Problem 113HP

Steady Flow Processes

A coflowing (same direction) heat exchanger, shown in Fig. P7.113, has one line with 0.5 kg/s oxygen at 17° C, 200 kPa entering, and the other line has 0.6 kg/s nitrogen at 150 kPa, 500 K entering. The heat exchanger is very long, so the two flows exit at the same temperature. Use constant heat capacities and find the exit temperature and the total rate of entropy generation.

FIGURE P7.113

Spencer Kociba CHEM 101 Lecture 11/15/16 THERMOCHEMISTRY ● Enthalpy ○ Represented as ΔH ○ Internal energy + pressure*volume ■ We will mostly be concerned with constant pressure. This is where the formula ΔH = ΔE + PΔV comes from ○ ΔH = q (enthalpy=heat gained or lost in the system) ● Properties of Enthalpy (ΔH ) ○ ΔH is directly proportional to mass ○ ΔH for a reverse reaction is equal in magnitude (quantity) but opposite in sign for the forwards reaction ○ Hess’s Law: ΔH is independent of the number of steps involved ■ If Reaction(1) + Reaction(2)=Reaction(3), then ΔH =3ΔH + 1H 2 ● Endothermic reactions ○ Gains heat from sur