bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Permeation of Vanadium(V) and Chromium(VI) through Anion Exchange and Supported Liquid Membranes
Authors: Kojima T. , Yagi S. , Nishijima K. , Matsukata M. 
Published: August 2010

AbstractSelective permeation of vanadium(V) and chromium(VI) using three types of membrane systems was studied. The first was an anion exchange membrane, the second and third were supported liquid membranes containing either a tertiary amine or a quaternary ammonium salt. The membrane was sandwiched between two glass cells. One cell was filled with a solution of identical concentrations of vanadium(V) and chromium(VI), and the other cell contained sodium hydroxide solution. The permeation rates of vanadium(V) and chromium(VI) were measured from the concentration change in the solution on the recovery side of the membrane. The selectivity of vanadium(V) over chromium(VI) was defined as the ratio of their rates. The selectivity of vanadium(V) over chromium(VI) was as high as 10 for pH of feed phase between 8 and 10 when using the quaternary ammonium salt and much better than these for the other membranes with an alkaline feed phase, which was used to simulate of the effluent from leaching of the heavy oil combustion ash and other wastes containing vanadium.
Multi‐Stage Flash Desalination Process: A Thermal Analysis
Authors: El‐Dessouky Hisham , Shaban Habib I. , Al‐Ramadan Hamida 
Published: August 2010

AbstractMulti‐Stage Flash (MSF) desalination processes play a vital role in the provision of fresh water in many areas of the World, particularly in the Arab Gulf countries. This paper describes a steady‐state mathematical model developed to analyze the MSF water desalination process. Relations between parameters controlling the product water cost (e.g. thermal performance ratio, specific heat transfer surface area, and specific flow rate of cooling water and recirculated brine) to other operating and design variables are established. These relations can be used to design new plants or to analyze existing units.The model assumes the practical case of constant heat‐transfer surface area per stage in each section. It considered the variation of water physical properties with temperature and salt concentration, the effect of fouling factors, and the presence of non‐condensable gases on the overall heat‐transfer coefficients, and variations in stage flash down and thermodynamic loss from stage to stage. The model also takes into consideration the heat transfer losses from the stages to the surrounding and through rejection of the noncondensable gases. The results obtained from the developed model are compared with data from six different MSF plants, and good agreement is obtained.
Mathematical Modeling of the Prereduction Process of Iron Ore in a Circulating Fluidized Bed
Authors: Hahn Y. B. , Im Y. H. , Kim K. J. , Park D. G. , Lee I. O. , Nam I. S. , Chang K. S. 
Published: August 2010

AbstractA mathematical model has been developed to describe the various subprocesses occurring in a circulating fluidized bed (CFB) used for pre‐reduction of iron ore particles in the smelting reduction iron‐making process. The model incorporates hydrodynamics, iron reduction kinetics, and heat and mass transfer. One of the key features is the inclusion of a wall‐to‐bed heat transfer model to describe the heat transfer phenomena occurring in the CFB. The predicted and measured heat transfer coefficients showed a minima in the lower part of the bed due to the irregular up‐and‐down movement of ore particles. The model predictions of the reduction degree of iron oxides based on shrinking‐unreacted‐core chemical reaction control mode showed satisfactory overall agreement with measured data. The performance of the CFB reactor has been tested extensively in terms of gas oxidation degree, inlet temperature, particle size and mean particle residence time. It was confirmed that the reduction degree is significantly affected by gas oxidation degree, wall temperature and particle size.
On‐Line Inferential Models in Nonlinear Multivariate Control Applications
Authors: Ansari R. M. , Tadé M. O. 
Published: August 2010

AbstractOn‐line product quality measurements suffer from excessive time delays and sampling intervals which limit their effectiveness as inputs for automatic control. Inferential models which are based on fast and continuously available temperature, pressure and flow measurements reduce the negative impact of the sample intervals and time delays with minimum compromise on accuracy. The resulting continuous and fast response keeps the product qualities on specifications and minimizes the quality giveaway. This paper highlights the development aspects of correlations, use of inferential models in both open and closed loop environments, laboratory update mechanism, operators acceptance and benefits of inferential models and their use as a controlled variable in nonlinear multivariable control applications.
Generating Operating Command Sequences for the Regulation of Complex Chemical Processes Using Artificial Intelligence Techniques
Authors: Roach J. R. , O'Neill B. K. , Strimaitis P. J. 
Published: August 2010

