Synthesis of an Optimizing Control Structure for Dual Mixed Refrigerant Process

This study was aimed to investigate the best control structure that provides optimal operation for dual mixed refrigerant (DMR) process. The steady-state operational map that correlates the refrigerant flow rate and the total compressor duty was drawn to locate the region the optimal operation of DMR process. This map also encompasses information of state variables in DMR process that in particular combinations provide the optimum solution. The steady-state operational map of DMR process was developed by conducting steady-state behavior analysis in a rigorous dynamic simulation of DMR process built in Aspen Hysys. The resulting steady-state operational map suggests that when the flow rate ratio of the two mixed refrigerants (WMR/CMR ratio) is kept constant, the operational of DMR process will remain within optimum region. From several control tests, the control structure that consists of WMR/CMR ratio loop has better performance on recovering the process after propagated by disturbances

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