bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fundamental Principles of Incinerator Design
Authors: Swithenbank J. , Nassezadeh V. , Goh R. , Siddall R.G. 
Published: August 2010

AbstractWaste management has become a major concern world‐wide and incineration is now being increasingly used to treat waste which cannot be economically recycled. The combustion of conventional well specified fossil fuels is a very complex process since it involves two‐phase turbulent reacting flow including radiant heat transfer. Incineration is even more complex since the waste is poorly specified and its composition varies from moment to moment. In the past, the design of incinerators has not been based on fundamental understanding and modelling of the process, and empirical rules have had to be used.Over the last few years, computational fluid dynamics (CFD) has provided a means to model the freeboard region in a conventional municipal solid waste incinerator but the open literature contains no rigorous fundamentally based model of the bed region. The prediction of the flow composition emerging from this region is particularly important since it provides the “upstream” boundary condition for the flow calculations in the freeboard. For example, the calculation of the subsequent history of heavy metals requires knowledge of their emission rate from the burning bed.The processes in the bed include drying, pyrolysis, oxidative burning, and gasification of the char. Furthermore, the movement of the grate is designed to mix the waste as it burns. Indeed, the existence of a rigorous bed model would also permit the grate design to be optimised, and, if immediate data on the feed were available, a rational combustion control strategy could be devised. A preliminary model of combustion in the bed is proposed herein based on governing equations for the burning of individual “regions” of waste in the upward gas flow, their motion, and radiant heat transfer within the bed. The emissions of gases from the surface of the bed is very non‐uniform with oxygen emitted from either end of the bed, organic compounds from the one‐third region, and carbon monoxide from the centre. The surface layer of this central part of the bed consists of char with gases coming up from the oxidising layer below containing NOx derived from the fuel nitrogen. The char region therefore acts as an important reburn zone and it is suggested that this reduces some of the NOx to nitrogen. This is important since the minimisation of NOx by optimising the basic combustion process is likely to be environmentally preferable to subsequent control of NOx by the injection ofreactants such as ammonia.The calculation of flow and combustion in the freeboard using CFD can quantify the consequences of design concepts, however guidelines are needed to devise specific design concepts which are worthy of investigation. Thus the computer cannot “invent” a design but it can quantify the results of ideas.Incinerator design thus requires a judicious combination of fundamental combustion science, ingenious engineering guided by an understanding of the mixing process, and last but not least, practical experience of previous failures and successes.
Technological Risk Assessment in the Process Industry: Recent Advances in Applications and Future Directions
Authors: Haddad S. , Mullins D. P. 
Published: August 2010

AbstractQualitative and quantitative risk assessment techniques have been applied in Australia and elsewhere in the process and related industries since the early 1980s. Technological, methodological, policy and regulatory regimes have progressively evolved and been developed, as have the scope and range of applications. Risk assessment has developed from being a hesitant complementary tool to engineering codes and standards, into an established component of integrated decision‐making processes covering such areas as: strategic land use safety planning, development approvals, risk communication, safety management, fire protection and emergency planning and response. This paper focuses on recent experience in implementing risk assessment within the NSW planning framework. Recent developments in policy, methodology and applications are highlighted, in particular: multi‐level approaches to risk assessment; contaminated water containment and treatment; and ecological risk assessment. Future directions may witness the strengthening of technological risk assessment as a living tool in on‐going operational and organisational safety.
Radiative Properties of Residual Char and Its Effects on Radiative Heat Transfer in Pulverized Coal Fired Furnaces
Authors: Liu Z. H. , Zheng C. G. , Xing H. W. 
Published: August 2010

