Page 455 - Elements of Chemical Reaction Engineering Ebook

Steady-State 8

Nonisothermal

Reactor Design

If you can’t stand the heat, get out of the kitchen.
Harry S Truman

We now focus our attention on heat effects in chemical reactors. The basic
design equations, rate laws, and stoichiometric relationships derived and used
in Chapter 4 for isothermal reactor design are still valid for the design of
nonisothermal reactors. The major difference lies in the method of evaluating
the design equation when temperature varies along the length of a PFR or
Heat effects when heat is removed from a CSTR. In Section 8.1 we show why we need the
energy balance and how it will be used to solve reactor design problems. Sec-
tion 8.2 concerns the derivation and manipulation of the energy balance for its
application to various reactor types. In Sections 8.3 and 8.4, the energy balance
is coupled with the mole balance, rate laws, and stoichiometry to design
nonisothermal reactors. In Section 8.5 a typical nonisothermal industrial reac-
tor and reaction, the SO2 oxidation, is discussed in detail. We address the mul-
tiplicity of steady states in Section 8.6 and close the chapter with Section 8.7,
nonisothermal multiple reactions.

8.1 Rationale
To identify the additional information necessary to design nonisothemal reac-
tors, we consider the following example, in which a highly exothermic reaction
is carried out adiabatically in a plug-flow reactor.

Example 8-1 What Additional information is Required?

Calculate the reactor volume necessary for 70% conversion.
A-B

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