Design of heat exchanger networks and plantwide control structure of butane isomerization plant

Abstract

In this work, the resilient heat exchanger networks to achieve dynamic maximum energy recovery and plantwide control structures and strategies are designed for Butane Isomerization plant. The control difficulties associated with heat integration are solved by adding auxiliary utilities which is kept minimal. Two alternatives of heat exchanger networks (HEN) designs of the Butane Iso-merization plant are proposed. Both use the heat from the reactor effluent stream to provide the heat for the column reboiler. The energy saved is 24.88% from the design without heat integration, but the capital cost raised is about 0.67% due to adding of a process to process exchanger and an auxiliary utility exchanger to the process. Four plantwide control configurations of heat-integrated plant are designed following Luyben’s heuristic method. The result shows the fourth control structure can reject disturbances better than other control structures. In general, the control systems for CS1 to CS4 in the butane isomerization process alternative 1 are better than that in alternative 2. However, the control systems for CS1 to CS4 in the butane isomerization process without energy integration are the most effective one compared with the other two alternaives. Various heat pathways throughout the network designed using Wongsri’s disturbance propagation method to achieve DMER. The designed control structure is evaluated based on the rigorous dynamic simulation using the commercial software HYSYS.