuration into the semiconductor wastewater recycling system, the granule-activated carbon bed adsorption efficiency for total organic carbon was compared with the granule-activated carbon adsorption efficiency for total organic carbon in traditional purification system, where the 185 nm UV lamp was used as oxidation unit. The experimental results showed that the hybrid low energy consumption catalytic oxidation/adsorption system had higher efficiency than the traditional high-energy-consumed oxidation/adsorption system for trace organic compound removal. This was because the radicals formed in the UV oxidation process reacted with the organic compounds adsorbed on the activated carbon and regenerated the adsorption sites. This self-cleaning mechanism effectively extended the lifetime of activated carbon bed and increased its adsorption capability. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Various technologies and materials have been applied for the storage of clean gas energy, which also could control the combustion process to reduce CO₂ emissions. Over the years, microporous and mesoporous materials have been developed as useful technology for gas storage and separation. However, no materials can adequately meet the needs of all applications. The present paper gives an overview of the various materials for gas storage and separation. The results showed that carbonaceous adsorbents were the most potential for meeting the US DoE system targets for gas (methane and hydrogen) storage. Meanwhile, the properties of metal organic frameworks and covalent organic frameworks (thermodynamics and kinetics) had significant improvements with the development of material science. Further, zeolites performed well in CO₂ separation, but necessitated a high temperature for recovery. It was concluded that the utility of any new material will ultimately be determined not only by its material performance but also by its system performance, and much work is still required to be performed in the application of microporous and mesoporous materials for gas storage and separation in the future. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

With the production of offshore oil and gas, wax deposition in multiphase crude pipelines has become a critical item for flow assurance. The emulsion pour point had a close relationship with the water cut of production liquid and made a significant effect on wax deposition. The investigation of the effects of water cut, pour point, and deposition enduring time on the wax deposition amount and the deposit components was conducted with static cold finger facilities. It was suggested that the effects of molecular diffusion and gelling on deposit thickness in oil–water emulsion are closely related to emulsion pour point. At a constant temperature, the function of molecular diffusion plays a leading role when it is at a low water cut and pour point. Otherwise, the function of gelling plays a leading role. This investigation offered a reference for the development of models for predicting oil–water two-phase wax deposition in the future. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

In this work, a new method of the synthesis of nano zero valent iron (nZVI) is presented. Ultrasonic wave as a novel method is used to synthesize nanoparticles and the physico-chemical properties of particles compared with conventional synthesis method. Among the various synthesis methods, chemical reduction is widely used because of its simplicity. The effect of ultrasonic power (500 W, 1000 W), FeSO₄.7H₂O concentration (0.02, 0.05 and 0.08 M), NaBH₄ concentrations (0.1, 0.25 and 0.4 M) and delivery rate of reducing agent on nZVI characteristics were investigated. Particle size distribution, morphology and surface composition were characterized by transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction (XRD), Brunauer, Emmett and Teller (BET) surface area and particle size analyzer. It was found that the morphology of nanoparticles changed from spherical type to plate and needle type under high ultrasonic power. The size of 50% of nanoparticles was decreased from 90.3 to 29.9 nm under high precursor/reductant concentration and high ultrasonic power. Also, BET surface area was increased from 10 to 42 m²/g while using ultrasonic waves. The XRD patterns showed that the crystallinity of the nZVI prepared using ultrasonic conditions was poor because of the inadequate time for nuclei growth and crystallization. Therefore, the ultrasonic power could impose dramatic effect on the characteristics of the nanoparticles. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

The major drawback that prevents commercialization of biodiesel is the high cost of vegetable oil feedstock. In this work, used cooking oil, which is much less expensive than fresh vegetable oil, is used as an alternative raw material. Prior to transesterification reaction, esterification was conducted and catalyzed homogeneously to eliminate free fatty acid. Heterogeneous catalyst derived from cheap and easily obtained egg-shell (industrial waste) was used for transesterification reaction. A 100% ester yield was obtained at the optimized reaction conditions, which is 5 h of reaction duration, 24:1 methanol to oil molar ratio and 4 wt% catalyst loading. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

This work is intended for extraction and recovery of toxic heavy metal components, viz. Cadmium (Cd), from the industrial wastewater using liquid membrane (LM)-based separation technique. Exploring environmental benignity in the solvent (LM) is the main aim of this work. Vegetable oils are potential candidates toward that. Presence of carrier component in solvent often augments the solute transport mechanism. Although N,N-dimethyloctylamine (DMOA) is a very good carrier to show excellent extraction, the recovery is poor possibly because of high stability of complex between Cd(II) and DMOA in the membrane phase. The performance of LM-based separation process is affected by various physical and chemical parameters viz. pH, concentration, stirring rate, temperature, carrier concentration. An optimum operating condition has been identified that would yield the most efficient transport of solute. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

A novel monitoring framework for multimode processes is proposed in this article. Generally, although the different modes have different process characteristics, they still share some common features, and the specific information is the unique characteristic that is not shared by all modes. On the basis of principal component analysis (PCA), a new statistical method, termed as local principal component analysis (LPCA), is developed for modeling multimode process data. LPCA is a modified version of PCA with the idea of maximizing local data variance, which aims to discover some directions that data, from all modes, share comparatively similar variance structure. In this low-dimensional representation, the common features are captured and the residual corresponding to each mode can be treated as specific features. With the obtained LPCA model, both the common and specific features are utilized for monitoring. Moreover, a Bayesian inference strategy is further adopted to derive global indices of specific features for fault detection. Its feasibility and validity of the proposed method are illustrated through a simple multivariate linear system and the Tennessee Eastman challenge problem. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Study of drying characteristics and kinetics of coal is necessary in order to optimize drying operation and design a dryer in industrial scale. Drying characteristics of Chinese lignite was investigated experimentally using thermogravimetric method, and the effect of drying variables on drying rate was systematically studied. For CFD modeling and scale-up purposes, it is useful to have an algebraic equation that describes the drying process of lignite. Therefore, different thin layer drying models given in the literature were employed to analyze coal drying kinetics under different conditions. During studying the consistency of all the models, statistical tests such as χ², residual sum of squares (RSS), F-value, and the coefficient of determination R² were employed. It was found that the Midilli–Kucuk model best describes the drying process within 99.9% accuracy. The effects of drying temperature and coal sample weight on the constants and coefficients of the selected model were also studied by multiple regression analysis. Apparent diffusion coefficient of moisture from sample was calculated using the experimental kinetics data. Higher drying temperatures and smaller sample weights resulted in higher diffusion coefficient, which was consistent with experimental data. Activation energy of moisture evaporation calculated from Arrhenius equation for drying process was 21.17 kJ/mol. The selected algebraic drying model can be used for CFD modeling during scale-up of drying facility for industrial applications. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

An externally applied electric field beside a plane layer of dielectric liquid can induce secondary flows. This phenomenon is called electrohydrodynamic (EHD) effect and can result in heat transfer enhancement. In this study the effect of EHD force on natural convection heat transfer coefficient of water through a vertical enclosure channel is investigated by numerical simulation, using Comsol Multiphysics software. Also, the interaction between EHD force, fluid flow field, pressure field and temperature field was investigated by computational fluid dynamics technique. Flow pattern, temperature distribution, back pressure and pressure due to suddenly expanded flow are substantially affected by applied electric field, especially at low Rayleigh numbers. The results show that by increasing the temperature difference up to 40 K and the applied voltage up to 100 V, the heat transfer coefficient is increased by more than 1000 kW/cm² K for three different enclosure channel lengths. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