AbstractComplex processing plants are operated (and for that matter designed) by individuals who cannot always envisage in sufficient detail the longer‐range consequences of their current actions. This is particularly the case where interactions can occur between sequential operating modes of a plant. Given that the desired outcome is the achievement of the overall process goals safely and efficiently, it is worthwhile considering the factors which can mitigate against the achievement of these aims and how they can be avoided. This study describes methods which can be used to help develop safer and more efficient plant operation by the use of the computer to devise operating command sequences which achieve consecutive sets of process goals subject to a variety of constraints (e.g. the avoidance of unsafe states). The operating command sequences are required to be generated in the form of a sequence of valve operations. A catalyst‐regeneration plant example originally devised by Rivas and Rudd (1974) is presented.
Peat for Environmental Applications: A Review
Authors: Mckay G. 
Published: August 2010

AbstractPeat occurs abundantly in nature in various forms. Its chemical composition varies widely with geographical region, age and within individual deposits due to the chemical reactions resulting in its formation. However, it is now realized that the basic chemical and physical properties of most peats are beneficial to sorption and ion exchange processes. The potential range of environmental uses for peat described in this paper vary from the treatment of oil spills and textile effluents to VOC removal and metalion removal from waste streams.
Development of a Particle‐Bubble Collision Model for Flotation columns
Authors: Egiebor N. O. , Zhou Z. A. , Nyavor K. 
Published: August 2010

AbstractParticle‐bubble collisions in bubble swarm systems have been modelled based on previous work on single bubble systems and bubbly flow characterization. This approach relates the overall collision probability to bubble and particle sizes, gas holdup, column height, and other operating parameters, thus providing a theoretical basis for column design and analysis of particle collection in flotation columns. The simulated results indicate that the existing collision models based on single bubble systems cannot be accurately applied to actual flotation columns for analysis of the particle‐bubble collision process. This is mainly due to the effect of gas holdup, bubble interaction, and multi‐layers of bubbles in a swarm. For column flotation of fine particles under normal operating conditions, a recovery zone of about 10 meters is sufficient to ensure that the collision probability approaches unity. For bigger particles, higher gas holdups, and smaller bubble sizes, much shorter recovery zone heights can be used to achieve the same high collision probability.
New Photocatalytic Reactors for Destruction of Toxic Water Pollutants
Authors: Ray A. K. 
Published: August 2010

AbstractRecent literature has established the potential of semiconductor photocatalysis technology to completely destroy toxic pollutants dissolved or dispersed in water into harmless substances. However, to date no viable pilot plant exists using this technology. In this paper, designs of two new photocatalytic reactors for water treatment are presented. One reactor consists of several hollow tubes employed as a means of light delivery to the catalyst present on the outside surface of the tubes, while the other design uses new extremely narrow diameter lamps. Experiments performed in both reactor configurations showed very promising results.
An Assessment of Hybrid Combined Cycle Power Generation Systems Based on a Coal Fired Pressurised Fluidised Bed Combustor
Authors: Evans R. H. , Mcmullan J. T. , Williams B. C. 
Published: August 2010

AbstractA hybrid combined cycle electrical power generating scheme burning coal and natural gas is examined using the ECLIPSE chemical process simulator. The technical, environmental and economic performance of this system is presented and comparisons are made with conventional power generation technologies. These comparisons show that the hybrid combined cycle offers improvements in efficiency, CO2 emissions and cost.
Investigation into the Use of Copper‐Loaded Natural Zeolite for the Reduction of NO Using Methane
Authors: Headon K. A. , Zhang D. K. 
Published: August 2010

AbstractThe suitability of a copper‐loaded natural zeolite for the selective reduction of NO using methane was examined in a packed‐bed tubular reactor. The natural zeolite was found to decompose NO to nitrogen with a maximum conversion of30% achieved at 420 °C when 2% NO, 1% CH4 and 2% O2 were used with a contact time of 0.9 gscm−3. Exchange of the zeolite to the H‐form prior to copper ion‐exchange was essential for catalytic activity to be promoted by the presence of oxygen. The catalytic nature of the decomposition reaction was confirmed through experiments in the absence of any catalyst. Calcination of the zeolites after ion‐exchange resulted in no discernible effect on catalytic activity, and the use of Mg as a cocation also did not promote the activity. For a H‐exchanged sample, activity was significantly decreased.
Crossing Reaction Equilibrium in an Adiabatic Reactor System
Authors: Nicol W. , Hildebrandt D. , Glasser D. 
Published: August 2010

