Performance evaluation of a triple-effect evaporator with forward feed using exergy analysis

SUMMARY The present study evaluates the performance of a triple-effect evaporator with forward feed (TEEFF) system by using exergy analysis based on actual operational data. The orange juice with a capacity of about 1.222 kg s � 1 is concentrated from a dry matter (DM) content of 12 to 65% in this TEEFF, which is situated in an orange juice concentrate line installed in a factory, located in Denizli, Turkey. A Visual Basic 6.0 program was also developed to show how the exergetic performance characteristics of the system vary with the feed flow rates ranging from 1.222 to 1.667 kg s � 1 . The total exergy efficiency of the TEEEFF is found to be on average 0.85. The largest exergy destruction occurs in the first-effect of the TEEFF system with 48.2% of total, followed by the third and second effects with 32.04 and 19.76% of that. Evaporator performance is also rated on the basis of steam economy, which is obtained to be in the range of 2.05–2.14 under the operation conditions. It is expected that the analysis presented here should provide a designer with a better, quantitative grasp of the inefficiencies and their relative magnitudes in the design, simulation and operation of multiple-effect evaporators. Copyright # 2005 John Wiley & Sons, Ltd.