LPG to Oxygen ratio for combustion
LPG to Oxygen ratio for combustion
(OP)
Hi all
what would be the Oxygen to LPG ratio for complet combustion of LPG. Our Oxygen is 95% pure.
what will happen if combution at high temperature (i.e.800 deg.C) is not complet. would cracking take over?
Thanks
what would be the Oxygen to LPG ratio for complet combustion of LPG. Our Oxygen is 95% pure.
what will happen if combution at high temperature (i.e.800 deg.C) is not complet. would cracking take over?
Thanks





RE: LPG to Oxygen ratio for combustion
But, I do know that the result of incomplete combustion depends on why the combustion is incomplete (i.e. xs air or xs gas.) Cracking could occur with xs gas (or poor mixing, but let's not get into that) but it would have to be quite a bit of xs gas.
RE: LPG to Oxygen ratio for combustion
As one ChemE to another, please employ units to identify specifically what "ratio" you are referring to. There are mole/mole, lb/lb, ft3/mole, etc., etc. ad infinitum ratios. Otherwise, you'll get a multitude of different responses - and each may be right(but without units!)
Go to "Liquefied Petroleum Gases"; Williams & Lom; Ellis Horwood Ltd.; Sussex, England. On Page 64 you will find:
m3 air req'd per m3 gas for combustion = 24 for commercial propane & 30 for commercial butane;
Ignition temp.(oC) in air = 450 for commercial propane & 420 for commercial butane;
Flame temperature (oC) = 1970 for commercial propane & 1975 for commercial butane.
LPG (Liquefied Petroleum Gas) is approximately 50% propane + 50% butane mixture. If you do an elementary stoichiometry combustion calculation you will easily get the theoretical amount of pure Oxygen required for complete combustion and you should compare that with the above figure (corrected for Oxygen).
Why you would not complete the combustion is anybody's guess. But the results would include CO and yes, some "cracking" down to CH4 and possibly C2H2 & others.
Art Montemayor
Spring, TX
RE: LPG to Oxygen ratio for combustion
You should first determine the actual component analyses of your LPG (preferable in mol percentages). Then, as Art Montemayor has pointed out, perform a stoichiomtric combustion calculation to determine the theoretical pure oxygen required for complete combustion.
Milton Beychok
mbeychok@xxx.net (replace xxx with cox)
(Visit me at www.air-dispersion.com)