It is possible to generate performance curves for the reactor in Section 22. 1. One type of performance curve would have the rate of cumene production \((\mathrm{kmol} / \mathrm{h})\) on the \(y\)-axis, and the percent propane impurity in the propylene on the \(x\)-axis. There would be lines for different operating temperatures all at constant pressure.

Assume that the feed to the reactor is \(108 \mathrm{kmol} / \mathrm{h}\) propylene, \(8 \mathrm{kmol} / \mathrm{h}\) propane, and \(203 \mathrm{kmol} / \mathrm{h}\) benzene. The pressure is kept constant at \(3000 \mathrm{kPa}\). Prepare performance curves on the same graph for temperatures from \(350^{\circ} \mathrm{C}\) to \(400^{\circ} \mathrm{C}\) in \(10^{\circ} \mathrm{C}\) intervals. Superimpose on this graph the maximum allowable conditions, which correspond to a steam-side pressure of \(4800 \mathrm{kPa}\). A process simulator should be used to generate points on the performance curves. Other data: reactor volume \(=7.89 \mathrm{~m}^{3}\), heat transfer area \(A=436 \mathrm{~m}^{2}\), overall heat transfer coefficient \(=65\) \(\mathrm{W} / \mathrm{m}^{2{ }^{\circ} \mathrm{C}}\).

Data from section 22.1

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Many industrially significant reactions are exothermic. Therefore, in a reactor, it is necessary to remove the heat generated by the heat of reaction. There are several ways to accomplish heat removal. For relatively low heats of reaction, staged adiabatic packed beds (packed with catalyst) with intercooling may be used. Here, no heat is removed in the reaction section of the equipment. Instead, the process fluid is allowed to heat up in the reactor and heat is removed in heat exchangers between short beds of catalyst (reactor sections). For larger exothermic heats of reaction, a shell-and- tube configuration, much like a heat exchanger, is often used. Here, the reaction usually occurs in the tubes, which are packed with catalyst. As the heat of reaction increases, tube diameter is decreased in order to increase the heat transfer area. For extremely large heats of reaction, fluidized beds with internal heat transfer surfaces are often used, due to the constant temperature of the fluid bed and the relative stability of such reactors because of the large thermal mass of well-mixed solid particles. In all three of these cases, the performance of the reactor and the heat exchanger are coupled. It is not correct to analyze one without the other. In this section, an example of the performance of a shell-and- tube-type reactor (tube bundle containing catalyst immersed in a pool of boiling water) with heat removal is used to illustrate the interrelationship between reactor performance and heat transfer. In Chapter 23. other examples of reactor performance are presented.