bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimisation of an Agitated Thin Film Evaporator for Concentrating Orange Juice Using Aspen Plus
Authors: Chawankul N. , Douglas P. L. , Chuaprasert S. , Luewisutthichat W.
Published: August 2010

This paper presents an application for the optimisation of an existing agitated sdthin film evaporator (ATFE) for concentrating orange juice using Aspen PlusTM. A rigorous heat exchanger mode (Heatx) and a rigorous two‐phase flash model (Flash2) were used to simulate the dominant effects of the ATFE. The thermo‐physical properties of orange juice, not available in Aspen Plus, were determined experimentally and correlated as functions of temperature and solids content by Boonsriudomsuk [1]. Effective heat transfer coefficients were calculated from measured temperatures and flow rates.

Experiments were performed on a laboratory‐scale and pilot plant system and compared with the simulation results. The Aspen Plus simulation model using experimentally determined heat transfer coefficients and thermo‐physical properties of orange juice compared well with the experimental data from the ATFE. When the mass and energy balance data were reconciled the errors between both experimental and simulation results were significantly decreased.

The optimisation results indicated that by operating at the optimum operating conditions the operating costs could be reduced by about 10%. This translates into savings of more than $10.000/vear in the case of the laboratory‐scale evaporator and $33,000/year in the case of the pilot plant. If a commercial ATFE process was optimised then the potential savings could approximate to $330,000/year. Clearly, process optimisation is a valuable tool in the design and operation of these processes.
Simulation of the Industrial Packed Bed Catalytic Reactor for the Partial Oxidation of Methanol to Formaldehyde:
Authors: Moustafa T. M.
Published: August 2010

A detailed diffusion‐reaction kinetic model was developed in this study for an industrial methanol partial oxidation reactor. Unlike, most of the kinetic models in the literature that either neglected or approximated the intra‐particle diffusion, the details of the mass transfer limitations were taken into consideration for this reaction system. The catalyst pellet was modeled using the rigorous dusty gas model based on Stefan‐Maxwell equations. Four reactions are considered and an efficient minimization routine was used to extract the kinetic rate coefficients for these reactions using industrial reactor data.
Production of Crystalline Boric Acid through the Reaction of Colemanite Particles with Propionic Acid
Authors: ZareNezhad Bahman
Published: August 2010

A new process for boric acid production is developed. In this process the crystalline boric acid particles are directly produced in a one‐stage crystallizer through the reaction of colemanite particles with propionic acid. Each porous colemanite particle is comprised of spherical solid grains. It is found that the solid boric acid produced precipitates on the unreacted core of the grains. The maximum overall conversion of colemanite particles can be increased to 97% if the propionic acid concentration, stirrer speed, concentration, stirrer speed, colemanite mean particle size and temperature are set at 16 kmol/m3, 20 Hz, 462 μ and 295 K, respectively. Therefore it is possible to use this process as an alternative for boric acid production, also having a useful side product. A particle‐grain model is successfully used for process simulation.
Desulfurization of Egyptian Petroleum Coke
Authors: Aly I.H.M. , Magdy Y.H. , Barakat N.A.M.
Published: August 2010

Ferric chloride and benzene were examined with many other chemicals to be used as solvents for the sulfur‐bearing compounds present in the Egyptian petroleum coke. The best results were obtained when ferric chloride and benzene were used consecutively, and more than 35% degree of desulfurization was obtained in this case. The kinetic study showed that the combination of the three rate processes, namely for diffusion of ferric chloric through a liquid film, surrounding the coke particles, and in the coke ash layer, plus chemical reaction of the ferric chloride with the sulfur‐bearing compounds present in the petroleum coke, will provide overall control of the process. Activation energy of the process was found to be 12 kJ/mol.
Solubility of Manganese Sulfate Monohydrate in the Presence of Trace Quantities of Magnesium Sulfate Heptahydrate in Water
Authors: Maeda Kouji , Matsuoka Wataru , Fukui Keisuke , Chandra Eric Sukma , Ang Ha‐Ming , Tadé Moses
Published: August 2010

The solubility of aqueous manganese sulfate monohydrate has been measured in the presence of magnesium sulfate as the second salt. Over the temperature range from 273 to 353 K, aqueous manganese sulfate on its own exhibited an unusual behavior in that its solubility reached a maximum at an intermediate temperature of 293K. The solubilities of manganese sulphate under and over the maximum solubility temperature were first predicted individually by the electrolyte NRTL model. The binary interaction parameters and solubility parameters were universal parameters that were applied to any salts consisting of manganese, magnesium and sulfate ions, and they were newly obtained from the binary solubility data. The predicted solubility curves could represent the experimental data quantitatively, and adequately described the effect of co‐salt of magnesium. The experimental solubility data were also satisfactorily correlated with the electrolyte NRTL model.
Flow Injection Analysis for Aluminium using 3‐Hydroxy‐4′‐Chloroflavone
Authors: Nishioka Hiroshi , Nagahiro Tohru
Published: August 2010

