Page 153 - Elements of Chemical Reaction Engineering 3rd Edition

hot hermal 4

Reactor Design

Why, a four-year-old child could understand this.
Someone get me a four-year-old child.
Grouch0 Marx

In this chapter we bring all the material in the preceding three chapters
together to arrive at a logical structure for the design of various types of ireac-
tors. By using this structure, one should be able to solve reactor engineering
Tying everything problems through reasoning rather than memorization of numerous equarions
together
together with the various restrictions and conditions under which each equa-
tion applies (Le., whether there is a change in the total number of moles, etc.).
In perhaps no other area of engineering is mere formula plugging more hazard-
ous; the number of physical situations that can arise appears infinite, and the
chances of a simple formula being sufficient for the adeqhate design of a real
reactor are vanishingly small.
This chapter focuses attention on reactors that are operated isothermally.
We begin by studying a liquid-phase batch reactor to determine the specific
reaction rate constant needed for the design of a CSTR. After illustrating the
design of a CSTR from batch reaction rate data, we carry out the design of a
tubular reactor for a gas-phase pyrolysis reaction. This is followed by a discus-
sion of pressure drop in packed-bed reactors, equilibrium conversion, and
finally, the principles of unsteady operation and semibatch reactors.

4.1 Design Structure for Isothermal Reactors
The following procedure is presented as a pathway for one to follow in the
design of isothermal (and in some cases nonisothermal) reactors. It is the
author’s experience that following this structure, shown in Figure 4-1, will lead
to a greater understanding of isothermal reactor design. We begin by applying

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