The aim of this research work is to investigate sorption characteristics of brown algae Sargassum bevanom (S. bevanom) for the removal of Cu(II) ions from aqueous solutions. The sorption of Cu(II) ions by batch method is carried out. The optimum conditions of biosorption were found to be: a biomass dose of 0.4 g in 100 ml of Cu(II), contact time of 100 min and pH 6, respectively. In optimum condition, removal efficiency was 88.45%. Meanwhile, the maximum adsorption capacity was 73.26 mg g^-1. Four equations, i.e. Morris–Weber, Lagergren, Elovich and pseudo second order have been tested to track the kinetics of removal process. The data are well described by pseudo-second-order model. The Langmuir, Freundlich, Temkin and Dubinin–Radushkevic (D–R) are subjected to sorption data to estimate sorption capacity, and the Langmuir shows the high performance in the fitting of equilibrium data. It can be concluded that S. bevanom has potential to remove Cu(II) ions from aqueous solutions at different concentrations. Also, it achieved 75% desorption efficiency using 0.1 M HCl, and reusing of adsorbent shows high ability in the Cu(II) removal from aqueous solution. The removal of Cu(II) by S. bevanom was also investigated in a fixed bed column. Experiments were conducted to study the effect of important parameters such as bed depth (10–20 cm), initial concentration and flow rate (5–15 ml min⁻¹). Meanwhile, the regeneration and reusability of this adsorbent for five cycles was studied. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

MnO₂ as the electrode material for supercapacitors has attracted much interest in recent years. However, there are still some restrictions for its application. In this paper, to improve the capacitive properties of MnO₂, material was synthesized by a facile and efficient low-temperature reduction reaction between KMnO₄ and Cu foil in sulfuric acid solutions. The results showed that the initial concentrations of KMnO₄ and the addition of concentrated sulfuric acid have distinct influence on the structure, morphology and electrochemical properties of the as-prepared MnO₂. Particularly, morphological characterization displayed that the sample synthesized in 0.05 mol L⁻¹ KMnO₄ and 16 mL concentrated sulfuric acid is composed of urchins with the average diameter of 0.7 µm. The product exhibits a discharge specific capacitance of 288.03 F g⁻¹ at the constant current density of 65 mA g⁻¹. The capacitance remains about 50% of the initial capacitance at 250 mA g⁻¹, and is 100.06 F g⁻¹ after the 100th cycle. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Cellulose acetate (CA) and polyethersulfone (PES) blend ultrafiltration membranes were prepared by phase inversion technique in the presence and absence of additive maleic acid with N,N-dimethylformamide as solvent. The prepared membranes were characterized in terms of pure water flux, percent water content, and molecular weight cut-off (MWCO) by solute rejection method. The percentage of rejection of protein such as bovine serum albumin, egg albumin, pepsin, and trypsin were studied. It was found that the pore size of the membrane and the hydrophilicity of CA/PES blend membranes increased with increase in blend composition and additive concentration, which is evident from the increase in water content and the morphological study of the membrane Thus, when the additive concentration in the blend system was enhanced from 0 to 10 wt%, there was an upward trend in the pore radius of the membranes thus enhancing the MWCO of the membrane. The decrease in number of pores also confirms the role of additive in the formation of pores and its interaction with the membrane material during gelation and membrane formation as evidenced by the scanning electron microscope analysis. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Dynamic optimization problems (DOP) in chemical processes are very challenging because of their highly nonlinear, multidimensional, multipeak and constrained nature. In this paper, we propose a novel algorithm named hybrid gradient particle swarm optimization (HGPSO) by hybridizing particle swarm optimization (PSO) with gradient-based algorithms (GBA). HGSPO can improve the convergence rate and solution precision of pure PSO, and avoid getting trapped to local optimums with pure GBA search. We further incorporate HGPSO into control vector parameterization (CVP), a method converting DOP into nonlinear programming, to solve five complex DOPs. These DOPs include multimodal, multidimensional and constrained problems. The experiments demonstrate that HGPSO performs much better in terms of solution precision and computational cost when compared with other PSO variants. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

A multistage dynamic optimization methodology with sequential implementation procedure is proposed, and the evolutionary optimizing features of differential evolution (DE) are exploited to implement the methodology for optimal control of a semi-batch copolymerization reactor. DE is designed and implemented to determine the optimal control policies for monomer addition rate and reactor temperature to produce a polymer with the desired copolymer composition and molecular weight distribution. Further, a similar multistage dynamic optimization strategy based on iterative dynamic programming is used for optimal control of copolymerization reactor and to compare with DE. The results show the effectiveness of the DE-based multistage dynamic optimization strategy in determining the optimal control policies that yield the desired polymer product characteristics. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

The present study examines the breakage of particulate granola produced by fluidised bed granulation during pneumatic conveying process. Granola was pneumatically conveyed in a purpose built conveying rig designed to mimic product conveying and packaging. Three different conveying rig configurations were employed: a straight pipe, a rig consisting two 45^o bends and one with a 90^o bend. Particle breakage increases with applied pressure drop, and a 90^o bend pipe results in more attrition for all conveying velocities relative to other pipe geometry. In terms of the fluidised bed granulation, there was no single operating parameter that was deemed to have a significant effect on breakage during subsequent conveying. A simple power law breakage model based on process input parameters was developed to describe aggregate breakage during pneumatic conveying. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

An experimental study of direct contact steam condensation has been conducted at both atmospheric and vacuum pressure, in a pilot scale column filled with Tupac 125Y structured packing. The local volumetric heat transfer coefficient of condensation determined by thermal balance has been given. The influences of the vapor and liquid flow rate, liquid temperature and operation pressure have been investigated. An empirical correlation based on dimensionless numbers has been put forward and verified by various experimental measurements, and the dimensionless numbers were calculated from the Delft hydrodynamic model of structured packing. The results will give some helpful guidance in the design and operation of direct contact condensers with structured packings. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

The applicability of different advance oxidation processes (UV, H₂O₂/UV, Fe²⁺/H₂O₂/UV and Fe³⁺/H₂O₂/UV, Fe²⁺/H₂O₂) to treat real tannery wastewater was investigated in this work, and their efficiency was compared. Reduction of chemical oxygen demand (COD) and removal of chromium was envisaged through two consecutive processes: COD reduction followed by chromium removal. Comparisons of the specific energy consumption between UV, UV/H₂O₂ system, UV/H₂O₂/Fe²⁺, UV/H₂O₂/Fe³⁺ system were also reported. The chemical precipitation processes with different precipitating agents, CaO, MgO and NaOH, for the removal of chromium was investigated. Chromium removal and sludge volume at different pH values for three precipitating agents were assessed. The sludge generated during chemical precipitation has been characterized. The experimental results show that optimum conditions for Fe²⁺/H₂O₂ are 2 M H₂O₂, 0.04 M Fe²⁺, pH 3 and for Fe²⁺/H₂O₂/UV these are 0.5 M H₂O₂, 0.04 M Fe²⁺. The photo-Fenton system with lower H₂O₂ dosage (0.5 M) and lower duration (60 min) could achieve same extent of COD reduction (97%) achieved in Fenton's treatment with higher (2 M) H₂O₂ dosage and longer duration (90 min) of treatment.

