[Stoves] Low temperature vs high temperature charcoal?

Sun Jun 16 22:00:01 CDT 2013

Josh,

Very good work here. Excellent article. Congratulations.

I am keen on making pine need pellets and letting minority people use them
to cook food and produce, at the same time, a pine needle biochar. The next
step would be to find markets for the pine needle biochar. This could be an
interesting source of income for these desperately poor people.

Thanks.

Paul Olivier

On Mon, Jun 17, 2013 at 7:49 AM, Josh Kearns
<yeah.yeah.right.on at gmail.com>wrote:

> High draft/high temp. chars are superior from a sorption perspective:
> http://www.wcponline.com/pdf/October2012Kearns.pdf
>
> The lower mass yields are more than offset by greater-than-proportional
> increase in sorption capacity. For water treatment/water quality
> applications 85-90%, or even a little more, mass loss is optimal.
>
> We'll have several papers coming out over the next couple of years filling
> in a lot of the details on research into a lot of the questions that have
> been brought up by Dan and others here....sorry, everyone, academic
> publishing is so painfully slow.....
>
> Josh
>
>
>
> On Sun, Jun 16, 2013 at 8:34 PM, <Carefreeland at aol.com> wrote:
>
>> **
>>  Tom, Tom, Listers,
>>     I would think that there would be a reduction in tars in the higher
>> temp chars. This might have some advantages in less surface tension of
>> water. The tars, on the other hand may have some beneficial use in
>> reducing, insects, fungus or bacteria growth in chars used for soil
>> enhancement. The chars created in a gasifier or less efficient system such
>> as an open fire or various older systems of char making would all contain
>> more ash. The extra ash would have benefits as a nearly balanced fertilizer
>> in the soil. Minus only nitrogen.
>>     It surprises me that higher temp chars would have a lower surface
>> area. Has anybody studied the relationship between the time it takes to
>> cook the char and the amount of surface area created?  I would think the
>> higher temperatures and faster cooking would rupture the cell membranes
>> violently and to a greater extent from flashing steam. Would this create
>> more or less surface area?  Would carbonized cells have a greater CEC with
>> tiny holes in them from slow cooking or larger more accessible ruptures
>> from fast cooking? Would some cells not rupture completely?  or be blocked
>> in large chunks of charcoal from acting to absorb water and minerals?
>>     Obviously, the type of biomass would also be a great variable in the
>> surface area equation as cells rupture based on their design. Old gunpowder
>> makers knew this from experience that is why low ash, high surface area
>> Willow and Dogwood were favored. The Dogwood for dense, high octane powder
>> and the Willow for light, fast burninig powder.
>>     I think that nature already has figured this out in a beautiful way-
>> as usual. Char for soil is best created in hot but inefficient forest
>> fires. Char for use as a fuel for man is best created with a high yield and
>> lots of hydrocarbons in a closed retort system. All other uses fall on a
>> scale in between. The Biblical saying "Render unto God what is God's" comes
>> to mind. And you thought it was just about taxes!
>>     I like to burn my brush in a big cut open tank in the garden. All the
>> ash flies out into the air and lands well distributed all over the garden.
>> This saves me the task of spreading the ash. In forest fires the majority
>> of the char forms underground or under ash. Again, Nature is still one or
>> many steps ahead of us.
>>     Only questions, no answers as usual. No lab or even a greenhouse
>> anymore to experiment with.  Have fun all you college types. Let me know
>> what you find. I do still read some of the letters now and then.
>>     Keep Charring and Stoving,
>>
>>     Dan Dimiduk
>>     From the peanut gallery.
>>
>> In a message dated 6/16/2013 4:41:37 PM Eastern Daylight Time,
>> tmiles at trmiles.com writes:
>>
>> Stephen Joseph should comment on the target "optimum" range set out by
>> Lehmann and others of 450-550 C which seems to have guided most research.
>> According to their work an increase in temperature to 500-700C would
>> appear
>> to result in slightly lower yield and surface area. pH and CEC would be
>> about the same. Trials with different plants and soils since this early
>> work
>> may tell us a different story.
>>
>> We have had good results with limited use of higher temperature pyrolysis
>> and gasifier chars, in the 500-700C range or even higher, when used in
>> erosion control, filtration, vermiculture and soil-less media. The main
>> drawback of a gasifier char is a lower char yield.
>>
>> Tom Miles
>>
>>
>>
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>>
>>
>
>
> --
> Josh Kearns
> PhD Candidate, Environmental Engineering
> University of Colorado-Boulder
> Visiting Researcher, North Carolina State University
>
> Director of Science
> Aqueous Solutions
> www.aqsolutions.org
>
> Mobile: 720 989 3959
> Skype: joshkearns
>
>
>
>
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-- 
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam

Louisiana telephone: 1-337-447-4124 (rings Vietnam)
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