Answer to Question #261925 in Chemical Engineering for Leke

Question

A shell-and-tube heat exchanger has one pass on the shell side and two passes

on the tube side (i.e.al-2shell and tube heat exchanger). It is being used for oil

cooling. The oil flows in the tube side. It enters at 1120C and leaves at 78 0C

The shell-and-tube fluid is water at a flow rate of1.35 kg/s, entering at 360C and

leaving at 78 0C. The heat capacity of water is 4180j/(kg. K), and the overall

heat transfer coefficient for the heat exchanger is 350 W/(m2.K). The geometry

factor, F is 1.15. Determine the heat transfer area required for the unit.

Answer 1

Baffles

In Figure 5.18, baffles are placed within the shell of the heat exchanger firstly to support the tubes, preventing tube vibration and sagging, and secondly to direct the flow to have a higher heat transfer coefficient. The distance between two baffles is baffle spacing.

Multiple Passes

Shell-and-tube heat exchangers can have multiple passes, such as 1-1, 1-2, 1-4, 1-6, and 1-8 exchangers, where the first number denotes the number of the shells and the second number denotes the number of passes. An odd number of tube passes is seldom used except the 1-1 exchanger. A 1-2 shell-and-tube heat exchanger is illustrated in Figure.