Page 433 - Handbook of Energy Engineering Calculations

Shellside, Eq. (11):

Tube wall, Eq. (18):

Fouling, Eq. (19):

Because SOP is greater than 1, the assumed exchanger is inadequate. The
surface area must be increased by adding tubes or increasing the tube length,
or the performance must be improved by decreasing the baffle spacing. Since
the maximum tube length is fixed by the conditions given, the alternatives are

increasing the number of tubes and/or adjusting the baffle spacing. To
estimate assumptions for the next trial, pressure drops are calculated. See
Table 7.

TABLE 7 Empirical Pressure-Drop Relationship for Rating Heat
Exchangers