Consider an alternative reactor configuration for the cumene reactor, R-801. The alternative is shown in Figure P18.1 and consists of a series of adiabatic catalytic packed beds through which the reactants pass. As the reactants and products pass through each bed, they are cooled by a cold shot of inert diluent—in this case, propane— before entering the next bed. The catalyst must be protected from excessive temperatures that cause it to sinter and to lose activity rapidly. For each of the control strategies given below, sketch the control loops that must be added to the system and discuss how the regulation is achieved—for example, “that is, as x increases, valve y opens, causing...”

Figure P18.1

1. Use the exit temperature from a given bed to adjust the amount of diluent fed to that bed.

2. Use the exit temperature from the previous bed to adjust the amount of diluent fed to the next bed.

3. To what types of control strategy do Parts (a) and (b) conform? Which scheme do you think is better for this type of reactor? Explain your reasoning.

4. Devise a control strategy that incorporates both the ideas used in Parts (a) and (b).

Transcribed Image Text:

Reactor Feed Propane -CXXXXD R-801 Reactor Effluent