Pressure Developed by Combustion of Propane.....
Pressure Developed by Combustion of Propane.....
(OP)
All,
If I have a closed cylinder of known dimensions(Height, diameter, volume,etc....) that contains a known mixture of propane and air, How can I figure out what pressure will remain in the cylinder after the mixture is ignited....
If I have a closed cylinder of known dimensions(Height, diameter, volume,etc....) that contains a known mixture of propane and air, How can I figure out what pressure will remain in the cylinder after the mixture is ignited....





RE: Pressure Developed by Combustion of Propane.....
TTFN
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RE: Pressure Developed by Combustion of Propane.....
Is this a theoretical problem or a real world issue?
If it's the latter, there are things called explosions and detonations to think about which involve flame temperature, dynamics and container conductivity as well as molar balance.
How close to a stoichiometric mixture will you be? Where and what is the ignition source?
Look into NFPA codes 68 and 69 which address how to design for explosive conditions.
David
RE: Pressure Developed by Combustion of Propane.....
I am working on a personal project and I want to establish a baseline before I start building prototype after prototype.
I only want to generate a pressure, the volume of the container can be considered as fixed.
I will most likely have a spark ignition source and I will be using the C3H8+5O2 mixture.{C3H8+(5)O2 => (4)H2O+(3)CO2)}
I think I'll have to pull out the chem and thermo books.
RE: Pressure Developed by Combustion of Propane.....
Assuming that ideal and complete combustion takes place, one can calculate the flame temperature of the combustion products for the given stoichiometry.
Then, one can use the ideal gas state equation to find out what the pressure should be: pV = mRT
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RE: Pressure Developed by Combustion of Propane.....
In your first query you mention air, therefore your reaction should include 18.8 N2 on both sides of the equation.
The initial state would show 24.8 moles; the final, 25.8 moles. Thus, the pressure increase due to the number of moles would be small.
The pressure increase will in fact be the result of thermal energy due to the blast.
My suggestion: read section 6 of Crowl & Louvar's Chemical Process Safety: Fundamentals with Applications Prentice Hall, where detonations and deflagrations inside vessels are explained.
RE: Pressure Developed by Combustion of Propane.....
RE: Pressure Developed by Combustion of Propane.....
The former is not something to be trivially bandied about, as fly shards of a broken cylindrical container will definitely ruin someone's day.
TTFN
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RE: Pressure Developed by Combustion of Propane.....
Pmax = 7.9 bar; NFPA 68, 2007 pg 62
RE: Pressure Developed by Combustion of Propane.....
- It seems that it would take forever to calc this out I haven't found any methods that will Yield the desired result. I'll post results if anyone's interested.
RE: Pressure Developed by Combustion of Propane.....
TTFN
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RE: Pressure Developed by Combustion of Propane.....
h
Now, it should not be difficult to find out what the pressure is for the given geometry ...
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