In multiple effect evaporators (MEE), evaporation takes place in stages; vapour coming from a stage loses its latent heat of vaporisation and acts as a heat source for the next stage. This process goes on till the last stage of evaporator where the desired concentration is achieved. MEE can be represented as a set process streams at different pressure/ temperature levels and its grand composite curve (GCC) can be generated. These process streams can be integrated with the background process to minimise the total energy consumption of the entire plant, rather than minimising the energy consumption of MEE and background process individually. An analytical methodology is developed to integrate (MEE) with the background process, such that the energy consumption for the entire pant can be minimised. A mathematical theorem is proposed to determine variation in overall energy requirement during integration of MEE with the background process. Proposed methodology is illustrated with the help of an example and up to 15.5 % of energy can be saved if the systems are integrated properly.
