Consider the exchanger in Problem 22.8. After 4 years of operation, the outlet of the oil reaches 30 C instead of 38 C with all other conditions remaining the same. Determine the fouling resistance on...

Consider the exchanger in Problem 22.8. After 4 years of operation, the outlet of the oil reaches 30C instead of 38C with all other conditions remaining the same. Determine the fouling resistance on the oil side of the exchanger.

Problem 22.8

A shell-and-tube heat exchanger is used for the heating of oil from 20 to 30C; the oil flow rate is 12 kg/s (). The heat exchanger has one shell pass and two tube passes. Hot water () enters the shell at 75C and leaves the shell at 55C. The overall heat-transfer coefficient based on the outside surface of the tubes is estimated to be 1080 W/m₂

K. Determine

a. the corrected logarithmic-mean temperature difference;

b. the required surface area in the exchanger.