bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of the Properties of Activated Bagacillo on Cr(VI) Adsorption
Authors: Valix M. , Siliezar J. , Zhang K. 
Published: August 2010

AbstractThe present study deals with the adsorption of Cr(VI) in a series of carbons prepared from bagacillo, which is a lignocellulosic by‐product from a sugar milling operation. Activated carbons were prepared by chemical activation using ZnCl2, CaCl2, H3PO4 and Ca(OH)2 and physical activation with steam and carbon dioxide. The effects of the chemical nature and the pore structures on the adsorption behaviour of these activated carbons were investigated. The functional groups present on the surface of the carbons were differentiated and related to the observed adsorption behaviour of the carbons. It appears that adsorption is strongly influenced by the pH of the carbon, where acidic functional groups appear to enhance the adsorption behaviour. Fine micropore structures appear to exhibit a molecular sieve effect. Restrictive pores, present in carbons with high surface areas, appear to inhibit the access of Cr(VI) into the micropore structures resulting in low adsorption.
Highly Effective Catalysts for N2O Conversion to N2—A Preliminary Study
Authors: Zhu Zhonghua , Zhuang Yahui , Shen Dixin , Lu G.Q.(Max) 
Published: August 2010

AbstractCatalytic conversion of N2O to N2 with Cu‐ and Co‐ impregnated activated carbon catalysts (Cu/AC and Co/AC) was investigated. The relationship between N2O conversion and metal (Cu and Co) content was examined. The catalysed N2O‐carbon reaction was studied in a fixed‐bed flow reactor at atmospheric pressure. Two modes of experiments were employed: (i) temperature‐programmed reaction (TPR) in a N2O/He mixture; and (ii) isothermal reaction at 350 d̀C to 380 d̀C. Both Cu and Co catalyse the N2O‐ carbon reaction effectively, which is shown by the decrease in activation energy and the substantial shift of N2O reduction curves toward much lower temperatures. A 20wt% metal loading has proved to be optimal for both Cu and Co, which can lead to 100% of N2O conversion at 400 d̀C for both cases. At lower temperatures, Co/AC is more active, whereas at higher temperatures Cu/AC is much more stable. The reaction mechanisms are discussed in this paper based on the TPR curves, the isothermal reactivity data and distribution of the products.
Modelling for Flash Calcination and Surface Area Development of Dispersed Limestone Particles
Authors: Ying Z. , Chuguang Z. , Zhaohui L. , Xuefeng S. 
Published: August 2010

AbstractA mathematical model for calcination, sintering and surface area development of dispersed limestone particles is presented in the paper. The model describes the calcination by considering heat transfer, mass transfer of CO2 through a porous CaO layer, and the chemical kinetics. Diffusion of CO2 in a porous product layer is discussed in detail. The extent of calcination, BET surface area, temperature and pressure distribution in a particle were calculated. The extent of calcination and BET surface area, obtained from the simulation, are consistent with experimental data.
Study on Emission Control of NOx and N2O in a Fly‐ash Recycle Fluidized Bed Test Rig
Authors: Zhong Z. , Lan J. , Jin B. , Han Y. 
Published: August 2010

AbstractExperiments on NOx and N2O release characteristics and emission control were studied in a fly‐ash recycle fluidized bed test rig. The total height of the fluidized bed is 4.4m. The fluidization section is 1.2m high with a cross‐section 0.23mx0.23m. The freeboard is 3.0m high with a cross‐section 0.460mx0.345m. The coal‐fired weight of the test rig is 30 kg/h, and coal is fed by a screw feeder. Fine ash is collected by a cyclone and recycled to the bed surface through a J‐valve, slag is then removed from the bottom. An oil‐fired start‐up burner is also used. Test fuels are Xuzhou bituminite and Kenan anthracite from China with particle range of 0‐8mm. When the bed temperature rises, NOx increases and N2O decreases. At the same temperature, N2O emission of bituminite is less than that of anthracite. While the secondary air ratio reached 15% under staged combustion, NOx emission decreased to 14% and N2O emission decreased to 24%. As the Ca/S molar ratio increases, NOx emission also increases while N2O emission decreases. Ammonia injection decreases NOx emission significantly, but it has no effect on the emission of N2O.
Study on Flow Properties of Coal‐Water Paste in Pipes
Authors: Meng L. , Zhang M. , Shen L. 
Published: August 2010