AbstractThe work presented in this paper looks at maximizing the conversion of an exothermic reversible reaction that is adiabatic overall, i.e. only allowing for internal heat exchange between streams. In a single adiabatic reactor the highest possible conversion is the equilibrium conversion. It is shown that an improvement can be made on this equilibrium conversion by using two reactors with two heat interchanging units. The heat interchange system can be further optimized by adding more reactors and heat interchangers. The optimum theoretical conversion for an adiabatic system was found to be the equilibrium conversion at the original feed temperature. This is achieved by operating a simultaneous heat interchanging and reactor structure. The work was extended to find a maximum conversion for a more practical system where account is taken of minimum temperature driving forces and incomplete conversions.
A Kinetic Investigation of the Copolymerization of Acrylonitrile and Vinyl Acetate in Bulk
Authors: Mcmanus N. T. , Penlidis A. , Rempel G. L. 
Published: August 2010

AbstractThe free radical copolymerization, initiated by 2, 2′ azo‐bis‐isobutyronitrile (AIBN), of acrylonitrile (AN) and vinyl acetate (VAc) in bulk has been examined. Reactivity ratios were evaluated using the error in variables model (EVM). In addition, full conversion range experiments were undertaken, which examined polymerization rate, molecular weight development and copolymer composition with respect to the effects of feed composition, initiator concentration and temperature.
A New Design Parameter ‐ “the Fit Factor” for the Retrofit Design of Heat Recovery Systems
Authors: Al‐Fakih N. , O'Neill B. K. , Roach J. R. 
Published: August 2010

AbstractRetrofit design of heat recovery networks is an increasingly significant industrial problem. Such concern is driven by two factors ‐ the old and non‐optimal designs of many existing process plants coupled with increased economic and environmental pressures to improve their energy efficiency. In this paper, a new evaluation technique for the retrofit design of heat exchanger networks is presented. The ‘block design’ philosophy proposed by Zhu et al. (1) provides the basis for development of the method The retrofit situation differs considerably from the design of green‐field networks. A clear objective of the designer in the retrofit situation is to optimise the incremental investment expended in changing the existing network. To aid in achieving this goal, a new parameter “K” is defined to enable the engineer to identify well‐placed existing units and to highlight areas that would benefit from change. The new method identifies all of the available options and indicates the candidate exchangers for retention within the network together with situations likely to benefit from modification. Examples are provided to demonstrate the effectiveness of the proposed method.
Holdup in Vertical Three Phase Flow
Authors: Woods G. S. , Spedding P. L. , Watterson J. K. , Raghunathan R. S. 
Published: August 2010

AbstractVertical three phase air‐water‐oil data in a. 0.026 m i.d. pipe were presented. The liquid holdup data presented as a complex pattern against f0 the oil liquid volumetric ratio for annular flow at one value of total superficial liquid velocity. The form of the pattern was explained in qualititive terms depending on the nature of the flow pattern present. Generally for the water dominated regime below f0 = 0.5 the overlying oil annular film protected the water annular from the momentum effects of the gas. Above f0 = 0.5 the opposite took place and the water annulus film thinned until inversion to oil dominated flow occurred. This was a region of intense mixing of the liquid phases and the hold‐up rose dramatically.
Options for Small and Medium Scale Power Generation from Biomass
Authors: McIlveen‐Wright D. , Williams B. C. , Mcmullan J. T. 
Published: August 2010

AbstractThe technical and economic performance of a variety of options for producing electric power from woody biomass are assessed using the ECLIPSE suite of computer programs. The studies have included both fixed and fluidised bed combustion and gasification of the biomass with power generation from a range of small and medium scale steam turbines, gas engines, fuel cells or gas turbines in conventional, STIG and ISTIG modes.For the small‐scale systems, gasification integrated with a gas engine was found to be the most appropriate of the current technologies, and gasification integrated with Molten Carbonate Fuel Cells the most promising technology for future development.For medium‐scale systems, the IGCC systems were found to be the most efficient, but the less efficient combustion systems were competitive on cost. STIG and ISTIG systems offer promise for the future.
NOx Reduction Technology in PF Boilers
Authors: Mccahey S. , Mcmullan J. T. , Williams B. C. 
Published: August 2010

AbstractTechnical, environmental and economic assessments were performed, using the ECLIPSE process simulator, for a supercritical coal fired PF power station to investigate the impact of NOx reduction technologies. The study was modelled upon the Amer 9 Power Station at Geertruidenberg, The Netherlands, and both combustion and post‐combustion NOxreduction technologies were evaluated. SCR gave the largest reduction in NOx emissions to below 50mg/Nm3, but at an electricity cost of 2.44p/kWh, compared with 2.23p/kWh for the reference case and 2.26p/kWh for coal‐over‐coal reburning. The latter produced a 50% reduction in NOx emissions to below 200mg/Nm3. Use of a microniser, to reduce coal particle size, in coal‐over‐coal reburning is not justified, unless its absence produces excessive unburnt carbon losses or requires a reburn coal 50% more expensive than the main coal. With natural gas‐over‐coal reburning, an unrealisable natural gas price of £0.98/GJ is required to make it competitive with coal‐over‐coal reburning and natural gas prices between £1.76/GJ and £1.93/GJ are required for it to compete with SCR.
Viscosity of Reconstituted Milk Protein Concentrate Solutions as a Function of Shear, Temperature and Concentration
Authors: O'Donnell S. , Butler F. 
Published: August 2010

