On-line Monitoring of Individual Anode Currents to Understand and Improve the Process Control at Alouette

Dion, Lukas; Lagacé, Charles-Luc; Victor, Ron; Kiss, László I.

doi:10.1007/978-3-319-48248-4_122

Cited by 9 publications

(5 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Important instabilities in the cell (e.g., during high-voltage anode effect) may provoke significant reoxidation of the aluminum metal pad for short amount of time, which, in turn may generate significant alumina additions to the electrolytic bath. This phenomenon was previously observed by the authors [29] when the cell's conditions reach LVAE or HVAE. In the current study, we can observe this phenomenon at the end of scenario #3 where there is a significant increase (half a percent) in the alumina concentration at both extremities of the cell even if no additional alumina feeding was provided by the cell's feeders.…”

Section: E Validation Of the Alumina Distributionsupporting

confidence: 79%

“…These MHD forces, added to the drag force exerted between the aluminum pad and the electrolytic bath, will create a movement of the bath that can affect significantly the movement of the dissolved alumina as demonstrated theoretically [19,21,28] and experimentally. [27,29] In this study, the movement generated by the magneto-hydrodynamic forces is not calculated by the simulator. Instead, the pattern of the electrolytic bath flow is considered similar to the results published by Hofer [21] as part of his Ph.D. thesis.…”

Section: Cell-scale Convection Loops (Module 4)mentioning

confidence: 99%

“…As illustrated in Figure 6, the mass exchange between the different volumes caused by bath movement is asymmetrical as observed experimentally in a previous work by the current authors. [29] The speed of the bath across the different respective volumes was also determined based on the Hofer's research with maximum values located in the corners of the cell with a magnitude of approximately 8 cm/s.…”

Section: Cell-scale Convection Loops (Module 4)mentioning

confidence: 99%

See 2 more Smart Citations

Simulator of Non-homogenous Alumina and Current Distribution in an Aluminum Electrolysis Cell to Predict Low-Voltage Anode Effects

Dion

Kiss

Poncsák

et al. 2018

Metall Mater Trans B

Self Cite

View full text Add to dashboard Cite

Perfluorocarbons are important contributors to aluminum production greenhouse gas inventories. Tetrafluoromethane and hexafluoroethane are produced in the electrolysis process when a harmful event called anode effect occurs in the cell. This incident is strongly related to the lack of alumina and the current distribution in the cell and can be classified into two categories: high-voltage and low-voltage anode effects. The latter is hard to detect during the normal electrolysis process and, therefore, new tools are necessary to predict this event and minimize its occurrence. This paper discusses a new approach to model the alumina distribution behavior in an electrolysis cell by dividing the electrolytic bath into non-homogenous concentration zones using discrete elements. The different mechanisms related to the alumina distribution are discussed in detail. Moreover, with a detailed electrical model, it is possible to calculate the current distribution among the different anodic assemblies. With this information, the model can evaluate if low-voltage emissions are likely to be present under the simulated conditions. Using the simulator will help the understanding of the role of the alumina distribution which, in turn, will improve the cell energy consumption and stability while reducing the occurrence of high-and low-voltage anode effects.

show abstract

Section: E Validation Of the Alumina Distributionsupporting

confidence: 79%

Section: Cell-scale Convection Loops (Module 4)mentioning

confidence: 99%

Section: Cell-scale Convection Loops (Module 4)mentioning

confidence: 99%

See 1 more Smart Citation

Simulator of Non-homogenous Alumina and Current Distribution in an Aluminum Electrolysis Cell to Predict Low-Voltage Anode Effects

Dion

Kiss

Poncsák

et al. 2018

Metall Mater Trans B

Self Cite

View full text Add to dashboard Cite

show abstract

“…Spatially-discretised thermal model.-The measurement of individual anode currents in a cell is unconventional, but has shown great benefits for cell monitoring and control. [24][25][26][27][28][29][30][31][32][33][34] As the heat generation in a cell is primarily ohmic, the anode current distribution readily represents the spatial distribution of energy in a cell. Therefore, similar to the work first presented by Cheung, 26 regions in the cell are discretised according to anode locations as shown in Fig.…”

