Carbon in Biochar
Posted 11 July 2011 - 10:32 PM
What percentage of the carbon in the wood can be sequestered in biochar?
Posted 18 July 2011 - 12:22 AM
these numbers correspond to the amount of fixed carbon in the biomass. the rest of the carbon is in the volatiles. with pressure and/or passing the gas back over the charcoal and lowered temp you can get secondary reactions and deposition that will increase the carbon yield in the charcoal. however, this may/might/possibly change the character of the charcoal in ways which are non-good for biochar purposes, though fine for charcoal as fuel purposes.
if i remember correctly, the absolute carbon amount in biomass by weight is 42%. biomass is chemically on average C H1.4 O.06. anyone want to multiply that out by the atomic weights of C, H and O to see what the real number is?
Posted 30 July 2011 - 01:07 AM
100 x .5 x .5 x .2 = 5
That means 100lbs of fresh cut wood turns into about 5lbs of char.
I just looked this fact up on the internet so it must be true....charcoal has about 12,800btu per pound.
And wood at 0% MC has 8,600btu per pound.
So using our approximate numbers from above.
50lbs of bone dry wood has 430,000btu
50 x 8,600 = 430,000btu
5 lbs of charcoal has 64,000btu
5 x 12,800 =64,000btu
so...430,000-64,000=366,000btu from volatiles or about 85% of the energy
The charcoal represents about 15% of the energy of the wood
If the charcoal represents 20% of the mass of the carbon but only about 15% of the energy than charcoal has less energy per pound than the volatiles?
So on a per pound basis, a pound of wood has 8600btu with about 7300btu from the volatiles and about 1300btu in the biochar.
Am I missing anything here or is this about right?
If you can then subtract out the energy used to boil off the water in the wood based on MC% feedstock and (I'm not sure I totally understand this part) the energy needed in the pyrolization process, from the quantified energy yielded from the volatiles, you have the Net yield in heat. Which is the number I'm looking for...cool!!!
Posted 30 July 2011 - 01:23 AM
Posted 07 April 2012 - 04:10 AM
Hydrogen 1.4 x 1=1.4
Oxygen .06 x 15.9994=.959964
12.0107 + 1.4 + .959964=14.370664
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