[Terrapreta] Overview on biochar production methods

[Adriana Downie]

Jeff,

If you know the mass of the wood in and the mass of the charcoal out,
then the balance will be what has volatilised into the gas phase so you
know the mass of gas out. It is very hard to control yield in batch
processes unless you bring down the temperature in a nitrogen
environment to prevent combustion. 

I get our char samples tested at our local coal laboratory (coal is a
big industry in Australia so there is a few labs). If you ask for a
'proximate analysis' this will give you volatiles, ash, and fixed carbon
levels. Also if you get a calorific value (CV) of both the feed and the
char you can do an energy balance. 

Moisture content is easy to do yourself (if you have a scale). Weight
some chips, put them in your oven at about 70C, measure until the weight
stabilises. The difference in mass in the physical moisture. 

Adriana Downie
BEST Energies Australia

-----Original Message-----
From: Jeff Davis [mailto:jeff0124 at velocity.net] 
Sent: Friday, 17 August 2007 11:54 AM
To: terrapreta at bioenergylists.org
Subject: [Terrapreta] Overview on biochar production methods

Tom, interesting. ...

Some say that Terra Preta charcoal needs to be a pure as the driven
snow.
Others say it needs to be high in volatiles, understandable at this
point.

The only thing I can say is this: About a week ago I made some of the
nicest cherry wood chips with the WC6. Used up my hog dressed cherry
lumber that I had stashed for about ten years. It wouldn't work for the
Imbert crowd but looks like good fuel for the Gas-of-Fire 1000,
stratified.

I plan on fueling the Gas-of-Fire with one or two GGE of these chips and
measure the amount of charcoal produced. I know of no way for me to
measure the amount of gas produced but if it wasn't too costly maybe I
could send a sample of the charcoal, somewhere, to be analyzed. Maybe
some
of the chips for moisture content.

Anybody know where I could send these samples to be tested???


Best regards,

Jeff



Tom wrote:
>Your mention of Ankur raises an interesting point. A gasifier can make
char
>by removing charcoal faster than you reduce it to gas. We did some
>experiments with a 200 kWe Ankur gasifier. During normal operation char
>production is about 5% with a  volatile Matter (VM) content of about
10% .
>When we ran at a high char withdrawal rate we were making about 10%
char
>with a VM of 28%.  The point is that if you run a gasifier as a
pyrolyzer
>then the quality of the char is likely to change.



-- 
Jeff Davis

Some where 20 miles south of Lake Erie, USA

_______________________________________________
Terrapreta mailing list
Terrapreta at bioenergylists.org
http://tech.groups.yahoo.com/group/biochar/
http://terrapreta.bioenergylists.org
http://info.bioenergylists.org