A flow injection system is described for the determination of aluminium. This method is based on the formation of a fluorescent complex with 3‐hydroxy‐4′‐chloroflavone. The maximum wavelength of its excitation and emission spectra are 397 and 455 nm, respectively. A 200μl aliquot of sample solution is injected into a carrier (distilled water) which is pumped at 1.1 ml min−1. The reagent solution is prepared by mixing the flavone ethanol solution (1x10−4 M) and buffer solution (PH 4) in the volume ratio of 5:1. The reagent solution is also pumped at 1.1 ml min−1. Aluminium ion in the sample solution reacts with flavone in the coil (0.5 mm i.d. x 3 m) to form a fluorescent complex. A linear relationship was observed between peak heights and aluminium concentrations in the range of 2.4‐100 ng ml−1. The relative standard deviation for five replicate injections is 0.9%. A routine sampling rate of 20 determinations per hour can be achieved by the proposed method.
On the Mechanism of the Interfacial Reaction in Extraction of Rare Earth Metals by D2EHPA
Authors: Tomita Akihiro , Kanki Tatsuo , Sano Noriaki , Asano Tsuyoshi , Imai Shingo
Published: August 2010

The mechanism of interfacial reaction was discussed based on the constituent of the crystal film which forms at the interface and the practical behavior of interfacial tension with the aid of intermolecular potential determined by ab initio molecular orbital calculation. It was shown that there are three different reaction zones depending on hydrogen ion and extractant concentrations. A couple of extractant monomer(s) and/or its anion(s) first react with a lanthanide ion to form 1:2 intermediate complex. At the concentration zone where the crystal formation occurs, the 1:2 intermediate complex reacts with adjacent extractant monomer or its anion to form crystallized 1:3 complex. At lower extractant concentrations, the 1:2 intermediate complex reacts with extractant monomer or its anion and further with extractant dimer to form the stable 1:6 complex which should dissolve into the organic phase. At higher extractant concentrations, the 1:2 intermediate complex reacts with extractant dimer to form the stable 1:6 complex dissolving into the organic phase.
Crystallization of Boric Acid through Reactive Dissolution of Oxalic Acid Crystals in Aqueous Borax Solution
Authors: Zarenehad B. , Garside J.
Published: August 2010

In the reaction between solid oxalic acid and aqueous borax solution, product boric acid precipitates in the solution phase after complete dissolution of oxalic acid crystals. This makes it possible to measure the dissolution and precipitation kinetics independently. The oxalic acid dissolution process was found to be diffusion controlled. Nucleation rates of product boric acid were influenced by heterogeneous primary nucleation and secondary nucleation, while growth rates were affected by both the bulk diffusion and surface integration processes. Dissolution of oxalic acid ctystals was described by a surface reaction model, and overall nucleation and growth rates were correlated in terms of the influencing process variables. Simulation analysis was carried out by linking the two processes of dissolution and precipitation in series. The trends of the predicted supersaturation profiles, number concentration, magma density and mean size of the product crystals are in good agreement with measured values.
Blown Film Processing Characteristics of Metallocene and Conventional Polyethylenes
Authors: Johnston A.D. , Mcnally G.M. , Clarke A.H.
Published: August 2010

Part A ‐ A range of polyethylene films were prepared from metallocene linear low density polyethylene (mPE) and linear low density polyethylene (LLDPE). The films were manufactured using blow up ratios (BUR) of 1.3 ‐ 2.5, haul‐off rates, and screw speeds to give a uniform thickness of 50 microns. Tensile analysis of the samples showed that modulus and elongation were related to both comonomer type and polymer density. The mPE resins possessed considerable improvement in mechanical performance compared to conventional PEs. Differential Scanning Calorimetry (DSC) analysis demonstrated that the degree of crystallinity was more dependent on extrusion processing conditions and polymer density than comonomer type.

Part B ‐ Films were prepared from a range of mPE resins of various comonomer types (hexene and octene). The films were manufactured at a constant blow up ratio of 1.6 by maintaining constant haul off speeds and screw speeds to give a uniform thickness of 50 microns. To effect the change in frostline height, the rate of cooling was changed. Tensile analysis of the samples showed that modulus and tensile stress were related to both comonomer type and polymer density and that frostline height variation had an effect on the final film properties. Change in the percentage crystallinity of each of the samples at the different cooling rates also demonstrated how the processing factors of the blown film line can influence film properties.
The Effect of Compatibilisation for Blends of Nylon 6 or Polybutylene Terephthalate (PBT) with Metallocene Linear Low‐Density Polyethylenes
Authors: Gribben F. , Mcnally G.M. , Clarke A.H. , Murphy W.R. , Mcnally T.
Published: August 2010

Polymer blends of polyamides and polyethylenes are immiscible and highly incompatible. These blends are characterised by high interfacial tension, a two‐phase morphology and poor physical characteristics due to reduced interaction across the phase boundaries. PBT like many other polymers is a brittle material with a high modulus value and is not suitable for certain applications. Blending and compatibilising with an incompatible polyethylene phase may improve these properties. The compatibilising agent, maleic anhydride‐grafted‐LLDPE, is physically miscible with the polyethylene phase and has a chemical functionality with the polyamide phase and the carboxylic and hydroxyl end groups of the PBT phase. The use of a new generation mLLDPE (ENGAGETM by Dupont) was also studied to investigate its suitability as a modifier for the polyamide and polyester grades. The influence of the percentage composition of the mLLDPE and the effect of the addition of the compatibiliser were both investigated for their effect on the mechanical properties. They were both shown to significantly improve the modulus and elongation with only a slight reduction in the impact properties of the final product.
Effect of Phthalocyanine Blue Pigment on Mechanical and Thermal Properties of polypropylene copolymers
Authors: Major I.F.M. , Mcnally G.M. , Clarke A. , Ross H.
Published: August 2010