AbstractIn this paper the similitude criterion known as generalized Reynolds number \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm{Re}}_g = \frac{{\rho VD\left[ {a^{n - 1} \left( {1 - a} \right)} \right]^{1/n} }}{{K^{1/n} \tau _y^{1 - 1/n} \left( {1 - U_s /V} \right)}}f\left( a \right) $\end{document} is proposed to characterize the flow state of coal‐water paste in pipes, on the assumption of coal‐water paste as a non‐Newtonian fluid and for slip flow phenomenon in pipes. It can be used to describe the no‐slip flow of non‐Newtonian and Newtonian fluids behaving as steady‐state laminar flow in pipes. A convenient new method of determining the resistance properties of coal‐water paste is suggested.
Process Control and Optimization in Energy Utilization and Environmental Protection
Authors: Tadé M. O. 
Published: August 2010

AbstractAn evolving goal in power plants for many decades is to have the process control system predict and optimize the set‐point changes continuously in real time and to automatically regulate flows, temperatures, and pressures. This goal has now become more significant and more involved because a fourth dimension, the environment, has been added to the three traditional dimensions (namely, safety, efficiency and cost) of real time power plant performance. In this paper, the emerging role of process control and optimization is reviewed within the context of energy utilization and environmental protection. Case studies that have been reported in this area are discussed. Some limitations of the current technology are identified.
Mathematical Model of a Continuous Galvanizing Annealing Furnace
Authors: Tian Y.‐C. , Hou C.‐H. , Gao F. 
Published: August 2010

AbstractA state space model discrete in time and space was developed for on‐line and realtime computation and prediction of strip temperature in a continuous galvanizing annealing furnace. The model development was based on a combination of physical modeling and system identification. An equivalent heat transfer coefficient was introduced to simplify the physical relations of the process. Compact model expressions suitable for on‐line and real‐time computation were obtained using the finite difference technique. A stability analysis of the model was conducted to guide the selections of time and space steps. System identification aspects were also discussed. The model was successfully applied to industry with good performance.
Guaranteed Cost Sampled‐Data Control for Refining Process
Authors: Lu Yingquan , Kong Yaguang , Wang Wenhai , Sun Youxian 
Published: August 2010

AbstractThis paper presents a synthetic design procedure of guaranteed cost sampled‐data control (GCSDC) for refining process. When a digital controller controls the refining process with appropriate sample and hold devices, the closed loop system is periodic time varying. Based on this sampled‐data system, considering the uncertainties in the continuous‐time plant, we define the guaranteed cost control and a controller that not only stabilizes the closed loop system but also guarantees an adequate level of the performance. Simulation results show that the control scheme is effective and practicable.
A Combined Model for Supervisory Control of Continuous Processes
Authors: Xianhui He , Chunhua Gao , Hui Wang 
Published: August 2010

AbstractUsing Hybrid Petri Nets (HPNs) together with a continuous mathematical model, a combined modeling method for continuous‐process dynamic scheduling and supervisory control is presented. This method can describe both continuous characteristics of a continuous process and its discrete control strategies on the same level. An ideal binary mixture distillation column is used as an example to illustrate the proposed method. Based on the combined model, a supervisory control scheme is also provided.
Finite Word Length Implementation for Digital Reduced Order Observer Based Controllers
Authors: Wu J. , Chu J. , Chen S. , Li G. 
Published: August 2010

AbstractImplementation issues for digital reduced‐order observer‐based controllers with Finite Word Length (FWL) considerations is studied. A tractable FWL stability related measure is derived, and the optimal FWL realization problem for digital reduced‐order obverser‐based controller is to find those realizations that maximize this related measure. This optimization problem is formulated as an unconstrained nonlinear programming problem which can be solved using the simplex search algorithm. A numerical example is given to illustrate the design procedure and the effectiveness of the proposed method.
Analysis and Implementation of the Double‐Controller Scheme
Authors: Tian Y.‐C. , Gao F. 
Published: August 2010

