Diagnosis and redesign of power plants using combined Pinch and Exergy Analysis

This paper applies the combined Pinch and Exergy Approach in analysing the operation and design of a typical steam power plant. This work quantifies the total, avoidable an unavoidable exergy loss for the equipment, which means, the potential for equipment improvement. On the other hand, the analysis of cross pinch heat transfer in the process identifies additional losses of energy due to the inefficient design of the heat recovery system. Results from this work show that the elimination of cross pinch heat transfer in the process operation conditions will allow an increment of 0.81% (from 29.48% to 30.30%) on the cycle efficiency and a reduction of 2.4% on the cooling water required (from 5032 t/h to 4914 t/h). This indicates that even when the plant efficiency can be improved by using new or rehabilitated equipment, some energy losses could remain due to an inefficient thermal integration. (C) 2014 Elsevier Ltd. All rights reserved.