Solvent Feeding Mode Full Charge

Effect oiF - Semi-Continuous Solvent Feeding Mode (Full Charge)... 

Here, the same mixture used for example 1 is considered. Semi-continuous solvent feeding mode with full charge strategy is opted in this example. The objective is to maximise the productivity of Task 1 of the STN shown in Figure 10.6. The specification on the distillate composition is 0.95 molefraction in Heptane. The optimisation problem (OP1) is considered and both the reflux ratio and solvent rate profiles are optimised. Again two time intervals are used for the entire operation period (Task 1). In each interval, constant reflux ratio and solvent feed rate are used, the values of which are optimised. The input data are the same as those in Table 10.1 except that the maximum reboiler capacity is 25 kmol. The solvent is introduced in plate 6 (Nf). 

Since the column is operating in full charge mode the constraints given by Equations 10.2 and 10.5 must be satisfied for the first and second intervals respectively. A number of cases were studied using different maximum allowable values for the solvent feed rate (E ) in the first interval. These give values for for the first interval. For each case, Table 10.8 shows the optimal reflux ratio, the solvent feed rate, the lengths of the time intervals and the productivity. The case 1 represents the base case where no solvent was introduced into the column. 

---