Testing

[arudhra]

Is there any simple testing method to find fixed carbon percentage in wood charcoal and what chemicals needed

[jake-the-peg]

I guess it depends on the accuracy reuired.

I'd burn a sample in an excess of oxygen and pass the gas through calcium hydroxide. I'd then collect and weigh the calcium carbonate precipitation and work it out from that.

You're assuming that all the carbon is converted to CO2 and that it is all precipitated out

[Teddio]

Accurately measure the mass of about 2kg of charcoal (to the nearest gram or better). Ignite the charcoal and let it "burn out". Accurately measure the mass of the ash.
mass of carbon = mass of charcoal - mass of ash
%age C = mass of charcoal minus mass of ash divided by mass of charcoal.

eg. Mass of charcoal = 1986g
Mass of ash = 146g
Mass of carbon = 1986 - 146 = 1840g
%age of carbon = 1840/1986 X 100% = 92.6%

Precautions and assumptions:
1. all the combustible material is carbon
2. none of the light ash is blown away

[jake-the-peg]

You might be interested in this site: http://www.fao.org/docrep/x5328e/x5328e0b.htm

It tells us that charcoal can be up to 10% water if left hanging around in the atmoshere.

Also the percentage of volatiles ( which are compounds not driven off when then charcoal is made) can be between 5 and 40 % depending on how well it is made.

So I'd suggest Teddio's method is good if you have high quality charcoal and want an approximate answer without chemicals but is probably unreliable in other cases