6.1.2. Dynamic simulation results
Based on the dynamic model and the same base conditionsit is interesting to investigate the effect of fouling on the milk outlet temperature. The latter is depicted in Fig. 8 as a function of time for two different values of the inlet protein concentration. As expected milk outlet temperature decreases with time. Over a period of operation of 6.66 h the overall decrease is 2.43C. Comparing with the shell and tube heat exchangers fouling seems to be less severe in PHEs (in terms of the outlet temperature).This can be explained since a PHE can be viewed as a series of co-current and counter-current shell and tube exchangers with strong thermal interactions between channels