Samples of two commercial polypropylene copolymers, one a random copolymer and the other a block copolymer, containing 0–8wt.% phthalocyanine blue pigment were injection moulded using mould temperatures of 40d̀C to 80d̀C. Dynamic Mechanical Thermal Analysis (DMTA) and Differential Scanning Calorimeter (DSC) analysis showed the presence of different crystalline phases in each polymer, the amount of each phase changing with increasing pigment loading. With these changes in the crystalline phases there was a progressive increase in tensile modulus, storage modulus (E') and glass transition temperature (Tg) for both copolymers. Impact performance of both pigmented copolymers decreased with an increase in pigment loading and mould temperature, with the most dramatic result shown for the random copolymer. These impact results were mirrored by the fall in loss modulii of both copolymers with increasing pigment loading.
Exfoliation Kinetics of a Phyllosilicate‐Organoclay Structure in a Polymer Matrix during Melt‐Extrusion Process
Authors: Lew C. Y. , Murphy W. R. , Mcnally G. M.
Published: August 2010

Nanostructured polymer‐composite materials were prepared by melt‐exfoliating the smectite structure of a synthetic tetrasilisic fluoromica in a nylon‐12 matrix, by means of a melt‐extrusion process using a single‐screw extruder. The structure and morphology of these materials were evaluated using the X‐ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Uniform dispersion of exfoliated slicate layers were observed throughout the polymer matrix. Rheological studies using a dual capillary rheometer showed that the melt viscosity of the nanocomposites was dependent on the degree of clay exfoliation, and in addition the orientation of the layered‐silicates in the polymer matrix. The exfoliation and orientation of layeredsilicates were in turn dependent on the processing conditions adopted. Typically a lower processing shear would improve the intercalation of the layered‐silicates while increasing shear enhanced their exfoliation. Improved exfoliation was shown to decrease the polymer melt viscosity, which may be attributed to the plasticising effect of the clay platelets.
Diffusion of Methanol, Ethanol and Toluene in Nylon 12 and Poly(butyleneterephthalate)
Authors: Mccourt M. P. , Mcnally G. M. , Ruddy A. C. , Murphy W. R.
Published: August 2010

This work investigates the diffusion of methanol, ethanol and toluene in polybutyleneterephthalate (PBT) and nylon 12 over a range of temperatures from 8d̀C to 60d̀C. The results show that substantial solvent uptake was noted for nylon in methanol and ethanol. Solvent uptake in PBT occurred only at the higher temperatures in toluene. Dynamic mechanical thermal analysis (DMTA) also showed progressive decrease in the glass transition temperature (Tg) and storage modulus (E') with increase in solvent uptake.
Momentum Balance for Two‐Phase Horizontal Pipe Flow Part 1: Friction Factors
Authors: Spedding P. L. , Cole J. S. , Donnelly G. F.
Published: August 2010

Estimations of gas wall, liquid wall and interfacial friction factors for two‐phase horizontal co‐current pipe flow are discussed critically after being checked against reliable data obtained under a wide range of conditions. The use of equivalent diameters and the Blasius relation were shown to be valid for estimation of the gas wall friction. Prediction of liquid wall and interfacial friction factors proved to be more difficult but estimation improved if consideration was given to the effects of liquid holdup and interfacial liquid shape.
Production Variance in Purified Carboxymethyl Cellulose (CMC) Manufacture
Authors: Stigsson Veronica , Wilson David I. , Germgärrd Ulf
Published: August 2010

This study investigates the variance in industrial production of carboxymethyl cellulose (CMC). Initially it was thought that the product exhibited excessive quality variations. However careful viscosity and molecular weight distribution measurements on both the raw material and the final product, supplemented with online quality measurements, showed that the product variations were less severe than originally thought. The most probable reason for this unfounded quality concern is due to imperfect routine measurements coupled with a limited reporting of the subsequent offline laboratory analysis. The situation where the routine quality analysis plays as much a role in the uncertainty as the production itself is believed to be of general relevance for the chemical processing industries.
A New Approach to Monitoring the Movement of Particulate Material in Rotating Drums
Authors: Davies C. E. , Williams A. , Tallon S. J. , Fenton K. , Brown N.
Published: August 2010

Rotating drums are widely used for a variety of particle processing operations including mixing, calcining, and granulation. The mode of motion of the particles can be characterized as one of seven regimes and three of these, “slumping”, “rolling”and “cascading” are relevant to industrial practice. This paper describes apparatus in which a rotating cylinder is mounted on a pivoted framework acting on a load cell. Changes in the position of the centre of mass of the material in the drum cause changes in the moment measured by the load cell, and experimental results are presented showing that the variance of the load cell signal can be used to track the transition from slumping to rolling. A simple model that can facilitate the interpretation of the load cell output in terms of gross movement of material in the drum is outlined, and load cell response in the slumping regime, is discussed with reference to video footage of particle motion.
Challenges in Multiscale Modelling and its Application to Granulation Systems
Authors: Ingram G. D. , Cameron I.T.
Published: August 2010

