bluuebunny/crossref_metadata_2025 huggingface dataset:
Landfill Gas Utilisation Trends in Australia
Authors: Xu X. , Rudolph V. , Greenfield P. F.
Published: August 2010

This paper presents the prospects for landfill gas (LFG) utilisation in the largest three cities in Australia, Sydney, Melbourne and Brisbane, based on their current Municipal Solid Waste (MSW) handling processes. The trends in landfill technology and legislation affecting the performance of gas capture and use are discussed. The traditional evaluation methodology to assess the economic feasibility for individual LFG exploitation projects is also discussed and criticised. Suggestions for desirable amendments which incorporate public judgements on the values of environmental conservation are included. Based on this analysis, utilisation is shown to be far more attractive than currently perceived.
Flotation of a Copper‐Zinc Ore Usingp‐Nonylcupferron as Collector
Authors: Natarajan R. , Nirdosh I. , Muthuswami S. V.
Published: August 2010

Bench‐scale flotation tests were done with a chalcopyrite, sphalerite and pyrite‐containing ore from Timmins, Canada using p‐nonylcupferron as collector. Effects of pH and the need for adding copper sulphate for zinc activation and lime as pyrite‐depressant were studied. The collector floated nearly 94% copper and 94% zinc without pyritic iron in 30% mass at pH 4 and 5, and 93% Cu and 78% Zn at pH 6 in 30% mass. At higher pH values, metal recoveries were poor. No copper sulphate was needed for activating zinc flotation. Addition of lime did not affect pyrite suppression.
Aqueous Phase Oxidative Degradation of 4–Hydroxy Nitrobenzene over a CuO‐TiO2 Catalyst
Authors: Suen C. L. , Adesina A. A.
Published: August 2010

The aqueous phase oxidation of 4‐hydroxy nitrobenzene (or p‐nitrophenol) has been carried out in a semibatch slurry reactor operating at the relatively mild conditions of 373‐393 K and 80‐150 kPa oxygen pressure. The catalyst employed has a composition 5CuO:5TiO2:100SiO2 and was maintained at 11.4 g/L in the reactor. Kinetic data were collected under conditions of negligible internal transport resistance. The degradation rate has an order of about 1.43 with respect to the 4‐hydroxy nitrobenzene but weakly dependent on the oxygen partial pressure (approx. 0.12). Analysis of the concentration‐time data revealed that the autocatalytic effect frequently seen during phenol oxidation was non‐existent in the reaction pathway. A Langmuir‐Hinshelwood single‐site mechanism involving the oxygen‐assisted cleavage of the benzene ring as the rate‐controlling step offered a kinetic model that accurately described the rate data. Estimates of the adsorption equilibrium constants for both p‐nitrophenol and oxygen were also thermodynamically consistent and activation energy was valued at 42 kJ/mol. Excellent activity of the catalyst was attributed to chemical synergy arising from the interaction between surface CuO and TiO2 crystallites to give a new sphene‐type phase containing the highly intrinsically active centres for the catalytic process.
Catalytic Conversion of LPG to High‐Value Aromatics: The Current State of the Art and Future Predictions
Authors: Al‐Zahrani S. M.
Published: August 2010

This paper is an attempt to summarize the current position of catalytic conversion of LPG to aromatics. The low reactivity of LPG has long impeded its utilization as a petrochemical feedstock. Except for its use in the cracking of ethylene, LPG fractions have mainly been consumed as fuel. Recently new catalytic processes now being commercialized have opened up new routes for the utilization of LPG as a source of valuable petrochemical intermediates. Five main processes are now available for converting LPG to aromatics, these processes are: M‐2 Forming, Cyclar, Aroforming, Z‐Forming, and the Alpha process. The aromatization reaction mechanisms are generally accepted to be through dehydrogenation of paraffins to olefins (which is the rate limiting step), then oligomerization to form dimers and trimers intermediates, followed by cyclization and dehydrogenation to aromatics. The most selective catalytic systems employed in the aromatization of LPG are mainly zeolite‐containing promoted catalysts.
The Utilization of Fluidized Bed Reactors for Oxidative Coupling of Methane
Authors: Al‐Zahrani S. M. , Abasaeed A. E.
Published: August 2010

A simple mathematical model for the oxidative coupling of methane in a fluidized bed reactor has been developed in order to investigate the possibility of exploiting the advantages of this reactor configuration for the important exothermic reaction, and also to provide an insight into potential scale‐up behaviour. The model is based on the two‐phase theory of fluidization, and the reaction kinetics are based on triangular kinetics obtained from the literature. Without adjusting any of the hydrodynamic or kinetic parameters, the model predicted fairly well the experimental results obtained from the literature under various reaction conditions, and it was then used to investigate the effect of scale‐up on the conversion and selectivity obtained in the methane oxidative coupling process. High C2 selectivities at reasonably high methane conversions are shown to be possible with large scale fluidized bed reactors.
The Effect of Other Cations in Wastewaters on the Ion‐Exchange Removal of Ammonium Ion
Authors: McVeigh R. J. , Weatherley L. R.
Published: August 2010

Traditionally in the water treatment industry biological filtration and activated sludge are the processes used to control ammonia levels. These processes have a slow response time to conditions such as shock loadings and temperature changes. Ion‐exchange can offer a tertiary clean up stage if the previous processes are unable to meet the ammonia consent levels. Secondary treatment wastewaters contain considerable concentrations of calcium, magnesium, potassium and sodium as well as ammonia in the cation form. Previous work has shown that clinoptilolite, a naturally occurring alumino silicate, has a high selectivity for NH4+ relative to other ions present in wastewaters making it an effective zeolite for the process of ion‐exchange.

