XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 889
values showing greater variability compared to the reference
setpoint. Considering the operational limits of the HPGR
in question, that limit the operating speeds to a maximum
of 1.2 m/s, throughput (Figure 6b) was limited to a maxi-
mum of 660 t/h.
The evolution of manipulated variables, as presented
in Figure 7, when analyzed in conjunction with the results
from Figure 6, justifies the limitations of the NMPC in
achieving the stipulated reference setpoints in case study
#2, considering that roll peripheral velocity values oper-
ated throughout the entire period at their maximum value
(Figure 7b), while pressure values presented relatively
abrupt changes (Figure 7a). It is also worth noting that, for
the first 60 minutes of operation, the HPGR was forced
to operate at its maximum pressure (120 bar) to achieve
the reference setpoint for the product BSA, although it was
limited to reaching 1942 cm2/g.
Figure 6. Response of the product BSA (a) and throughput (b) in 180 min time window for case study #2. Changes in the
HPGR feed BSA (process disturbance) followed predictions made by Eq. (21) and presented in Figure 2b
Figure 7. Response of the operating pressure and gap (a) and roll peripheral velocity (b) in 180 min time window for case
study #2. Changes in the HPGR feed BSA (process disturbance) followed predictions made by Eq. (21) and presented in
Figure 2b
values showing greater variability compared to the reference
setpoint. Considering the operational limits of the HPGR
in question, that limit the operating speeds to a maximum
of 1.2 m/s, throughput (Figure 6b) was limited to a maxi-
mum of 660 t/h.
The evolution of manipulated variables, as presented
in Figure 7, when analyzed in conjunction with the results
from Figure 6, justifies the limitations of the NMPC in
achieving the stipulated reference setpoints in case study
#2, considering that roll peripheral velocity values oper-
ated throughout the entire period at their maximum value
(Figure 7b), while pressure values presented relatively
abrupt changes (Figure 7a). It is also worth noting that, for
the first 60 minutes of operation, the HPGR was forced
to operate at its maximum pressure (120 bar) to achieve
the reference setpoint for the product BSA, although it was
limited to reaching 1942 cm2/g.
Figure 6. Response of the product BSA (a) and throughput (b) in 180 min time window for case study #2. Changes in the
HPGR feed BSA (process disturbance) followed predictions made by Eq. (21) and presented in Figure 2b
Figure 7. Response of the operating pressure and gap (a) and roll peripheral velocity (b) in 180 min time window for case
study #2. Changes in the HPGR feed BSA (process disturbance) followed predictions made by Eq. (21) and presented in
Figure 2b