Since the mid 1990s there has been on increasing recognition of chemical engineering's multiscale nature. Multiscale modelling attempts to create flexible and efficient models by linking two or more partial models that describe phenomena at different characteristic length and time scales. In the first part of this paper, we briefly review multiscale modelling in chemical engineering. Three key tasks used in multiscale modelling are identified, and the current practices and unresolved issues in each are discussed. The second part of the paper examines the modelling of a wet granulation circuit from a multiscale perspective. A ‘scale map’ for drum granulation is proposed to assist in visualising the multiscale nature of the system. The three multiscale modelling tasks are considered in turn and some suggestions for modelling are proposed. Through this paper we are seeking to promote discussion on multiscale modelling and to receive feedback on its application to granulation.
Gas/Liquid Mass Transfer in Hot Sparged Systems
Authors: Zhu Y. , Wu J.
Published: August 2010

Understanding the effect of temperature on the volumetric mass transfer rate is of vital importance for the design of chemical reactors operated at elevated temperatures. The present study is motivated by a poor understanding of this effect due to previous limited investigations. Such an effect has been studied at the CSIRO Energy & Thermofluids Engineering Laboratory in a mechanically agitated air‐water mixing tank with operating temperatures in the range of 20‐80d̀C at atmospheric pressure. The oxygen concentration of the liquid is measured by a dissolved oxygen probe. The volumetric mass transfer rate is estimated using a dynamic method. It has been found that the saturated oxygen concentration of the liquid does not change significantly with the gas sparging rate and impeller speed. The change of temperature affects the saturated oxygen concentration significantly. The volumetric mass transfer rate increases with the increase of liquid temperature in the range of 18‐60d̀C. Beyond 60d̀C, the transfer rate decreases. Such a decrease is mainly due to the dramatic drop in the gas void fraction.
Iron Ore Characterisation during High Temperature Thermal Processing
Authors: McCann G. , Strezov V. , Lucas J. A. , Evans T. , Strezov L.
Published: August 2010

Ironmaking essentially involves different ways of combining iron ores and energy sources to produce metallic iron. The thermal properties of the iron ores determine the amount of energy required for processing. Investigating and understanding these thermal properties is thus extremely important with respect to controlling the ironmaking processes.

Using experimental and mathematical techniques, six iron ores from different origins were thermally characterised in this study. Chemical and structural changes in the iron ore during heating were investigated using SEM, EDS, and XRD analysis. Throughout the process, a number of transformations and reactions were apparent, and these have been quantified for each ore.

Goethite was found to decompose between 250‐350 d̀C. This endothermic reaction was found to be the most important stage with the energy requirement to heat iron ore samples dependent upon the amount of goethite in the iron ore. The endothermic kaolinite decomposition occurred at 600 d̀C while the exothermic partial reduction of hematite to magnetite occurred at 850 d̀C. Differences between the raw and sintered iron ores were investigated.
A Tutorial on Model Predictive Control: Using a Linear Velocity‐Form Model
Authors: Wang Liuping
Published: August 2010

Model Predictive Control (MPC) has a long history in the field of control engineering. It is one of the few areas that has received on‐going interest from researchers in both industry and universities. It has been recognised that there are three major branches of MPC algorithms consisting of step‐response model based design: Dynamic Matrix Control (DMC); transfer function model based design: Generdised Predictive Control (GPC); and a general state space model based design. The DMC and GPC algorithms can also be caste in the state space framework. Along the genera lines of state space methods, there are two mainstreunts: one solves for the optinzal control signal while the other solves for the increment of the optimal control signal. The latter can be implemented in a velocity form analogous to the implementation of a PID controller on an industrial plant. Motivated by this advantage. and that integral action is naturally embedded in the algorithm, this tutorial paper focuses on an introduction to Model Predictive Control based on the state space approach using a linear velocity‐form model.
Use of Sorption Isotherms for the Estimation of Shelf Life of Two Zimbabwean Flours
Authors: Ikhu‐Omoregbe D. I. O. , Chen X. D.
Published: August 2010

The water sorption characteristics of two Zimbabwean flours, i.e. maize‐meal and millet, were obtained using the gravimetric method at temperatures of 20, 30 and 4Od̀C. The GAB, BET and the modified BET models were found to describe the data reasonably well. The heat of sorption, which varied from 1.915 kJ.mol−1 at 20% moisture content to 30.5 kJ.mol−1 at 1% moisture content dry‐basis was calculated for the maize meal. Similar values for the millet were found to vary from 1.87 kJ.mol−1 at 20% moisture content to 18.3 kJ.mol−1 at 1% moisture content. The shelf lives for both materials were estimated from the sorption data, and recommendations on packaging and storage conditions are suggested.
Stochastic Model Reduction by Maximizing Independence
Authors: Zhang Hui , Sun You‐Xian
Published: August 2010

By analysing information descriptions in state space models of linear stochastic systems, this paper proposes two model reduction methods via principles of maximizing independence and conditional independence among the reduced state vector, respectively. These methods are based on state aggregation. The independence and conditional independence are measured by the Kullback‐Leibler information distance. It is demonstrated that the maximum conditional independence method is not only applicable to stable systems, but also applicable to unstable systems. Simulation results illustrate the efficiency of the present methods.
Dynamic Simulation and Advanced Control of a Heat Integrated Plant
Authors: Tellez R. , Svrcek W. Y. , Young B. R.
Published: August 2010