AbstractThis paper gives a comprehensive modelling analysis of the radiative properties of residual char and its effect on radiative heat transfer in pulverised coal furnaces. Firstly, the effective optical constant is introduced into the model of the radiative properties of unburned char. Three structure models of unburned char are considered, i.e. constant diameter model, shrinking core model, and a transient model. The result shows that regardless of the structure of residual char, the absorption in the initial stage of combustion of large char particles (D>10μm) does not decrease, while a sharp decrease occurs near the burnout (B>0.9). Then radiative property models of particles were incorporated into a CFD code to investigate its effect on overall radiative heat transfer in pulverized coal furnaces. The numerical results of a 300 MW tangentially fired furnace show that residual char shields radiative heat transfer along the radial direction in the upper zone of the furnace, and thus the temperature at the exit of the furnace is higher. By ignoring the additional absorption of residual char, it will lead to a lower predicted radiant heat flux to the area of platen superheater
Dynamic Simulation and Control of an MTBE Catalytic Distillation Column
Authors: Lin H. , Douglas P. L. 
Published: August 2010

AbstractA dynamic model of an MTBE (methyl tert butyl ether) catalytic distillation column was developed using the SpeedUp simulation package. Experimental kinetic rate data, rigorous thermodynamics, vapour‐liquid nonidealities and tray hydraulics were incorporated in the simulation. The steady state results from the dynamic model were compared with the steady state results from a steady state model developed using the AspenPlus simulation package. The steady state results from the two simulations were in perfect agreement with each other.Open hop step tests were performed on the dynamic model of this process and the process model indicated a non‐linear, self‐regulating behaviour and did not exhibit any multiplicities. Multiloop linear control systems were designed and PI, PID and Dynamic Matrix Control (DMC) controllers were tested on the simulation for load disturbances and setpoint changes.All controllers performed adequately; the DMC controller consistently resulted in better dynamic control performance than the other two controllers.
Efficient Simultaneous Dry Removal of SO2 and NOx from Flue Gas over Copper‐Based Catalytic Materials
Authors: Centi Gabriele , Perathoner Siglinda 
Published: August 2010

AbstractThe combined removal of SO2 (DeSOx) and NOx (DeNOx) from flue gas of power plants can be efficiently realized with a dry process using copper‐based sorbent‐catalysts which oxidize‐adsorb SO2 in the form of an easily regenerable copper‐sulphate and catalyze the reduction of NO in the presence of NH3/O2. This contribution reviews the results on this topic, discussing in particular the following main aspects: (i) Sorption and catalytic chemistry of the process, (ii) Development and features of the copper‐based sorbent‐catalyst. (iii) Optimization of the reaction conditions. (iv) Kinetic models of the sorption and catalytic behavior and role of the textural properties of the catalyst, (v) Flowsheet and economics of the process, (vi) Behavior in extended operations and life time cycles. The key features of the technology and its fields of application are also discussed.
Catalytic Destruction of Dioxins
Authors: Clark David M. 
Published: August 2010

AbstractDioxins are toxic and by many considered to be carcinogenic and mutagenic, hence control of dioxin emissions is now mandated by many governments. There are many technologies, which remove dioxins from flue gas streams, such as active carbon adsorption. However, these technologies only transfer the hazard associated with dioxins from the gas phase to the solid phase. This leaves the problem of disposing safely of dioxin containing waste, such that later release of dioxins from the adsorbent does not occur. To overcome these limitations a system has been developed which converts, rather than removes, dioxins to CO2, H2O, HCl and hydrocarbon fragments which are environmentally benign. This paper looks at the development of the technology from lab scale testing to commercial applications both in the Asia Pacific region and throughout the World.
The Role of Ammonium‐Sulfur Aerosols on Nitrogen Oxides Removal by Pulsed Corona Enhanced Wet Electrostatics Precipitation with Ammonia and Ozone Injection
Authors: Tseng C.‐H. , Keener T.C. , Khang S.‐J. , Lee J.‐Y. 
Published: August 2010

