For the base case considered above, the reflux ratio is 2.58.
Here four selected input variables Feed flow rate (80-120 lb.mole/hr), Feed Temperature (60-100[degrees]F), Reflux Ratio (2-3) and Reboiler heat flow (1.5-2.3 Btu/hr) are used to generate sequence of random signals with varying amplitudes.
Similarly, three manipulated variables were defined, the reflux ratio
(R), the heat duties supplied to the reboilers (C, and the third variable was the side stream flow rate (L).
The design of the steam stripper/distillation process includes the ability to recover heat from the effluent, vary the liquid to vapor (L/V) ratio and reflux ratio, pass fine solids through the system, access the Ways for cleaning, and allow cleaning of condensed ammonium salts from the condenser.
The selected column is a tray-type column with thirty valve trays operating at an average L:V ratio of 4:1 and a reflux ratio of 12:1.
The reflux ratio was set at 4 and the bottoms flowrate was specified to be 10 mol/s.
However, while lowering the feed tray the problem becomes harder to solve with the given reflux ratio and bottom flow rate specifications.
To test the methodology proposed in previous section, a depropanizer process (Lee, 1993) is used as a case study where the mole fractions of propane in distillate and isobutane in bottom product are controlled by simultaneously adjusting the reflux ratio
(RR) and boil-up rate (Q) in the face of sinusoidal disturbances in feed composition.
Models are used to fully understand the impact of such options as recycling intermediate cuts, using an entrainer, controlling the reflux ratio
to maintain distillate purity, and bringing a column back to total reflux during distillation.
Also, only problems with standard column specifications of reflux ratio
and distillate rate are solved so that the suitability of these methods for other reasonable column specifications remains in question.