Investigations into the effect various cations may have on the ion‐exchange removal of ammonium have been carried out. Results are presented of isotherm studies and packed bed breakthrough work for NH4+ uptake onto the zeolite. Findings show that K+ ions tend to have the greatest inhibitory effect on the physio‐chemical process and that ammonium removal capacities can be reduced by over 20%.
The Effect of Stunning Method on the pH of Lamb
Authors: Mcgeehin B. , Butler F. , Sheridan J. J.
Published: August 2010

The postmortem pH decline of lamb M. longissimus thoracis was measured to investigate how it is affected by two methods of animal stunning at slaughter. Electrical stunning was compared to captive bolt stunning but there was no difference between the pH of these groups at any of the times postmortem. Both of the stunning techniques produced a wide range of pH values, even as early as 0.5 h postmortem, indicating that other factors are the cause of pH variability in lamb M. longissimus thoracis.
Experimental Analysis of Rotating Instabilities in Swirling and Cyclonic Flows
Authors: O'Doherty T. , Griffiths A. J. , Syred N. , Bowen P. J. , Fick W.
Published: August 2010

This paper reviews the work carried out since 1990 in establishing the characteristics and properties of rotating instabilities found in swirling flows, such as those of cyclone dust separators and swirl burners. Considerable efforts have been made over the years in establishing the cause and use of these instabilities in swirling flows. The general conclusion indicates that there is potential benefit in its existence in combustion systems, but is detrimental within dust separation/classification systems. The analysis of these flows have included laser diagnostics (Laser Doppler anemometry, particle image velocimetry and flow visualisation), temperature mapping and numerical analysis. Many of the experimental measurements use a phase locking system based on cyclic pressures. The following paper reviews and updates the numerical modelling of the instability found in rotating flows.
Effect of Ash Components on the Ignition and Burnout of High Ash Coals
Authors: Feng B. , Yan R. , Zheng C. G.
Published: August 2010

The effect of the ash components on the ignition and burnout of four Chinese high ash coals were studied by thermogravimetric analysis. To investigate the influence of the ash components, comparative experiments were carried out with original, deashed and impregnated coals. Eleven types of ash components, such as SiO2, CaCO3, MgO, Na2CO3, K2CO3, Al2O3, TiO2, Fe2O3, FeS2, NH4Fe(SO4)2. 12H2O and FeSO4(NH4). 6H2O were used in the present study. It was found that most of the ash components have negative effects. The strong influence of some ash components suggests that the combustion characteristics of high ash coal may be determined by the ash composition.
Synthesis Gas Production Using Carbon Dioxide as a Source of Carbon—Current Research and Perspectives
Authors: Max Lu G.Q. , Wang S.
Published: August 2010

CO2 is a major greenhouse gas, but it is also an important source of carbon. Catalytic reforming of methane with CO2 to synthesis gas is a promising technology in utilisation of CO2. This process has attracted increasing attention among the research communities in the world, and much progress has been made. This paper presents an overview on the recent advances in catalyst development, reaction mechanism and kinetics. It is found that catalytic activity and stability strongly depend on the nature of support, metal‐support interaction, metal precursor and addition of promoters. Further fundamental research on the reaction and coking mechanisms and kinetics will lead to a high performance catalyst system that will deliver high conversion at low temneratures and with lone‐term cokine‐free oDeration.
Emission Control During Co‐Combustion of Coal and Biomass in a Fluidized Bed Combustor
Authors: Wang Jinghong , Liu Hao , Lu Jidong , Liu Dechang , Xia Xiaotao , Ma Liqiang
Published: August 2010

Co‐combustion of coal and biomass in a bench‐scale bubbling fluidized bed was carried out to investigate the effects of co‐combustion on emissions of NOx, N2O and SOx. The objective of these experiments was to find a feasible method of simultaneous NOx/N2O/SOx control. Several coals and coal chars were used and mixed with wood chip and rice husk respectively. The influences of temperature, coal property and fraction of biomass on emissions were investigated.

The experimental results revealed that co‐combustion of coal and wood chip or rice husk could reduce NOx/N2O/SOx emissions simultaneously compared to combustion of coal alone. The effect of emission reduction depended on the coal property. The higher the fuel‐N and the lower the volatile matter (VM) content of the coal, the greater the emission reduction. Moreover, the higher the fraction of biomass (wood chip or rice husk), the lower the NOx/N2O/SOx emissions. In addition, it was found that when co‐combusting coal char and wood chip or rice husk, NOx and N2O as well as SOx could be reduced compared to combustion of coal char alone. From the experiments, it was found that heterogeneous reactions played an important role in N2O reduction during co‐combustion of coal and biomass.

