Plantwide control structures design for alkylation process

Abstract

The plantwide control structure design is complex because of material and energy recycles designed for economic. This research used plantwide control procedure of Wongsri (2009) to develop the control structures for alkylation process. The alkylation process is a complex multi-unit process, which features several unit operations. The main reaction is the combination of isobutane and butene to form iso-octane. Iso-octane is valuable for making gasoline. In this research using software HYSYS to simulate alkylation process at steady state and dynamic. Then we design eight plantwide control structures (CS1 to CS8) for alkylation process using new design procedure of Wongsri (2009) and evaluate the dynamic performance of the designed control structures compare with base case control structure (Luyben, 2002) by two types of disturbances: material and thermal disturbances. The designed control structure has a good performance because it can handle disturbances entering the process and can maintain product quality as compared by integral absolute error (IAE) and total energy use low. Therefore this research establishes that the Wongsri's procedure, which combines heuristics, analytical method and dynamic simulation, a useful design procedure that leads to a good-performance plantwide control system.