TABLE OF CONTENTS In Chapter 2 we showed how to develop a simple network achieving energy targets for a given. This is the maximum energy recovery or minimum energy requirement (MER) design. In this section, we cover more advanced concepts, including:
More complex MER designs involving stream splitting (Section 4.3).
Network relaxation eliminating small exchangers with a minor energy penalty (Section 4.4).
Situations with constraints, multiple pinches, utility pinches and pinch regions (Sections 4.5 and 4.6).
Revamp and retrofit of existing heat exchanger networks (Section 4.7).
Operability aspects and multiple base cases (Section 4.8).
We also briefly look at the main available types of heat exchangers (Section 4.2) and illustrate all the key themes by application to our case study on the organics distillation unit (Section 4.9).
In simple terms, heat exchange equipment can be divided into three families: shell-and-tube, plate and recuperative exchangers.
The shell-and-tube family is generally used for heat exchange between liquids, but may include gases or condensing/boiling streams. Fluid flows through a set of tubes and exchanges heat with another fluid flowing outside the tubes in crossflow, countercurrent, cocurrent or mixed flow. Double-pipe exchangers are a special case of this type where there is just a single central tube with an annular shell around it. Construction is strong and rigid, well suited for high pressures and temperatures as found in many chemicals applications. However, adding additional area requires either major retubing or additional shells.
The plate family...