AbstractThis paper gives some insight into the double‐controller scheme proposed recently. The double‐controller scheme has good robustness as well as simultaneous fast set‐point tracking and good load rejection. Investigations show that it enhances the conventional feedforward control. The stability and robustness of the control scheme are analyzed in the frequency domain and compared with those of the Smith predictor. To further improve the performance of the double‐controller scheme, techniques are proposed to accommodate large uncertainties in process delay time and gain. Two control signals of the double‐controller scheme are employed for extraction of process parameter information and on‐line tuning of the control system. The effectiveness of the proposed techniques is verified through numerical simulations.
An Integrated L‐Lysine Fermentation Model with Agitation Speed as the Manipulated variable
Authors: Yao H.M. , Tian Y.‐C. , Tadé M.O. , Ang H.M. 
Published: August 2010

AbstractThe L‐lysine fermentation process by Brevibacteria lactofermentum was investigated for improvement of process performance by manipulating cellular environmental conditions through computer monitoring and control. The main factor under consideration was dissolved oxygen concentration (DOC) in the broth. An integrated process model with agitation speed as the manipulated variable was developed for the model‐based controller using combined kinetic study and material balances. The selection of rate equations, which properly describe the specific process, was studied and the influence of different dissolved oxygen (DO) conditions to model parameters was discussed. A first order with time delay model was used to describe the oxygen transferred from gas to liquid phase. The dynamic behaviour of time constant, system gain, yields and maintenance coefficient were considered and closely correlated to the broth concentrations. The Nelder and Mead optimisation method was used for identification of all model parameters.
Hybrid Automaton Model and Control of Hybird Systems
Authors: Zhang Wei , Sun Youxian 
Published: August 2010

AbstractA hybrid automaton model is proposed in this paper for hybrid systems. The model, with particular emphasis on process control applications, is based on the dynamic features of hybrid systems. It takes into account the discrete dynamics of hybrid systems in particular and can clearly separate the controller from the closed‐loop system. The definition of controllability of hybird systems with respect to the marked regions is also given. An analyzing algorithm and sufficient and necessary condition for controllability based on the hybrid automaton model are discussed. At the same time, the property of the loops in the trajectory of the closed‐loop plant is studied. Finally, the synthesis scheme for a hybrid controller is given. In this scheme, the controller consists of two parts, the discrete supervisor and the continuous regulator. The closed‐loop plant with the controller is state‐controllable.
Formulae of the Infimal Controllable and Observable Sub‐language and Synthesis of Its Supervisor
Authors: Wenjun Yan , Weinong Shentu 
Published: August 2010

AbstractThe Supervisory Control Theory of Discrete Event Dynamical Systems (DEDS) is one main approach of studying DEDS in recent years. The existing condition of the supervision and the synthesizing method under partial controllable and observable events are investigated. A formula for the infimal prefix closed controllable and observable sub‐language of a given language is presented. The effectiveness of the method is illustrated with two examples.
Robustness Bound of LQ Guaranteed Cost Control Systems for Parameter Uncertainty
Authors: Xue Anke , Chen Yao , Sun Youxian 
Published: August 2010

AbstractThe problem of robustness bound for parameter uncertain systems with LQ guaranteed cost controller is considered in this paper. A parameter dependent robustness bound for parameter uncertainties is derived. Then, an optimization problem of improving the robustness of parameter uncertain systems is proposed. And also, the responding optimization technique is given in the paper.
The Partitioning of Arsenic, Selenium, Cadmium, and Cesium during Pulverized Coal Combustion in a 17 kW Downflow Combustor
Authors: Seames Wayne S. , Wendt Jost O. L. 
Published: August 2010

