Project Description

Kerosene HDS Plant – Control Loops Tuning

The Kerosene HDS plant control loops were re-tuned as part of re-tuning all the control loops in the HDS plants.

Loops were tuned to get the best performance to their duty and efforts were done to compare it’s functioning prior and after the tuning

Tuning was done by “Ziegler Nichols” approach – namely – finding the ultimate process gain and ultimate process dynamics and setting the controller’s parameters accordingly – bearing in mind the controller duty and the characteristics of the expected behavior..

The control performance is calculated and presented using two indices:

1.      Process value Standard Deviation (STD)


2. Process Value Travel Index (Process travel)

Among other things:

  • Top Reflux valve was identified as “Sticky” and had been mended.
  • Instrumentation ranges changed to give true and effective ranges of operation.
  • Change logic of Reflux operation to “Reflux Ratio” to better follow changes in plants throughput.