The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
H. Vogt - One of the best experts on this subject based on the ideXlab platform.
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Essential Readings in Light Metals: Aluminum Reduction Technology, Volume 2 - On the Anode Effect in Aluminum Electrolysis
Essential Readings in Light Metals, 2016Co-Authors: J. Thonstad, T A Utigard, H. VogtAbstract:Anode Effects are detrimental in that they result in reduced energy efficiency and cause emissions of CF4 and C2F6. With prospects of future CO2 taxes, the emissions of these greenhouse gases may become costly. With a CO2 tax of 15 US$ per tonne, each Anode Effect minute per day per cell will increase the production cost by about 1.2%. Research work related to Anode Effects has been reviewed and analyzed. The wetting of the Anode deteriorates as the alumina content decreases, leading to increased gas coverage of the base of the Anode. With decreasing Effective surface area, the actual current density increases. Anode Effects then occur when the alumina content becomes too low and the local current density exceeds the critical current density. The paper concludes by analyzing various methods that may be used to decrease the frequency and duration of Anode Effects in prebake as well as Soderberg cells.
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on the Anode Effect in aluminum electrolysis
2016Co-Authors: J. Thonstad, T A Utigard, H. VogtAbstract:Anode Effects are detrimental in that they result in reduced energy efficiency and cause emissions of CF4 and C2F6. With prospects of future CO2 taxes, the emissions of these greenhouse gases may become costly. With a CO2 tax of 15 US$ per tonne, each Anode Effect minute per day per cell will increase the production cost by about 1.2%. Research work related to Anode Effects has been reviewed and analyzed. The wetting of the Anode deteriorates as the alumina content decreases, leading to increased gas coverage of the base of the Anode. With decreasing Effective surface area, the actual current density increases. Anode Effects then occur when the alumina content becomes too low and the local current density exceeds the critical current density. The paper concludes by analyzing various methods that may be used to decrease the frequency and duration of Anode Effects in prebake as well as Soderberg cells.
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On the various types of uncontrolled potential increase in electrochemical reactors—The Anode Effect
Electrochimica Acta, 2013Co-Authors: H. VogtAbstract:Abstract Various types of uncontrolled potential increase must be distinguished at gas-evolving electrodes. A theoretical analysis on the basis of fundamental relationships shows that the increase in potential – commonly associated with the so-called Anode Effect at cells with constant or varied current – is caused in some cases by limitation of mass transfer. In other cases it is the result of reaching a summit current value created by the presence of gas bubbles in contact with the electrode surface. Which of the causes is the controlling one depends on the bulk concentration of the reacting substance and on the state of the electrode surface, particularly on material and roughness directly acting on the wettability. It is not sufficient to attribute any uncontrolled potential increase solely to mass transfer control as hitherto done. Several types must be taken into consideration.
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The voltage of alumina reduction cells prior to the Anode Effect
Journal of Applied Electrochemistry, 2002Co-Authors: H. Vogt, J. ThonstadAbstract:Alteration in cell voltage of industrial cells after each feeding of fresh alumina is initially small and accelerates to become extremely fast immediately prior to the incipience of the Anode Effect. Estimates of the components of the cell voltage on the basis of a mathematical model particularly taking account of the action of the gaseous phase underneath the Anode are compared with experimental data from industrial cells. The fundamental agreement (in spite of inevitable model insufficiencies) supports the view that the Anode Effect is induced as the actual anodic current density approaches the limiting one.
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On the mechanism of the Anode Effect in aluminum electrolysis
Metallurgical and Materials Transactions B, 2000Co-Authors: H. VogtAbstract:The dependency of the critical current density in aluminum electrolysis on the bulk concentration of alumina has been reported in various forms. Some workers found different relationships in restricted ranges of the alumina content and concluded on possible changes of the reaction mechanisms and various types of Anode Effect. A previously developed mathematical model could show that the Anode Effect is initiated as the actual current density equals the limiting one. The model is now applied to check some of the available theories. Comparison with experimental data shows that the varying Effect of the alumina concentration can be described by a single relationship taking account of the combined action of mass transfer, fluid dynamics of gas release, and wettability for all values of the alumina content. The results suggest that there is every reason for the view that only one process occurs. A distinction of various types of mechanisms provoking the Anode Effect is unnecessary.
