Network Pinch—The Bottleneck of Existing Heat Recovery System

2 NETWORK PINCH—THE BOTTLENECK OF EXISTING HEAT RECOVERY SYSTEM 

1 Difference Between the Process Pinch and the Network Pinch 

FIGURE 10.3. Example network at the heat recovery limits. 

The network pinch identifies the heat recovery limit inherent in an existing heat exchanger network and therefore indicates the requirement of structural changes to the HEN. In other words, when a network reaches its network pinch limit, the only way to overcome it or increase heat recovery is to make stmctural changes if no process changes are considered. 

However, not all network stmctural changes are able to overcome the network pinch, but only those that can move heat from below to above the network pinch can. This principle provides a valuable guideline for screening out nonbeneficial modification options, which will be discussed next. 

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