AbstractThe combustion of coal liberates arsenic, selenium, cadmium, and cesium into the environment. These toxic metals, which are discharged with the flue gas or collected with fly ash, may vaporize in the hot portions of the combustor then return to the solid phase in cooler zones of the process downstream. Understanding the mechanisms by which toxic metals partition between the vapor and solid phases is an important step for predicting and mitigating the effect of these metals upon the environment. An investigation of these partitioning mechanisms was performed. The results suggest that the dominant heterogeneous partitioning mechanism for transformation to the solid phase in the post‐combustion zone is the reaction of metal vapor on the surface or within the pores of a supermicron ash particle for the Pittsburgh seam and Illinois #6 coals but not for the Ohio blend coal. A relationship between the concentration of supermicron phase arsenic, selenium, and cadmium to calcium was also observed, suggesting the formation of As‐Ca, Se‐Ca, and Cd‐Ca reaction products. Selenium appears to be more reactive than arsenic for the formation of these calcium‐based complexes.
A Model for Flue Gas Desulfurization with Lime Absorbent at Middle Temperature
Authors: You Chang‐Fu , Qi Hai‐Ying , Wang Wei , Xu Xu‐Chang 
Published: August 2010

AbstractA model to simulate the desulfurization process for reaction of flue gas with lime at middle temperature (400‐800d̀C) has been established based on the grain model. The rationality of the model has been examined by making comparison between the calculated values of the model and the experimental results. The effects of certain parameters on conversion of CaO have been analyzed. Establishment of this model provides the initial foundation for the development of flue gas desulfurization technology with lime absorbent at middle temperature.
Time Optimal Control of a Binary Distillation Column
Authors: Luus Rein 
Published: August 2010

AbstractTime optimal control problems involving high dimensional systems are generally very difficult to solve. Instead of using suboptimal control based on reduced system, iterative dynamic programming is used directly to establish the time optimal control policy of a binary distillation column described by 11 ordinary differential equations. The resulting optimal control policy that is bang‐bang in nature was obtained very rapidly. The minimum time of 2236 seconds obtained here is substantially better than 4120 seconds obtained by a suboptimal control policy. Simulations show that the procedure may be used for on‐line optimal control of the distillation column, since the optimal control policy can be established very fast on a personal computer.
Simulation and Optimization of Linear Alkylbenzenes Distillation Process
Authors: Hu Yongyou , Su Hongye , Lu Jingwei , Mu Shengjing , Chu Jian , Wu Jun 
Published: August 2010

AbstractThe pure linear alkylbenzenes (LAB) are widely used in detergent manufacture, which are generally obtained by alkylation of benzene with linear C9‐C13 olefins How to decrease the loss of LAB during the distillation process is always the focus of manufacturers' attention In this paper, a mathematic model of a newly rebuilt LAB distillation process is established and some operation and control problems are studied by simulation and analysis we not only find the bottleneck and the optimal operating conditions of the distillation process, but also locate the new sensitive plates with optimal ranges of temperature The simulation results indicate that the loss of LAB can be reduced from 1.0% to 0.05%, simultaneously with the distillate of regular LAB product (>99.5% mass fraction) increases of 600 kg/h under the optimal operating conditions
Application of Adaptive Fuzzy Neural Network for Forecasting Coal Slagging in a Power Station
Authors: Zheng Chuguang , Liu Gehui , Huang Yongli 
Published: August 2010

AbstractAsh related problems in coal‐fired power plants result in decreased efficiency, unscheduled outages, equipment failures and cleaning problems Assessing the potential impact of ash on power plant performance is extremely complicated and difficult due to coal variability, complexity of the ash behavior processes and changes in operating conditions involved This study introduces a new method of coal slagging forecast This method employs a hybrid‐learning rule composed of recursive least‐squares estimation and a gradient descent algorithm The forecast results are compared with measured data The comparison shows that the method based on adaptive fuzzy neural network for the prediction of coal slagging has the advantages of high precision, fast convergence and perfect adaptability
Internal Heating Effect and Application of Microwaves with Fluidization of Electrically Conductive Particles in the Ceramic Drying Process
Authors: Itaya Y. , Okouchi K. , Uchiyama S. , Mori S. , Hasatani M. 
Published: August 2010