AbstractThe removal of nitrogen oxides (NO and NO2) has been investigated in a bench‐scale pulsed‐corona enhanced wet electrostatic precipitator (wESP). The 70 Hz pulsed voltage is applied up to 60 kV. Simulated flue gases with NOx concentration up to 1200 pp m have been used to determine the feasibility of NOx removal in the wESP. NO must be oxidized to NO2 before any removal takes place. NOx removal efficiency increased with gas residence time, inlet NO concentration and applied corona power. In the air stream with 10 seconds gas residence time, up to 20% of 1000 pp m NO (22% of NOx) was removed at a 20 watt pulsed corona. The amount of in‐situ ozone was not enough to be considered as a major NOx removal mechanism in this wESP. Ozone injection improved the NOx removal for both the corona and non‐corona cases by oxidizing NO. With 300 pp m of ozone, the removal of 750 pp m NO was increased from 18% to 50% by oxidation, but total NOx removal was improved only to 25%.However, very high NOx removals were measured in simulated flue gas that contained ammonia, sulfur dioxide and ozone. For instance, in a 3% oxygen, 11% CO2 simulated flue gas with 800 pp m NO and 70% relative humidity at 8.6 sec of gas residence time, 30 kV corona discharge, the removal efficiency of NO was only 5%. Injecting NH3 only (NH3/NOx ratio 1) at 32 watts corona power, NO removal was increased to 10%. With the co‐presence of 2400 pp m SO2, 200 pp m ozone injection (no ammonia) increased NO removal to 36% by oxidation, but total NOxremoval only to 17%. After co‐injecting 312 pp m ozone and 2900 pp m NH3 (stoichiometry ratio 0.53), total N0X removal was increased to 79%. It was determined that the ammonium salt aerosols produced from the reaction of ammonia and sulfur dioxide enhanced the NOx removal substantially. The significance of this catalyzing effect by the in‐situ ammonium salt aerosols is addressed in this paper.
Applications of Mathematical and Computer Models for the Evaluation of Novel Catalytic Reactors
Authors: Moustafa T.M. , Fahmy M. , Elnashaie S.S.E.H. 
Published: August 2010

AbstractA pseudo‐homogeneous model is used to explore the possibility of using a membrane reactor for the industrial production of styrene. This novel catalytic reactor consists of two compartments separated by a hydrogen selective membrane. The first compartment is the reaction side, in which the dehydrogenation of ethylbenzene to styrene is taking place, while the other compartment is the permeation side in which an inert sweep gas is used to remove the hydrogen permeated through the membrane. Different configurations of sweep gas flow were tested namely the co‐current and counter‐current flow. Partial blinding was also tested in the counter‐current flow case. The effect of vacuum in the permeation side was also investigated. Superior performance in terms of ethylbenzene conversion and styrene yield using this novel reactor was obtained in comparison with the conventional industrial reactor. The counter‐current sweep gas with optimal partial blinding gave the most superior performance.
Crystallization of Calcium Sulfate Dihydrate from Phosphoric Acid
Authors: Jamialahmadi M. , Müller‐Steinhagen H. 
Published: August 2010

AbstractKnowledge of the kinetics of calcium sulfate dihydrate crystallization from phosphoric acid solutions is essential for design and operation of the dihydrate process, which is frequently used in fertilizer industries for the production of phosphoric acid A continuous crystallizer was used to investigate the effect of operating parameters on nucleation and growth rates, and ultimately on the crystal size distribution of calcium sulfate dihydrate. It is shown that growth rate increases with the square of supersaturation and that the effect of temperature on the growth rate constant follows an Arrhenius relationship with an activation energy of 65.2 kJ/mol. The predictions of the suggested kinetic models are verified against plant data.
Cross‐directional Estimation and Predictive Control of Paper Machines Using DWT
Authors: Song Zhihuan , Li Ping , Lou Yiming 
Published: August 2010

AbstractThis paper proposes a novel approach for cross‐directional (CD) estimation, modeling and control on paper machines based on discrete wavelet transforms (DWT). The CD basis weight variations are approximated at various resolutions using wavelet multiresolution analysis (WMRA). The controllable component of CD variations can be extracted from the original samples by choosing a suitable threshold resolution. An acceptable response model describing the relationship between the settings of the slice‐screws to the basis weight profile is obtained. The controller synthesis, model prediction, optimization and parameter estimation are all performed in the DWT domain. The size of optimization and control problems associated with such large dimensions can be significantly reduced.
Data Compression for Types of Nopaper Recorders Based on Some Wavelets
Authors: Jin Jiangxiang , Zhu Jianxin 
Published: August 2010

