As described earlier, the synthesis of combined heat and mass exchanger network must
concern about the trade off between investment cost of mass exchangers and the total cost for
heat exchangers – utilities and investment cost. The main factor in trading off these costs is the
equilibrium relation for each MSA. In this work, we classify the type of equilibrium relation into two
types which are High temperature favorable equilibrium relation and Low temperature favorable
equilibrium relation. The principle of these equilibrium types are described as follow;