A closed metallic boiler drum of capacity 0.24m3 contain steam at a pr

1.	A closed metallic boiler drum of capacity 0.24m3 contain steam at a pressure of 11bar and a temperature of 200ºC. Calculate the quantity of steam in the vessel. At what pressure in the vessel will the steam be dry and saturated if the vessel is cooled?
Answer» Given that: Capacity of drum V₁ = 0.24m³ Pressure of steam P₁ = 11bar Temperature of steam T₁ = 200ºC At pressure 11bar from super heated steam table At 10 bar and T = 200ºC; Å =0.2060 m³/kg At 12 bar and T = 200ºC; Å =0.1693 m³/kg Using linear interpolation: (Å – 0.2060)/(0.1693 – 0.206) = (11 – 10)/(12 – 10) Å = 0.18765 m³/kg Quantity of steam = V/Å = 0.24/0.18765 = 1.2789 kg From Saturated steam table At 11bar; T_sat= 184.09ºC 2000C > 184.09ºC i.e. steam is superheated If the vessel is cooled until the steam becomes dry saturated, its volume will remain the same but its pressure will change. From Saturated steam table; corresponding to Å_g= 0.18765, the pressure is 1122.7KPa

A closed metallic boiler drum of capacity 0.24m3 contain steam at a pressure of 11bar and a temperature of 200ºC. Calculate the quantity of steam in the vessel. At what pressure in the vessel will the steam be dry and saturated if the vessel is cooled?

Answer»

Given that:

Capacity of drum V₁ = 0.24m³

Pressure of steam P₁ = 11bar

Temperature of steam T₁ = 200ºC

At pressure 11bar from super heated steam table

At 10 bar and T = 200ºC; Å =0.2060 m³/kg

At 12 bar and T = 200ºC; Å =0.1693 m³/kg

Using linear interpolation:

(Å – 0.2060)/(0.1693 – 0.206) = (11 – 10)/(12 – 10)

Å = 0.18765 m³/kg

Quantity of steam = V/Å = 0.24/0.18765 = 1.2789 kg

From Saturated steam table

At 11bar; T_sat= 184.09ºC

2000C > 184.09ºC

i.e. steam is superheated

If the vessel is cooled until the steam becomes dry saturated, its volume will remain the same but its pressure will change.

From Saturated steam table; corresponding to Å_g= 0.18765, the pressure is 1122.7KPa