Two different control structures are explored for the single reactive column process. The first is the two-temperature structure considered in Chapter 10. This system uses only temperatures and does not require a direct composition measurement. The second control structure uses a composition analyzer to measure a composition of one of the reactants on a selected tray in the column to adjust one of the fresh feeds.
The system is the same base case considered in Chapter 4 with five stripping, nine reactive, and five rectifying trays, operating at 8 bar with 1000 mol on reactive trays and 356 mol on separation trays. The column diameter is 0.805 m, and the reflux ratio is 2.66. Figure 11.1 presents the flowsheet with stream information and equipment sizes. The production rates are 12.6 mol/s of both products with purities of 95 mol%. The corresponding conversion is 95%. Figure 11.2 and Figure 11.3 give the temperature and composition profiles, respectively. The peaks in the concentration profiles of reactants A and B occur at their respective feed trays: tray 6 for A and tray 14 for B. The temperature profile is flat in the reactive section but changes fairly rapidly from tray to tray in both the stripping and rectifying sections.
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