Heat integrated plants involving exothermic chemical reactions show a degree of positive feedback and instability when trying to control the outlet temperatures of process‐to‐process, feed‐effluent heat exchangers. This is the case for the hydrodealkylation (HDA) of toluene process. In this study a 2 × 2 Model Predictive Control (MPC) scheme was implemented for the first time on a dynamic simulation of the HDA Plant. Comparison of its performance against the classical Ziegler‐Nichols and IMC tuning techniques for PI control was also carried out. The performance tests implemented suggest that PI control and MPC implemented over PI control are good choices to control this heat‐integrated plant.
Accurate Location Method of Drilling Hole Activities on Oil Pipelines based on Wavelet Packet
Authors: Wang Qiang , Zhou Ze‐Kui , Zhang Guang‐Xin , Gu Xiao‐Hong
Published: August 2010

A method of detecting drilling hole activity and locating accurate sources in buried oil pipelines was developed, based on vibration signal propagation and wavelet packet transform (WPT). Experiments were performed to locate man‐made damaging sources. Complicated disturbances in the field cause large location errors with the direct cross correlation method. Therefore, WPT is used to decompose the signal into a series of time domain signals, each of which covers specific frequency band information. Packets containing large amounts of energy are focused on, and selected as, feature packets to reconstruct the signal, then cross‐correlation analysis is applied. Finally, by comparing the correlation coefficients of the reconstructed signal, the time point corresponding with maximum correlation coefficient is selected as delay time, which determines the location of the drilling site. Results show that the proposed method improves location precision in detection.
On‐line Fault Detection and Diagnosis in Industrial Processes Using Hidden Markov Model
Authors: Zhou Sha‐Yuan , Wang Shu‐Qing
Published: August 2010

For many on‐line fault diagnosis schemes based on process data, a moving time window is an indispensable technique to track dynamic data. In this paper, a novel approach combining variable moving window and hidden Markov model (HMM) for on‐line identification of abnormal operating conditions is proposed. The main feature of this method is that the window length can be changed with time. Before fault diagnosis, some process measurements are used for fault alarm. As a tool for feature extraction, principal component analysis (PCA) is employed in order to reduce the large number of correlated variables. The effectiveness of the approach is illustrated by case studies from the Tennessee Eastman process.
An Experimental Study on Flue Gas Desulphurisation by Fluidised Absorption
Authors: Zhong Z.P. , Lan J.X. , Jin B.S. , Chen S.B. , Gen H.
Published: August 2010

This paper presents a novel wet flue‐gas desulphurisation (FGD) process using fluidised absorption with lime/limestone. A series of experiments were conducted using a hot‐state test facility of a capacity of 2000 Nm3/h flue gas in order to evaluate this FGD technology. The results indicate that the desulphurisation efficiency increased with slurry concentration, immersed depth of the bubbling pipe under the slurry, and the velocity of agitation. A high desulphurisation efficiency (95%) can be achieved under conditions of pH 5 to 8. an immersed depth of bubbling pipe under the slurry of 160 to 200 mm, a jet rate of 10 to 25 m/s, a slurry concentration of less than 7%, a temperature of 55 to 60d̀C, and the application of agitation
The Oxidation Kinetics of Mercury in Hg/O/H/Cl System
Authors: Qiao Y. , Xu M.H.
Published: August 2010

The potential for regulation of mercury emission from coal‐fired boilers is a concern for the electric utility industry. Field data show a wide variation in the fraction of mercury that is emitted as a vapor versus that retained in the solid products. The reason for this variation is not well understood. Near the end of the flue gas path, mercury exists as a combination of elemental vapor and HgCl2 vapor. The data show that HCl2 is more likely to be removed form the flue gas. The need to describe accurately mercury reaction products and their concentration‐time correlation prompted investigation of mercury chemical kinetic mechanisms and their application to real combustion systems. This paper uses chemical equilibrium analysis to study the speciation of mercury in flue gases during coal combustion and gasification. The paper presents a simple kinetic model of mercury oxidation in the Hg/O/H/Cl system. The results porn the model calculation are in reasonable agreement with the Mamani‐Paco and Heleble [1] experimental data
Sensitivity to Hydrogen Peroxide of Growth and Hyaluronic Acid Production by Streptococcus zooepidemicus ATCC 39920
Authors: Mashitah M.D. , Masitah H. , Ramachandran K.B.
Published: August 2010

The sensitivity to hydrogen peroxide (H2O2) of growth and hyaluronic acid (HA) production by Streptococcus zooepidemicus ATCC 39920 was studied under various conditions. In sheep blood agar‐plates, no detectable zone was observed even when the concentration of H2O2 was increased to 0.15 mM. With brain heart infusion‐agar and chemically defined medium‐agar plates, a profound zone was detected at 0.015 mM concentration of H2O2. To determine the minimal inhibitory concentration (MIC) of the strain in culture broth, various concentrations of H2O2 (0‐200 mM) were maintained in the medium prior to fermentation. The result showed that for higher concentrations of H2O2 in the medium, the greater was the inhibition. Streptococcus is catalase‐negative and known to produce H2O2 which may affect growth, HA production and glucose utilization. In order to determine at which growth phase H2O2 had the maximum inhibitory activity, a batch fermentation of S. zooepidemicus was conducted in shake flask culture. It was found that H2O2 production took place during the growth phase, and HA production started after the growth had reach late exponential phase when H2O2 in the culture media was depleted. This indicates that H2O2 produced by the cells did not affect cell growth but influenced HA production.
Initial Screening of Fermentation Variables for the Production of Cyclomaltodextrin Glucanotransferase (CGTase) from Local Isolated Bacillus stearothermophillus HR1
Authors: Wong T.E. , Illias R.M. , Rahman R.A. , Ismail A.F. , Salleh M. M. , Hassan O. , Kamaruddin K.
Published: August 2010

