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been bothering me
Posted: Mon Jun 25, 2007 6:15 am
by sandman
ok for the past week ive been thinking bout this.
Can you compress propane and oxygen so much that the kinetic energy of the particles surpasses the activation energy of the reaction, and hence you get a boom?
i only have 1 year of chem under my belt so obviously i dont know everything

Posted: Mon Jun 25, 2007 6:18 am
by jackssmirkingrevenge
what, like in a diesel engine?
Posted: Mon Jun 25, 2007 6:22 am
by spud yeti
Do you mean propane and oxygen mixed together, or seperately? I guess in theory it
could be correct, but really, I think its only a nice thought!
I guess one could relate it to the compression of gun powder, so it makes one think........
(Freak I hope Im not talking crap with the gun powder!!

)
Posted: Mon Jun 25, 2007 6:54 am
by chaos
do you mean like Super-critical mass like an A-Bomb?
Posted: Mon Jun 25, 2007 7:01 am
by jrrdw
No, i think once you compress it so much, you just can't make it any smaller. The compression just stops??? Does that make any sence?
Posted: Mon Jun 25, 2007 7:15 am
by jackssmirkingrevenge
jrrdw wrote:No, i think once you compress it so much, you just can't make it any smaller. The compression just stops??? Does that make any sence?
as you compress it, it heats up and eventually should ignite spontaneously
Posted: Mon Jun 25, 2007 7:18 am
by joannaardway
This process is known as Dieseling (as JSR suggested) - it would be possible to ignite a propane/oxygen, or propane/air mix by extreme compression of the mixture.
Rapid compression of the mixture is preferable, as then heat is produced, which will make it even easier to do.
If you knew the activation energy of propane/air or Propane/oxygen, you could predict the required compression needed.
Posted: Mon Jun 25, 2007 12:17 pm
by homedepotpro
im pretty sure the propane would just liquefy at those high pressures unless you heated it considerably, and once its liquifide it can't be compress anymore
Posted: Mon Jun 25, 2007 1:07 pm
by schismatized
uhh wait its summer and im a little rusty on chem, but as pressure increase kinetic energy increases right? therefore the temp would go up by itself.. why would it liquify?
Posted: Mon Jun 25, 2007 2:10 pm
by rednecktatertosser
I dont believe the energy of compression would be enough keep propane from going into liquid form.
Posted: Mon Jun 25, 2007 4:28 pm
by sandman
oh, so we are talking bout massive pressures?
cause i was thinking of a super burst disk, but it was just a thought

Posted: Mon Jun 25, 2007 4:49 pm
by jimmy101
If you compress propane and air enough it will indeed ignite. Even if the propane liquifies it will still ignite.
You can ignite a piece of paper in a air filled piston+cylinder if you can get the compression ratio up over something like 15:1. (This is called a "Fire Piston".)
Posted: Tue Jun 26, 2007 7:53 pm
by boilingleadbath
Adapted diesel engines can burn propane... and I believe they are known for their longevity.
Posted: Tue Jun 26, 2007 8:02 pm
by sandman
so, in other words not useful for spudguns?
Posted: Tue Jun 26, 2007 8:15 pm
by Fnord
You can ignite a piece of paper in a air filled piston+cylinder if you can get the compression ratio up over something like 15:1. (This is called a "Fire Piston".)
I've never seen this before. The paper doesn't ignite by itself does it?