[Stoves] Characteristics of biochar was Re: [biochar] grassifier & cedar chip char

[Crispin Pemberton-Pigott]

Dear Josh

 

I appreciated this:

 

>The ASTM determination of "volatile matter" for coals really is not a good
fit for biochar. It's not really clear what you're measuring when applying
that method to biochar, as the prescribed heating (devised originally for
coal) alters the char. 

It is not really good for coal stove either. It is an old method that was
possible using simple equipment and the coal people got used to it. The
'moisture' they give is not the moisture content, the fixed carbon is not
the carbon content, the hydrogen figure is suspect, and when reporting these
elements, they first remove Sulphur from the total mass (!) meaning all of
the numbers have to first be corrected for the missing S.

If that was not clear, adding up the standard reported % of mass for H2O, C,
S, H and O2 gives more than 100% because the S is ignored when the
calculation is made, hard as this is to believe, but that is what they do if
you do not ask for a non-standard reporting method.

There is a method (and several papers) on attempts made to calculate the
ultimate analysis from the proximate analysis (which is much cheaper to
get). I was impressed at how close they got the results - certainly closer
than assuming that biomass is 50% carbon and 5.6% Hydrogen.

Regards

Crispin

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