Control Structure with C4 Feedflow Controlled

The dynamic parameters in the Aspen Plus file are inserted. The volumes of the reflux drum (144 m ) and the column base (177 m ) are calculated so that the holdup times are 5 min when the levels are at 50%, based on the total liquid entering. Aspen Plus Tray Sizing gives a diameter of 7.4 m. Aspen Plus Packing Sizing gives a diameter of 5.4 m, and this 

044 m on the reactive trays. Pressure drops over the four valves in the system and pump heads are set to give adequate rangeability for all of the flows (about 4 atm pressure drop at design flowrates with control valves 50% open). The file is pressure checked and exported to Aspen Dynamics. 

The temperature of stage 13 is controlled at 412.5 K by manipulating the reboiler heat input whose steady-state value is 8.15 x 10 cal/s. 

The reflux-drum level is controlled by manipulating the distillate flow. 

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