A low cost optimizer
Advanced Process Control (APC) is a way to optimize your plant performance without changing the hardware. This makes APC solutions very cost effective.
Large process revamps can increase the production capacity with 10% to 40% at the cost of sometimes hundred million dollars/euros.
With APC the capacity increase is more in the range of 1% to 5% at the cost of a few hundred thousand dollars/euros.
Besides pure production increase or lower specific energy consumption APC also brings other advanced process control benefits:
- More stable operations, meaning less variations.
- Less operator interventions
- less alarms
- Less wear and tear on the equipment resulting in longer run lengths, less downtime,..
- better understanding of the process
How MPC creates benefits?
The graph to the right shows an example of the effect on plant operation from installing an APC application. In this particular case the example is shown for a single process variable
Consider one variable that has a specific normal variation, and a high limit. In the first part of the graph, on the left side, the variable is shown with its normal variations. As a result of the variations in the variable, the operators tend to keep the average value of the parameter well below the limit, so that even with the relatively high variations in the variable, the value never exceeds the high limit.
By implementing APC, the variance of the variable is greatly reduced. This is seen in the middle part of the graph. With this reduced variation, the average value of the variable can now safely be moved closer to the limit. APC will move the average value smoothly closer to the limit, if the optimization calculations conclude that bringing this variable closer to its limit will result in a more economical operation of the process.
The power of APC lies not just in the reduction of the variation of key process parameters, but more in its ability to “think in a multivariable way”, i.e. truly optimize the process operation whilst taking all plant variables and all relationships in the process into account. As a result, APC will shift the entire operation closer to the most economical limits of the plant.
What does that mean for operations?
The figure to the left shows the “normal operation” of the plant away from the limitations, and the new operational region is displayed after commissioning an APC application.
During operation with APC, the process is operated closer to the most economical limitations, and the variability of the key parameters in the process is greatly reduced, as witnessed by the smaller size of the ellipse indicating the operational region with APC. A greatly reduced variance obviously directly relates to a more stable operation of the plant, typically leading to higher on-stream factors.