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mt05
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1) Feed water enters a boiler at 172.52 degrees Celsius. The boiler produces super heated steam at 5600kpa and 472 degrees Celsius. The boiler efficiency is 82%. Find the Heat required by fuel.
2)
I interpolated the value given for feed water and super heated steam.
h@5600kpa 472 degrees Celsius = 3359.0128 kj/kg
hf@ 172.52 degrees Celsius = 730.30 kj/kg
So...
delta h = 3359.0128 kj/kg - 730.30kj/kg
delta h = 2628.7128 kj/kg (this is the energy that the boiler would produce running at 100% to make the given steam right?)
So...
Qfuel = (2628.7128 kj/kg)(1.18) (I'm multiplying by 1.18 to make up for the 18% efficiency difference)
Qfuel = 3101.88 kj/kgefficiency = Qsteam/Qfuel
.82 = 2628.7128/Qfuel
Qfuel = 3205.07 kj/kg3) I get two different answers for quantity of heat required by fuel. Can someone please explain why? Thank you.
2)
I interpolated the value given for feed water and super heated steam.
h@5600kpa 472 degrees Celsius = 3359.0128 kj/kg
hf@ 172.52 degrees Celsius = 730.30 kj/kg
So...
delta h = 3359.0128 kj/kg - 730.30kj/kg
delta h = 2628.7128 kj/kg (this is the energy that the boiler would produce running at 100% to make the given steam right?)
So...
Qfuel = (2628.7128 kj/kg)(1.18) (I'm multiplying by 1.18 to make up for the 18% efficiency difference)
Qfuel = 3101.88 kj/kgefficiency = Qsteam/Qfuel
.82 = 2628.7128/Qfuel
Qfuel = 3205.07 kj/kg3) I get two different answers for quantity of heat required by fuel. Can someone please explain why? Thank you.
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