4.2
Heat Exchanger Duty (E-102)
Given is: T5
=
382 k
T7
=
423k
& Thus T5
= nair [ Cp.dT ]
H
T7
=
283.724[28.09(423-382) + 0.1965x10-2 (4232 -3822) 2 -5 3 3 + 0.4799x10 (423 -382 ) - 1.965x10-9(4234 -3824)] 3 3 283.724 [1151.69+32.247+31.9-5.267]
Hair
=
343518.83kJ
Since
=
η (h7 –h5) = q5-7 = m S
=
Now, Medium pressure steam is at 1200 kPa & at this pressure S
=
1984.3 kJ/kg
m
=
343518.83kJ 1984.3kJ/kg
m
=
141.5kg/hr
Thus:
42