Marc Dupuis

Marc Dupuis
GeniSim Inc. · R&D

Ph. D. Cheminal Engineering

About

120
Publications
25,859
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Introduction
Dr. Marc Dupuis is a consultant specialized in the applications of mathematical modeling for the aluminium industry since 1994, the year when he founded GeniSim Inc. Before he graduated with a Ph.D. in chemical engineering from Laval University in Quebec in 1984, and then worked 10 years as a research engineer for Alcan. His main research interests are the development of mathematical model of the Hall-Héroult cell dealing with the thermo-electric, thermo-mechanic and MHD aspect of the problem.

Publications

Publications (120)
Article
The electrolytic current in an aluminum smelter can amplify resonant motions on the Al–electrolyte interface, producing a circulating wave that can grow out of control. Thick electrolyte layers prevent this magnetohydrodynamic metal pad instability (MPI) but sacrifice efficiency because the electrolyte is a poor conductor. In high-fidelity simulati...
Presentation
Full-text available
The newly developed modeling technique is applied to illustrate possible optimization of the feeder locations, the variable mass, and feeding time intervals for possible adjustments suitable for commercial cells.
Preprint
The metal pad instability (MPI) imposes a minimum electrolyte layer thickness for stable operation of aluminium (Al) electrolysis cells, which limits cells' energy efficiency. The MPI is a magnetohydrodynamic process that depends on a coupled resonance between hydrodynamic gravity wave modes, driven by the cell's electrolytic current, appearing as...
Preprint
Full-text available
Humankind produced 63.7 million metric tons of aluminium in 2019, nearly all via an electrochemical process in which electrical current liberates molten Al from dissolved alumina. That year, Al production required 848 TWh of electricity1, 3% of the worldwide total, and caused 1% of human greenhouse gas emissions. Much of the electricity and emissio...
Chapter
Modern aluminium production cells are pushed to the limits of high amperage at the lowest possible energy consumption. The linear MHDMHD stability theory conditions of small amplitude wave perturbation, fixed magnetic field and electric current distribution, and the neglect of large horizontal circulation velocities are not valid in large cells. Th...
Chapter
In order to be able to assess the rate of heat transfer between a new anode and an anode butt, it is critical to measure the interface thermal contact resistanceThermal contact resistance between them. For that purpose, a lab experiment has been set up and tests have been carried out to record the thermal response of the system after a cold anode b...
Article
Full-text available
A full 3D model of a section of a Hall-Héroult anode cover and hooding system was developed using the code AUTODESK CFD. The model solves the thermo-electric behavior of the anode, the radiation between the solid surfaces in the model and the air flow inside and outside the cell hooding system. In addition of the heat dissipated by the anode panel,...
Article
Full-text available
The current approach of increasing amperage simply by making cells longer has introduced operational problems. How­-ever, using copper collector bar technology opens the door to a new­ cathode design that extracts 100% of the current directly on the dow­nstream side. It means w­e can design a w­ider cell w­ithout generating harmful horizontal curre...
Chapter
Full-text available
Two innovations presented by the authors recently at ICSOBA conferences allow to very significantly reducing both the cathode and the busbar voltage drop (Dupuis in A new aluminium electrolysis cell busbar network concept, 2015; Dupuis in New busbar network concepts taking advantage of copper collector bars to reduce Busbar weight and increase cell...
Conference Paper
Full-text available
At the 2015 ICSOBA conference a reversed compensation current (RCC) busbar network concept was presented. There is no return potline as the full return current passes under the cells back to the rectifiers. The concept preferably uses upstream and downstream anode risers to produce a symmetric upstream/downstream steady-state bath-metal interface d...
Article
In recent years extensive modeling work has been done to assess if the usage of an irregular cathode surface does or does not increases the MHD cell stability. So far, 2 types of studies have been carried out: full 3D steady-state analysis and 2D shallow layer dynamic analysis. Cell stability being a transient phenomenon, steady-state results are n...
Chapter
Mathematical models have become essential for the design of modern, efficient high-amperage reduction cells, but the models are only one part of the cell design process. Since many of the inputs to a thermal balance model are difficult to evaluate, a process for validation of the predictions of the model is essential.
