problems related to the potshell mechanical behavior
are one of the main reasons why the industry trend to
use bigger and bigger cells in new greenfield smelter
projects has been considerably slowing down in recent
years.
fins or forced air convection are not required as far as
the cell heat balance aspect of the cell design is
concerned. Yet potshell cooling fins are now a
standard feature of the AP30-35 technology and forced
air convection is used in AP50 technology. Why then
if is not used to enhance the heat loss dissipation?
[2], those devices are required to reduce the thermally
induced vertical potshell deflection which becomes
quite harmful to the cell operation as the cells get
bigger and bigger. It was also demonstrated in [2], that
the use of forced air convection is more efficient than
cooling fins to reduce or even completely eliminate the
vertical potshell deflection. But should we conclude
from these results that for cell amperage of 500 kA and
more, the usage of forced air convection is mandatory
in order to prevent the vertical potshell deflection to
have an harmful effect on the cell operation?
is to assume that as the potshell gets longer, the
problem of the vertical potshell deflection gets worse.
Recent modeling results demonstrated that, depending
on the potshell design, it might not be necessarily the
case.
model mesh and temperature loading for a standard
design without cooling fins and forced air convection.
Figure 10 presents the resulting vertical potshell
deflection calculated using elasto-plastic mechanical
steel properties. Figure 11 compares that vertical
deflection with those obtained for 300 kA and 500 kA
cell's potshell in similar conditions. Because of the
change of aspect ratio the 26.2 meters long potshell
behaves differently and, as a result, the vertical
deflection is about the same as the 300 kA cell case
instead of being worse than the 500 kA cell case.
anyway, the vertical deflection remains small because
that VAW 300 inspired potshell design [6] is very
flexible in the upper section of the potshell side walls
12).
further by using cooling fins, but following results
presented in [2], it is important to ensure that those
cooling fins are not increasing the upper side walls
rigidity.
run enough alternative cooling fins designs in order to
discover one that actually improve the situation before
this article publication deadline.
design, it is clear that there is no limit to the size of
cells that could be designed.
have the data in hand to be so assertive, but there is no
reason to believe that technically, we are facing a size
limit. On the other hand, if for very high amperage
cells, the solution to the potshell vertical deflection
problem can only be solved by using expensive forced
air convection devices, it is possible that the usage of
those devices annihilates the financial incentive to
keep designing bigger and bigger cells.
the Internal Wave in the Aluminum Reduction Cells",
Light Metals, TMS, (2005), 455-460
Connection Between Very High Intensity Electrolysis
Cells for the Production of Aluminium Comprising a
Supply Circuit and an Independent Circuit for
Correcting the Magnetic Field", US patent no
4,713,161, (1987).
Instability of Liquid Metal-electrolyte Interface in