A workstation-based simulator of an aluminium electrolytic cell has been constructed. A mathematical model of the cell is integrated with a database and a knowledge base, and the simulator serves as a tool for the training of personnel and for research related to cell dynamics and cell control. When used in conjunction with an expert system, it provides a powerful decision-making tool or an efficient supervisory system. The mathematical model, the simulator itself, the user environment, the interactive simulation procedure as well as examples of the use of the simulator are presented in detail.List of Symbols
a
i
parameters of electrolyte density calculation
-
AlF
3
aluminium fluoride content [w%]
-
Al
2O
3
alumina content of electrolyte [w%]
-
b
i
parameters of electrolyte specific heat
-
c
i
parameters of bath electrical resistivity
-
c
p
i
specific heat of electrolyte [J/kg°C]
-
c
p
2
specific heat of freeze [J/kg°C]
-
c
p
3
specific heat of metal [J/kg°C]
-
C
alumina content of electrolyte [w%]
-
C
s
saturation concentration of alumina [w%]
-
CaF
2
calcium fluoride content of electrolyte [w%]
-
CR
cryolite ratio
-
H
F
heat of fusion of electrolyte [J/kg]
-
I
line current [kA]
-
k
1
parameter of solution 1 [1/s w%]
-
k
2
parameter of solution 2 [1/s w%]
-
k
3
parameter of settling [1/s]
-
k
4
parameter of alumina feeding [kg/s]
-
k
5
parameter of metal production [kg/s kA]
-
k
6
ratio of alumina-metal mass transformation
-
m
1
mass of electrolyte [kg]
-
m
2
mass of freeze [kg]
-
m
3
mass of molten metal [kg]
-
m
a
rate of alumina addition [kg/s]
-
m
m
rate of metal production [kg/s]
-
m
t
rate of metal tapping [kg/s]
-
Q
total heat loss [kW]
-
Q
A
heat flow from electrolyte to anode [kW]
-
Q
B
heat flow from metal to cathode bottom [kW]
-
Q
F
heat flow from freezing zone to freeze [kW]
-
Q
F1
heat flow from electrolyte to freezing zone [kW]
-
Q
F2
heat flow from metal to freezing zone [kW]
-
Q
Ha
energy needed for alumina heatup [kW]
-
Q
K
heat flow from electrolyte to cathode [kW]
-
Q
s
heat flow from freeze to side-wall [kW]
-
S
1
solution rate of disperesed alumina [kg/s]
-
S
2
solution rate of settled alumina [kg/s]
-
S
3
settling rate [kg/s]
-
T
1
temperature of electrolyte [°C]
-
T
2
temperature of freeze [°C]
-
T
3
temperature of molten metal [°C]
-
T
F
temperature of freezing zone [°C]
-
T
L
cryolite liquidus temperature [°C]
-
U
total cell voltage [V]
-
U
a
voltage equivalent of enthalpy of metal production [V]
-
x
1
mass of dispersed alumina [kg]
-
x
2
mass of settled alumina [kg]
-
x
3
mass of dissolved alumina [kg]
-
i
parameters of cryolite liquidus temperature
-
density of bath [kg/m
3]
-
electrical resistivity of bath [m]
-
c
electrical conductivity of bath [1/m]
- Note
w% means percentage by weight
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