1) Plantwide Inventory Control for Sustainable Process Operation
A robust plantwide regulatory control system is installed on continuous chemical processes for closing all the independent material and energy balances to drive the process operation to steady state. Economic and sustainability concerns are usually addressed by adjusting the regulatory setpoints to minimize a cost objective. At the optimum steady state, typically multiple constraints are active. Optimal process operation then boils down to designing the plantwide control system such that the variability in the active constraint process variables (PVs) is minimized to drive the process operation as close as possible to the active constraint limits with just enough back-off to avoid constraint violation. Because material balance transients are usually a major source of variability in the constraint PVs, the design of the plant inventory control system that closes the individual unit operation as well as the plantwide material balances, plays a key role in determining an operating plant's economic performance. This thesis comprehensively investigates the same.
There are two major decisions in the design of the plantwide inventory control system:
(i) The choice of the material flow stream rate that sets the process throughput, also referred to as the throughput manipulator (TPM)
(ii) The controller algorithm and tuning of each of the SISO inventory controllers.
The TPM choice (item (i) above) dictates an outwardly radiating material balance control structure that propagates flow transients away from the TPM. The severity of the flow transients thus typically increases as one moves further away from the TPM. The location of the TPM relative to the active constraint PVs then affects the variability in the active constraint PVs. The control algorithm and tuning of each of the SISO inventory controllers (item (ii) above) determines the severity of the propagated flow transients for a given flow disturbance. Typically, the loosest possible level control without violating the high/low level alarm limits is desired for all the surge inventories such as the reflux drum or bottom sump level in a column. This maximizes flow filtering and is referred to as averaging level control (ALC).
2) Process Integration and Control in Chemical Process Industry: Reactive Divided Wall Column
My research interest focuses on process integration and control of the complex industrial process. Distillation is the widely used unit for process integration but it is energy extensive process. I aim to design a column in such a way that is energy efficient as well as cost-effective. So, R-DWC works perfectly here. It integrates the reactor and separation unit into a single unit which in turn save fixed as well as operating cost. Many valuable products used in daily life are derived from the chemical industries. If the cost of operation is less than the cost of the product also be less that's how I can contribute to society.