5.46 At a certain point in the processing of crude oil, it must be heated. The heating occurs in a 1-4 (1-shell pass, 4-tube pass) STHX. The oil is flowing at a rate of 110,000 lbm/h and it enters the heat exchanger at 80°F. The heating will be accomplished with hot water entering the heat exchanger at 150,000 lbm/h at a temperature of 200°F. The heat exchanger has a shell diameter of 23¼ in. and contains 6 baffles. The tubes are 1-in. OD, 13 BWG tubes on a 1¼-in. square pitch.

The tubes are 12 ft long. The oil is routed through the tubes and the water through the shell. The average properties of the crude oil can be taken as

 = = 

μ =  =  

46.2 lbm/ft 0.49 Btu/lbm R 8.22 lbm/ft h 0.0763 Btu/h ft °F oil 3

,oil oil oil c

k p

a. Determine the expected outlet temperatures and pressure drops when the heat exchanger is new and just put into service.

b. The engineer overseeing this processing line is interested in knowing the performance of the heat exchanger if the water flow rate is varied.

Construct two plots: one that shows the water and oil outlet temperatures as a function of the water flow rate and one that shows the shell-side pressure drop as a function of the water flow rate. Run the calculations for water flow rates between 50,000 and 300,000 lbm/h.