This paper presents results on the effect of fermentation variables on CGTase production from Bacillus stearothermophilus HR1. Initial screening of temperature, pH and agitation speed was determined using a 2‐level full factorial design. In this study, we have improved the production of cyclodextrin glucanotransferase (CGTase) from Bacillus stearothermophilus HR1 in flasks using the experimental design approach. The regression model generated for the correlation of CGTase with the variables was 99.97% accurate. Results of the screening process indicated that pH and agitation speed were of greater significance compared to temperature. Results suggested that only two variables, namely pH and agitation speed, should be considered in future optimization studies. Temperature was least significant and it was set at 55d̀C where CGTase production of 10.41 U/ml was slightly higher compared to temperatures of 37d̀C, 45d̀C, 50d̀C and 60d̀C.
Photobiological Hydrogen Production from Synthesis Gas: Carbon Sources, KL a and Kinetics Evaluation
Authors: Najafpour G. , Younesi H. , Ismail K.S.K. , Mohamed A.R. , Kamaruddin A.H.
Published: August 2010

Photo‐evolution of hydrogen from synthesis gas using Rhodospirillum rubrum was studied in batch fermentation. Culture of R. rubrum was initially grown on malate, also with various initial concentrations of acetate and synthesis gas. The synthesis gas was a mixture of H2, CO and CO2. It was found that the doubling time of bacterium on 2.5 g/l of malate, and 2.5 g/l and 6 g/l of acetate were 8.4, 31.8, and 68.6 h, respectively. The growth of R. rubrum was not significant at high concentration of acetate. The cell density of microbe was 0.3 g/l on 2.5 g/l malate for incubation period of 5 days. The cell concentrations of 1.4 and 0.41 g/l were obtained in 2.5 and 6 g/l of acetate, respectively for duration of 5 days. Inhibition of substrate was clearly observed on cell yield and hydrogen production with high concentration of acetate. Maximum hydrogen production (1.8 mmol/l) was obtained when R. rubrum was grown on 2.5 g/l of acetate. Effect of agitation rate was carried out and it was found that more hydrogen production (1.8 mmol) was achieved at 250 rpm. Mass transfer and kinetic studies were performed on 2.5 g/l of acetate. Maximum specific growth rate (m̈m) and Monod constant (KH) were obtained at 9.8 h−1 and 0.14 atm, respectively. No substrate inhibition occurred at CO concentration of 0.56 atm.
Operational Stability of Lipase Enzyme: Effect of Temperature and Shear
Authors: Shamel M.M. , Hasan M. , Ramachandran K.B.
Published: August 2010

The operational stability of the lipase enzyme from Candida rugosa (formerly known as Candida cylindracea) has been investigated. The activity was found to be dependent on shear rate, temperature and emulsifier concentration. The enzyme remained active (the activity was about 80% of the original) up to a shear rate of 122 s−1 for 2 hours at 40d̀C. Concentrated enzyme was more resistant to shear rate than the diluted enzyme. It was also found that the presence of emulsifier increased the enzyme inactivation. The enzyme lost almost all its activity in 45 minutes at an emulsifier concentration of 0.5%.
Direct Treatment of an Acidic and High‐Strength Nitrate‐Polluted Wastewater Containing Heavy Metals by Using a Bio‐electrochemical Reactor
Authors: Watanabe Tomohide , Jin Hong‐Wei , Cho Kyung‐Jin , Kuroda Masao
Published: August 2010

The fundamental performance of a bio‐electrochemical reactor for treatment of metal pickling wastewater was investigated experimentally. A carbon anode and cathode were installed in the reactor. On the cathode, denitrifying microorganisms were immobilized. Continuous experiments were carried out by feeding a synthetic wastewater containing nitrate and binary heavy metal ions (copper and lead) at different loads and current densities. Acetate was added at 1.0 of C/N mass ratio which was less than the stoichiometric amount for the overall denitrification reaction. Experimental results indicated that the dissolved copper and lead removal, denitrification, and neutralization, could be achieved simultaneously in a single bio‐electrochemical reactor. Dissolved heavy metals were removed by electrochemical deposition on the cathode and by other phenomena such as the formation of insoluble suspensions and sorption on suspended bacterial sludge. Denitrification proceeded effectively with the utilization of both the added acetate and the hydrogen gas generated by electrolysis of water. The pH value increased close to neutral value due to the occurrence of denitrification, although the influent pH was less than 3. The removal efficiencies of heavy metals and nitrate increased with an increase in the current density. The denitrification rate decreased with increasing lead loading. The electric current was indispensable for sustaining stable treatment in the reactor.
Investigation of the Effect of Different Comminution Methods on the Quality of Chilli Powder
Authors: Zhou W. , Goh J.
Published: August 2010

