Improving throughput positions any organization for greater return and competitiveness, regardless of market condition. When capacity constrained, you can produce more with existing assets. When market-limited, you can achieve your target output with fewer operating units.
However, most plants are not running at optimum throughput. Actual loop setpoints are set conservatively-compensating for process variability and unexpected disturbances. The predictive capabilities of PlantWeb can eliminate this variability and warn you of unexpected disturbances. This gives you the confidence to set loop setpoints closer to constraints, improving throughput.
To improve throughput, start by reducing variability. With less variability, plus with PlantWeb's predictive intelligence, you have the confidence to move setpoints closer to theoretical operating limits-for better process performance, and thus better throughput.
In order of greatest return your priorities should be:
- Control valves
- Regulatory control
- Advanced Control
- Real time Optimization
Think of process control as a hierarchy. Everything must work at the lower levels for the higher levels to work.
Better control requires sensors, transmitters, and valves that consistently deliver the measurement and control performance you need:
• PlantWeb's intelligent HART and fieldbus devices include a variability index so you know when and where action is needed to keep the process running smoothly.
• Our FOUNDATION fieldbus devices can also alert PlantWeb’s DeltaV or Ovation automation system when the instrument signal status is bad or uncertain, so you never control off bad data.
• PlantWeb’s DeltaV Inspect [PDF] software constantly monitors loop variability and highlights degraded performance, abnormal conditions, and other potential trouble spots.
Once lower-level controls are operating optimally, you can increase throughput even more by using PlantWeb's integrated Advanced Process Control to further reduce variability and move setpoints closer to optimum. For example,
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Multivariable Model Predictive Control technology in DeltaV Predict [PDF] easily handles excessive deadtime, long time constants, and loop-to-loop interactions. PredictPro's embedded linear program also enables it to find the best combination of multiple setpoints for maximizing throughput.
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Because these easy-to-use advanced controls are embedded in the DeltaV controller rather than a separate workstation, they run at the controller cycle time — typically 1-2 seconds — rather than the longer cycles common in separate MPC systems. And the faster the update, the more variability can be smoothed out, so you can run closer to constraints.
