AR09 Fire: I'm contemplating my wood...

[phil24_7]

There will be no need to buy any wood. If those who are coming by car/van/truck/bus or other caged vehicle wish to bring some wood sourced locally from wooded areas and suchlike, then that's fine.

I have a decent amount and will be getting some more on the weekend so should be fine. Nobody has told me how big the fire will be or is allowed to be though (remember, as a pyromaniac, I'm thinking it'll be huge and capable of burning several 100 year old oak trees!) so I am not 100% sure of how much wood we'll require!

[Messie]

I did say, I said HUUUUUGE!

By that I mean around 1.5 metres by 1.5 metres

[Spiderman]

Phil, if you have a look here you can see the firepit. http://www.youtube.com/watch?v=fEcslqSE8Dg at about 1.20, its the metal thing with all the rubbish in it as the camera pans left.

i'm all in favour of a fire so big it can been seen in 3 counties but i know we have to keep it to a sensible size.

[phil24_7]

Mmmm...

I shall now shrink the size of the fire in my mind and try to calculate the fuel needs, assuming an average wind speed, dry conditions and a warm evening...

Wood is made of predominantly cellulose, hemicellulose, and lignin. all three are predominantly composed of carbon, hydrogen and oxygen in various combinations. So if we say wood is

CxHyOz

then burning of wood is

CxHyOz + O2 ------> CO2 + H20

if you know x, y, and z, you can balance the equation.....

So, who can help me with x,y and z?



Anyway... I reckon I should have enough wood by the end of next weekend!

I'll post pics of how much I have and you can all make an educated guess as I don't wanna get it wrong!

[keith_d]

Cellulose is a polysaccharide, lots of glucose (C6H10O5) rings assembled in chains.

But the breakdown doesn't occur in a single step unless you divide it very finely and go for a powder explosion.

Usually you'll get some dehydration, then production of methanol and a whole assortment of aldehydes and ketones from partial ring breakdown. Sometimes there's a bit of methane in there too. These products burn to produce the pretty yellow flames.

Finally we get oxidation of the remaining carbon to carbon monoxide and/or carbon dioxide. Carbon monoxide is responsible for the translucent blue flames above a bed of charcoal when it takes the last step to carbon dioxide.

Keith (and you thought you were a pyromaniac)

[Spiderman]

Erm, yeh ok lads. I get you both. So what we are saying is we need about 2 large trees worth right?

[chris8886]

Originally Posted by phil24_7

I happen to be a pyromaniac by the way!

i happen to be a bigger one!

[ophic]

Originally Posted by keith_d

But the breakdown doesn't occur in a single step unless you divide it very finely and go for a powder explosion.

ok so how do we do this again?

[chris8886]

Originally Posted by ophic

ok so how do we do this again?

lighters, matches and aerosol cans are enough to satisfy me (with the odd firework or similar here and there )!

Originally Posted by keith_d

Cellulose is a polysaccharide, lots of glucose (C6H10O5) rings assembled in chains.

But the breakdown doesn't occur in a single step unless you divide it very finely and go for a powder explosion.

Usually you'll get some dehydration, then production of methanol and a whole assortment of aldehydes and ketones from partial ring breakdown. Sometimes there's a bit of methane in there too. These products burn to produce the pretty yellow flames.

Finally we get oxidation of the remaining carbon to carbon monoxide and/or carbon dioxide. Carbon monoxide is responsible for the translucent blue flames above a bed of charcoal when it takes the last step to carbon dioxide.

Keith (and you thought you were a pyromaniac)

i love you