The Impact of Cell Ventilation on the Top Heat Losses and Fugitive Emissions in an Aluminium Smelting Cell

  • Haiam Abbas
  • Mark P. Taylor
  • Mohammed Farid
  • John J. J. Chen

Abstract

Problems associated with aluminium smelting cell ventilation, caused by leakage of fume gases through pots superstructure gaps into the potroom, are normally solved by increasing the fume suction rate (draught) above certain levels. It is also known that, fugitive emissions are associated with reducing the draught below certain critical levels. Top heat losses are increasing in smelting cells as line amperage is raised. This drives further fugitive emissions through greater buoyancy of the fume/air mixture. A quantitative understanding of the relationship between fugitive emissions, superstructure tightness, top heat loss, and cell draught is crucial in the environmental context. It is also important if this top heat loss could be recovered for re-use.

This problem is studied here computationally using the ANSYS-CFX software. Possibilities to improve cell ventilation and to decrease fugitive emissions are analysed for a typical industrial cell. The computed cell emissions and temperatures are compared with measured values. The impact of draught on ventilation and heat loss is also discussed

Keywords

draught top heat loss fugitive emissions cell ventilation gaps area negative pressure heat transfer coefficient 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Reference

  1. 1.
    M.D. Gadd, Barry Welch, and A.D. Ackland. The Effect of Process Operations on Smelter Cell Top Heat Losses, Light Metals 2000 pp [231, 238].Google Scholar
  2. 2.
    Gadd, M.D., Aluminium Smelter Cell Energy Flow Monitoring, in Chemical and Materials Engineering. PhD thesis, 2003, The University of Auckland: Auckland, New Zealand.Google Scholar
  3. 3.
    Karlsen M., et al. Factors influencing cell hooding and gas collection efficiencies. Light Metals 1998 pp [303, 310].Google Scholar
  4. 4.
    Elaine Y.-L. Sum, Chris Cleary, and Tseng T. Khoo Understanding And Controlling Hf Fugitive Emissions Through Continuous Hf Monitoring And Air Velocity Characterisation In Reduction Lines. Light Metals 2000 pp [357, 364].Google Scholar
  5. 5.
    Dando N.R., and Tang R., Impact of Tending Practices on Fluoride Evolution and Emission from Aluminum Smelting Pots. Light Metals 2006 pp [203, 206].Google Scholar
  6. 6.
    Lindsay S.J. Effective Techniques to Control Fluoride Emissions. Light Metals 2007 pp [199, 203].Google Scholar
  7. 7.
    Al-Ojaimi H.H. Employees Behaviour In Improving Roof Emission In Reduction Potlines 1–3. in 9AASTC Proceedings 2007.Google Scholar
  8. 8.
    Xian Chun Shen, Margaret Hyland, and Barry Welch. Top Heat Loss In Hall-Heroult Cells. Light Metals 2008 pp [501, 504].Google Scholar
  9. 9.
    Y. A. M. Al Farsi, A. Meghlaoui, and N. Aljabri. Cd20 Reduction Cell Upgrade For Dubal’s Expansion Project. in TMS Aluminum Committee. Light Metals 2005 pp [297, 302]. San Francisco, California: TMS Aluminum Committee.Google Scholar
  10. 10.
    Perry R.H., and Green D. W., Perry’s Chemical Engineer’s Handbook. Vol. 6th edition. 1984: McGraw Hill.Google Scholar
  11. 11.
    Ketil A. Rye, Jomar Thonstad, and Xiaoling Liu. Heat Transfer, Thermal Conductivity, and Emissivity of Hall — Heroult top Crust. Light Metals 1995 pp [441, 449].Google Scholar
  12. 12.
    Kia Grjothem, and Barry Welch., Aluminium Smelter Technology. Vol. 2nd Edition. 1988: Aluminium Verlag.Google Scholar
  13. 13.
    M.P. Taylor, et al., Dynamic Model for the Energy Balance of an Electrolysis Cell. Trans IChemE 74, 1996. 74(Part A): p. 913, 933.Google Scholar
  14. 14.
    Biedler Philip, and L. Banta Analysis And Correction Of Heat Balance Issues In Aluminum Reduction Cells. Light Metals 2003 pp [441, 447].Google Scholar
  15. 15.
    Wesseling, P., Principles of Computational Fluid Dynamics. 2001.CrossRefGoogle Scholar
  16. 16.
    Delsante A.E., and Clarke R.E., Measurements and calculations of temperature and heat transfer coefficients in an aluminium smelter potline. 1991, CSIRO Australia/Division of Building, Construction, and Engineering. DBCE Doc. 91/59 (M), report 236.Google Scholar
  17. 17.
    Holt N. J, et al., Ventilation of Potrooms in Aluminium Production. Light Metals 1999 pp [263, 268].Google Scholar
  18. 18.
    Lid, O. and Q. Haugen. Potroom Ventilation System by Segragated Air Layers. Light Metals 1984 pp [743, 753].Google Scholar
  19. 19.
    Frank P. Incropera, D.P.D., Introduction to Heat Transfer. Vol. Fourth Edition. 2002.Google Scholar

Copyright information

© The Minerals, Metals & Materials Society 2016

Authors and Affiliations

  • Haiam Abbas
    • 1
  • Mark P. Taylor
    • 1
  • Mohammed Farid
    • 2
  • John J. J. Chen
    • 1
  1. 1.Light Metals Research CentreUniversity of AucklandNew Zealand
  2. 2.Chemical and Materials EngineeringUniversity of AucklandNew Zealand

Personalised recommendations