The results demonstrated that the photo-Fenton process was superior over other processes. The wastewater treated with CaO and MgO met the stringent discharge limit of below 1 mg/L for total chromium. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

An advanced flue gas conditioning technology was developed through in situ oxidation of SO₂ using dielectric barrier discharge and heterogeneous condensation of SO₃ on fly ash (FA). Orthogonal experiments were carried out for the design of discharge structure, whereas the optimal condition was achieved at 8 kV of discharge voltage, 2 mm of discharge gap and 56 cm² of discharge area; single factor experiment was introduced here to investigate impacts of various elements (gas flux, temperature, concentration of SO₂ and relative humidity) on oxidation of SO₂, results showed that the oxidation of SO₂ was in inverse proportion to gas flux and SO₂ concentration, whereas in direct proportion to relative humidity, the optimal temperature was detected at 45 °C. Physical and chemical characterizations of treated samples were performed in this work using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). Particle coagulation was found in the SEM, and a continuous peak rise of sulfate at 1086 cm⁻¹ was detected by the FTIR analysis, which indicated that SO₃ generated by in situ oxidation of SO₂ could be successfully absorbed by the surface of FA particles. The specific resistance of conditioning FA showed a remarkable decrease from 1.41 × 10¹³ to 5.74 × 10¹¹ Ω cm compared with the untreated sample. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

The modification of hydrocyclone geometry changes the dynamics of the flow, so the particle cut size is affected. Computational fluid dynamics was applied to predict particle classification according to size. Fluent code was used to perform computer simulations for five different hydrocyclone geometries using large eddy simulation and volume of fluid models. The sensitivity to computed modifications in particle classification was evaluated by changing basic design variables, such as spigot diameter, vortex finder diameter, and cone angle. The results show that the particle cut size can be predicted for changes in geometric configuration for a wide range of slurry concentration with a small degree of error using computational fluid dynamics. The error can be attributed to the absence of particle–particle and fluid–particle interaction modeling. However, this assumption is known to be valid only for diluted slurries and some regions within the hydrocyclone. As soon as the particles enter the system, most of them are located within the walls, creating diluted slurry conditions in the main core of the hydrocyclone. The computed results for more concentrated slurries were therefore close to the experimental cut-size values. In all cases, the particle cut size was predicted successfully. Therefore, the evaluation of changes in the standard geometry to manipulate the dynamics and achieve the desired particle cut size becomes possible. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

This paper presents a model predictive control (MPC) method for a single supply chain (SC) unit. In order to make the most profit, the prediction of demand and the policy of inventory are the key factors for an SC unit. The ordering is a manipulate variable for an SC unit, and the pricing is introduced as another manipulate variable in this paper. The supposed price has determinate effect on the demand. The demand then can be regarded as a determinate part and a stochastic part. The inventory is regarded as a probability problem because of the stochastic demand. The two manipulate variables bring different dynamics into the SC unit. An MPC is designed, and the two-time scale characteristic of the two manipulate variables is considered simultaneously for the SC unit. By comparing with MPC without dynamic pricing policy and order-up-to-level policy, we found that the simulation results approve the validity of the MPC with dynamic pricing policy. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Pulsed jets in various configurations have shown potential for improving transport phenomena. In this study, a system of confined laminar two-dimensional pulsed impinging streams of air is simulated numerically by solving the governing conservation equations using the control volume method. The key parameters examined in this study are as follows: frequency and amplitude of pulsation, mean jet Reynolds number and phase difference between the nozzle exit velocity profiles. The effects of these parameters are computed and discussed comprehensively. Temperature is used as a passive tracer to quantify the degree of mixing in the system. Results show that flow pulsation has significant effects on the flow field, vortex formation and secondary structures, which are generated. These vortex structures influence the thermal shear layer and improve the mixing behavior. A better mixing index is observed as a result of the formation of larger vortices due to increased amplitude of the pulsation velocity amplitude. In the range of parameters tested, the frequency of the pulsation is found to have negligible effect on the mixing behavior of the system. Also, it is observed that by introducing a phase difference between the two jet velocity profiles, the stagnation point oscillates between the two jets and, in general, the system with phase differences shows better mixing behavior. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

An in-furnace urea pyrolysis coupled with selective catalytic reduction (SCR) system was applied on a 125 MW tangentially coal-fired utility boiler in China. The coupling system was well-designed to distribute NO and NH₃ more uniformly in the flue gas at the inlet of the SCR reactor. The experimental results showed that the homogeneous NO and NH₃ concentrations distribution could result to better performance of the SCR reaction. A 15 wt% urea solution directly injected into the furnace at the same flow rate of 1.2 t/h in Cases 4–6, corresponded to the normalized stoichiometric ratio of 1.40, 1.47 and 1.35. The coupling system showed a high NO reduction efficiency of up to 85–89% and could control NO emission to as low as 40, 34 and 27 ppm, respectively, with NH₃ slip less than 5 ppm. The calculated urea utilization efficiency was above 58% in the cases. The high utilization efficiency of the urea solution would significantly reduce the running cost of the system. There were only five injectors at the boiler's front wall, and one layer of total 90.3 m³ catalysts in the two SCR reactors, which would drastically reduce the initial investment. The effects of the urea solution flow rates were studied at 100  and 125 MW boiler loads; it was found that 1.2 t/h was the suitable flow rate of the urea solution, and the NO emission could be controlled lower than 40 ppm. The coupling system was stable, efficient and cost-efficient in industrial operation.

Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Turbulent heat transfer in the thermal entrance region of the pipe was studied by numerical solution of the energy equation using finite difference technique under different operating conditions. The turbulence effect was accounted for by introducing thermal eddy diffusivity term in the energy equation in both axial and radial directions. The axial and radial temperature profiles, the local heat transfer coefficient in the entrance and fully developed regions, and the entrance lengths were obtained and discussed. In addition, the role of thermal eddy diffusivity in the thermal entrance region and fully developed region was investigated. The finite difference numerical solution was also commented on. The theoretical results were compared with previous experimental works, and a reasonably good agreement was found. It was found that the temperature gradient in axial direction is very steep, close to the leading edge near the pipe's surface and becomes almost negligible after a distance equals few pipe diameters, depending on Reynolds number (Re), Prandtl number (Pr), and heat flux (q). The radial temperature profile was very steep, close to the pipe's surface near the leading edge and becomes almost constant at a very short distance from the pipe surface, depending on Re, Pr, and q. The entrance length (L_t) was found to be reached after 0.5–3.5 pipe diameters distance for the investigated ranges of Re, Pr, and q. Thermal eddy diffusivity plays an important role in axial and radial transport. Ignoring it, causes underestimation in the heat transfer coefficient and overestimation in the entrance length. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Nitrogen species distribution during coal pyrolysis with Ca addition in N₂, CO₂ and Ar was studied at 1000 °C using a horizontal tube furnace. In particular, the effect of Ca on the distribution of nitrogen species in N₂ and CO₂ atmospheres, which were closer to pyrolysis processes of conversional air and oxy-fuel combustion in comparison with inert Ar environment, was investigated for the first time in this work. It was found that Ca has a great effect on nitrogen species distribution during both coal and demineralized coal pyrolysis; on the other hand, CO₂ causes the formation of NO. Demineralization increases the formation of HCN and char nitrogen, but there is little effect on NH₃ formation during pyrolysis in N₂, in contrast to pyrolysis in Ar atmosphere, which decreases NH₃ formation. A significant reduction in char yield was found after char gasification in CO₂ at 1000 °C. With two different Ca-based additives, i.e., (CH₃COO)₂Ca and Ca(OH)₂, char yield decreases with the increasing amount of Ca additives in both cases. The effect of Ca on HCN and NH₃ formation during pyrolysis depends on both the form of Ca and the amount of addition. In most cases, HCN and NH₃ formation decreases with Ca addition in Ar, but increases in N₂. Ca addition slightly promotes HCN formation during pyrolysis in CO₂. There is no NH₃ detected during pyrolysis in CO₂ because of the reaction of NH₃ and CO₂ in the background. In addition, NO concentration decreases sharply with increasing the amount of Ca addition in the atmosphere of CO₂, which means that Ca has an effect not only on pyrolysis, but also on gasification of char in CO₂. In most cases, char nitrogen increases with Ca addition in N₂ or Ar. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