Hence the process has been proved to be a feasible, economical and promising technique for simultaneous NOx/N2O/SOx control.
Numerical Simulation of NOx Emission from Char Combustion with Detailed Gas Phase Mechanisms
Authors: Feng B. , Zhou Y.B. , Shi X.F. , Zheng C.G. , Okazaki K.
Published: August 2010

The present paper proposed a mathematical model for the simulation of NOx emission from char combustion. The one‐dimensional two‐phase model developed by Kuo [9] was simplified, and a detailed gas‐phase reaction scheme was included, based on the work of Miller and Bowman [19] with updated reaction rates of some important reactions. The scheme includes 289 reactions and 51 species. Two global models for char oxidation were used and compared. The heterogeneous formation of NOx from char oxidation, the reaction of NOx destruction on the char surface, and the reaction of NO destruction by CO catalysed by char were taken into account during char combustion. Our work showed that NOx destruction is sensitive to the char oxidation rate. The heterogeneous reactions for both char oxidation and for NOx formation and destruction require further investigation.
Designing a Process Hazards Analysis Programme in the Microelectronics Industry
Authors: Mckay Gordon
Published: August 2010

A Process Hazard Analysis (PHA) component has been developed and implemented as part of a Process Safety Management Programme (PSMP) for a microelectronics company producing wafers in a plant employing over 2,500 people and having a capital investment of US$16.5 billion. Initially a review of the existing PSMP system was carried out, and key sectors of concern were identified. The main area identified for detailed study was the area of Process Hazards Analysis (PHA) to cover a number of interacting departments responsible for designing and implementing new projects and process changes.

To create awareness and develop PHA expertise in the company, a training programme was designed and presented to each of the Process, Safety and Environmental, Projects Maintenance and Operations Departments. Basically these five departments were involved in handling well over 100 new projects per year ranging in value from US$50,000 to US$1,000,000 each.

The company has implemented a detailed PHA procedure to ensure full and appropriate safety measures are assessed in an economic manner prior to project implementation, as an integral part of the company PSMP. The essential element of the programme is that a HAZOP Study is required for all projects involving chemicals. For small projects, a specialist “Small Project HAZOP Group” was established and specialist training provided.
Improving Management Control of Process Hazards through Structured Monitoring and Auditing Protocols
Authors: Cao J. , Tweeddale H. M. , Walsh P. K.
Published: August 2010

This paper describes an integrated, computer‐based approach to improved management control of process hazards, through generation of structured protocols for monitoring and auditing of process safety. These protocols are developed to match the plant‐specific hazards which are identified by three diverse methodologies operating in parallel with their results collated and sorted. They draw on databases that contain (a) checklists of generic hardware and software topics to be routinely monitored, and (b) checklists of generic topics to be periodically audited. A calculated frequency of monitoring is displayed, together with a suggested frequency from the database, as an aid to experienced judgement. The content of the protocol for any particular audit is determined both by the plant‐specific hazards and the consequent monitoring protocol, together with a Monte Carlo process of selection from a longer list of possible audit topics. The probability of inclusion of any particular audit topic being preset between zero and unity. A case study is described.
A Model of Heat Transfer Across an Epoxy Based Fire Retardant Layer Undergoing Sublimation, Intumescence and Degradation
Authors: Bhargava A. , Griffin G. J. , Green J. C. A.
Published: August 2010

A model has been developed to predict the rate of heat flux through fire retardant coatings subjected to a surface flame at 1080°C. The model includes the effect of the material subliming, intumescing and degrading, and of temperature effects on the material properties. Temperature profiles were compared with experimental data obtained on commercial fire retardants using a small‐scale fire testing apparatus developed for the study of passive fire protection materials. Temperature predictions of the model agreed within 10% of experimental results except when erosion and cracking of the retardant was observed.
Effect of Ullage on Properties of Small‐Scale Pool Fires
Authors: Dlugogorski B. Z. , Wilson M.
Published: August 2010

An experimental technique is described for accurately measuring the steady‐state fuel consumption rates in small‐scale pool fires, less than 7 cm diameter. The technique is applied to studying ethanol fires burning in cylindrical vessels constructed from various materials. The results indicate that the distance between the top of a vessel and the fuel surface profoundly influences the properties of liquid pool fires, including their structure and their burning rates. For combustion in glass cylinders, the burning rates decrease exponentially with increasing freeboard until a critical ullage is attained. At this ullage, the fuel begins to burn on the inside of the vessel, and the burning rate tends to increase slightly. With a further increase of the lip height, flame instabilities develop leading ultimately to flame self‐extinction. The exponential decline in fuel consumption with the lip height depends strongly on the vessel material of construction. For fires in cylinders constructed from better conducting materials (copper and mild steel), the ethanol starts to boil beyond a certain ullage. The appearance of this phenomenon redefines the fuel consumption curve. Finally, free convection leads to non‐negligible heat losses, especially from the more conducting copper and steel vessels, with the burning rates becoming dependent on the outside surface area of the cylinders.
Fundamental Investigation of Microwave Pretreatment on the Flotation of Massive Ilmenite Ores
Authors: Fan X. , Rowson N. A.
Published: August 2010

Microwave energy was used as a novel method to modify massive ilmenite surface properties and improve ilmenite flotation. Studies concentrated on an investigation into the effect of microwave radiation pre‐treatment on the flotation behaviour of a massive ilmenite ore sample from Norway. Experimental programmes were carried out in both Hallimond‐tube and Denver‐cell flotation devices.

