Synthesis of Triple- Effect Evaporator System

Abstract

In the present paper a new graphical technique named “Enthalpy rectangle (ER) diagram” has been developed for the analysis of complicated temperature paths of a multiple effect evaporator (MEE). The present technique provides the necessary insights for the synthesis of MEE by partitioning the feed into different segments such as concentrated liquid product stream and “n” number of condensates streams, where n is the total number of effects. The present ER diagram offers two parameters for the analysis of feed flow sequences of MEE, first, the shortest temperature path which consumes minimum hot and cold utility and second, the total amount of internal energy exchanged by different segments of feed stream. On the basis of the above parameters, the optimal feed flow sequence (OFFS) is considered to be that sequence which requires minimum hot & cold utilities and minimum amount of total internal enthalpy exchange.

To demonstrate the effectiveness of the present technique, it is applied for the synthesis of OFFS of a triple-effect evaporator (TEE). Finally, the paper suggests a few heuristics for the synthesis of OFFS, for a MEE.