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Figure 4.15 Reactive and recovery columns for 20% excess of reactant A.

TABLE 4.4 Recovery Column Design for 20% Excess of A or B

Excess A Excess B

Nt2 20 20

Shell 119.2 96.5

Condenser and reboiler 138.9 107.4

Total annual (103$/year) 158.0 116.5

Figure 4.14 provides composition profiles in the recovery column, and Figure 4.15 shows the temperature profiles in the two columns. Table 4.4 compares the designs of the recovery column for 20% excess of A and 20% excess of B. The former is significantly more expensive in both energy and capital cost. This is due to the higher vapor boilup in the recovery column (16.45 vs. 11.07 mol/s) that results from the larger recycle flowrate (2.36 vs. 1.458 mol/s). The impurity of B in the bottom from the reactive column is 12.99 mol% in the 20% excess B case. In the 20% excess A case, the distillate of the reactive column contains significant impurities of both A and B (9.96 and 8.32 mol%, respectively). It appears that it is easier to keep A from going out the

Figure 4.14 provides composition profiles in the recovery column, and Figure 4.15 shows the temperature profiles in the two columns. Table 4.4 compares the designs of the recovery column for 20% excess of A and 20% excess of B. The former is significantly more expensive in both energy and capital cost. This is due to the higher vapor boilup in the recovery column (16.45 vs. 11.07 mol/s) that results from the larger recycle flowrate (2.36 vs. 1.458 mol/s). The impurity of B in the bottom from the reactive column is 12.99 mol% in the 20% excess B case. In the 20% excess A case, the distillate of the reactive column contains significant impurities of both A and B (9.96 and 8.32 mol%, respectively). It appears that it is easier to keep A from going out the

440 430 420 410 g 400 Ê 390 380 370 360 350

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