According to the conventional mobility control requirement, the displacing phase mobility (e.g. polymer) should be equal to or less than the sum of the mobilities of several displaced phases (e.g. water and oil). When the oil mobility is much lower than the water mobility, the sum of the displaced phase mobilities will be almost the same as the water mobility. Then, according to the requirement, the displacing polymer mobility is almost the same as the water mobility. As a result, the polymer solution will flow preferentially along water channels, leaving oil undisplaced.

In this paper, we propose that the displacing phase mobility (polymer) should be equal to or less than the lowest mobility of displaced phases (generally, oil phase mobility) multiplied by its normalized saturation. This mobility requirement is validated by extensive simulation results at different conditions. It is also justified by field practices. Some published experimental data are analyzed to justify the proposed requirement. The proposed mobility requirement provides a criterion for mobility control design in multiphase displacement processes in porous media. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

High gravity (HIGEE) technology, which uses centrifugal force to intensify mass transfer, has been applied to chemical processing industries. A rotating packed bed is a conventional HIGEE with a rotor filled with packings. A rotating zigzag bed (RZB) is a novel HIGEE with a rotor containing coupled rotational–stationary baffles as discrete steps, which are called HIGEE trays, to provide gas–liquid contact. RZB power consumption is mainly the power requirement for liquid flow. With the ideal liquid flow in an RZB rotor, this study develops a model that can predict the power requirement for ideal liquid flow at zero gas flow. The power requirement for liquid flow is equal to the model-predicted power requirement multiplied by two departure coefficients of real liquid and gas. Experiments were performed in two RZBs by using air–water system, and the consumption with gas rate, liquid rate, and rotational speed was measured. The departure coefficient of real liquid increased with increasing liquid rate and rotational speed, and its value at the greatest liquid rate ranged from 1.14 to 1.28 at various rotational speeds. The departure coefficient of gas increased with increasing gas rate and decreased with increasing liquid rate and rotational speed. The value of the departure coefficient of gas at the greater gas rate ranged from 1.36 to 2.80 at various liquid rates and rotational speeds. The power requirement for liquid flow in RZB was approximately 2.5 times as that of rotating packed bed, so the RZB power consumption should be given more attention. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

This study was to develop a detailed steady state model for an industrial combustor-style fluidized catalytic cracking regenerator consisting of high efficiency combustor and second stage regenerator. A rigorous model was developed for the combustor to predict profiles of important variables such as gas volume fraction, gas/cluster velocity, temperature, pressure, and gas/solid composition. The model for the second stage regenerator was also integrated so that the steady state behaviors of the reactor consisting of two distinct regions (dense bed region and free board region) could be accounted for. The model was programmed using FORTRAN language into five types of custom unit models of AspenPlus^TM software. The custom unit models were then solved together on AspenPlus^TM user interface level. The plant data of the industrial unit operated by SINOPEC were used to validate the proposed model. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

This work presents an experimental investigation and modeling of fouling mechanisms involved in ultrafiltration of oily wastewater streams. Hermia's models were used to investigate the fouling mechanisms. The experimental results performed at different cross flow velocity (CFV) (0.5, 1, and 1.5 m/s) and transemembrane pressure (TMP) (1.5, 3, and 4.5 bar) showed that the best fit to the experimental data corresponds to the cake layer formation model followed by the intermediate blocking model for all the experimental conditions tested. Furthermore, this work explores the application of the ANFIS as a model to predict permeation in ultrafiltration (UF) system. The selected experimental data were trained by a hybrid learning algorithm combining the forward pass and the backward pass. The good agreement of the model with experimental data underscores the ease and accuracy of the ANFIS in modeling such a complex systems. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Cr/SiO₂ catalysts are important industrial ethylene polymerization catalysts, mainly including Phillips catalyst (also called oxo chromium/SiO₂) and silyl chromate/SiO₂ systems (named as SC/SiO₂, also called UCC S-2 catalyst). Compared with Phillips catalyst, SC/SiO₂ catalyst is not fully investigated. In this work, SC/SiO₂ catalyst was prepared, and triethylaluminum or triisobutylaluminium was used as cocatalyst for ethylene homopolymerization. The effects of cocatalysts on polymerization kinetics and polymer microstructure were investigated. It is found that the kinetic curves using SC/SiO₂ catalyst in the presence of triethylaluminum or triisobutylaluminium seem to be a hybrid type composed of two types of basic polymerization kinetics: one is a fast built-up and fast decay type, and the other is a slow built-up and slow decay type, which indicates the existence of two types of polymerization active sites. Plausible mechanisms of the formation and transformation of active sites were proposed to rationalize the unique polymerization behavior. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Back-pulsing to reduce concentration polarization in a reverse osmosis process is studied in this article by solving the convection–diffusion equation. This was observed that the concentration depolarization starts with dispelling the concentrated layer from the membrane surface, followed by rapid homogenization of the boundary layer. The time taken to accomplish the aforementioned steps depends on the extent of polarization prior to back-pulse. The stopping of forward flux has substantial depolarizing effect on the boundary layer. The gain from this scheme, after accounting for the loss of permeate to the feed stream, is found to decrease with increase in forward filtration time, reverse flux, or the duration over which the reverse flow is continued. Also, the gain is studied as function of bulk concentration and transmembrane pressure differential. In cross-flow mode, the expulsion of concentrated layer from the membrane surface is observed. However, the concentration gradient for back-mixing is not substantial in the presence of cross-flow. The gradient in concentration along the distance from the inlet end is preserved when the fluid layer is pushed away from the membrane surface during reverse flow. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