Section: Model Developmentmentioning

confidence: 99%

Modelling of Coupled Mass and Thermal Balances in Hall-Heroult Cells During Anode Change

Wong

Yao

Bao

et al. 2021

J. Electrochem. Soc.

View full text Add to dashboard Cite

As the most routine work practice in an aluminium reduction cell, anode change introduces substantial perturbations that adversely affect the mass and heat balance of the cell which may lead to loss of process efficiency and increased energy consumption. The literature lacks a dynamic mathematical model that describes the interactions among cell variables (e.g., electrolyte temperature and flow, anode current distribution, and cell heat loss) during and following this operation, which could otherwise be used to understand the process in greater depth and to develop changes that improve process operations and control. This paper presents a spatially-discretised dynamic model for anode replacement that integrates mass balance, thermal balance and cell voltage to describe and predict local cell variables. It was experimentally validated with an industrial cell undergoing an anode change procedure. This generic model can be applied to different cell design or process conditions by using appropriate parameters (e.g., heat transfer coefficients, conductivities, and flow patterns). The model can be used to improve existing process operations or control strategies for higher process efficiency, lower energy consumption, and lower emissions.

show abstract

“…Most of these are related to individual current monitoring as it offers local data on the cell behaviour. More importantly, it supplies indirect information regarding the alumina distribution 21 and the influence of changing anodes. The list of the seven indicators:…”

Section: List Of Indicatorsmentioning

confidence: 99%

Prediction of Low-Voltage Tetrafluoromethane Emissions Based on the Operating Conditions of an Aluminium Electrolysis Cell

Dion

Kiss

Poncsák

et al. 2016

JOM

Self Cite

View full text Add to dashboard Cite

Greenhouse gas (GHG) generation is inherent in the production of aluminium by a technology that uses carbon anodes. Most of those GHG are composed of CO 2 produced by redox reaction that occurs in the cell. However, a significant fraction of the annual GHG production is composed of perfluorocarbons (PFC) resulting from anode effects (AE). Multiple investigations have shown that tetrafluoromethane (CF 4 ) can be generated under low-voltage conditions in the electrolysis cells, without global anode effect. The aim of this paper is to find a quantitative relationship between monitored cell parameters and the emissions of CF 4 . To achieve this goal, a predictive algorithm has been developed using seven cell indicators. These indicators are based on the cell voltage, the noise level and other parameters calculated from individual anode current monitoring. The predictive algorithm is structured into three different steps. The first two steps give qualitative information while the third one quantitatively describes the expected CF 4 concentration at the duct end of the electrolysis cells. Validations after each step are presented and discussed. Finally, a sensitivity analysis was performed to understand the effect of each indicator on the onset of low-voltage PFC emissions. The standard deviation of individual anode currents was found to be the dominant variable. Cell voltage, noise level, and maximum individual anode current also showed a significant correlation with the presence of CF 4 in the output gas of an electrolysis cell.

show abstract

On-line Monitoring of Individual Anode Currents to Understand and Improve the Process Control at Alouette

Cited by 9 publications

References 6 publications

Simulator of Non-homogenous Alumina and Current Distribution in an Aluminum Electrolysis Cell to Predict Low-Voltage Anode Effects

Simulator of Non-homogenous Alumina and Current Distribution in an Aluminum Electrolysis Cell to Predict Low-Voltage Anode Effects

Modelling of Coupled Mass and Thermal Balances in Hall-Heroult Cells During Anode Change

Prediction of Low-Voltage Tetrafluoromethane Emissions Based on the Operating Conditions of an Aluminium Electrolysis Cell

Contact Info

Product

Resources

About