Peter J. Ryan, Principal
Advanced process control is often utilized to realize process optimization goals such as specific energy consumption reduction or increased throughput. The flexibility of modern Distributed Control Systems (DCS’s) has made it possible to quickly modify control strategies without capital investment – simply introduce new control algorithms and modules on to the DCS. Figure 1 below shows such an example.
The Six Sigma team identified that the control to Reactant A to the reaction system had an unacceptable amount of variability that caused the unit to run at nominal rates. Introducing an advanced process control (APC) algorithm to this feed system reduced the variability in the Reactant A feed to one third of its earlier level. Once Reactant A feed control had been established, the amount of Reactant A feed was reduced to its lower control point, and, because less Reactant A was entering the reactor, the average production throughput was increased by 5.8%. As throughput increased, the unit’s specific energy consumption (kg steam/kg product) was also reduced.
Figure 1: Advanced Process Control Example