A carbon-based solid acid was successfully synthesized by sulfonating a carbon precursor from pyrolysis of phenol residue, which is a solid waste from coking industry and contains higher phenols. The unit structures of the phenolic residual-based solid acid are fused aromatic rings bearing CH₃ side chains besides phenolic-OH, COOH and SO₃H groups. The direct pyrolysis and carbonization process of phenol residue abounding in phenolic hydroxyl groups avoids the loss of sulfonic acid groups instead of low temperature carbonization in concentrated sulfuric acid. Reaction kinetics of sucrose heterogeneous hydrolysis over the solid acid was studied to assess its catalytic activity and stability. The results indicate that the carbonization temperature for the preparation of carbon precursor significantly affects the catalytic performance of the solid acid because of the difference in the compact degree of carbon skeleton. The activation energy calculated is 74.67 kJ mol⁻¹, which reveals good catalytic activity. And the catalyst is fairly stable after repeatedly being used five times. It can substitute enzymes and sulfuric acid in sucrose hydrolysis. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Various surveys including geophysical, trench, topographical, and global positioning system were performed to evaluate the status of fuel–oil pollution in Y city in Korea. The target area was a railway station, that has been in operation since 1973. The total petroleum hydrocarbon (TPH) and benzene, toluene, ethylbenzene, and xylene (BTEX) were analyzed in samples collected from 54 representative points and from soil gas in sampling wells. The mean value of TPH and BTEX was 7504, 10 mg/kg. The target area for the remediation process for TPH was estimated at 18 376 m³. The results suggested that soil flushing is a possible purification method for this polluted area. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Environmental concerns have stimulated proper treatment in utilizing sewage sludge derived from different industries. The main objective of the present study is to prepare high-quality petroleum coke–sludge slurry (PCSS) with low viscosity and good stability by adding sewage sludge into petroleum coke–water slurry (PCWS), and a systematic investigation of the rheological properties of PCSS and PCWS, along with the sewage sludge, is conducted. The experimental results show that the PCWS is a dilatant fluid and has inferior stability; sewage sludge is a pseudoplastic fluid. As a certain amount of sewage sludge is added into PCWS to obtain PCSS, rheological properties are changed from a shear-thickening property to a shear-thinning property. Raw sewage sludge has higher bound water content and larger viscosity. Alkaline chemical additives are selected as sewage sludge modifiers to turn bound water into free-flowing water and reduce the viscosity. The static stability of PCSS was analyzed by the water separation ratio. Results indicate that sewage sludge has a significant impact on the static stability of PCSS. Water separation ratio decreases and the static stability is improved after addition of the sewage sludge. The higher the sewage sludge amount, the better the static stability of the PCSS. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Corrosion behavior of carbon steel and aluminum alloy in hydrochloric acid and sulfuric acid solutions was studied using microwave heating and conventional water bath heating method, respectively. The effect of microwave heating on corrosion time was investigated by using weight loss method and the surface morphology of metals was studied by using scanning electron microscope, too. The conclusion that microwave heating is a good method to accelerate corrosion process can be obtained from the test results and surface morphology. Both the mass loss of the metals and the pH of the solutions increase with the microwave power increasing and the immersion time prolonging. The mass loss of the specimens heated by microwave is notably higher than that heated by water bath under the same corrosion time and temperature. For all of the four corrosion systems, the corrosion results obtained using microwave heating at 75 °C lasting 40 h are equivalent to that obtained by using water bath at 55 °C, lasting 168 h, whereas more than 70 h is needed to achieve the same corrosion results by using the water bath at 75 °C. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

In this work, we propose the incremental proper orthogonal decomposition (POD) method and the recursive Galerkin projection to achieve model order reduction (MOR) for high-dimensional dynamical systems arising in the processes of heat transfer for green buildings. For MOR of high-dimensional dynamical systems, we use a batch of historic data to initially extract a sequence of POD modes and derive a low-dimensional system to approximate the high-dimensional heat transfer system. Then, we check the prediction error at every subsequent sampling moment by using the obtained POD modes. If the approximation error is larger than the pre-given threshold value, we then add the new snapshot into the collected sampling ensemble. Instead of recalculating the POD-oriented eigenvalue decomposition problem at each ensemble augmentation (which is time-consuming), the incremental POD method applies the updated singular value decomposition approach to increase the number of POD modes and adjust the shape of POD modes, and also change corresponding POD eigenvalues through a matrix rotation transformation. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

In this work, a new six-parameter semi-empirical equation has been developed for the predictions of the compressed liquid densities of n-alkanes from C₂ to C₁₀. The resulting functional form was established with the quasi-Newton optimization algorithm, which considers the experimental data sets for different fluids simultaneously. During the fitting process, the functional form of the equation is numerically very stable, and the substance-specific coefficients can be obtained easily. The calculated values from the new model were compared with the available experimental data and the values from reference equations in the literature. In most cases, the deviations are not more than ±0.5% for temperatures up to 0.7 times the critical temperature, whereas the agreement is within ±1.0% in the temperature range from the triple point to the critical point at reduced pressure up to 15. It was shown that the new semi-empirical equation was able to represent the compressed liquid densities of n-alkanes in wide thermodynamic ranges. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Two-dimensional unconfined flow and heat transfer across a long tapered trapezoidal bluff body are investigated for the range Re = 1 to 150 (thereby covering both steady and unsteady periodic regimes) and Pr = 0.7 (air). A number of engineering parameters, e.g. drag and lift coefficients, Strouhal and Nusselt numbers, and others, is calculated for the above range of conditions. No flow separation occurs from the surface of the trapezoidal cylinder for the range Re ≤ 5; however, flow starts to separate from the rear surface of the cylinder at Re = 6. Therefore, the onset of flow separation exits between Re = 5 and 6. The critical value of the Reynolds number (i.e. transition from steady to unsteady) exists between Re = 46 and 47. The drag coefficient decreases with increasing Reynolds number in the steady regime; however, the drag increases with Reynolds number in the unsteady regime. The Strouhal number and the average Nusselt number increase with increasing value of the Reynolds number. Finally, the simple correlation for the average Nusselt number is obtained in the steady flow regime. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Soot nanoparticles play a key role in heat transfer. A single-phase model is proposed to study effects of soot nanoparticles on heat transfer in a fire-tube waste heat boiler used in the process of bitumen gasification. In this model, the syngas containing a large amount of soot nanoparticles is treated as soot nanofluid. The model is applied in the numerical simulation of heat transfer in a fire tube in the waste heat boiler. Results show that soot nanoparticles enhance heat transfer not only by heat radiation mainly but also by the effects of microscale of soot nanoparticles especially at high temperature. Smaller sizes or larger quantities of soot nanoparticles can intensify heat transfer of the soot nanofluid. It is also indicated that structures of fire tubes affect the temperature and velocity fields significantly. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Biofiltration is one of the air pollution control technologies (APCTs) used widely in treating the odorous and volatile organic compounds (VOCs). Reliability and robustness in measuring the pollutant degradation rate and carbon dioxide production is considered most important in a biofiltration system. In this current work, a gas chromatography (GC) system and carbon dioxide analyser were introduced online to a lab scale differential biofiltration reactor with water content control. Toluene, one of the potential VOCs, was used as a model pollutant in our current study. The feasibility and limitations of online GC and CO₂ analyzer was evaluated by measuring the inlet and outlet toluene concentrations along with CO₂ concentrations and compared with the regular offline measurements. Furthermore, a simple diffusion system was proposed and used in the current work to improve the robustness of toluene vapour production. The results indicate that the modifications carried out in the lab scale biofiltration reactor and in the diffusion system improved the data collection and stability. This improved system can be used effectively in the lab scale biofiltration research. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

In this paper, we present an experimental protocol for following the kinetics of phase-transfer catalyzed synthesis of butyl 2-(4-methoxyphenyl) acetate from the esterification of 4-methoxyphenylacetic acid with the presence of potassium hydroxide as a base and potassium carbonate by gas chromatography. Hydrolysis of the ester product was curtailed by using low concentration of potassium hydroxide and potassium carbonate (inorganic salt) during esterification. The reaction is greatly enhanced by adding a small quantity of phase-transfer catalyst (k_app = 4.75 × 10⁻³ min⁻¹). Rate of esterification was investigated at various experimental parameters, namely. stirring speed, amount of catalyst, different solvents, different volumes of water, different inorganic salts, different phase transfer catalysts and temperature. When the degree of agitation exceeded 20.93 rad.s⁻¹, the mass transfer resistance for the reaction can be ignored. As the catalyst amount was increased (from 0.5 to 1.2 g), the rate constant values also increased (from 2.32 × 10⁻³ min⁻¹ to 6.13 × 10⁻³ min⁻¹). A kinetic model was proposed for the esterification, and the experimental data were well described by the pseudo-first-order equation. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