The experimental results indicate that the flotability of massive ilmenite was greatly improved after microwave‐induced thermal pretreatment. In comparison with conventional flotation, at the same optimised flotation conditions, massive ilmenite subjected to microwave heat treatments floated well in both the roughing and cleaning stages. Ilmenite recoveries were greatly increased over non‐treated samples. The major factors affecting ilmenite microwave‐pretreatment flotation are microwave power level and irradiation time.

The investigation into the surface zeta potential indicates that microwave irradiation enhanced the adsorption of oleate ions in the Helmholtz layer of the ilmenite particles and resulted in ilmenite surface charge being more negative. Improved ilmenite flotation recovery was observed after microwave pretreatment.
Experimental and Mechanism Studies on a Different‐Velocity Circulating Fluidized Bed for Flue Gas Desulfurization
Authors: Wu Y. H. , Feng B. , Huang Z. , Li D. J.
Published: August 2010

Experimental studies of flue gas desulfurization were carried out in a different‐velocity circulating fluidized bed reactor, using dry slaked lime as the sorbent. S02 removal efficiency could be as greater than 80% when the Ca/S molar ratio was 1.1, and when a small amount of water was added into the process. By considering the main aspects that influence desulfurization efficiency in the experiment, it was found that the water sprayed into the reactor plays an important role. In addition, a preliminary investigation was performed on the desulfurization mechanism. The desulfurization reaction occurs quickly in the water film on the surface of the sorbent.
Direct Numerical Simulation of Dense Gas‐Solid Two‐Phase Flows
Authors: Zhulin Y.
Published: August 2010

Based on Newton's law and the classical physical laws, Eulerian and Lagrangian methods are respectively used to deal with gas‐field and discrete particles. The three‐dimensional viscid air‐field and three‐dimensional discrete particle field are solved in each time step Δt. Collision and friction between individual particles are taken into account when establishing the mathematical models, including individual particle diameter, density, stiffness and friction coefficient. Particles mixing in ball mills, particles dropping from hoppers, and particles fluidizing in fluidized beds are used as examples of the simulations. Selected simulated results are compared to experimental results.
Low Temperature Pyrolysis of an Australian Brown Coal in a Fluidised Bed Reactor
Authors: Shen L. , Zhang D. K. , Yan H. M. , Roach J. R. , Nguyen Q. D.
Published: August 2010

The pyrolysis of Loy Yang coal was investigated under rapid heating conditions in a fluidised bed with a feed rate of 10g/h. Nitrogen was used as the fluidising gas operating at fives times the minimum fluidising velocity. The yields of tar, total volatile matter and C1‐C3 hydrocarbons are obtained for pyrolysis temperatures between 300 to 600°C. A maximum tar yield of 24.3% w/w (dry ash‐free coal) was achieved at 550°C and 1.82 s gas residence time. Fourteen fractions were identified in the tar dissolved in methanol. Yields of C1‐C3 hydrocarbons increased with increasing temperature to 3% w/w at 600°C. Elemental analysis showed that the composition of char and the tar yields were strongly dependent on temperature. The effects of gas residence time and feed particle size were also investigated.
Photodegradation of the Volatile Organic Compounds in the Gas Phase: A Review
Authors: Ray Madhumita Bhowmick
Published: August 2010

A review of photodegradation processes suitable for the treatment of Volatile Organic Compounds (VOCs) present in the effluents from air‐stripping and soil‐vapor extraction is presented. This paper outlines and summarizes the essential factors such as kinetics and mechanism, intermediates of degradation processes, and reactor modeling which lead to the successful application of this useful technology. In addition, the effects of operating parameters such as humidity, temperature, additives and types of VOCs are discussed. The review also identifies the areas where further work is needed.
Heterogeneous Photocatalysis in Environmental Remediation
Authors: Chen Dingwang , Sivakumar M. , Ray Ajay K.
Published: August 2010

Semiconductor‐based photocatalytic processes have been studied for nearly 15 years due to their many intriguing advantages in environmental remediation and other areas. In this paper, underlying principles and mechanism of the photocatalytic degradation process were discussed, followed by thermodynamics, kinetics, mass transfer effects were discussed. The kinetics of photocatalytic degradation was analysed with the aim of determining the favourable conditions to obtain high quantum yield. Primary parameters that influence the process such as catalyst loading, dissolved oxygen, pH, temperature, light intensity, crystalline structure, etc. have been discussed in detail. Different types of photocatalytic reactors, process efficiencies and applications in environmental engineering as well as in other areas have also been mentioned. The main barrier to the commercialization of the processes is the low quantum yield. However, it is expected that large‐scale applications could be achieved with significant progress by improvement of process performance.
The Effect of Additives and Impurities on the Partition of Ethanol into n‐Decanol from Aqueous Solutions
Authors: Carolan N. , Weatherley L.R.
Published: August 2010