Article
Mathematical models have become essential for the design of modern, efficient high-amperage reduction cells, but the models are only one part of the cell design process. Since many of the inputs to a thermal balance model are difficult to evaluate, a process for validation of the predictions of the model is essential. The validation process typical...
Chapter
In recent years extensive modeling work has been done to assess if the usage of an irregular cathode surface does or does not increases the MHD cell stability. So far, 2 types of studies have been carried out: full 3D steady-state analysis and 2D shallow layer dynamic analysis. Cell stability being a transient phenomenon, steady-state results are n...
Chapter
In view of the existing status with aluminum overcapacity and lower aluminum price in China, many companies adopted various measures to reduce the production cost and the energy consumption, but there has been no a normalization theory and method as yet. Aimed at the existing status and the market demand, this paper puts forward the evident effects...
Chapter
Full-text available
Reduction of cell voltage through redesign of the stub holes of cast iron rodded anodes is an attractive idea. In practice, stub hole optimisation is not an easy task and in situ trials may yield what seem to be counter-intuitive results. A closer examination reveals a complex behaviour of the steel stub - cast iron - carbon joint. It was shown in...
Chapter
Full-text available
One of the key components of an aluminum reduction cell design is the potshell design. The potshell must be designed in such a way that it will not deform excessively in operation and will remain as much as possible in elastic deformation mode. Yet, over-designed potshell are very costly. So, it is important to achieve a design where all sections a...
Chapter
Full-text available
With the recent power shortage in the USA, aluminum smelters are getting strong incentive to reduce their power consumption during peak demand. This power modulation can be quite harmful to the cells if not done properly. Yet, some smelters in Brazil [1,2] are now successfully managing power modulation on a routinely basis following a long and expe...
Chapter
Full-text available
This paper presents a typical application of thermoelectric mathematical models to produce a thermally balanced aluminum reduction cell lining design. The paper is structured as a tutorial, the selected example is a modern prebaked PBF cell running at 400 kA. The models used are the now standard steady state thermo-electric 3D full cell slice model...
Chapter
Full-text available
Over the last ten years, the industry standard for modeling aluminum reduction cell energy balance went gradually from 2D “in-house” codes to 3D commercial codes, like the ANSYS® finite element code. In this transition, many different modeling tools have been developed: 3D cathode slice, half anode, full cell slice, cathode corner/quarter and full...
Book
ONE OF A FOUR-BOOK COLLECTION SPOTLIGHTING CLASSIC ARTICLES Landmark research findings and reviews in aluminum reduction technology Highlighting some of the most important findings and insights reported over the past five decades, this volume features many of the best original research papers and reviews on aluminum reduction technology published f...
Article
Different operational parameters are known to influence cell stability like ACD, ledge toe position and metal level. Irregular cathode surface design is also thought to influence cell stability but how significantly as compared to the above operational parameters? In the present work, cell stability analyses are performed on 3 types of cathode surf...
Article
Full-text available
With the increase in market's demand and the development of technology, high amperage electrolytic cells in China have become widely used. In recent years, over 40 prototype cells each operating around 420 kA have been constructed. With different electricity prices in different regions and hence different cell heat balance requirements, a wide vari...
Chapter
Full-text available
Different operational parameters are known to influence cell stability like ACD, ledge toe position and metal level.
Chapter
Full-text available
With the increase in market’s demand and the development of technology, high amperage electrolytic cells in China have become widely used. In recent years, over 40 prototype cells each operating around 420 kA have been constructed. With different electricity prices in different regions and hence different cell heat balance requirements, a wide vari...
Article
In the recent years, the Chinese aluminum industry has started to extensively use irregular top surface cathode blocks.in its new cell designs. The increase popularity of these new types of cell designs in China is explained by the fact that they can be operated at a much lower cell voltage. The cell voltage can be reduced because irregular top cat...
Chapter
Full-text available
In the recent years, the Chinese aluminum industry has started to extensively use irregular top surface cathode blocks in its new cell designs. The increase popularity of these new types of cell designs in China is explained by the fact that they can be operated at a much lower cell voltage. The cell voltage can be reduced because irregular top cat...
