![]() in order to reduce the utility requirements of the combined system. The Appropriate Placement Principles provide insights for proper integration of key equipments like distillation columns, evaporators, furnaces, heat engines, heat pumps etc. ∙ Plus/Minus and Appropriate Placement Principles: The “Plus/Minus” Principles provide guidance regarding how a process can be modified in order to reduce associated utility needs and costs. The essence of the pinch approach is the speed of economic evaluation. Using this method, it is possible to obtain an accurate estimate (within 10 - 15%) of overall heat recovery system costs without having to design the system. ∙ Total Cost Targeting: Used to determine the optimum level of heat recovery or the optimum DTmin value, by balancing energy and capital costs. ∙ Energy and Capital Cost Targeting : Used to calculate total annual cost of utilities and capital cost of heat exchanger network. ∙ Grand Composite Curve: Used to select appropriate levels of utilities (maximize cheaper utilities) to meet over all energy requirements. ∙ DTmin and Pinch Point : The DTmin value determines how closely the hot and cold composite curves can be ‘pinched’ (or squeezed) without violating the Second Law of Thermodynamics (none of the heat exchangers can have a temperature crossover). ∙ Minimum number of exchanger units required. ![]() ![]() ∙ Minimum energy (both hot and cold utility) required, ∙ Combined (Hot and Cold ) Composite Curves : Used to predict targets for ![]() With the advent of pinch analysis concepts, the network design has become very systematic and methodical.Ī summary of the key concepts, their significance, and the nomenclature used in pinch analysis is given below: As explained in the previous section, the traditional design approach has resulted in networks with high capital and utility costs. The design of such a network is not an easy task considering the fact that most processes involve a large number of process and utility streams. To meet the goal of maximum energy recovery or minimum energy requirement (MER) an appropriate heat exchanger network (HEN) is required. In the present energy crisis scenario all over the world, the target in any industrial process design is to maximize the process-to- process heat recovery and to minimize the utility (energy) requirements. Most industrial processes involve transfer of heat either from one process stream to another process stream (interchanging) or from a utility stream to a process stream. ![]()
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