The quality degradation of chilli during comminution was investigated through modelling. Two different comminution methods were studied, namely grinding and high‐speed cutting. The colour of the chilli powders, the concentration of two major capsaicinoid compounds, and moisture loss in the powders were taken as the quality indicators. The kinetics of quality degradation was modelled. It was found that although the quality indicators of chilli powder produced by grinding were generally inferior to those by high‐speed cutting, the rate of quality degradation by the former was much lower than that by the later. The mechanism behind this finding is also discussed in this paper.
Two‐ and Three‐Phase Flow Through a 90 Degree Bend
Authors: Spedding P.L. , Benard E. , Mcnally G.M.
Published: August 2010

Data are presented for two‐phase air/water pipeflow and three‐phase air/oil/water in a 0.026 m i.d. pipe and elbow bend (R/d = 0.654) for vertical to horizontal flow. The two‐phase results were shown to be dependant on the flow regimes present in the system. The elbow bend acted either to smooth the transition from vertical to horizontal flow when the liquid rate was below the bubble rise velocity in the inlet leg (when negative bend pressure losses were achieved), or to generate droplets and increase the bend pressure drop substantially at higher fluid rates.

Three‐phase data also showed significant but not such dramatic differences, depending on the combined liquid rate being above or below the bubble rise velocity in the inlet leg. Again the variation of pressure drop for the system could be qualitatively explained by the observed flow regimes.

For both two‐phase and three‐phase systems, the observed bend pressure drop could be correlated using a Lockhart‐Martinelli approach based on the single‐phase flow data for the bend.
Small‐scale Steam Reformation of Ethanol over Supported Metal Catalysts at Low Temperature and Pressure
Authors: Cussins M. J. , Williamson C. J. , Earl W. B. , Gardiner A. I.
Published: August 2010

Ethanol was steam reformed over various supported metal catalysts at 300°C and pressures up to 3 bar gauge. The catalysts trialled included a commercial methanol synthesis catalyst (Cu/ZnO/Al,OJ, and also catalysts with nickel and/or copper impregnated on γ‐alumina extrudates. The effect of the ethanol concentration in the feed was assessed in terms of ethanol conversion and hydrogen yield for each catalyst. It was found that a copper/nickel/yalumina catalyst achieved the highest ethanol conversion (∼100%) and hydrogen yield (1.3 moles hydrogen per mole ethanol reacted) at 300°C and atmospheric pressure with excess water in the feed solution. While both the methanol synthesis catalyst and the Nickel/γAlumina B catalyst achieved high selectivity for hydrogen, their relative performances were hindered by thermal instability and coking respectively. Tests at 300°C and up to 3 bar gauge indicated that increasing the pressure decreased the hydrogen yield.
Energy Efficiency of an Integrated Process Based on Gasification for Hydrogen Production from Biomass
Authors: Weber G. , Fu Q. , Wu H.
Published: August 2010

Hydrogen production from CO2—neutral biomass is expected to play an important role in renewable hydrogen supply. This study investigates the overall energy eflciency of hydrogen production from biomass via an integrated process based biomass gasipcation. Key parameters and experimental data of the process were obtained from the literature, considering six cases of air‐blown biomass gaslfiers due to the availability of experimental data in the literature. The results show that such an integrated system can generally have an overall energy efficiency of 40‐6096, depending on biomass properties and process configurations. Significant efficiency improvement can be achieved i f the gasifier operates at a similar pressure to the reformer, which typically operates at elevated pressures. Analysis further suggests that the gasijkation with steam and other oxidiser (e.g. air) is the most energy efficient way for hydrogen production and such a strategy also delivers a high amount of hydrogen. Other strategies for efficiency improvements include increasing reaction conversion in the reformer, enhancing CO conversion in the shift reactor and improving process heat recovery. Limitations of this work and future necessary improvements are also discussed in this paper.
Silica Nafion Modified Composite Membranes for Direct Methanol Fuel Cells
Authors: Rodriguez J. I. Garnica , Dicks A. L. , Duke M. C. , Diniz Da Costa J. C.
Published: August 2010

Direct Methanol Fuel Cells (DMFCs) operate by electro‐oxidation of methanol and the transport of the protons by means of a polymer electrolyte membrane. Current systems employ Nafion (perjluorosulphonic acid) membranes as the transport media for the protons, which experience a high methanol crossover reducing the efficiency by the oxygen reduction reaction at the anode side of the fuel cell. This work investigated the microstructural modification of Nafion membranes with silica nanoparticles. It was shown that this mod4cation led to reduced methanol crossover, whilst methanol permeability was slightly reduced without compromising the conductivity at the normal DMFC operation temperature (75‐80°C). Methanol uptake was reduced by 55% with the incorporation of the silica nanoparticles into the Nafion matrix. In addition, pure methanol uptake appeared to be less effective than methanol mixtures. These results indicated the presence of water assisted methanol permeation as the hydrophilic sulphonic group and the hydrophobic polymeric backbone of Nafion were sensitive to methanol solvation.
Flow Mode Characterization in a One Metre Diameter Rotating Drum
Authors: Davies C. E. , Jones J. R. , Hussein K. , Fi?vez S. , Tallon S. J.
Published: August 2010

