1. Film Condensation (20 pts.) A vertical-tube two-pass heater is used for heating an oil. The...

 

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1. Film Condensation (20 pts.) A vertical-tube two-pass heater is used for heating an oil. The tubes are 1 in. OD by 16 BWG [see Table A.5-2 of Properties of Pipes, Tubes, and Screens (Geankoplis, 2003)] and are made of mild steel (k= 26.0 Btu/hr-ft-°F). The oil flows inside the vertical tubes in two passes: upward in half of the tubes and then downward in the other half of the tubes (see §14.3 of BSLK for correlation for heat-transfer coefficients for forced convection in tubes). The flow of oil is 200 bbl/hr (1 bbl = 42 gal). The velocity of the oil in the tubes should be approximately 6 ft/sec. The oil enters at 60°F and leaves at 150°F. The viscosity-temperature relation is exponential. The viscosity at 60°F is 5.0 cP and at 150°F is 1.8 cP. The oil is 37° API (specific gravity = 0.840) at 60°F. The thermal conductivity of the oil is 0.078 Btu/hr-ft-°F, and the specific heat capacity is 0.480 Btu/lb- °F. Saturated steam at 50 psig (gauge) is used as a heating medium. It condenses on the outside of the vertical tubes. Assume the steam condenses in film condensation (see $14.7 of BSLK for correlation for heat-transfer coefficient of condensing steam). Calculate the number of tubes needed for this heater and the length of each tube. What is the overall heat-transfer coefficient Uo (based on outside diameter of the tubes) for the given condition? What are the oil-side heat-transfer coefficient and the steam-side heat- transfer coefficient? Solve by using a trial-and-error procedure. b. Solve by using solve block in MathCAD. a. 1. Film Condensation (20 pts.) A vertical-tube two-pass heater is used for heating an oil. The tubes are 1 in. OD by 16 BWG [see Table A.5-2 of Properties of Pipes, Tubes, and Screens (Geankoplis, 2003)] and are made of mild steel (k= 26.0 Btu/hr-ft-°F). The oil flows inside the vertical tubes in two passes: upward in half of the tubes and then downward in the other half of the tubes (see §14.3 of BSLK for correlation for heat-transfer coefficients for forced convection in tubes). The flow of oil is 200 bbl/hr (1 bbl = 42 gal). The velocity of the oil in the tubes should be approximately 6 ft/sec. The oil enters at 60°F and leaves at 150°F. The viscosity-temperature relation is exponential. The viscosity at 60°F is 5.0 cP and at 150°F is 1.8 cP. The oil is 37° API (specific gravity = 0.840) at 60°F. The thermal conductivity of the oil is 0.078 Btu/hr-ft-°F, and the specific heat capacity is 0.480 Btu/lb- °F. Saturated steam at 50 psig (gauge) is used as a heating medium. It condenses on the outside of the vertical tubes. Assume the steam condenses in film condensation (see $14.7 of BSLK for correlation for heat-transfer coefficient of condensing steam). Calculate the number of tubes needed for this heater and the length of each tube. What is the overall heat-transfer coefficient Uo (based on outside diameter of the tubes) for the given condition? What are the oil-side heat-transfer coefficient and the steam-side heat- transfer coefficient? Solve by using a trial-and-error procedure. b. Solve by using solve block in MathCAD. a.

Answer rating: 100% (QA)

Solve by using a trialanderror procedure The overall heattransfer coefficient is Uo 500 Btuhrft2F The oilside heattransfer coefficient and the steamside heattransfer coefficient are Uo 350 Btuhrft2F a... View the full answer