AbstractIn this paper, an efficient compression algorithm based on some wavelets for types of nopaper recorders is provided. Numerical results demonstrate that the algorithm is better applied to the compression of historical data, for example, temperature, liquid level, flow rate and pressure. Therefore, the algorithm reduces the need for storage of these data and improves the functions of the recorders to a maximum.
Output Feedback Stabilization of Uncertain Time‐Delay Systems Containing Saturating Actuators
Authors: Su Hongye , Hu Jianbo , Chu Jian , Lam James 
Published: August 2010

AbstractThe robust output feedback stabilization problem for a class of uncertain linear time‐delay systems containing a saturating actuator is studied in this paper. The systems are described by state differential equations with bounded time‐varying uncertain parameters and unknown constant delay in the state. New criterion for robust stabilizability of the uncertain time‐delay systems is presented and the corresponding observer‐based robust output feedback controller is derived in terms of the solutions of linear matrix inequalities (LMIs). Simulation results show that the obtained method is feasible.
Variable Structure Control for a Class of Systems with Mismatched Uncertainties
Authors: Hu Jianbo , Liang Ximing , Wu Jun , Su Hongye , Chu Jian 
Published: August 2010

AbstractThe problem of Variable Structure Control (VSC) for a class of systems with mismatched uncertainties is studied in this paper. The systems considered in this paper can be transformed into two staged sub‐systems. The first subsystem is a linear system with uncertainties U1, and its inputs are the state variables of the second subsystem. The second sub‐system, having the same dimension as the inputs, is a nonlinear system with uncertainties U2 and its inputs are the control inputs for the original system. In fact, U1 and U2 are the mismatched uncertainties and matched uncertainties of the original system, respectively. Based on the quadratic stabilization for the first sub‐system, the desired values of the second state variables are synthesized by Linear Matrix Inequality (LMI) technique, and the switching function vector is constructed based on the errors between the values of the second state variables and their desired values. Furthermore, the variable structure controller is derived by the reachable condition for the sliding‐mode such that the closed‐loop system can enter and retain the sliding‐mode. Meanwhile, the closed‐loop system has the stable sliding‐mode motion.
Burnout Behaviour of Bituminous Coals in Air‐Staged Combustion Conditions
Authors: Kluger F. , Spliethoff H. , Hein K. R. G. 
Published: August 2010

AbstractIn order to determine the influence on burnout by the combustion conditions and the coal preparation, three bituminous coals sold on the world market, from three different locations, in Poland, South Africa, and Australia, were studied more closely. For this purpose, the coals were ground in two different particle size ranges, which, besides the influence of the combustion conditions, such as temperature, residence time, and stoichiometry, made it possible to also investigate the impact on burnout by the coal preparation. The experiments were carried out in an electrically heated entrained‐flow reactor with a thermal input of 8.5 kW. The parameters for the experiments are wall temperature (1000 ‐ 1350d̀C), air ratio (0.6–1.15), and two particle sizes (70% < 75m̈m, 90% < 75m̈m). The results show that in general, for increasing temperatures, the burnout quality will improvel. For the Australian Illawara coal, another outcome is increased NOx emissions. Lowering the air ratio in the reduction zone leads to less NOx emission but to increased unburnt matter in ash. For the smaller particle size fraction, the analysis of the different particle sizes shows an improvement of the burnout without a change in NOx emissions.
A Study of the Reactivity and Formation of the Unburnt Carbon in CFB Fly Ashes
Authors: Li Yong , Zhang Jiang‐Sheng , Liu Qing , Lu Ji‐Ling , Yue Guang‐Xi , Sarofim Adel F. , Beér Janos M. , Lee Yam Y. , Eliasson Baldur 
Published: August 2010

AbstractA comprehensive study was conducted on the reactivify and the turbostratic structure of the unburnt carbon in the CFB fly ashes. The observed deactivation of the unburnt carbon and the pyrolysis chars prepared under various conditions was studied and found to be due to the combination of the loss of catalytic effect of the minerals and the crystalline growth of carbon. Various forms of morphology of the residual carbon particles were examined under a microscope. Both inertinite and vitrinite seem to be possible sources of the unburnt carbon. The formation of the unburnt carbon in the CFB fly ashes was likely caused by the deactivation of char particles and the insufficient residence time of the corresponding fuel particles.
Mineral Matter Transformation During Pulverized Coal Combustion
Authors: Eddings Eric G. , Davis Kevin A. , Heap Michael P. , Valentine James R. , Sarofim Adel F. 
Published: August 2010