Chapter
Over the last ten years, the industry standard for modeling aluminum reduction cell energy balance went gradually from 2D "in-house" codes to 3D commercial codes, like the ANSYS® finite element code. In this transition, many different modeling tools have been developed: 3D cathode slice, half anode, full cell slice, cathode corner/quarter and full...
Chapter
One of the key components of an aluminum reduction cell design is the potshell design. The potshell must be designed in such a way that it will not deform excessively in operation and will remain as much as possible in elastic deformation mode. Yet, over-designed potshell are very costly. So, it is important to achieve a design where all sections a...
Book
ONE OF A FOUR-BOOK COLLECTION SPOTLIGHTING CLASSIC ARTICLES: Original research findings and reviews spanning all aspects of the science and technology of casting. &Since 1971, The Minerals, Metals & Materials Society has published the Light Metals proceedings. Highlighting some of the most important findings and insights reported over the past four...
Article
The magneto-hydro-dynamic stability of an aluminum reduction cell has an important influence on aluminum electrolysis production. The paper introduces the research theory of magneto-hydro-dynamic stability of a cell and puts forward the concepts of "stationary state" and "transient state" of a reduction cell. A magneto-hydro-dynamic stability softw...
Article
In view of the existing aluminum overcapacity and lower aluminum price in China, many companies took measures to reduce the production cost and the energy consumption, but there has been no normalized theory and method defined as yet.To address these issues, this paper puts forward the evident effects of energy-saving and current efficiency improve...
Article
Full-text available
Assuming that the cell is not excessively mucked and hence that the evolution of the cell resistance is mostly dictated by the evolution of the concentration of the dissolved alumina in the bath, it is fair to say that calculating the slope of that cell resistance can now be considered as an exact science. During the underfeeding regime from the le...
Article
In view of the existing status with aluminum overcapacity and lower aluminum price in China, many companies adopted various measures to reduce the production cost and the energy consumption, but there has been no a normalization theory and method as yet. Aimed at the existing status and the market demand, this paper puts forward the evident effects...
Article
Extended electrical power interruptions often result in the shutdown and restart of aluminum cells in potlines. Cooling cells to ambient temperature causes irreversible and non-repairable damage to the carbon cathode lining, and ultimately causes the formation of numerous, often deep, cooling cracks on the surface of cathode blocks and in the seams...
Article
Full-text available
This paper puts forward the benefits of energy-saving in an aluminium reduction pot by minimising heat loss through the use of a new thermal insulation lining, an insulated and sealed hood, composition and thickness of the anode covering layer and installing an 'irregular' cathode with bevelled edges.
Article
Full-text available
Since the beginning of 2012, STAS is the world distributor of the STARprobe TM developed by Alcoa [1, 2]. Demonstration measurement campaigns have been conducted in different smelters around the world. During those campaigns, the STARprobe TM bath properties measurements have been compared with standard bath properties measurements regularly carrie...
Chapter
Full-text available
Extended electrical power interruptions often result in the shutdown and restart of aluminum cells in potlines. Cooling cells to ambient temperature causes irreversible and non-repairable damage to the carbon cathode lining, and ultimately causes the formation of numerous, often deep, cooling cracks on the surface of cathode blocks and in the seams...
Article
Full-text available
Two well established reliable and commercially available mathematical tools specially designed to assist the improvement of the thermal balance of Hall-Héroult cells during a retrofit study are being presented. The first tool, Dyna/Marc, is a Windows-based lump parameters+ steady-state and dynamic model designed to give fast answers to "what if" qu...
Article
After the successful development and application of an ANSYS based thermo-electro-mechanical anode stub hole design tool [1], an ANSYS based thermo-electro-mechanical collector bar slot design tool has been developed. Since the average contact resistance at the cast iron/cathode block interface is higher than the contact resistance at the cast iron...
Chapter
Full-text available
After the successful development and application of an ANSYS based thermo-electro-mechanical anode stub hole design tool [1], an ANSYS based thermo-electro-mechanical collector bar slot design tool has been developed. Since the average contact resistance at the cast iron/cathode block interface is higher than the contact resistance at the cast iron...