The recovery of biological products from fermentation media by direct liquid‐liquid extraction is complicated by the presence of impurities. These may comprise either side products of the bio‐transformation or residual species from the pre‐fermentation substrates. As a corollary to the detrimental effect of impurities upon extraction, addition of reagents, for example salts, can be used to enhance the extraction and mitigate to some extent against these. This paper describes an experimental study of the partitioning of ethanol from aqueous solutions into 1–decanol. Specific groups of impurities and additives were identified, comprsing: electrolyte compounds (including acids, bases, and salts), ionic and non‐ionic surfactants, commercial de‐emulsifiers, organic acids, polysaccharide compounds (i.e. sugars and starch), protein, biomass (including yeast and bacteria), and 1–propanol. A number of thermodynamic models for predicting the effect of each additive on the phase distribution behaviour of ethanol were screened and tested. The additives considered in this paper are confined to those of relatively simple chemical structure and included 1–propanol, oleic acid, glucose, sodium chloride, sodium hydroxide, calcium chloride, ammonium chloride, ammonium sulphate, and hydrochloric acid. These were added in controlled amounts to the principal extraction system components and the effect upon the partition coefficients of ethanol determined.
Robust Digital PI Control for Uncertain Time‐delay Systems in Process Industry
Authors: Liu Xiang , Wang Wenhai , Sun Youxian
Published: August 2010

A new robust digital PI controller for a class of typical systems with uncertain time delays is developed for use in process industry. Using this Controller the satisfactory locations of poles of the closed‐loop systems will change slowly with the varied time delays, and the robust stability is guaranteed for the time varied time‐delay on a large scale. Simulation results show that the robust controller also works for the systems in the presence of unmodelled dynamics.
Modeling of Fourdrinier and Cylinder Machines
Authors: Zhang W.D. , Xu X.M. , Sun Y.X.
Published: August 2010

In this paper, an “equivalent paper machine” is presented which possesses the features of both the fourdrinier machines and cylinder machines, and a universal model is developed by mechanism analysis. The model is not only an external description as often obtained by system identification, but an internal one in which internal process variables are included. Experiments show that the model agrees closely with the plant data.
A Modified Augmented Lagrange Multiplier Method for Large‐Scale Optimization
Authors: Liang Ximing , Hu Jianbo , Zhong Weitao , Qian Jixin
Published: August 2010

A modified augmented Lagrange multiplier method for large‐scale nonlinear optimization problem is studied in this paper. The basic steps of the proposed algorithm comprise an outer iteration, in which the Lagrange multipliers and various penalty parameters are updated, and an inner iteration, in which a nonlinear optimization with simple bound constraints is solved. The algoritm presented has been implemented in a general routine denoted as MALMM. Numerical results are presented for a variety of problems, which show the stability and effectiveness of the algorithm in large‐scale problems.
H∞Control of Discrete Time Linear Systems Subject to Input Saturation
Authors: Xiong Xuequan , Xue Anke , Sun Youxian
Published: August 2010

In this paper, we consider the H∞control problem of discrete‐time linear systems subject to input saturation. Some sufficient conditions are derived which make the closed‐loop system satisfy local asymptotically stability and the H∞performance prior given. According to these sufficient conditions, the synthesis of state feedback controller is considered. All of the results are described in LMI.
Self‐Desulphurization and Self‐Denitrification Properties and Mechanisms in Biobriquette Combustion
Authors: Kim Hee‐Joon , Lu Guo‐Qing , Maruchi Hidenobu , Li Tian‐Ji , Noda Hiroyuki , Sadakata Masayoshi
Published: August 2010

To control pollutant emissions from the combustion of both domestic stoves and small‐capacity industrial boilers, a new artificial solid fuel called biobriquette with self‐denitrification and self‐desulphurization has been developed. It is manufactured from a mixture of coal, biomass (agricultural wastes, cornstalk, etc.), desulphurizer and denitrificator such as limestone, seashell and pulp black liquid (industrial wastes) under a high compression pressure. In this study, the experiments of briquetting, pyrolysis and combustion were performed in order to reveal its characteristics of briquetting, self‐denitrification and self‐desulphurization.

The main results are that pulp black liquid and/or biomass improves the briquetting and combustion of biobriquette. The seashell called scallop has high desulphurization efficiency, but they only slightly reduce NOx emissions in biobriquette combustion. The pulp black liquid mixed in the biobriquette has not only a good desulphurization but also significant denitrification result. The denitrification reaction happens mainly in the char combustion stage and slightly in the volatile combustion stage. The denitrification efficiency of about 40% can be obtained when the mixture reaches 10 mass%. The main mechanism of denitrification was considered to originate from NH3 and NaOH included in the pulp black liquid.
Effect of Char Properties on N2O Formation and Reduction during Circulating Fluidized Bed Coal Combustion
Authors: Liu Hao , Kojima Toshinori , Feng Bo , Liu Dechang , Lu Jidong
Published: August 2010

