8- 308.54 (cont’d) d. TTfa2345061=°⇒=°CCT&E, TTfa2136552=°⇒=°CCT&Ee. In an adiabatic system, when a liquid evaporates, the temperature of the remaining condensed phase drops. In this problem, the heat transferred from the air goes to (1) vaporize 90% of the acetone in the feed; (2) raise the temperature of the remaining wet film above what it would be if the process were adiabatic. If the feed air temperature is above about 530 °C, enough heat is transferred to keep the film above its inlet temperature of 35 °C; otherwise, the film temperature drops. 8.55TpsetpsiaF=≈°200100bg(Cox chart – Fig. 6.1-4) a.Basis:3.0010SCF1 lb - moleh359 SCFlbmoleh CH338×=⋅8 357.8.357 lb-mole C3H8(v)/h 8.357 lb-mole C3H8(l)/h 200 psia, 100oF 200 psia, 100oF ±m(lb - mole HO(l) / h2±m(lb - mole HO(l) / h270oF 85oF The outlet water temperature is 85oF. It must be lessthan the outlet propane temperature; otherwise, heat would be transferred from the water to the propane near the outlet, causing
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