In: Other
A 2-shell passes and 4-tube passes heat exchanger is used to heat process stream from 35°C to 80°C by hot water available at 90°C, which enters the thin-walled 2.5-cm-diameter tube with total length of 65 m. The convection heat transfer coefficient is 76 W/m2 .°C on the process stream (shell) side and 190 W/m2 .°C on the water (tube) side. For a desired factor, FT = 0.95
a) Determine the rate of heat transfer in the heat exchanger.
b) Consider a fouling factor of 0.0012 m2 ·°C/W at the inner and outer surfaces of tube, determine the new rate of heat transfer
c) Evaluate the mass flow of hot water needed to compensate the heat loss due to fouling. Assume cp of hot water is 4.2 J/g.°C.
d) If the existing operating conditions are to be remained unchanged, evaluate the new area to compensate the heat loss due to fouling.