J. Thonstad - One of the best experts on this subject based on the ideXlab platform.
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Essential Readings in Light Metals: Aluminum Reduction Technology, Volume 2 - On the Anode Effect in Aluminum Electrolysis
Essential Readings in Light Metals, 2016Co-Authors: J. Thonstad, T A Utigard, H. VogtAbstract:Anode Effects are detrimental in that they result in reduced energy efficiency and cause emissions of CF4 and C2F6. With prospects of future CO2 taxes, the emissions of these greenhouse gases may become costly. With a CO2 tax of 15 US$ per tonne, each Anode Effect minute per day per cell will increase the production cost by about 1.2%. Research work related to Anode Effects has been reviewed and analyzed. The wetting of the Anode deteriorates as the alumina content decreases, leading to increased gas coverage of the base of the Anode. With decreasing Effective surface area, the actual current density increases. Anode Effects then occur when the alumina content becomes too low and the local current density exceeds the critical current density. The paper concludes by analyzing various methods that may be used to decrease the frequency and duration of Anode Effects in prebake as well as Soderberg cells.
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on the Anode Effect in aluminum electrolysis
2016Co-Authors: J. Thonstad, T A Utigard, H. VogtAbstract:Anode Effects are detrimental in that they result in reduced energy efficiency and cause emissions of CF4 and C2F6. With prospects of future CO2 taxes, the emissions of these greenhouse gases may become costly. With a CO2 tax of 15 US$ per tonne, each Anode Effect minute per day per cell will increase the production cost by about 1.2%. Research work related to Anode Effects has been reviewed and analyzed. The wetting of the Anode deteriorates as the alumina content decreases, leading to increased gas coverage of the base of the Anode. With decreasing Effective surface area, the actual current density increases. Anode Effects then occur when the alumina content becomes too low and the local current density exceeds the critical current density. The paper concludes by analyzing various methods that may be used to decrease the frequency and duration of Anode Effects in prebake as well as Soderberg cells.
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The voltage of alumina reduction cells prior to the Anode Effect
Journal of Applied Electrochemistry, 2002Co-Authors: H. Vogt, J. ThonstadAbstract:Alteration in cell voltage of industrial cells after each feeding of fresh alumina is initially small and accelerates to become extremely fast immediately prior to the incipience of the Anode Effect. Estimates of the components of the cell voltage on the basis of a mathematical model particularly taking account of the action of the gaseous phase underneath the Anode are compared with experimental data from industrial cells. The fundamental agreement (in spite of inevitable model insufficiencies) supports the view that the Anode Effect is induced as the actual anodic current density approaches the limiting one.
Muzeyyen Marsoglu - One of the best experts on this subject based on the ideXlab platform.
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Anode Effect elimination by subsonic and sonic vibrations
JOM, 2009Co-Authors: Tuba Karahan, Ismail Duman, Muzeyyen MarsogluAbstract:The only method so far used industrially to produce primary aluminum is the combination of the Bayer process with the Hall-Héroult process. The production process of aluminum which was patented by Charles Martin Hall and Paul Louis Toussaint Héroult in 1886, has long been important in our daily lives and that importance is likely to increase year by year. In this study, different subsonic and sonic vibrations, which were obtained from a 0.30 kW, 1,400 rpm three-phase motor, also a 0.55 kW, 2,800 rpm three-phase motor and 0.75 kW frequency converter, were applied to a laboratory-type aluminum electrolysis cell and the possibility of eliminating the Anode Effect was investigated.
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Anode Effect elimination by subsonic and sonic vibrations
JOM, 2009Co-Authors: Tuba Karahan, Ismail Duman, Muzeyyen MarsogluAbstract:The only method so far used industrially to produce primary aluminum is the combination of the Bayer process with the Hall-Heroult process. The production process of aluminum which was patented by Charles Martin Hall and Paul Louis Toussaint Heroult in 1886, has long been important in our daily lives and that importance is likely to increase year by year. In this study, different subsonic and sonic vibrations, which were obtained from a 0.30 kW, 1,400 rpm three-phase motor, also a 0.55 kW, 2,800 rpm three-phase motor and 0.75 kW frequency converter, were applied to a laboratory-type aluminum electrolysis cell and the possibility of eliminating the Anode Effect was investigated.
Simon-pierre Déry - One of the best experts on this subject based on the ideXlab platform.
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Retrofit of a Combined Breaker Feeder with a Chisel Bath Contact Detection System to Reduce Anode Effect Frequency in a Potroom
Light Metals 2011, 2016Co-Authors: Jonathan Verreault, Bernard Desgroseilliers, René Gariépy, Claude Simard, Xavier Delcorde, Christophe Turpain, Serge Simard, Simon-pierre DéryAbstract:Chisel bath contact detection is a feedback system installed on aluminum reduction cell alumina point feeders to ensure that the crust breaker (or chisel) touches liquid bath. The benefits of chisel bath contact detection on Anode Effect reduction are well known on AP Technology ™ operating with a separate system of breakers and feeders. The present paper describes the technology adaptation for a safe hot change installation of chisel bath contact detection applied to the combined breaker/feeder in a P-155 cell while, at the same time, introducing a longer pneumatic cylinder stroke. Mechanical modifications allowing the reuse of most of the existing breaker/feeder parts as well as the results obtained on four experimental cells during the development phase are presented. The retrofit procedure is also described in the context of a hot change while controlling health, safety and environment (HSE) related aspects.