AbstractIn the ceramic drying process, it takes a long time to completely remove internal moisture from molded ceramics due to large resistance of internal migration. Microwave heating is an effective internal heating method and will promote the moisture movement rate inside ceramics due to the elevation of vapor pressure. The effect of internal uniform heating on the ceramic drying behavior is first studied by theoretical analysis. The effectiveness and problems of drying of a slab heated by microwaves were evaluated experimentally and compared with hot air heating. The drying proceeded successfully and quicker than hot air heating when the internal temperature could be controlled below 380 K, by introducing intermittent heating or low power irradiation of microwaves. Additionally, a technique for improving uniformity of the microwave field by fluidization of electrically conductive particles was proposed. The distribution of the microwave field became successively uniform by the diffuse reflection of microwaves in a fluidized bed of plastic foam particles wrapped in aluminum foil.
Pulse Combustion and Supercritical Fluid Techniques as Examples of Innovative Drying Technologies
Authors: Rogacki G. , Strumillo C. , Wawrzyniak P. , Zbicinski I. 
Published: August 2010

AbstractIn this paper the need for innovative drying techniques is suggested. Pulse combustion and supercritical fluid techniques which were developed in the drying laboratory of the Lodz Technical University are presented as examples. In the section concerned with pulse combustion, valved and valveless pulse combustors are described and several features of both types are identified. The advantages and drawbacks of the pulse combustor are presented. The selection of a pulse combustor, its geometry and atomizer as well as enhancement of drying rate are discussed. The importance of the high driving force in this process intensification is stressed. In the section dedicated to supercritical fluid techniques, high‐ and low‐temperature procedures of drying are described. The most important aspects of the drying cycle are discussed with special reference made to the kinetics of diffusive solvent exchange inside a wet gel body.
Separation and Mineralogical Analysis of Bayer Red Mud
Authors: Picaro T. , Pei B. , Kane A.R. , Thornber M.R. , Fletcher A.B. 
Published: August 2010

AbstractThis paper describes preliminary work to assess the potential for recovering valuable components from Queensland Alumina Limited (QAL) red mud by physical beneficiation. Upgrading of Weipa bauxites residue was trialed using a 50 mm hydrocyclone and a Mozley Multigravity Separator (MGS) to recover desilication product (DSP) and TiO2 fractions. The mineralogy of the original red muh and the various sub‐fractions produced was studied by chemical assay, selective leaching, XRD and SEM techniques.DSP is present in QAL red mud in two forms: (i) as balls in the size range from 0.8 to 10 μm that appear to be liberated; and (ii) as finely grained DSP intermixed with the other minerals. The hydrocycloning tests produced a DSP rich (39.5 wt%) fraction at 89% recovery from a feed containing 31.9 wt.% DSP. This represents an upgrade (enrichment) of 1.24 times. These results suggest that the greatest DSP enrichment will be achieved by targeting the 0.8 to 10 μm DSP balls.The richest TiO2 fraction produced varied from 20 to 36 wt.% TiO2 from a feed value of 7 wt.% at a recovery of 7.5%. Mineralogical examination showed that most of the TiO2 in this fraction was as liberated particles in the size range 8 to 20 μm. Most of the TiO2 particles in the other fractions were not fully liberated from mainly iron minerals.The present work indicates that it is possible to further upgrade DSP fractions by investigating finer particle separation techniques, e.g. smaller, 25 mm and 10 mm, hydrocyclones.
Thoughts on Recovering Particle Size Distributions from the Moment Form of the Population Balance
Authors: Flood A. E. 
Published: August 2010

AbstractThe moment form of the population balance is a very popular method of modeling the evolution of particle size in many particulate systems. In many cases the moments of the particle size distribution are sufficient to characterize the system for engineering purposes, however in some cases an approximation to the particle size distribution itself is desired. The traditional method to achieve this approximation is to write the set of (known) moments in matrix form, μ = A.n, and then solve this equation, via matrix inversion, to obtain the population density, n, in a finite number of size classes. The method of matrix inversion may result in a poor approximation, particularly if the distribution is too complex to be represented by a small set of finite width pulses. Several alternative methods are discussed including a similar method based on the central moments, and fitting the moments to known types of distribution functions, the gamma distribution in particular. The inversion method involving central moments improves the conditioning of the matrix. This did not improve the result when small numbers of moments (six or less) were used, because accurate inverses of the matrix for the moments about the origin could be achieved. Fitting moments to known distributions is computationally more difficult than the inversion technique because of the optimization required, but this is not a significant drawback due to the widespread availability of computation mathematical programs. This method was particularly successful in reproducing accurate distributions.