Determine the amount of heat required to produce 1Kg of steam at a pressure of 7 bar, at a temperature 29 degree Celsius, under the following . (i) When the steam is wet having dryness fraction 0.87 (ii) When the steam is dry saturated Assume specific heat = 2.35KJ/KgK

Determine the amount of heat required to produce 1Kg of steam at a pressure of 7 bar, at a temperature 29 degree Celsius, under the following . (i) When the steam is wet having dryness fraction 0.87 (ii) When the steam is dry saturated Assume specific heat = 2.35KJ/KgK 
by

1 Answer

Answer :

P 7bar

T 29ᵒC

x=0.9

m =1kg

C p =2.35 KJ/KgK

At pressure 7 bar saturation Temp

T sat =165 ᵒC

h f =697.2 KJ/Kg

h fg= 2064.8 KJ/Kg

i) Heat required when steam is wet

h=hf+xhfg

 =2555.52

since the water is at 29 ᵒC ,

heat already in water = specific heat of water* rise in temperature

 =4.2*29

 =121.8

Heat actually required =h-heat already in water

 =2555.52-121.8

=2433.72KJ/Kg


ii) When the stem is dry saturated

hg=hf+hfg

=2762 kj

Heat actually required = 2762-121.8

= 2640.2 kj


by

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