Design of control structures of energy-integrated HDA plant with minimum auxiliary reboilers

Abstract

The problem of design plantwide control structure for a highly heat integrated plant is quite difficult task. It requires design modifications to the process to ensure controllability. Operability and profitability. In this research, we outline the plantwide control design approach that would be taken for a complex heat-integrated scheme like Alternative 6 of the HDA process. It starts with specifying the disturbances and their magnitudes, and then designing the resilient heat exchanger network is designed at the minimum heat supply and maximum heat demand condition. We can solve the control difficulties associated with Alternative 6 by adding an auxiliary reboiler to the process instead of three as suggested by Luyben (1999). The three new control structures are proposed and their performances are evaluated. CS2 is the best control structure for handle disturbances due to it gives better control performances. In this control structure, the recycle column feed flow rate is flow-controlled so that fluctuations in the process are not propagated to the next downstream unit operations.