The process control improvement program described in the June 2012 Control Talk column “The Human Factor” was a success at the company I worked for because of one person, Glenn Mertz. Glenn was able to get agreement from plant management on the benefits achieved – no easy task.
Process efficiency and capacity vary with maintenance, season, days versus nights, operating points, raw materials, recycle streams, and operators. Mechanical and process engineers work to improve the equipment and the process. Operations tries to come up with better operating procedures. If there is an improvement, these people tend to get the credit because they have a better process or operational understanding and are closer to the action than are the automation engineers.
By way of illustration: In a batch reactor where an override control system was fixed and the key controllers were tuned, the process engineers took credit for the reduction in batch cycle time and the more consistent batches. The process engineers had more credibility than the automation engineers. After all, the details of override control, split range, back calculation connections, and the whole tuning thing are confusing at best to the people who are making decisions on the source and quantification of benefits.
How, then, can you as an automation engineer get well-deserved credit? First, you need to develop a good working relationship with process technology, operations, and maintenance (Tips #51 and #52). In particular, create a synergy between your skills and those of the process engineer supporting the unit. Get trend charts of before and after, ideally with metrics or at least with key process variables. In the case of the batch reactor example, a trend with feed rate, temperature, and batch time for the batches immediately before and after the configuration fixes and tuning would have provided the necessary evidence. Piping and equipment changes take much longer to implement than process control improvements.
An operating point change resulting from a setpoint change can be fast but tests often need to be done and management-of-change procedures followed. In addition, the chance that an operating point change is made for the same batch that the override control system was fixed would be unlikely.
Unfortunately, once an improvement is made you can’t undo it to show conclusively that the benefits were due to an improvement in process control. You can, however, use a virtual plant to show the “before” and “after.” If the virtual plant can be made to match the process, the case will be more convincing when you turn off the process control improvements.
You should run and adapt the virtual plant to be in sync with the real plant and speed up scenarios as necessary for your demonstration (Tip #99). You have to be proactive, and prepare for people trying to take credit that should be yours. In the end, some negotiation may be required and the calculated benefits split up. If you are working with a process engineer, you should assign most of the benefits to him or her so you both look good, fostering future opportunities to work together. Success is a team effort and you would be wise to be generous in sharing the credit (Tip #57).
Concept: Getting proper credit for process control improvements requires snapshots and an analysis of process performance immediately before and after the improvements, along with a generous sharing of credit with the team, particularly the process engineer. A virtual plant can be used to demonstrate the improvements attributable to control improvements.
Details: Work closely with process engineers and operators to fully understand the problem and solution. Compute process metrics online, such as total raw material and total energy use for a batch or a shift (Tip #61). Get trend chart results of metrics and key process variables immediately before and after the process control improvements. Write a report briefly describing the improvements, benefits, and team effort. Review the report with the team members and your management and then ask for permission for it to be presented to the management of the team members.
Watch-Outs: Management of other disciplines may react negatively to the assignment of benefits outside of their section. Sharing the credit and getting the buyin of team members can help mitigate this potential backlash. Remember also that shifts perform differently. Try to compare shifts with the same operators to help eliminate the variability.
Exceptions: Once you gain the confidence of plant management, you may be able to proceed immediately to the next improvement.
Insight: You need to have documented proof of the benefits of process control improvements in order to get the resources to advance your skills and expand your horizon to innovations instead of simply doing what has been done before.
Rule of thumb: Capture and report trends of key process variables and metrics immediately before and after process control improvements.