A reverse flow diverter (RFD) is a key fluidic component in RFD pumps, which are air-powered, low-maintenance devices used for transferring hazardous liquids. Despite several decades of practical application, no clear characteristic numbers exist for the suction ratio q = 1.0 and for the peak value of q, nor are there clear dimensionless performance curves for the reverse-flow portion of the pumping cycle. We experimentally investigated the effects of suction gap length and nozzle exit diameter on RFD flow and pressure under the condition of diffuser entrance to nozzle exit area ratio of m = 1.0. The results were used to derive two dimensionless performance curves (q = A · exp[−δ/B] + C · exp[−δ/D] + E and q = k · α + F) and characteristic numbers at q = 1.0 and the peak value of q. These curves and numbers are useful to simplify the design program and ease the selection of operation parameters for RFD pumping systems. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Generally, a comprehensively distributed reactor model must incorporate a momentum balance equation to calculate velocity gradient. However, the momentum balance equation also leads to the increasing complexity of the reactor model, which was neglected in previous works. In this work, issues whether the velocity gradient can be neglected or not are addressed. On the basis of mass, energy and momentum balances, polymerization kinetics as well as the thermodynamic state equations, two dynamically distributed reactor models either considering or neglecting axial velocity gradient are presented to examine its effect in tubular loop polymerization reactors. The results indicate that the axial velocity gradient has an important effect on the reactor flow-field parameters (i.e. propylene concentration, catalyst concentration, hydrogen concentration, polypropylene concentration, temperature and pressure) at low recycle ratios (R_ec < 50) and its effect on these aforementioned parameters can be neglected yet at high recycle ratios (R_ec ≥ 50). Namely, herein, we suggest that the momentum balance equation must be incorporated into the reactor model at R_ec < 50 and it can be neglected for the reactor model at R_ec ≥ 50, which is helpful to the distributed modeling of the tubular loop polymerization reactor. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

In this work, the potential of chitosan and activated carbon coated with chitosan for palladium and platinum adsorption from aqueous solutions was investigated. The observed results showed that the optimum operating conditions for palladium and platinum adsorption on chitosan were initial pH 2, particle size of adsorbent = 0.21 mm and adsorbent dose = 10 g/L. Equilibrium studies showed that palladium and platinum adsorption on chitosan was of spontaneous and exothermic nature. Equilibrium results fitted with Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models for two adsorbents. The maximum adsorption capacities for palladium and platinum adsorption were 62.50 and 66.66 mg/g of chitosan and 43.48 and 52.63 mg/g of activated carbon coated with chitosan, respectively. Kinetic data were found to confirm pseudo-second-order kinetic model. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

A continuous melt suspension crystallization process has been presented for the purification of the phosphoric acid in this study, which is conducted in the cascade of a continuous mixed suspension and mixed product removal (MSMPR) crystallization and subsequent countercurrent solid–liquid contact in a gravity wash column. With magma withdrawn from the MSMPR crystallizer being fed into the top of the gravity wash column, crystals settle down toward the bottom of column and the reflux melt rises upward, whereas the sweating of crystals and counter-current contact between crystal particles and the melt lead to high separation capability of impurities. The gravity wash column used in this study is a vertical agitated cylindrical column, whose configuration is different from the inclined column crystallizer. The feasibility of suspension crystallization equipment for purification of phosphoric acid was studied. Distribution of impurities in the wash column was also investigated as a function of the feed concentration, crystal bed height, reflux ratio and stirring speed. Reflux ratio has been found to play an important role in the process. Food grade phosphoric acid can be achieved when the process is operated with feed concentrations of 84 ~ 86 wt.%, reflux ratios of 3.4 ~ 6.2, stirring speed of 10 rpm and crystal bed height of 150 ~ 250 mm in a gravity wash column. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

In this work, a new fault detection method based on non-negative matrix factorization (NMF) is presented for non-Gaussian processes. NMF is a new dimension reduction technique that can preserve spatial relationships corresponding and retain the intrinsic structure of original data. The basic idea of our approach is to use NMF to extract the latent variables that drive a process and to combine them with process monitoring techniques. A modified alternating least squares algorithm with an order constraint and a fixed initialization is proposed for solving the NMF problem. In addition, kernel density estimation is adopted to calculate the confidence limits of defined statistical metrics for NMF-based monitoring method. Afterwards, the proposed method is applied to the Tennessee Eastman process to evaluate the monitoring performance, comparing with principal component analysis and independent component analysis. The experiment results clearly illustrate the feasibility of the proposed method. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

In order to improve permeability and selectivity of membranes, especially for gas separation applications, a mixed matrix membrane was prepared from acrylonitrile butadiene styrene (ABS) and cadmium sulfide (CdS) nanoparticles with 1, 1.5, 2.5 %wt. Gas permeation and separation characteristics of the membranes for nitrogen, methane, carbon dioxide and helium have been studied. Scanning electron microscopy and X-ray diffraction analysis were also utilized in nanoparticles and membranes characterizations. The results showed an increase in permeability for mixed matrix membranes in comparison with neat ABS membrane. Furthermore, as the nanoparticle content increased, membrane gas permeability was enhanced. The selectivity for (CO₂/CH₄), (CO₂/N₂) and (He/CH₄) initially were increased by increasing CdS nanoparticle concentration up to 1 %wt in the prepared membrane and then began to decrease with more additives loading. The membrane with 2.5 %wt CdS nanoparticle content showed the highest permeability compared with others. Also, the membrane with 2.5 %wt CdS nanoparticles showed appropriate selectivity compared with the neat ABS membranes. Obtained results revealed that membranes with 1 %wt CdS nanoparticle content had the best selectivity for (CO₂/CH₄), (CO₂/N₂) and (He/CH₄). Moreover, membrane thermal stability was improved in the presence of cadmium sulfide nanoparticles. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Membrane fouling caused by natural organic matter is an important problem in drinking water treatment. In this study, bench-scale experiments using three different types of ultrafiltration (UF) membranes were carried out with the surface water of the Songhua River in China in order to investigate the effect of natural organic matter on membrane fouling. Organic matter that caused reversible and irreversible fouling in the filtration operation was desorbed from the fouled membranes and subjected to chemical fractionation and Fourier transform infrared analyses. These analyses revealed that hydrophilic organic matter accounted for the majority of both reversible and irreversible fouling, regardless of the type of membrane. Results also demonstrated that the type of organic matter responsible for fouling differed significantly and depended on the type of membrane. The main types of organic matter that caused reversible fouling were hydrophilic organic matter and hydrophobic acids, for the polyvinyl chloride (PVC) and polysulfone (PS) membranes and hydrophilic matter and weakly hydrophobic acids, for the polyvinylidene fluoride (PVDF) membrane. Hydrophobic acids were largely responsible for the irreversible fouling of PVDF membranes. The PVC membrane was more vulnerable to fouling because of the hydrophilic fraction, and the PS membrane was most easily fouled by the hydrophobic neutral fraction. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Jatropha curcas I. is an oil-bearing seed plant with a wide range of applications. The oil from the seeds of this plant has been used as an industrial raw material for many years. One of the important characteristics of jatropha oil is its potential for fuel and biodiesel production to meet the global energy demand. In this paper, solid–liquid extraction of jatropha oil from seeds using petroleum ether was optimised on the basis of the amount of the extracted oil. Four main factors, namely temperature, the solvent-to-solid ratio, the reaction time and the size of the raw material, were investigated to optimise extraction conditions for achieving the highest oil yield under experimental conditions. The kinetics of the extraction using petroleum ether as the solvent were also studied and fitted to a second-order model. The free fatty acid (FFA) content of the oil was used as an index of the oil quality. The optimum conditions were found to be 7 h of reaction time, a temperature of 68 °C, a coarse particle size of 0.5–0.75 mm and a solvent-to-solid ratio of 6 : 1. Storing the ground seeds for one week before extraction had a remarkably negative effect on the quality of the oil produced (FFA ≈ 6.99%), whereas the quality of the oil was satisfactory when extracted from the seeds immediately after grinding (FFA ≈ 0.62%). The experimental data fitted well to the second-order model with the saturation extraction capacity and the initial extraction rate increasing with increasing temperature. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