The mechanism and effect of char on N2O formation and reduction during circulating fluidized bed coal combustion were examined in a bench‐scale circulating fluidized bed. It was found that char derived from coal with high volatile matter content has a higher conversion ratio from char‐N into N2O during char combustion. Furthermore, char with greater pore volume and specific surface area not only shows a higher conversion ratio from char‐N into N2O, but also has stronger N2O reduction ability. Big pores play the main part in N2O diffusion inside char particles whereas small pores play the main part of chemical reaction. Molecular diffusion and Knudsen diffusion are both important for N2O diffusion in char. The reactivity of char concerning N2O formation and reduction is closely related to its pore characteristics, which is an important factor to account for the diverse N2O emissions from combustion of various coals in a circulating fluidized bed.
Investigation and Application of “Bluff‐body in Cavity” Burner for Pulverized Coal Combustion
Authors: Chen Gang , Qiu Ji‐Hua , Xu Ming‐Hou , Zheng Chu‐Guang
Published: August 2010

The flow and combustion process of a new type of pulverized coal burner, the “bluff‐body in cavity”, is studied in this paper. This is an improvement on the basic principle of the ordinary bluff‐body burner. Mean and fluctuating velocity components and turbulence characteristics of the flow in the outlet of the “bluff‐body in cavity” burner were measured using a three‐dimensional laser particle dynamics anemometer (3D‐PDA). Combustion tests showed that this burner is better than an ordinary burner with only a bluff‐body regarding the ignition and flame stability. Application of this new burner in several power plant boilers (65‐670 t/h) showed that the temperature in the flame zone is high, the combustion process is very stable, and the boiler efficiency is increased. These improvements indicate a promising future for the burner.
Modelling and Simulation of a Top‐Fired Primary Steam Reformer using GPROMS
Authors: Dunn A.J. , Yustos J. , Mujtaba I.M.
Published: August 2010

A top‐fired primary steam reformer is modelled and simulated using gPROMS, a general purpose modelling package Validation of the model is performed against industrial data A sensitivity analysis of the key operating parameters of pressure, temperature, steam to carbon ratio, and feed rate are comparable to previous observations in the published literature Optimisation of the burner profile and the reactant gas distribution enhanced the balance of the furnace, which will significantly improve the operating lifetime of the steam reformer for a given performance
Optimisation of Methyl Tert‐Butyl‐Ether (MTBE) Synthesis Processes using Aspen‐Plus
Authors: Kim S. , Douglas P.L.
Published: August 2010

Four different configurations for the production of MTBE were simulated and optimised using AspenPlus All process configurations were simulated and costed using AspenPlus The total annual cost (TAC), i e the sum of the individual annualised capital and operating costs, was calculated using models consistent with the conceptual design level Optimisation of each process configuration using AspenPlus simulation models was performed to determine the optimal design and operating variables The optimised configurations were compared on an economic basis

It was possible to achieve iso‐butylene conversions in the range of 90 to 97% with a single conventional reactor followed by a distillation tower However, by using a reactive distillation column it was possible to achieve iso‐butylene conversions > 99% The optimal configuration was found to be a combination of an isothermal reactor followed by a catalytic distillation column The optimal TAC of this configuration was 22% lower than its nearest competitor, the catalytic distillation column

It was found that the net MTBE reaction rate remains high until a substantial amount of iso‐butylene is converted, and then decreases quickly as the reacting liquid composition approaches the reaction equilibrium Therefore, it is not surprising that the best means of synthesis is to carry out the bulk of the initial conversion using a conventional reactor and to apply reactive distillation to the reactor effluent that is close to equilibrium at the exit temperature
Models of an Industrial Evaporator System for Education and Research in Process Control
Authors: Kam Kiew M. , Saha Prabirkumar , Tadé Moses O. , Rangaiah G. P.
Published: August 2010

Realistic models of typical industrial processes are essential for effective and practice‐oriented education and research in process control This paper presents two mechanistic models of an industrial five‐effect evaporator system, and also indicates their potential applications in process control‐related research and training Simulation programs for these models in four different platforms (viz, MAPLE, MATLAB, Simulink and C++) are developed Relative merits and application‐specific usefulness of these four platforms in process control studies are discussed
Drying Research ‐ Current State and Future Trends
Authors: Mujumdar Arun S.
Published: August 2010

Research and development activity in the inter‐ and cross‐disciplinary area of thermal drying has been escalating rapidly over the past two decades. It is clearly motivated by economic incentive to improve the operation to produce a better quality product at a lower cost in terms of resources, energy consumption as well as environmental impact. The focus to date has been on improving the engineering aspects of design and operation to produce “engineered” products of desired characteristics. Much remains to be achieved in relation to the material science aspects of drying, e.g. the prediction of quality parameters which are product‐dependent. What is needed is a generalised drying theory that incorporates the transient transport phenomena involved in drying along with appropriate models to account for the morphological changes, as well as chemical processes that may occur during drying.