A newly developed instrument for characterising flow behaviour in a rotating drum senses particle motion with a load cell positioned under a pivoted framework that holds a 130 mm drum. Changes from the slumping regime to the rolling regime have been correlated with decreasing variance of the load signal for an increasing rotation rate. This paper extends earlier work to investigate the validity of applying results obtained in a small drum to large‐scale equipment. Load cell signals from equipment with a drum of I metre diameter, constructed with the same design basis as the 130 mm characterisation instrument, were digitally filtered to remove noise believed to be associated with vibration of the framework, and also frequencies demonstrated to arise from the drive train. As with the 130 mm equipment, decreasing avalanching activity was found to be associated with decreasing variance. Bed profiles obtained from digital video images were consistent with the observedflow regimes.
Mixing in a Fluid Jet Agitated Tank: Geometric Effects
Authors: Zughbi H. D. , Siddiqui S. W. , Fatehi A. I.
Published: August 2010

Experimental and numerical investigations of mixing in fluid jet agitated tanks were carried out. Experiments were performed in a 23 litre tank. Numerical models to describe mixing in such a tank were developed using computational fluid dynamics (CFD). and the results validated against experimental data. The effects of alternative shapes of the tank bottom were investigated. An improvement in mixing time was observed when a hemispherical base was used instead of a flat base. The mixing time reduced by about 25% for a jet Reynolds number of 9000, and by about 15%for a jet Reynolds number of 40,000. Further reduction in mixing time was also observed when a conical base was used instead of a flat base. The 99% mixing time (t99) was also calculated and compared with the predicted 9.5% mixing time (t95), and with other predictions using published correlations.
Material Transformation and Recycling of Automotive Shredder Residues: An Industrial Case Study
Authors: Gomes V. G.
Published: August 2010

Environmental pressures have pushed automotive shredder residues (ASR) into the hazardous waste category, and hence special disposal measures need to be investigated urgently for its sustainability. The possible impacts of ASR on the environment were assessed by using the Toxicity Characteristic Leaching Procedure (TCLP. US EPA 1311) and the Specific Contaminant Concentration (SCC, US‐EPA 3050). these were performed with the aid of an ICP‐AES (Inductively Coupled Plasma with Atomic Emission Spectroscopy) instrument. A suite of options were analyzed for wuste ryres and the ASR generated by companies in the Greater Sydney region. Four classes of recycling options were considered, namely primary, secondary, tertiary, and quaternary recycling, in order to determine the extent to which they can help improve the overall optimisation of materials and energyflows for the ASR.
Use of Municipal Solid Waste for Integrated Cement Production
Authors: Cheung W. H. , Choy K. K. H. , Hui D. C. W. , Porter J. F. , Mckay G.
Published: August 2010

A Waste Reduction Framework Plan was initiated by the Hong Kong Environmental Protection Department in 1998 to set out a 10‐year programme and a set of targets for waste reduction. By combining cement production and power generation, waste incineration has improved its competitiveness. The co‐combustion of Municipal Solid Waste (MSW) is a novel and highly integrated design combining cement and electricity productions (Co‐Co process). By carefully integrating these three processes, energy generated from MSW co‐combustion can be used eficiently for cement production and electricity generation. In this process, MSW is incinerated in a rotary kiln with additional fuel followed by the secondary combustion unit (SCU) and extra fuel is burnt in the SCU to raise the combustion temperature to 1200°C. Flue gas exiting porn the SCU will then enter a calcinations scrubber for acid gas removal. The flue gas then enters into a waste heat boiler for steam generation. A pilot plant is being designed and will be constructed to test this design.
Degradation of Low‐Density Polyethylene over Modified Zeolites
Authors: Tu P. , Pratt K. , Kosior E. , Malherbe F.
Published: August 2010

The potential of catalytic processing as an effective method for polymer recycling was studied using various modfled zeolites catalysts in the degradation of low‐density polyethylene (LDPE). Particular attention was paid to catalytic activity, and selectivity and yield of liquid products. Two types of catalysts were evaluated: acid catalysts (HX and HY), and, pure NaX and its base‐modified derivatives (NaX impregnated with MgO, CaO, SrO and BaO). As a benchmark, thermal degradations were performed at 623 K, 673 K, 698 K, and 723 K, to identify optimum operating conditions for the catalytic reactions. Thermal degradation at 623 K showed no conversion during the first 7 hours run, while at other temperatures conversion was 100% and liquid yields at 673 K, 698 K, and 723 K were 21, 77 and 80wt% respectively. Catalytic cracking tests were performed at 673 K to improve liquid yield, and showed significant increases in the following catalyst order: HX (SOwtN) > HY (40wt%) > modified NaX (33wt%) NaX (30wt%) > thermal (21wt%).
Application of a Liquid Membrane to Recover Cadmium
Authors: Bansal B. , Mahajan R. , Hossain Md M. , Liaw M. S.
Published: August 2010

Recoveiy of toxic metals from industrial wastewaters is an important environmental issue. The use of liquid membrane technology has gained momentum in recent years as it allows the reuse of water and toxic metals. In this study, a bulk liquid membrane consisting of D2EHPA (ionic extractant) in n‐hexane (solvent) was used to extract cadmium from an aqueous solution simulating industrial wastewater, and ammonium acetate solution was used to strip cadmium from the membrane phase. Initially, equilibrium and kinetics experiments were performed to identrfL favourable operating conditions as well as extraction and stripping rates. Then bulk liquid membrane experiments, with simultaneous extraction and stripping, were performed. More than 90% of the cadmium was recovered using the bulk liquid membrane in 120 minutes.