Stoichiometric Ideal Mix for Butane?

Heathen

Hi all,

I am trying to find out the Ideal mix for Butane..

As far as flammability limits go i know this so far..
I know the lower explosive limit is 1.8% and anything below that is too lean
and that the upper explosive limit is 8.4% and anything above that is too rich.

Butane has a max temp of 1,970 °C so I am just looking for the ideal mix between 1.8 and 8.4 to achieve such a temperature?


Thanks

Capt'n Midnight

the mass balance is

2C4H10 + 13O2 --> 8CO2 + 10H2O

You just convert all the C's to CO2
and all the H's to H2O

and count the O's you need
and then halve it to get the O2's you need


as a first approximation for gases at the same pressure and temperature they all occupy the same volume per mole (only really changes much at higher pressures or temps nearer boiling point ) so you for every 2L of Butane you would need 13L of Oxygen

Air is 21% oxygen so you would need 31 tiimes as much Air as Butane


Or check google for welding / heating


Note: in the real world you would probably use more air than necessary to ensure complete combustion, whereas for rocketry you would use more fuel to prevent oxidation or just to benefit from the expansion - especially if you use Hydrogen as a fuel

Note: in the real world butane will be colder than air since it's either boiled off from liquid or at least it's had it's pressure reduced. And being colder it will be denser PV=nRT so you will need more Air

PV=nRT - ie volume is proportional to Kelvin temperature if pressure stays the same, you can get ICE formed on gas clinders even in 36 Degree heat - that's well over 1/7th of a volume change