This paper will focus on the current developments in drying as well as recent trends. Some areas where more R&D is needed and which provide opportunities to make definitive contributions will be identified. For example, sophisticated analytical measurements at the micro‐scale are needed in order to examine the movement of moisture during drying, and also detect any changes in the physical structure as well as solute transport that can occur in drying of foodstuffs or solids containing a dissolved solid in the liquid phase. Even today, there is need to devise more efficient and compact dryers. Whether we will ever need “micro‐scale” dryers is a speculative question but certainly there will be the need to design dryers with high “volumetric” efficiency, unlike most dryers built today. Finally, there will be further developments and extended applications for superheated steam dryers, heat pump‐assisted hybrid dryers and multi‐stage dryers using different dryer types in each stage. Mathematical models for drying as well as for dryers will continue to be in demand to allow reliable design and scale‐up, as well as the control of industrial dryers.
Theoretical Study of Stress Reversal Phenomena in Drying of Porous Media
Authors: Kowalski Stefan Jan
Published: August 2010

Drying of capillary porous materials may generate internal stresses, the magnitude of which depends on both the drying techniques and the mechanical properties of dried materials. Acoustic emission (EA), a method to monitor for damage control during drying, shows an enhanced emission of acoustic impulses and energy from the material in some stages of drying. A particularly interesting phenomenon is the occurrence of enhanced emission of the acoustic impulses at the final stage of drying, that is, at the time when the drying induced stresses are expected to disappear. This phenomenon is explained by the stress reversal, i.e. the change of stress signs from negative (compressive) inside the material at the beginning to the positive (tensional) at the final stage of drying. A theoretical analysis is presented in this paper using the viscoelastic model. Stress reversal was predicted and analyzed from drying cylinders of ceramics‐like material and wood.
Effect of Drying‐Aid Agents on Processing of Sticky Materials
Authors: Benali Marzouk , Amazouz Mouloud
Published: August 2010

Thermal drying is considered as an attractive option to slurry disposal especially for complex industrial residues containing fibers and/or sticky components such as animal fat. The proposed Jet‐Spouted Bed Dryer with inert particles (JSBDryer) is an advanced and energy efficient technology to obtain powders from solutions, slurries and pastes by drying on the surface of inert particles brought into intensive and random motion. An experimental study carried out on a 300 kW‐test bench for drying of meat‐rendering slurry in the JSBDryer is presented. Some basic characteristics of the jet‐spouted bed for Teflon cubes used as inert particles are also presented. The effects of calcium carbonate and wheat bran, used as drying‐aid agents, on the reduction of slurry stickiness are also discussed.
Application of Electrical Fields in Dewatering and Drying
Authors: Chen G. , Mujumdar A. S.
Published: August 2010

The application of electrical fields to dewatering and drying is reviewed. In particular, the developments in electroosmotic dewatering (EOD) of colloidal slurries are discussed in terms of fundamental associated phenomena, as well as the methods of enhancement of EOD. The electrohydrodynamic (EHD) drying of biological materials are discussed in terms of its fundamentals, current status, and advantages and disadvantages. The potential applications of this emerging technique are evaluated along with a discussion of R&D needs in these areas.
Correlation for Equilibrium Solubility of Calcium Sulfate Phases in Industrial Phosphoric Acid Production
Authors: Mukhopadhyay S. , White E.T.
Published: August 2010

The equilibrium solubility of gypsum (and calcium sulfate hemihydrate) in phosphoric‐sulfuric acid mixtures, similar to those used in practice in industrial wet phosphoric acid manufacture, was determined. The experimental data from this work and literature data were combined to develop solubility correlation equations for both calcium sulfate hydrate species over a full range of industrial conditions.
Computer‐aided Measurement of Vapour‐Liquid Equilibria in a Dynamic Still at Sub‐Atmospheric Pressures
Authors: Joseph M.A. , Ramjugernath D. , Raal J.D.
Published: August 2010

A compact new dynamic VLE apparatus has been developed capable of rapidly and accurately furnishing data suitable for separation process design. The equipment is computer controlled to fine tolerances of pressure and temperature and can produce either isobaric or much useful isothermal VLE data. The design incorporates a packed equilibrium chamber of the Yerazunis et al. [1] type in a novel arrangement. It is suggested that VLE stills relying only on a Cottrell pump are unlikely to reach true equilibrium regardless of how long the recirculation period, particularly for system of high relative volatility and or high liquid viscosity. To test the performance of the apparatus, isobaric VLE data were measured for the cyclohexane‐ethanol system at 40 kPa, and isothermal VLE data at 313.15K, 323.15 K and 333.15K. The isobaric data were in good agreement with the data of Morachevsky and Zharov [2]. The isothermal VLE data were found to be thermodynamically consistent. Infinite dilution activity coefficients, in good agreement with literature values were found from the isothermal data by the method of Maher and Smith [3]. Reasonably accurate excess enthalpy estimates were also calculated. The VLE data were best correlated with the Wilson [4] equation. An analysis of the temperature‐pressue sensitivity for binary systems defines the precision required in the control of either pressure or temperature and dictates the choice of equipment for a given system.
The Rheological and Mechanical Performance of Polyvinyl Chloride/Ethyl Vinyl Acetate Formulations for Medical Device Applications
Authors: Mcconnell D.C. , Mcnally G.M. , Murphy W.R.
Published: August 2010

