A petroleum oil having the properties given in Table 15.3 is to be heated in a horizontal multipass heater with steam at 60 lb_ƒ/in.² gauge. The tubes are to be steel, ³/₄-in. OD by BWG 16, and their maximum length is 15 ft. The oil enters at 100°F. leaves at 180°F, and enters the tubes at about 4 ft/s. The total flow rate is 200 gal/min. Assuming complete mixing of the oil after each pass, how many passes are required? 

Table 15.3

Transcribed Image Text:

TABLE 15.3 Data for Prob. 15.4 Temperature, 'F 100 120 140 160 180 200 220 240 260 Thermal conductivity. Btu/ft-h-F 0.0739 0.0737 0.0733 0.0728 0.0724 0.0719 0.0711 0.0706 0.0702 Kinematic viscosity. 10³ ft²/s 36.6 21.8 14.4 10.2 7.52 5.70 4.52 3.67 3.07 Density, lb/ft² 55.25 54.81 54.37 53.92 53.48 53.03 52.58 52.13 Specific heat, Btu/lb F 0.455 0.466 0.477 0.487 0.498 0.508 0.519 0.530 0.540