Rationalisation of external cooling demand on a paper mill site

A case study is presented, where rigorous process simulation, Pingh Analysis and HEN design have been used for analysis and design of a heat exchanger network for a paper mill integrate.The objective is to minimise the use of external cooling thus minimising the capital expenditure required for a coolin tower.Two distinct cases, summer and winter, have been studied.Pinch analysis results indicated that in the winter case no cooling is required and the selection of hot utilities for covering the heating deficit is not critical from the cooling demand point of view.For the summer case, however, hot utilities must be selected more carefully due to high Pinch temperature. Also some external cooling is required for the summer case.A heat exchanger network was constructed to demonstrate thet with a practical design it is possible to get close to the utility consumption targets.Practical constraints concerning lay-out etc. were taken into account to achieve a design, which provides a practical target.