[Stoves] Suggested calculations

Wed Apr 24 16:29:19 CDT 2013

Dear Otto,

In the little example below I was using actual Carbon values determined in a
lab for the calculations. So to me it doesn't matter to the moisture, if
something went wrong or the ash content because all I am following is the
Carbon. When calculated back to the tree (or dung, grasses, etc) we need to
know the carbon in percent of as-Received material (wet weight) to calculate
the mass of biomass or footprint needed for each task.

When a tree is cut and used it all gets used no matter what. We just need to
determine where it is used and what it did. During its use, I'm thinking, in
each BOX there can be an improvement and that improvement just moves more
carbon down the line to be used somewhere else. If a decision is made to
flame off into the air for no purpose (task)  the Carbon  / Task ratio looks
very bad using BOX 1 and BOX 6. 

Something like that. 

Thanks for reading and comment. 

Regarding

Frank

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of
Otto Formo
Sent: Wednesday, April 24, 2013 1:54 PM
To: Stoves Bioenergylist
Subject: Re: [Stoves] Suggested calculations

Dear Frank,

According to lab tests done by FAO in Nairobi in 1986?, they got 250 kg of
char out of one tonne of very dry wood, 25%.

How much C (carbon) is it in charcoal - 95%?  and 5% ash?

Estimates done from traditional kilns, gives charcoal yields around 150 kg,
out of one tonne of wood, moisture content unknown, but normaly and most
likely sundried.

One out of five kilns goes "wrong" and gives no char (burn out) or char of
poor or low quality. 

This issues has to be taken into consideration as well when you compare
woodchips and charcoal in rural Africa.

Thanks for higlighting this for us.

Otto

  _____  

From: frank at compostlab.com
To: stoves at lists.bioenergylists.org
Date: Wed, 24 Apr 2013 13:08:55 -0700
Subject: [Stoves] Suggested calculations

Dear Stovers, 

When looking at the total picture of trees (fuel) per end use I suggest two
different possible approaches. 

ONE

The tree chips have 40% carbon and we use a total of 100 kg of chips in a
TLUD stove. We start with 40 kg of carbon. We boil water then steam rice and
have left 30 kg of carbon in the char left so using 10 kg of carbon ( 25 kg
of tree) in the process.

The 30 kg carbon left is char chips and we use that for heating food as a
street vender. At the end of the day we take home 10 kg carbon to add to our
soil. So 20 kg carbon (50 kg tree) used for heating and 10 kg carbon (25 kg
tree) for the soil. 

We start with 100 kg tree.

25 kg tree used for boiling water

50 kg tree for heating street food

25 kg tree for garden. 

 = 100 % total tree

We do not follow energy but follow the fuel (in this case the tree).  

TWO

Same problem:

To boil the water it took 100 kg of tree

To get the 20 kg of char for the street vender we would need to have 50 kg
tree to make the char to do that job. 

To get the 10 kg char to add to the soil we would need 25 kg of tree to make
the char for that garden. 

That's a sum of (100+50+25)= 175 kg of tree. But we only used 100 by
combining the processes so we have saved 75 kg of tree (or 43% of the
forest) by combining uses. 

I think I like the second method better to illustrate the savings when piggy
backing the uses of fuel but still thinking about it. 

Thanks

Frank

Thanks 

Frank Shields

BioChar Division

Control Laboratories, Inc. 

42 Hangar Way

Watsonville, CE  95076

(831) 724-5422 tel

(81) 724-3188 fax

frank at biocharlab.com

www.controllabs.com

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