[Stoves] Calculating cooking costs and char costs ----Re: [biochar] Where to discuss STOVES AND CARBON offsets and drawdown

Paul Anderson psanders at ilstu.edu
Sun Sep 17 08:00:55 CDT 2017


Frans,

Thanks.

I really like the numbers that    1 kg of wood contains (or can yield) 4 
KWh.    That is a very useful figure.

One revision of your other comments.
Pyrolysis releases about 70% of the energy (some might say 67%, about 
2/3rds).   And 30 % resides in the charcoal.

At the same time, the remaing charcoal does have about 50% of the carbon 
atoms.

The explaining factor is that in the carbohydrate fuels, there are 
Hydrogen atoms that will all be combusted during pyrolysis, giving the 
extra energy although only about 50% of the carbon atoms were "burned".

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype:   paultlud    Phone: +1-309-452-7072
Website:  www.drtlud.com

On 9/17/2017 2:36 AM, Frans Peeters wrote:
>
> Paul,
>
> First cracking wood gives H20 out of its O+2H
>
> Dry wood is called 15% H2O content ……
>
> Wett wood 16-30% H2O ;needs 3 years drying .
>
> Biomass with leaves just cut  60% H20  !
>
> LABO dry means 24 h at 120 °C for 1cm thick .
>
> Analytic is for definitions .  Charcoal makers may think different .
>
> You get enery from 1Kg wood= 4KWh.
>
> If you like the half now out of your wood,you can it ,during pyrolysis .
>
> You like  the other half out your charcol LATER ….You can ,and 
> evitting rotting !.Get easy distribution .
>
> You NEED enery to get cracking ; but that energy is not LOST …..Use it 
> for something the same time !
>
> Regards
>
> F.
>
> *Van:*Stoves [mailto:stoves-bounces at lists.bioenergylists.org] *Namens 
> *Paul Anderson
>
> To all.
>
> Thanks for the explanation of 47%C
> Something is still not clear:
>
> Beginning with the baseline fuelwood use of 187,800 kg of fuelwood per 
> year per village, if we assume a 10% moisture content, the baseline 
> fuelwood is equivalent to 170,700 kg of dry fuelwood.
>
> I can accept that.   That is about 5 kg of wood per household per day.
>
> We assume that dry mass can be converted to carbon mass using 47%C 
> (Ryan et al., 2011),
>
> I do not yet accept this (above).   Dry biomass is carbohydrates.   C 
> and O and H, in the approximate proportion  of   CH_2 O (Tom Reed has 
> more refined proportions, but I cannot find it at this moment) .   H 
> has almost no weight.  The O  (at atomic weight 16) is a bit heavier 
> than C at 12..  So when the O is gone during pyrolysis, about half of 
> the total dry weight (47%) is attributed to carbon.  That much is fine.
>
> But during pyrolysis, almost half of the carbon leaves the scene in 
> the form of pyrolytic combustible gases that include C atoms.  How 
> much of the C gets converted into graphine sheets of charcoal can vary 
> with the pyrolysis temperature. When pyrolysis is at less than 450 deg 
> C, some of the carbon still  hangs around in tarry / greasy content 
> inside of charcoal, but it is not the same as the carbon of the charcoal.
>
> So, if the dry  wood is 170,700 kg, and half of the weight leaves as 
> exiting oxygen  atoms, then that would be what the article said was
>
> resulting in 80,240 kgC per year per village.
>
> But that is the TOTAL of carbon.   About half of that C is gone in  
> the pyrolytic gases, leaving about 40,100 kg C per year per village.
>
> Did I miss something?   Am I talking about something different?  I am 
> here to learn.
>
> But if I am correct, what are the implications for the Jagger article?
>
> Paul
>
>
>
>
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