Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: CZARCAR on 19/08/2010 15:56:30

Title: ?wood burning @ higher altitude---3 phases?
Post by: CZARCAR on 19/08/2010 15:56:30

assuming water boils @ sealevel @ 212*f & @ a lower temp in higher altitude & wood burning would be 212* to boil water, 600*f to produce offgassing of pyrogas, & 1400*f for flash/combustion of the pyrogas.
@ higher altitude, the water would boil @ a lower temp, the offgassing would be @ a lower temp, but would the flashpoint of the pyrogas also be lowered? thanx

Title: ?wood burning @ higher altitude---3 phases?
Post by: lightarrow on 20/08/2010 15:45:06

It's a nice question but not very easy for a complete answer, so I'll give you the simplistic version: no.
The production of gases by heating wood depends on heat decomposition and not on the boiling of some liquid. Actually heat decomposition IS influenced on pressure, simply because the products are in the gas phase, but I suppose the dipendence is very little.

Title: ?wood burning @ higher altitude---3 phases?
Post by: CZARCAR on 20/08/2010 17:34:44

thanx. i was assuming the wood would heat up & go thru a liquid state [creosote] before it gassified?

Title: ?wood burning @ higher altitude---3 phases?
Post by: lightarrow on 22/08/2010 14:10:21

Probably when wood burns in a flame, most of the gas comes from direct decomposition of the solid, instead of boiling or decomposition of creosote, anyway I'm not sure.