• A Model Based Parametric Study of Alumina Feeding and Dissolution 

      Aase, Simen; Bekkevoll, Simen; Forberg, Sigmund A.K. (Bachelor thesis, 2020)
      Alumina blir brukt som råmateriale i den energikrevende Hall-Hèroult-prosessen for produksjon av aluminium. I denne prosessen blir aluminapulver matet til et kryolittbad med jevne mellomrom. Det utfordrende miljøet i den ...
    • A Treatise on Interpolar Transport Phenomena 

      Einarsrud, Kristian Etienne (Doktoravhandlinger ved NTNU, 1503-8181; 2012:201, Doctoral thesis, 2012)
      This thesis contributes to the understanding of mechanisms for mass transport in aluminium electrolysis cells. Fundamental studies are undertaken of ow patterns and mass transport in the interpolar region under various ...
    • Alumina Dissolution in Cryolite Melts - Formation and Behavior of Rafts 

      Gylver, Sindre Engzelius (Master thesis, 2018)
      Alumina is the raw-material used for aluminum production in the Hall-Héroult process. Though the process is used for several years, some phenomena is not fully investigated yet. One of those is the formation of floating ...
    • Alumina feeding and raft formation: Raft collection and process parameters 

      Gylver, Sindre Engzelius; Omdahl, Nina Helene; Prytz, Ann Kristin; Meyer, Astrid Johanne; Lossius, Lorentz Petter; Einarsrud, Kristian Etienne (Journal article; Peer reviewed, 2019)
      Alumina, alongside with electricity and carbon, is the raw material used for production of aluminium in the Hall-Héroult process. An efficient dissolution process is important to acquire stable conditions for the cell, ...
    • Assessment of Established and New Separation Methods for Water-in-Oil Emulsions 

      Woxholt, Eirik Giil; Stavrum, Jørgen Sivertsen (Bachelor thesis, 2020)
      Råolje er en kjemisk blanding av hydrokarboner, heteroatomer, metalliske forbindelser og mange komplekse organiske forbindelser. Sammensetningen av disse varierer avhengig av hvor og når hentet, samt flere ander faktorer. ...
    • CFD Modelling of Alumina Feeding 

      Einarsrud, Kristian Etienne; Gylver, Sindre Engzelius; Manger, Eirik (Journal article, 2018)
      The dissolution and distribution of alumina in molten cryolite bath is a complex process, involving heat and mass transfer, phase transition and dynamics for a particle population with variable size and properties. Although ...
    • Comparison of Surface Tension Models for the Volume of Fluid Method 

      Vachaparambil, Kurian J.; Einarsrud, Kristian Etienne (Journal article; Peer reviewed, 2019)
      With the increasing use of Computational Fluid Dynamics to investigate multiphase flow scenarios, modelling surface tension effects has been a topic of active research. A well known associated problem is the generation of ...
    • Comparison of Surface Tension Models for the Volume of Fluid Method 

      Vachaparambil, Kurian J.; Einarsrud, Kristian Etienne (Journal article; Peer reviewed, 2019)
      With the increasing use of Computational Fluid Dynamics to investigate multiphase flow scenarios, modelling surface tension effects has been a topic of active research. A well known associated problem is the generation of ...
    • Dynamic Modelling of Heat and Mass Transfer in the Silicon Arc Furnace 

      Hajdini, Fatbardha (Master thesis, 2019)
      Grunstoffet silisium er av stor betydning for det moderne samfunn. Selv om silisium er det vanligtse grunnstoffet i jordskorpen etter oksygen, så finnes ikke silisium i sin elementære form i naturen. Silisium kan produseres ...
    • Electrodialytic Energy Storage System: Permselectivity, Stack Measurements and Life-Cycle Analysis 

      Krakhella, Kjersti Wergeland; Morales, Marjorie; Bock, Robert; Seland, Frode; Burheim, Odne Stokke; Einarsrud, Kristian Etienne (Peer reviewed; Journal article, 2020)
      Reverse electrodialysis and electrodialysis can be combined into a closed energy storage system, allowing for storing surplus energy through a salinity difference between two solutions. A closed system benefits from simple ...
    • Energy generation and storage by salinity gradient power: A model-based assessment 

