Heat exchanger network blocks

Synthesis is the step in design where one conjectures the building blocks and their interconnection to create a structure which can meet stated design requirements. This review paper first defines chemical process synthesis and indicates the nature of the research problems—to find representations, evaluation functions and search strategies for a potentially nearly infinite problem. It then discusses synthesis research and the most significant results in each of six areas—heat exchanger networks, separation systems, separation systems with heat integration, reaction paths, total flowsheets and control systems. 

Flowsheet analysis and HEN synthesis problem. A material balance has been completed for a process to manufacture styrene and an ethylbenzene byproduct from reactions involving methanol and toluene. See Figure 10.61 for a block flow diagram of the process with the results of material balance calculations. You are to develop an optimal heat exchanger network for this process. Note that ... 

Zhu XX, O NeiU BK, Roach JRC, Wood RM. A method for automated heat exchanger network synthesis using block decomposition and non-hnear optimization. Trans IChemE 1995 73(8) 919—30. 

The second example is a small heat exchanger network described in detail in Paloschi(1997). It is decomposed in five nonlinear groups, the largest being of size five. In this case, the dimension of Qi is also one in the five decomposed blocks. 

G. Stephanopoulos, Synthesis of Networks of Heat Exchangers—A Self-Study Block Module, Project PROCEED, Massachusetts Institute of Technology, Cambridge, 1977. 

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