A titania film imprinted by atrazine molecule at the surface of a quartz crystal was prepared using molecular imprinting and surface sol–gel process. The quartz crystal microbalance technique was employed to in situ investigate the degradation behavior of atrazine on the molecularly imprinted titania film. The obtained results reveal that the molecular imprinting can enhance degradation of atrazine on titania films, and the degradation rate constants (K) estimated from the in situ frequency measurement is about 0.62 × 10⁻³ s⁻¹, which is two times higher than that obtained on non-imprinted titania films. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

This research was concerned with the solubility of ilmenite (Tin Tailing) in acids (sulfuric, hydrochloric, oxalic and citric) and bioleaching by Aspergillus niger, Penicillium citrinum and Bacillus megaterium. Ilmenite concentrate was soluble in 1.5 M sulfuric acid and 1.5 M hydrochloric acid solutions at 90 °C. However, improved leaching was obtained with 8 and 12 M sulfuric acid solutions. The chemical leaching results for different stirring speeds showed that a speed of 750 rpm was favourable to iron and titanium dissolutions. Metal dissolution rate can be enhanced with increasing leaching time. The optimum percentages of iron and titanium extraction occurred at 750 rpm for 6 h leaching in 8 M sulfuric acid solution and amounted to 64 and 57%, respectively. However, the optimum condition of chemical extraction was 1 M citric acid, which is considered weak, 750 rpm for 20 h extraction time at 90 °C. This led to the maximum titanium concentration of 63% that was comparatively very high compared with low iron dissolution of only 11%. Spores of A. niger and P. citrinum solutions were individually transferred at the culture ratio of 1 : 0, 0 : 1 and 1 : 1 in a shake flask containing Sabouraud dextrose medium. The flasks were incubated in a rotary shaker at 30 °C and 200 rpm. The bioleaching experiments after 35 days gave the highest iron extraction of 0.45% in the presence of pure culture (A. niger) and mixed culture (A. niger and P. citrinum), whereas the titanium dissolution was observed to be very low (<0.28% extraction). For the bioleaching, B. megaterium was subcultured in solution in a shake flask containing nutrient broth. The flasks were incubated in a rotary shaker at 30 °C and 200 rpm. The bioleaching experiments after 3 days gave the highest iron and titanium extraction of 0.2 and 0.4%, respectively. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Optimizing experiments for the bottom tuyere configuration and blowing parameters of the 120 tonne top and bottom combined blowing converter at Shaoguan Iron & Steel Co. were carried out in a reduced-scale water model. Results showed that the former configuration with 6 bottom tuyeres in the converter was not suitable with bath stirring because of the two tuyeres arranged in 0.33D pitch circle which caused the cavity deformation and stirring energy loss. Ideal bath stirring in the converter was obtained by using a new arrangement with 4 bottom tuyeres, two being in 0.57D pitch circle and the other two in 0.42D pitch circle. The optimal blowing parameters of the converter with the new bottom tuyere configuration were 1.26 Nm³/h of bottom gas flow rate, 160 mm of top lance height, and 30.52 Nm³/h of top gas flow rate.

The use of direct reduced iron (DRI), hot metal, cold pig iron, decarburized granular iron, iron carbide, and complex metal charges to replace scrap metal as the feedstock to an electric arc furnace not only resolves the lack of scrap supply, but is also very helpful in diluting the residual elements in the scrap, thus improving the quality of the steel. It has now become possible to produce high-quality steel in an electric arc furnace. In this paper, the characteristics and effectiveness of various metallic charges for use in an electric arc furnace (EAF) are discussed.

In this study, a mathematical model describing the three-dimensional turbulent flow, heat transfer and inclusion behavior in continuous casting tundishes was developed. Numerical calculations were performed to study the characteristics of flow, heat transfer and inclusion behavior in a one-strand tundish with/without flow control. The results show that it is necessary to employ flow control devices in order to improve the effectiveness of removal of nonmetallic inclusions in the tundish. Without flow control, the hot melt ascends and cooled melt descends and then recirculates back to the inlet along the bottom of the tundish. However, the phenomenon of temperature stratification occurs after the steel flow passes through the dam in the tundish. Inclusions with diameter greater than 30 m̈m can be removed in the tundish, and reasonable flow control devices will assist the removal of inclusions of size 20-25 m̈m.

The thermophysical properties of premelted slag and synthetic slag were measured under laboratory conditions. The tests of liquid steel desulfurization using CaO-Al₂O₃-SiO₂-MgO series premelted slag and a synthetic slag have been carried out with a MoSi₂ electric resistance furnace. It was shown that the former had better desulfurization capacity than the latter. Thus, the premelted slag was chosen to be the desulfurizer for RH-KTB refining. A plant trial at a 250 ton RH-KTB unit used the premelted slag as desulfurizer and the average initial sulfur content in steel was 41.9 × 10⁻⁶. The results showed that the mean sulfur content in steel at the end of RH-KTB refining had decreased to 30 × 10⁻⁶, the lowest sulfur content was 22 × 10⁻⁶, and the mean desulfurization efficiency was 28.1%.

A molten salt layer composed of PbO-PbCl₂ is formed when the vaporization rate of PbCl₂ is slower than its formation rate. Kinetic analysis has been performed of the chlorination-vaporization reaction of Pb-oxychloride in the pyrometallurgical recycling process of dust and ash. Simulation calculations for the bulk diffusion have been carried out, and also by applying the quasi-steady principle the profiles of relative chemical potentials, compositions, and mass flux across the molten salt as well as the intermediate compound layers of Pb-oxychloride, have been obtained. For the chlorination-vaporization reaction, the effects of temperature and Cl-potential in the gas phase (log(P²_HCl / P_H2O) have been evaluated.

The SReM model associates with super order sub-regular melts. It is intended to describe systematically the component activities in the entire region of a homogeneous phase, either liquid or solid, in a multiple alloy or slag. A reliable evaluation of component activities can be provided for engineering problems. In this paper the model characteristics, its formalism and a simplified version are introduced. The thermodynamic restrictions utilized to check the evaluated parameters were suggested by the SReM model. According to this self-consistent approach, the evaluated parameters of this model are reliable.

