Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: hardy10 on October 09, 2014, 02:24:58 AM
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Hello,
I have a natural gas combustion in pure oxygen related query,
CH4 + 2 O2 = CO2 + 2 H2O + heat
The Heat of combustion is for CH4 is ΔHc = 802.3 KJ/mol, for complete combustion of methane.
Now, the natural gas is coming at a certain mass flow rate (Kg/hr), which I can convert to mol/hr by dividing the flow rate with Molar mass of methane (g/mol). The number of moles per hour (mol/hr) can be multiplied to determine the Heat generated (KJ/hr) or released upon the reacting with pure Oxygen.
The question is, Am i doing it right ? Also, How does flow rate (quantity) of oxygen supplied for combustion influence the heat released. In other words how do I account for Oxygen as it does not have a calorific value (not a fuel) ?
Will appreciate your response,
Thank You :)
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You are given oxygen mass flow? Check stoichiometry.
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Yes, I do have the mass flow rate for oxygen. Do you mean to say I should find Heat of reaction ?
thanks,
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Check if there is enough oxygen for the complete combustion.
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Yes, the oxygen is in abundance (pure O2) and process is known to causes high temperatures up till 3000 C.
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If the combustion is complete, amount of heat produced per hour is - as you suggested in your first post - number of moles of methane times molar heat of methane combustion.
I have a gut feeling you are not asking the right question, as if you were solving different problem than you told us. But I can be wrong.
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Thanks for your reply,
The question is right, might have worded it wrong (apologies).
Can the amount (no. of moles) of Oxygen (not a fuel) be applied towards heat of combustion adding to the ΔHc for amount of methane combusted?
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Can't add anything that wasn't already said.
Oxygen is not a fuel, so it doesn't increase maximum heat output. But if there is not enough oxygen, you'll never reach the upper limit.