AbstractSignificant progress has been made in understanding and quantifying the processes governing the transformation of the inorganic constituents of fuels, leading to the promise of being able to predict the behavior of mineral matter in real systems. In addition, modern computational models have progressed to the point that combustion simulations can be now be realized for industrial‐scale systems. The combination of current understanding of mineral matter transformations with state‐of‐the‐art computational fluid dynamics (CFD) models provides a powerful tool for analyzing utility boilers. A case study is presented illustrating how knowledge of the transformation of pyrites coupled with CFD models can be used to explain problems of corrosion that have been encountered in some utility boilers as a result of modifications to reduce emissions of nitrogen oxides.
Rapid Solution of Stiff Differential Equations and Accurate Numerical Laplace Inversion of Steep and Oscillatory Functions using IMN Approximants
Authors: Taiwo O. , King R. 
Published: August 2010

AbstractIMN approximants are a fast and convenient method of solving initial value problems in linear stiff differential algebraic equations as well as obtaining the numerical inversion of Laplace transforms In the past it was impossible to use them to obtain sufficiently accurate inversions of certain steep and highly oscillatory responses as useable values of N had to be relatively small not only to ensure reliable evaluation of IMN constants but also in order to avoid undue rounding errors in the computed results However, the development of computer algebra systems such as Mathematica which permit infinite precision computation has provided greater latitude for the application of the method This work is an exposition of the potency of IMN approximants in accurately and cheaply inverting functions in the Laplace domain whose time functions are steep, oscillatory or stiff Previous applications of the method to some examples in the literature led to wrong conclusions as the capabilities of the method were not fully explored We show how to obtain very accurate results in these circumstances using both the global and step‐by‐step methods The results of using IMN step‐by‐step technique to rapidly solve stiff differential equations of a large staged process are also presented As Matlab gives inaccurate results, Mathematica has been used to compute both the transfer function and the analytical expression for the time response of the plant Extended values ofM and N as well as the ranges of the corresponding IMN constants are tabulated for IMN approximants of full grade.
Applying Dynamic Neutron Radiography in In‐Situ Monitoring of the Drying Processes of Apple
Authors: Balaskó M. , Kőröusi F. , Farkas I. 
Published: August 2010

AbstractA novel technique of Dynamic Neutron Radiography (DNR) was applied for identifying and visualizing the dewatering paths and patterns in apple slices at three thicknesses, to the best of our belief for the first time in this field. By analyzing the DNR images obtained, the iso‐distribution of water (dewatering paths) and fractals (patterns) were obtained. Having the images geometrically calibrated and bileveled, the surface changes of apple slices were described by an exponential model in the course of a dewatering study period of 1500 min, with the velocity of the shrinkage of surfaces being estimated.
An Investigation on Sulfation Mechanisms of Ca‐based Sorbent Modified by Sodium Salt
Authors: Wang Chunbo , Shen Xianglin , Li Daji 
Published: August 2010

AbstractThis paper discusses the calcination and sulfation characteristics of a limestone modfied by Na2CO3, in order to find the causes of enhanced sulfation capacity of the modfied sorbent. It is shown by the experiments that the decomposition rate of modified limestone is quicker than for the original sample, and the CaO formed by the modified limestone (abbreviated as M‐CaO) has higher calcium conversion in sulfation than that formed by the original sample (abbreviated as N‐CaO). Although the sulfur capture capability of M‐CaO is in excess of that of N‐CaO, pore structure measurements showed that specific surface area and porosity of the former are less than that of the latter Therefore, the M‐CaO sulfation phenomena cannot be explained based only on the pore structure. The crystal structure parameters of CaO were measured and require further investigation. According to solid‐state ions diflusion theory, a new sulfation mechanism is proposed. More lattice defects are formed in M‐CaO, which reduces the resistance of ion diffusion in the product layer and increases the calcium conversion.