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:[email protected]] 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: [email protected] To: [email protected] 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 [email protected] www.controllabs.com _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
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