- #1
Andy86
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Homework Statement
A fuel gas consists of 75% butane (C4H10), 10% propane (C3H8) and 15% butene (C4H8) by volume. It is to be fed to the combustion chamber in 10% excess air at 25ºC, where it is completely burnt to carbon dioxide and water. The flue gases produced are to be used to generate 5 bar steam from water at 90ºC.
(i) If 5% of the heat available for steam production is lost to the atmosphere, determine the amount of steam raised per hour when the total flow of flue gases is 1400 kmol h–1.
Water Inlet temp = 90°C (Given in question)
Steam temp @ 5bar = 152°C (from steam tables)
Flue Gas inlet = 1997°C (Based on flame temp)
Flue Gas outlet = 300°C (Given in question)
Latent heat of steam @ 5 bar = 2108KJ/KG (from steam tables)
TOT flow of flue gas = 1440 kmol h-1
Homework Equations
Mass flow rate (H) * Heat Capacity * (ΔH) = Mass flow rate (C) * Heat Capacity (C) * (ΔC)
Rearrange to make "Mass flow rate (C)" the subject>
Mass flow rate (C) = (Mass flow rate (H) * Heat Capacity * (ΔH)) / (Heat Capacity (C) * (ΔC))
The Attempt at a Solution
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Mass flow rate (C) = (1400 * Heat Capacity) * (1997-300) / (4.2 * (288-90))
To attempt this question I need the heat capacity of the fuel gas mix, I am not sure how to calculate this and once I do am I using the correct equation??
Thanks
Andy