Hydration-resistant CaO refractory was synthesized by using lightweight CaCO₃ powder as starting material with MgO addition. The addition of MgO not only promoted densification of the compact by inhibiting the grain growth of CaO, but also modified the microstructure of the clinker. Homogeneous microstructure, with well growing MgO grains occupying most of the boundary triple points of CaO grain, formed by the addition of 20 mol% MgO. The hydration resistance of the clinker was significantly improved due to the formation of CaO solid solution, promotion of densification, and modification of microstructure by the addition of MgO.

This paper introduced the sonic level monitor for continuous detection of slag condition, forecasting end-composition of molten steel using artificial neural network, dynamic modeling and computer simulation of the steelmaking process.

A mathematical model is developed based on the reaction kinetics and mass balance to investigate the decarburization rate based on operational parameters of the UHP electric arc furnace charged with hot metal. Thus, the evolution of carbon content can be described accurately, and the carbon content at the end of melting can be controlled dynamically. The calculated results are in good agreement with the production data of a 150 ton DC-UHP electric arc furnace. Simulated results show that the decarburization rate is proportional to the flow rate of oxygen at high carbon contents, to the square root of carbon content at intermediate carbon contents, and to the carbon content at low carbon contents. The decarburization rate, especially at low carbon contents, can be enhanced by bath agitation. For optimum operating conditions, less oxygen flow rate is required as the carbon content decreases.

The effect of the refining slag composition on the inclusions in molten steel was studied in MgO crucible by using MoSi₂ furnace. The experimental steel was heavy rail steel and Si-Ca-Ba alloy was used as the deoxidizer. The results showed that the total oxygen content of steel, and the total quantities, total areas and average radius of inclusions decreased with the increased basicity of refining slag. The total quantities and total areas of inclusions were the least when Al₂O₃ content in refining slag was between 13% and 20%, while the proportion of small inclusions increased when Al₂O₃ content was higher than 20%. The contents of SiO₂ and Al₂O₃ in inclusions were affected directly by the SiO₂ and Al₂O₃ contents in refining slag, and it was very remarkble when the slag composition was CaOAl₂O₃2SiO₂. Therefore, it's feasible to control the composition of inclusions by controlling the composition of refining slag.

A mathematical model was developed for the simulation of gas flow, combustion and heat convection in the vacuum chamber of RH-KTB process at Baosteel. Under different conditions, the model was used to predict the influence of the top oxygen blowing lance on the gas flow; chemical reactions and temperature distribution were calculated. The optimum position of the lance is suggested for the RH-KTB process.

Due to improved requirements for high casting speed, slab quality, variety of steel in continuous casting, it is increasingly important to accurately control the mould/strand lubrication and friction behavior. In this study, by means of combining analysis of the measured friction data from plant trials with numerical calculations, an empirical formula for the friction coefficient of strand/mould is obtained. The mathematical model is established in order to determine the strand/mould lubrication and friction behavior, and to obtain the profiles of thickness and internal pressure of liquid slag film, and the distribution of liquid friction between strand and mould. These values enable calculation of the local mould friction. It was found that mould friction increased when some cracks and breakouts take place, thus showing that the influence of mould friction on mechanical behavior of the solidified shell as well as the thermal stress are taken into account.

A coupled thermo-mechanical model has been established including the finite difference method (FDM) simulating the mould heat transfer based on the inverse problem algorithm from measured temperatures, and the finite element method (FEM) predicting the strand stress. Calculation results show that the distribution of mould heat flux, which determines the shell thickness, corresponds to that of thermal resistance between the mould and shell. The safety index of billet quality illustrates that the surface cracks are likely to originate near the meniscus and propagate from beneath the surface at the lower part of mould. In this study, the thickness distributions of liquid and solid slag films are also calculated, showing that the heat transfer is determined mainly by the solid slag film in the upper mould.

New developments that utilize metallurgical slag as resource materials are important in order to decrease the land used for disposal of slag, reducing environmental pollution, and also promoting the continuous and highly efficient development of China's metallurgical industry. Current major problems and possible future uses of metallurgical slag are discussed based on assessments of present uses. Improving the use of metallurgical slag as resource materials requires the development of new high-value-added products.

The solid material used in most metallurgical reactions can be considered as porous media consisting of the accumulated pellets. When the fluid flows through the porous media, various chemical reactions may occur between the fluid and solid matrix which have a significant effect on the transfer process in the porous media. Based on derivation of the overall rate formulation of the representative elementary volume (REV), a mathematical model describing the transfer process in the porous media was established. The model was tested numerically by applying the implicit formulation finite volume method. The predictions were validated by comparison with the experimental results and literature data. For the indirect reduction of iron ores, the influence of the flow rate, the particle size, reaction rate, the dimension of the reactor, and the ratio of the Thielet number to the Peclet number on the distribution of gas concentration and the solid conversion degree were analyzed.

The continued high cost of energy has mandated that the Chemical Process Industries reduce operational and capital costs through process heat integration. However, the heat integration of process streams can lead to process structures that are difficult to operate and control. This paper addresses the control of heat exchanger networks and it shows the importance of dynamic simulations in the synthesis of workable control structures. Steady-state simulations were used to delineate the trade-off between flexibility and capital costs of networks. Dynamic simulations were used to assess the placement of the by-pass on the process-to-process heat exchangers. Steady-state and dynamic simulations showed that the use of stream splitting should be avoided as a control scheme. The analysis of several simple case studies allowed the proposal of heuristic rules to identify the best control strategy for a heat exchanger network.

In this paper, microencapsulation based on emulsification coupling with solvent evaporation, ionotropic gelation, coacervation technique, and spray drying are critically reviewed. The introduction of biocompatible polymers, especially polyelectrolytes, as wall-forming materials are included. Membrane emulsification, surface modification, preparation of multilayer microcapsules, characterization methods, as well as modeling of drug release are summarized. This review suggests that membrane emulsification coupled with the ionotropic gelation/complex coacervation is the most promising method for microencapsulation under the mild conditions. Multilayer microcapsules using layer-by-layer complex coacervation, are efficient in obtaining the desired properties.

In this paper, the mechanisms of scale formation from oilfield water are presented. An accurate model for predicting the scaling phenomena due to mixing of incompatible waters, changes in thermodynamic, kinetic and/or hydrodynamic conditions in oilfield operations is suggested. This model can predict scaling tendency of common oilfield waters in disposal wells, water-flooding systems and in surface equipment and facilities. The model is developed based on experimental data and empirical correlations, which match the oil field conditions accurately. Furthermore, the simultaneous deposition of different oilfield scales and the competition of various ions to form scale are incorporated in the model. The suggested model has been used to investigate the potential for scale precipitation in various Iranian on-shore and off-shore oil fields, where water injection is being performed for the water disposal of desalting units or as a method of secondary recovery or reservoir pressure maintenance.

Prediction of two-phase pressure drop using published correlations and a wide data base showed that no single correlation could predict across the whole range of possible flow patterns. Particular difficulty was found in attempting to predict the intermittent SI and BTS patterns. However, successful prediction was achieved for the St + RW, St + RW + D, D and A + RW patterns.

Two-phase pressure drop predictive correlations were extended to the three-phase situation. Detailed evaluation identified three correlations which gave reasonable prediction of intermittent flow pressure drop. An adaptation is presented that enhances the prediction of these correlations for three-phase flow. The separated three-phase patterns could not be predicted to an acceptable standard using these types of correlations.