The incentive for this research is a result of the current issues arising over the use of flexible polyvinyl chloride (PVC) in medical devices, particularly with respect to their disposal and the use of migratory low molecular weight plasticisers. The debate at present involves consideration of the disposal of PVC by incineration, creating dioxins which environmentalists claim are harmful and the use of phthalates as leaching plasticisers which also present a health risk. This work investigates the suitability of ethyl‐vinyl acetate (EVA) copolymer as a permanent polymeric replacement plasticiser for use in flexible PVC formulations particularly for medical device applications. A range of powdered EVA copolymers and PVC formulations were compounded at ratios 100:0, 60:40, 50:50, 40:60 and 0:100 respectively. Two grades of EVA with 20% and 27% vinyl acetate (VAc) content and a grade of PVC with a K‐value of 71 were used in the investigation. Mechanical analysis was performed on injection moulded samples of these blends and the results showed that the tensile and flexural modulus decreased significantly with increasing EVA concentration. Rheological analysis was performed using dual capillary rheometry and the results showed only slight changes in shear viscosity with increasing EVA content even at lower shear rates. Dynamic mechanical thermal analysis showed partial miscibility of the PVC and EVA over the range of concentrations studied, thus indicating that EVA does have a plasticising effect on PVC.
Gasification of Waste Medium Density Fibreboard as a Route to Power Generation
Authors: Williams B.C. , Mcilveen‐Wright D. , Rezvani S.
Published: August 2010

Medium density fibreboard (MDF) processing in Northern Ireland generates about 40 tonnes of MDF dust per week, which gives significant disposal problems and costs. The overall aim of this project was to develop an environmentally friendly, energy efficient and economically acceptable means of generating “green” electricity from MDF dust.

The project is based on using a down draught fixed bed gasifier with a modified diesel engine generator. Before MDF dust can be used in the gasifier it must first be briquetted. Although many equipment manufacturers claim to be able to briquette MDF dust, only two were able to prove this capability, PLC Products and Kahl. Trials were arranged and as a result a B10 Bio‐Compactor was purchased and installed. However, good quality briquettes could not be produced reliably due in part to a lack of experience in operating the B10 Bio‐Compactor and in part to mechanical failures. Changes were made to the B10 Bio‐Compactor to improve its mechanical integrity and further trials will be performed to establish the conditions required to make MDF briquettes reliably.

In order to provide MDF briquettes for the gasification trials it was decided to use MDF off‐cuts sawn to the correct size. The project team was happy that these off‐cuts possess very similar properties to the briquettes produced by the B10 Bio‐Compactor and would therefore give very similar gasification behaviour. The gasification trials were very successful, with 8 hours continuous operation without problems. The calorific value of the fuel gas produced was 4.8 MJ/nm3, which is almost identical to that obtained from normal hardwood chip fuel. From the gasifier a mixture of diesel and MDF fuel gas was fed to the diesel engine generator. This is the normal practice for these types of engines in order to maintain smooth and efficient combustion. No problems were experienced when changing over from diesel to the fuel gas mixture
Biomass Gasification for Combined Heat and Power In the Chipboard Industry
Authors: Williams B. C. , Henderson P. , Mcilveen‐Wright D.
Published: August 2010

This paper provides details of a feasibility study into the application of small‐scale wood chip gasification‐based combined heat and power (CHP). Gasification itself is not a new technology, however there has been renewed interest recently in the quest for small‐scale gasification from renewable energy sources, such as biomass and wood waste. The UK Government is committed under the Kyoto Protocol and various EC regulations and recommendations to reducing greenhouse gas emissions, increasing the use of renewable energy sources and increasing energy efficiency through the use of CHP. This technology will help to achieve all three of these goals.

There has been an assessment of the wood chip supply position in Ireland, based on information from Balcas, the largest timber milling company in Ireland, and the Northern Ireland Forestry Service. This study shows that there has been a 30% increase in output from Ireland's forests over the last five years. A conservative estimate is that over the next five years the output will increase by another 60%, mainly in the North West of Ireland. Therefore, the volume of wood chips required for any proposed size of CHP unit is not expected to have any noticeable impact on the market price or availability of wood chips.
Two‐Phase Flow, Momentum and Energy Balances Revisited
Authors: Raghunathan R.S. , Spedding P.L. , Cooper R.K.
Published: August 2010

The apparent differences between the momentum balance and energy balance derivation for the case of two‐phase flow are resolved by examination of the liquid holdup within the system.
Robust Process Control Based on the Passivity Theorem
Authors: Bao J. , Lee P. L. , Wang F. , Zhou W.
Published: August 2010

A robust process control strategy based on the passivity theorem is proposed in this paper. The uncertainties are characterised in terms of a revised passivity index. The passivity‐based robust stability condition is derived and the tradeoffs between the robustness and nominal performance are analysed. Using Semi‐Definite Programming, a two‐step controller design procedure is developed to meet both the passivity‐based stability condition and nominal performance specifications. As both the phase and gain information of the uncertainties are taken into account, the control method proposed may achieve better performance for the same robustness requirement than conventional H∞ control. This is illustrated by an example of the control of a reactor.