Article
Full-text available
At the 2009 TMS conference, we could observe a renewed interest for the optimization of anode stub hole design. This is not surprising considering that 50 mV is costing about 1 MM$ per year to a typical modern prebaked anode smelter producing around 220,000 T per year according to Richard [1] and that we can estimate that the contact resistance vol...
Conference Paper
Reduction of cell voltage through redesign of the stub holes of cast iron rodded anodes is an attractive idea. In practice, stub hole optimisation is not an easy task and in situ trials may yield what seem to be counter-intuitive results. A closer examination reveals a complex behaviour of the steel stub - cast iron - carbon joint. It was shown in...
Article
Full-text available
In previous publications [1,2], it was rationalized that a large vertical potshell deformation may have a negative impact on the operations of very high amperage cells. The MHD-Valdis non-linear Magneto-Hydro-Dynamic model was therefore extended to take into account the displacement of the potshell. The MHD cell stability behavior of a 500 kA cell...
Article
Full-text available
Cell voltage noise removal and cell voltage (or resistance) slope calculation are critical aspects of modern high amperage cell controller operations, yet, those operations are not covered much in the literature. In the present work, the efficiency of several algorithms is compared.
Article
Full-text available
The aluminium electrolysis process is an energy-intensive alumina reduction process which is more and more suffering under the high energy cost. Under these conditions, power could become a trading asset for the aluminium industry. Partly, actual power contracts contain clauses for power supply reduction and buyback, which have to be carefully cons...
Conference Paper
Full-text available
Start-up of a Hall-Héroult cell is a delicate task. Modern practices for high amperage cells involve preheating the lining before the molten electrolyte is poured in. The optimum preheating method for a rapid production of metal and a long pot life is elusive. Numerical modeling is an invaluable tool to gain insights into the complex phenomena taki...
Article
Full-text available
The main goal of a cell stability MHD model like MHD-Valdis is to help locate the busbars around the cell in a way that leads to the generation of a magnetic field inside the cell that itself leads to a stable cell operation. Yet, as far as the cell stability is concerned, the uniformity of the current density in the metal pad is also extremely imp...
Article
Full-text available
Start-up of a Hall-Héroult cell is a delicate task that can affect pot performance and pot life. Modern practices for high amperage cells involve preheating the lining before the molten electrolyte is poured in. Different preheating methods and heat-up schedules are used throughout the industry, and the optimum between a short start-up and damage m...
Article
Full-text available
In 2005 in another article published in ALUMINIUM [1], it was demonstrated that as far as the thermal balance aspect of the cell design is concerned, there is no limit to the size of cells that could be designed. In order to substantiate that declaration, the thermal-electric design of a 740 kA cell was presented. But what about the cell MHD stabil...
Article
Full-text available
It is well known that horizontal current density in the metal pad contributes greatly to the generation of MHD driven bath-metal interface wave. It is possible to compute very accurately the metal pad current density using a very detailed finite element model [1], but a MHD model must be compatible to this level of mesh refinement and to recalculat...
Article
Full-text available
It has been previously demonstrated [1] that there is no obvious thermal balance related issue limiting the size of a Hall-Héroult cell. Yet, it is well known that a forced-air sidewall cooling system is part of the AP50 cell design [2]. In the present study, the authors analyze the impact of thermal loading on the mechanical deformation of high am...
Article
Full-text available
In the present study, the full 3D thermo-electric model of a 500 kA demonstration cell has been weakly coupled with the non-linear wave MHD model of the full version of the same cell. In the MHD model, the horizontal ledge distribution calculated in the thermo-electric model has been incorporated as part of the model geometry. In the thermo-electri...
Article
Full-text available
It has been previously demonstrated (1,2) that using selective collector bar rodding has a big impact on the uniformity of the current density at the top surface of the cathode block and hence on the intensity of the horizontal current in the metal pad. The present study investigates the impact of using selective collector bar rodding on the MHD st...
Article
Full-text available
In the present study, a full 3D cell-cathode thermo-electric model of a 500 kA demonstration cell has been developed. In parallel, a non-linear transient wave MHD model for the same 500 kA demonstration cell, taking into account the shielding effect of the optimized geometry of the potshell, has been developed. Preliminary results of the impact of...