[Stoves] What about carbonization? Re: Composting at 70 deg C ?

[Kevin]

Dear Andrew and Paul

Certainly, one intuitively thinks of "char" and "fixed carbon" as the result 
of a "pyro-process.

What about the fact that the ignition temperature of wood has been 
demonstrated by the National Fire Protection Association (NFPA) as being as 
low as about 180 degrees F?

What about "carbonization" of biomass in a pond over the winter? What about 
carbonization of waste material in a septic tank? Does not anaerobic 
digestion of biomass result in an end product with more "fixed carbon?"

How fixed must fixed carbon be fixed to be fixed?

We have the "High Temperature Carbonization" (HTC) process, where biomass is 
reacted with water and temperature, to "fix" the carbon. At lower 
temperatures and pressures, the process would proceed, but at a somewhat 
slower rate.

I did a quick Google on "Temperature of Formation of Coal", and other than 
frequent repetition of "Coal is formed when biomass is subjected to 
temperature and pressure for a considerable period of time", there is 
nothing specific about the minimum temperature, pressure and time required 
to form coal. Coal formation seems to be a loosey goosey collection of 
intuitives.

Some people also assume that the Amazonian Terrapretians actually went out 
of their way to make charcoal to put in the ground so stuff would grow 
better, yet I have not seen any credible papers that show conclusively that 
this is the case. There is no evidence of structures that have been clearly 
identified as facilities for making charcoal. I do know that when I burn 
weedwood in my garden area, not all the weedwood burns to completion, and I 
am left with charcoal. I don't bother to rake away the charcoal. Given the 
tropic climate in Amazonia, I wouldn't think the Amazonians would bother to 
rake away the charcoal from weedburning either.

I have broken open a pile of horse manure that was left unattended, and have 
seen black material, and a silvery looking ash on black material, that had 
every appearance of having been the charcoal and ash from a fire, yet the 
outside of the manure pile had the characteristics of sun dried manure. 
There are certainly remarkable things happening there, and charcoal 
production is one of them. :-)

Best wishes,

Kevin





----- Original Message ----- 
From: <ajheggie at gmail.com>
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
Sent: Monday, May 30, 2011 11:46 AM
Subject: Re: [Stoves] What about carbonization? Re: Composting at 70 deg C ?


>
> Content analysis details:   (0.0 points)
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>  pts rule name              description
> ---- ---------------------- --------------------------------------------------
> _SUMMARY_
>
> On Monday 30 May 2011 14:59:15 Paul S. Anderson wrote:
>> Dear all,
>>
>> Frank's original message was about creation of fixed carbon at low
>> temperatures in a composting situation.  I think it cannot happen.
>> Any comments?
>
> I too don't think it can happen in a composting situation, I wonder if the
> case which Frank cites is more a pickling, where the volatile solids are
> respirated in low oxygen micro spaces and the pH drops to inhibit further
> attack by bugs, silage and peat come to mind.
>
> It is possible to carbonise something at low temperatures, pour
> concentrated sulphuric acid onto paper as an an example.
>
> AJH
>
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