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Jul
15

Adaptive Tuning – Field Experience

The adaptive tuning capability included in DeltaV was field tested at four customer sites during the initial stages of product development. This field trail was conducted over a six month period and include over 1000 control loops. One of the field trail sites was at Lubrizol, Deer Park, TX where this adaptive control capability was applied to a number of batch reactors. The reactor temperature and pressure are integrating processes with extremely small process gain. As shown below, the reactor control includes a cascade strategy with over-ride control – very challenging with the difficult process dynamics.

As discussed in Chapter 5 of Advanced Control Foundation – Tools, Techniques, and Applications, on of the characteristics of the reactor pressure control is that the gain associated with the reactor pressure changes throughout the batch with increases in reactor level i as illustrated below.

Through the application of adaptive tuning it was possible to automatically adjust the tuning of the pressure control loop to compensate for the changing gain an dynamics associate with the pressure process. After the installation of the adaptive control a significant e reduction in process variability was observed as illustrated below.

After the field trial YouTube video was created to document the installation. In this video some of the people we worked with at Lubrizol discuss the field trial and impact of adaptive tuning on their process operation. The Lubrizol installation illustrates how adaptive tuning may be used to improve plant operation.