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Light Metals 2011 - Retrofit of a Combined Breaker Feeder with a Chisel Bath Contact Detection System to Reduce Anode Effect Frequency in a Potroom
Light Metals 2011, 2011Co-Authors: Jonathan Verreault, Bernard Desgroseilliers, René Gariépy, Claude Simard, Xavier Delcorde, Christophe Turpain, Serge Simard, Simon-pierre DéryAbstract:Chisel bath contact detection is a feedback system installed on aluminum reduction cell alumina point feeders to ensure that the crust breaker (or chisel) touches liquid bath. The benefits of chisel bath contact detection on Anode Effect reduction are well known on AP Technology™ operating with a separate system of breakers and feeders. The present paper describes the technology adaptation for a safe hot change installation of chisel bath contact detection applied to the combined breaker/feeder in a P-155 cell while, at the same time, introducing a longer pneumatic cylinder stroke. Mechanical modifications allowing the reuse of most of the existing breaker/feeder parts as well as the results obtained on four experimental cells during the development phase are presented. The retrofit procedure is also described in the context of a hot change while controlling health, safety and environment (HSE) related aspects.
Sihai Guo - One of the best experts on this subject based on the ideXlab platform.
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Anode Effect prediction based on support vector machine and K nearest neighbor
2017 Chinese Automation Congress (CAC), 2017Co-Authors: Kaibo Zhou, Sihai GuoAbstract:The prediction of the Anode Effect has long been a challenging industrial issue in aluminum electrolytic production. For improving the prediction precision of the Anode Effect, this paper combines support vector machine (SVM) and K nearest neighbor (KNN) algorithm. First of all, samples are extracted from the real-time production data and weighted with Relief algorithm. Afterwards, the classifier is selected from the two methods depending on the distance from the test sample to the optimal hyperplane of SVM. Compared with traditional approaches, the hybrid method can predict the Anode Effect more accurately. The prediction accuracy can reach about 89% and the predictable time can up to half an hour. Extensive experimental results validate the proposed method's Effectiveness.
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Cell resistance slope combined with LVQ neural network for prediction of Anode Effect
2015 Sixth International Conference on Intelligent Control and Information Processing (ICICIP), 2015Co-Authors: Kaibo Zhou, Bin Cao, Zhikai Lin, Ziqian Wang, Sihai GuoAbstract:It is an important part in aluminum electrolysis production to control the Anode Effect (AE). Since there are some shortcomings in traditional methods of Anode Effect prediction in aluminum electrolysis, this paper combined two methods, the slope of cell resistance and learning vector quantization (LVQ) neural network, to predict Anode Effect. First of all, the first prediction of Anode Effect will be conducted based on the slope of cell resistance. Afterwards, the inaccurate data are supposed to be re-predicted. The second prediction consists of two steps, one is to estimate the power spectrum from the signal of cell resistance by means of periodogram, the other is to re-predict the Anode Effect with the LVQ neural network, since the energy of frequency bands are served as the input feature variables of neural network, so as to raise the accuracy of prediction. It turned out that the success rate of ten-minute in advance prediction for Anode Effect can be above 85%, though just cell resistance signal is studied.
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Anode Effect prediction of aluminum electrolysis using GRNN
2015 Chinese Automation Congress (CAC), 2015Co-Authors: Kaibo Zhou, Bin Cao, Zhikai Lin, Ziqian Wang, Dengzhi Yu, Sihai GuoAbstract:Aimed to improve accuracy rate and time advance of the Anode Effect (AE) prediction in aluminum electrolysis cell, a new prediction method by means of the Generalized Regression Neural Network (GRNN) is proposed. The structure and advantages of the GRNN are introduced, then modeling the Anode Effect system of aluminum electrolysis cell by means of system identification based on the GRNN. The structure of samples is analyzed emphatically in the process of modeling, and the influence of sample size to model prediction accuracy is analyzed by experiment. The prediction model based on GRNN is trained and tested by sufficient samples extracted from the production data of the 400kA aluminum electrolysis cell. It's proved that the accuracy rate of the AE prediction is more than 90% on average in advance 30 minutes. In addition, results tested for different aluminum electrolysis cells show that the method has extensive applicability while keep high prediction accuracy and its Effective.