Question

In large steam power plants, the feedwater is frequently heated in a closed feedwater heater by using steam extracted from the turbine at some stage. Steam enters the feedwater heater at 1 MPa and 215°C and leaves as saturated liquid at the same pressure. Feedwater enters the heater at 2.5 MPa and 50°C and leaves at 10°C below the exit temperature of the steam. Determine the ratio of the mass flow rates of the extracted steam and the feedwater. The enthalpies of steam and feedwater are h₁ = 2862.74 kJ/kg, h₂ = 762.51 kJ/kg, T₂ = 179.9°C, h₃ = 209.34 kJ/kg, and h₄ = 718.55 kJ/kg.

Answer 1

steam h2=762.51 kolly closed feed water heater P=1MPa 215 c Impa, Ta Pa mist Esat = Ty=179.9'6 h = 2862.74 Folky ③ is Mech, feed water P=2.5MPa 4 = 718.55 8.55 Agling T=soc ho= 206,34 kalky para To msz (2:8 62:74 762.51) = m fw (718.55-209134) ha mist mifu = (718.55 - 209.34) = 0.24 (28 (2862-74-76251) spyr $12 TA mist mifw Ratio = 0.24 = from