Heat exchanger networks recovery

After maximizing heat recovery in the heat exchanger network, those heating duties and cooling duties not serviced by heat recovery must be provided by external utilities. The outer-most layer of the onion model is now being addressed, but still dealing with targets. 

Example 16.1 The process stream data for a heat recovery network problem are given in Table 16.1. A problem table analysis on these data reveals that the minimum hot utility requirement for the process is 15 MW and the minimum cold utility requirement is 26 MW for a minimum allowable temperature diflFerence of 20°C. The analysis also reveals that the pinch is located at a temperature of 120°C for hot streams and 100°C for cold streams. Design a heat exchanger network for maximum energy recovery in the minimum number of units. 

Heat Recovery, Energy Balances, and Heat-Exchange Networks. The goal of heat recovery is to be sure that energy does the... 

Determine the pinch temperatures and the minimum utility requirements for the streams set out in the table below, for a minimum temperature difference between the streams of 20°C. Devise a heat exchanger network to achieve the maximum energy recovery. 

Figure 18.34 Maximizing the energy recovery of the existing heat exchanger network even down to AT = 0°C gives an energy performance worse than the energy target. (From Asante NDK and Zhu XX, 1997, Trans IChemE, 75A 349, reproduced by permission of the Institution of Chemical Engineers.)...

The existing heat exchanger network is shown again in Figure 18.35 with its recovery increased to an absolute... 

Heat exchangers are a prime means of conserving energy in process plants by exchanging heat between process streams that need to be cooled and those that need to be heated. Much attention is directed toward optimization of heat conservation and recovery by selecting the proper heat exchanger network. 

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