A Brief Introduction to the Pinch Analysis

930 Words Jun 23rd, 2018 4 Pages
The economics of industrial production, limitation of global energy supply, and the realities of environmental conservation are an enduring concern for all industries. Wherever you turn, there’s another entreaty to save energy, reduce carbon emissions and protect the environment for posterity. Pinch analysis is a tools used to design a heat exchanger networks (HEN) that reduce the energy usage. This paper will be about brief introduction for the pinch analysis, application of the second law of thermodynamics in design heat exchanger network

Pinch Analysis:
Pinch technology is the technology that provides a systematic methodology for energy saving in processes and total sites. The methodology is based upon first low and second low of
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Minimizing the total entropy produced by heat exchanger network lead to minimizing the use of high energy quality. The entropy can define for single heat exchanger i.e. exchange heat of one hot stream with one cold stream as

S=∮▒dS=∫▒dq/T
S=∫_(T_Hi)^(T_Ho)▒(C_H dT_H)/T_H -∫_(T_Ci)^(T_Co)▒(C_C dT_C)/T_C
〖S=C〗_C ln⁡〖(T_Co/T_Ci 〗)-C_H ln⁡〖(T_Hi/T_Hi 〗)

Sets of heat exchanger network will have constant total entropy when they use same type and amount of utilities. On the other hand, the entropy will vary for networks having different types and amount of utilities. The networks’ entropy that is used high energy qualities is higher than the one that used low energy qualities. The changes come from using high energy qualities, and this lead to have higher temperature different in some heat exchangers, hence high entropy. Due to that, the total area of the networks also will vary with the use of different utilities since total area is in related with temperature different in heat exchanger. As the temperature different increase the area will decrease.
Furthermore, total entropy can be used as objected furcation in mathematical programing. Total entropy can help to find total energy required with from each energy levels in small code.

Case study:
The objective of this case study is show the change of total entropy when different types of utility used i.e. LP steam, MP steam and HP steam. The case study has three hot streams and three
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