AbstractThe viscosity of reconstituted milk protein concentrate solutions was determined at various shear rates, (50‐1000 s−1), temperatures, (20‐60°C) and concentrations, (200‐260 g/kg). For a given temperature and concentration, the solutions were shear thinning and the effect of shear was adequately described by the Ostwald power law model. Viscosity increased with concentration and decreased with temperature. The effect of temperature on the consistency index followed an Arrhenius type relationship. The effect of concentration on the consistency index was modelled with both a power and an exponential relationship. The flow behaviour index was independent of temperature and concentration. The combined effects of shear rate, temperature and concentration on viscosity were modelled using an extended power law model.
Theoretical Investigations of Rotating Instabilities
Authors: Bowen P. J. , O'Doherty T. , Lucca‐Negro O. 
Published: August 2010

AbstractThis paper collates recent theoretical work which sets out to model the characteristics of rotating instabilities often generated by industrial swirl generators such as swirl burners and cyclone dust separators. Results generated from three modelling approaches are discussed: a perturbation analysis about an axisymmetric viscous flow; a two‐dimensional variational approach of incompressible inviscid flow; and numerical solutions of the three‐dimensional Navier‐Stokes equations using contemporary turbulence models. Each modelling approach can predict some of the features of the complex flowfield associated with these rotating instabilities.
The Impact of Scaling Criteria on the Characteristics of Pulverised Coal Flames
Authors: Smart J. P. , Van Kamp W. L. De 
Published: August 2010

AbstractResults are presented of a series of experiments where a 12 MW, large‐scale swirl stabilised burner is compared with two 2.5 MW, geometrically similar burners designed around a constant‐velocity and constant‐residence‐time scaling criterion. High and low NOx flames were produced from all burners and selected flames were extensively probed to determine in‐flame thermo‐chemical structures. Results show that complex differences exist between flames. Results are also presented on the effect of scale on the ignition properties of axial turbulent jet flames. Experimental findings show an important effect of ignition distance on NOx that has important implications with respect to scaling effects on these flame types. The results detailed in the text are interpreted with reference to the effect of scale on turbulent mixing, two‐phase interactions and ignition properties. Results confirm that, regardless of the scaling criterion selected, similarity of the in‐flame thermochemical features is almost impossible to maintain as burner scale is changed irrespective of the scaling approach employed.
Research on the Properties of A Novel Granular Filter in Fluidized‐Bed
Authors: Zhang Shihong , Liu Dechang , Lu Jidong , Zheng Chuguang 
Published: August 2010

AbstractA novel granular filter in fluidized‐bed is under developing in National Laboratory of Coal Combustion (NLCC) which can be applied in advanced coal‐fired power conversion systems. The characteristics of the filter, the parameters of a 3‐dimension lab‐scale filter facility in NLCC are analyzed in this paper. The results of preliminary investigation on the properties of the filter are also presented, which suggest that the novel filter can effectively clean the fine particles from gas streams, the mean size of the permeated particle is about 5 micron in diameter, the permeated particle volume flux is about 0.0000908cm3/sec/cm2 when sand is served as bed material. The filter unit immersed in fluidized bed is found to be a key factor which influences the fluidizing features of the filter.
Modeling of a Low Temperature Pyrolysis Process Using ASPEN PLUS
Authors: Yan H. M. , Zhang D. K. 
Published: August 2010

AbstractAn ASPEN PLUS based simulation model has been developed for a low temperature pyrolysis process, incorporating triple fluidised beds with solid circulation, for both valuable fuel oil production and power generation from low‐rank coal. This paper reports preliminary simulation results using a Loy Yang brown coal as the feed. Simulations indicate that, for the coal modelled, combustion of char and remaining volatiles after pyrolysis not only provide enough energy required for the endothermic pyrolysis reactions and the wet coal drying, but also can supply extra energy for power generation. About 2.7 MW power and 0.26 kg s−1 fuel oil can be produced from 1 kg s−1 dry coal feed to the process. Simulation also shows that the initial moisture content in the coal does not affect the tar yield in the pyrolyser but has an effect on the power generation from the process. Fraction of the non‐condensable fuel gas burnt in the combustor does not have significant effects on the power generated from the process.