      Jalili, Zohreh; Krakhella, Kjersti Wergeland; Einarsrud, Kristian Etienne; Burheim, Odne Stokke (Journal article; Peer reviewed, 2019)
      Three energy storage systems based on mixing and desalination of solutions with different salt concentrations are presented, namely, reverse electrodialysis, pressure retarded osmosis and capacitive Donnan potential, coupled ...
    • Explanation of Bubble Nucleation Mechanisms: A Gradient Theory Approach 

      Vachaparambil, Kurian J.; Einarsrud, Kristian Etienne (Journal article; Peer reviewed, 2018)
      A Helmholtz free energy description of the four nucleation mechanisms used to explain the bubble nucleation in electrochemical systems is presented. The mechanisms are compared based on the nucleation energy barrier and ...
    • Heat to H2: Using Waste Heat for Hydrogen Production through Reverse Electrodialysis 

      Krakhella, Kjersti Wergeland; Einarsrud, Kristian Etienne; Burheim, Odne Stokke; Seland, Frode; Bock, Robert (Journal article; Peer reviewed, 2019)
      This work presents an integrated hydrogen production system using reverse electrodialysis (RED) and waste heat, termed Heat to H2. The driving potential in RED is a concentration difference over alternating anion and cation ...
    • Heating New Anodes Using the Waste Heat of Anode Butts: Establishing the Interface Thermal Contact Resistance 

      Dupuis, Marc; Gudbrandsen, Henrik; Einarsrud, Kristian Etienne (Peer reviewed; Journal article, 2021)
      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 resistance between them. For that purpose, a lab experiment has been ...
    • Interface resolved simulations of continuum scale electrochemical hydrogen evolution 

      Vachaparambil, Kurian J. (Doctoral theses at NTNU;2020:363, Doctoral thesis, 2020)
      An important aspect of improving the efficiency of water electrolysis is to remove the electrochemically generated hydrogen and oxygen bubbles. The evolution of these gases, which are associated with increased electrical ...
    • Inverse modelling of interfacial tension between ferroalloy and slag using openfoam 

      Bublik, Sergey; Einarsrud, Kristian Etienne (Chapter, 2020)
      The entrainment of molten ferroalloy droplets in slag during tapping operations is strongly related to turbulence and interfacial forces between alloy and slag. Therefore, interfacial phenomena are of great importance for ...
    • Lab Scale Experiments on Alumina Raft Formation 

      Gylver, Sindre Engzelius; Solheim, Asbjørn; Gudbrandsen, Henrik; Follo, Åste Hegglid; Einarsrud, Kristian Etienne (Chapter, 2020)
      During feeding of alumina into a Hall-Héroult cell, rafts floating on the bath surface may be formed. In this study, rafts were created in a laboratory furnace by adding 4 g secondary alumina in industrial bath. Samples ...
    • Modeling interfacial mass transfer driven bubble growth in supersaturated solutions 

      Vachaparambil, Kurian J.; Einarsrud, Kristian Etienne (Peer reviewed; Journal article, 2020)
      A commonly encountered phenomenon in chemical processes is bubble evolution driven by supersaturation. On the continuum scale, this essentially involves interfacial mass transfer resulting in the growth of bubbles and their ...
    • Modelling of gas-solid reactions - Usage of industrial off-gas for pre-reduction of manganese ores 

      Gustum, Mathias Grønberg (Master thesis, 2018)
      The traditional way of making manganese alloys are by reduction of different manganese oxides, iron oxides and silicon dioxide in a standalone electric furnace. That being said, manganese alloy producing companies may ...
    • New Insights into Computational Fluid Dynamic Modeling of the Resistivity and Overpotential in Reverse Electrodialysis 

      Jalili, Zohreh; Burheim, Odne Stokke; Einarsrud, Kristian Etienne (Journal article; Peer reviewed, 2018)
      The resulting electrical potential of a reverse electrodialysis is reduced both due to ohmic and non-ohmic resistances. The non-ohmic resistance is mainly controlled by concentration polarization which is a considerable ...