Question

A chemical process stream enters a shell-and-tube exchanger at a temperature of 200.0°Fand does two passes on the shell side, exiting the exchange at 170.0°F. The Heat exchanger Spring 2021 has 200 stainless steel tubes that are 2-in.ODand 10.0ft long. Indicate whether the temperature of the process stream will increase, decrease, or remain the sameunder the following scenarios. You must justify your answerto receive full credit.a)The flow rate of the cooling fluid is increased.b)There are 200 tubes that are 1.0-in. OD and 20.0ft long.c)The number of shell passes is doubled.d)The tube material is changed to copper.

Answer 1

a) Decrease

b) Decrease

c) Decrease

d) Decrease

Step-by-step explanation:

Ti= 200°F ,

Te = 170°F

Area of heat exchanger =
`\pi *(2 )* 10` = 20π

A) when The flow rate of the cooling fluid is increased

Temperature of process stream will decrease and this is because the tube side heat transfer coefficient will increase and this will increase the rate of heat transfer thereby decreasing the temperature of the process stream.

B) when There are 200 tubes that are 1.0-in. OD and 20.0ft long

The temperature of the process stream will decrease and this is because the heat transfer coefficient will increase likewise the heat transfer rate

C) When The number of shell passes is doubled

This will cause an increase in the overall length of the shell, an increase in velocity of constant volumetric flowrate, hence the Temperature of the process steam will decrease as well

D) When The tube material is changed to copper.

Due to the high thermal conductivity of copper when compared to steel , switching to copper will cause a decrease in the temperature of the process steam