Plantwide Surge Capacity Control for Sustainable Process Operation

The potential of “loose” liquid surge inventory control towards sustainable operation of integrated plants is evaluated. It reduces the variability in the optimally active constraints allowing the process operation to be pushed closer to the constraint limits with consequent economic/sustainability benefits. Surge inventory control algorithms are assessed for ester purification and acetone manufacturing processes. Results show significantly higher surge capacity utilization using model-predictive optimal inventory control compared to conventional fixed tuning P/PI control. In the ester purification process, this results in 12.68% energy savings at a given throughput (Mode I) and 1.56% higher maximum production (Mode II) for a regulatory control structure with the throughput manipulator (TPM) at the fresh feed. The corresponding figures for the acetone process are 5.98% Mode I energy savings and 2.23% higher maximum production (Mode II). The study underscores the potential of leveraging surge capacity through inventory control for sustainable plant operation.