Benzene flowing at 12.5 kg/s is to be cooled continuously from 82°C to 54°C by 10 kg/s of water available at 15.5°C. Using Table 10.6, estimate the surface area required for 

(a) Cross-flow with six tube passes and one shell pass, with neither of the fluids mixed, and
(b) A counter flow exchanger with one shell pass and eight tube passes, with the colder fluid inside tubes.

Data from in Table 10.6

Transcribed Image Text:

TABLE 10.6 Approximate overall heat transfer coefficients for preliminary estimates Overall Coefficients, U Duty Steam to water instantaneous heater storage-tank heater Steam to oil heavy fuel light fuel light petroleum distillate Steam to aqueous solutions Steam to gases Water to compressed air Water to water, jacket water coolers Water to lubricating oil Water to condensing oil vapors Water to condensing alcohol Water to condensing Freon-12 Water to condensing ammonia Water to organic solvents, alcohol Water to boiling Freon-12 Water to gasoline Water to gas oil or distillate Water to brine Light organics to light organics Medium organics to medium organics Heavy organics to heavy organics Heavy organics to light organics Crude oil to gas oil (Btu/h ft² °F) 400-600 175-300 10-30 30-60 50-200 100-600 5-50 10-30 150-275 20-60 40-100 45-120 80-150 150-250 50-150 50-150 60-90 35-60 100-200 40-75 20-60 10-40 10-60 30-55 (W/m²K) 2,270-3,400 990-1,700 57-170 170-340 280-1,130 570-3,400 28-280 57-170 850-1,560 110-340 220-570 255-680 450-850 850-1,400 280-850 280-850 340-510 200-340 570-1,130 220-425 110-340 57-200 57-340 170-310