4.2-5. Steam Boiler and Overall Energy Balance. Liquid water under pressure at 150 kPa enters a boiler at 24C through a pipe at an average velocity of 3.5 m/s in turbulent flow. The exit steam leaves at a height of 25 m above the liquid inlet at 150C and 150 kPa absolute, and the velocity in the outlet line is 12.5 m/s in turbulent flow. The process is steady state. How much heat must be added per kg of steam? GIVEN: State 1 - Liquid Inlet Stream T1 = 24 C, P1 = 150 kPa, zl = 0 m (Reference Elevation State), vl = 3.5 m/s State 2 - Steam Vapor Exit Stream T2 = 150 C, P2 = P1 = 150 kPa (Isobaric Process), z2 = 25 m (above the Inlet Stream), v2 = 12.5 m/s Both inlet and exit streams are turbulent flow systems. Steam Vapor Steam Outlet (2) Boiler Liquid Inlet (1) Qadded to the system