----- Original Message -----
From: Richard Stanley
To: Discussion of biomass cooking stoves
Sent: Tuesday, August 07, 2012 1:50 PM
Subject: Re: [Stoves] material processing for briquettes few tips ontechnique
Am all ears
# Is that a corn pun? ;-)
Kevin & Andrew.
Clearly its not hydrated lime but rather directly powdered rock lime we are
seeing.
# I don't know the technology involved in corn treatment, , but "lime
burning" goes back a long way:
CaCO3 + Heat ---> CaO + CO2 (Lime Burning)
Limestone and heat yield Calcium Oxide and CO2.
# The CaO can be produced as "Lump Lime", or the "Lump Lime" can be hammer
milled or ground to produce "crushed lime", "ground lime", "powdered lime",
etc. This is very different from limestone, ie, Calcium Carbonate, that is
crushed, ground, milled, etc., which is commonly known as "ground limestone",
agricultural limestone, ag-lime, land lime, etc.
# If the lime is dropped in water, it hydrates to produce Hydrated Lime:
CaO + H20 ---> Ca(OH)2 (Hydrated Lime Production.)
This is also known as "Slaked Lime", and "Mason's Lime."
# When dissolved in water, to make "Lime Water", the lime is very reactive,
at high pH.
# Now, there is a problem here... the highly reactive Ca(OH)2 has a big
affinity for CO2. It can easily remove CO2 from the air, to "air slake", or, if
in a slurry, can remove CO2 from solution. A lump of calcined CaO can "air
slake" to produce "powdered limestone."
CaO + CO2 ---> CaCO3
# There can be a two step process involved in "air slaking".... first the CaO
can hydrate to Ca(OH)2, and then it can carbonate to CaCO3:
How would either variety, Hydrated or not effects the removal of shells off
the corn kernels --as done there in large 50 - 75 liter sized vats of hot water
is my question.
# I don't know the process, but would guess that Hydrated Lime would be
employed, and that ground limestone would not "do the job." I would guess
also that the reactive, high pH hydrated lime would become "spent" in the
process of de-hulling. The "spent lime" may be present as part of an organic
compound of some sort, or, it may also have been precipitated out as CaCO3, if
CO2 was present.
Best wishes,
Kevin
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The efficient management of the partial decomposition of selected
agricultural residues makes or breaks a production activity from an economic
standpoint. In lieu of sophisticated machinery, it often comes down to finding
an efficient and locally managed method to accelerate the breakdown of the
plant material, preserving its fiber content while dissociating it from the
matrix material all left-still -, in a combustible state.
Its particularly, the loosened flexible ganglia of fibers, recombined in a
water slurry of other plant and granular combustibles, forms the kind of
tight, well infilled and relatively hot briquette that sells well, in the
local market.
If they don't have the fibers at work they can resort to paper if they have
it but paper is never going to burn like selected natural plant material which
they are familiar with and are best assured to be able to utilise on a
sustainable basis.
When it comes to practical briquetting based on traditional skills, there is
more collective wisdom in this truck than you can imagine. Its through these
incredible folks, and about 300 more, that the production trainers for the
region will soon emerge.
------------------------------------------------------------------------------
Am very busy learning from both ends of the candle here !
Your information could not be more timely:
Thanks again, Kevin and Andrew.
Richard Stanley
www.legacyfound.org
===========
On Aug 7, 2012, at 6:42 AM, Kevin wrote:
Dear Andrew
Very interesting possible explanation for why "spent agricultural lime" helps
with the anaerobic retting process!
While Ca(OH)2, or "Hydrated lime" can have a pH as high as about 12.5, and
is indeed very caustic, CaCO3 or "Limestone", "agriculture lime, "land lime",
has a pH in the range of about 8, which is not very caustic at all
Is there perhaps another possibility, that being that a marginal change in
alkalinity favours growth of different bacteria?
More specifically, is it perhaps the minor change in pH is "shifting the bug
balance", rather than making local chemistry harsher? In other words, are the
"retting fungus forms" more favoured with slightly higher pH, while the fungus
forms that consume cellulose are repressed?
Best wishes,
Kevin
----- Original Message ----- From: <[email protected]>
To: "Discussion of biomass cooking stoves" <[email protected]>
Sent: Saturday, August 04, 2012 2:04 PM
Subject: Re: [Stoves] material processing for briquettes few tips ontechnique
On Fri, 3 Aug 2012 10:32:14 -0700, Richard Stanley wrote:
If processed correctly, natural fibers will flex and then tend to
interlock once blended with other materials in a water slurry.
One does not achieve this by simple chopping or even direct use of the
fiber without some form of softening (thru partial decompsition, in a hot humid
anerobic environment, (under such as a black plastic bag), or as we are
learning from our Mayan colleagues in Guatemala, use of agricultural lime
(which is traditionally discarded after its use in hot water to soften and
de-shell their corn kernals).
As always I find your posts on briquetting educational.
Alkalis, lime being calcium hydroxide, dissolve lignin and I expect
this is what the bugs do in retting fibres out of the stem
(simplistically wood rotting fungi can be classified into brown, white
and soft rots, the white rots attack lignin and leave the cellulose,
brown eat the cellulose and soft rots invade all the cells), it's
lignin that hold all the stringy fibres together. So I can see how
lime would separate out the fibres.
Your observation that the bugs work better in anaerobic conditions
may be that this is what favours a white rot. Flax sheaves where laid
in a water filled ditch to ret.
I may have missed something in Rok's post: Rok mentions 16cms diameter
briquettes with a 5 cms hole, I take it it is the length he is varying
between 3-12 cms and favouring a length of between 5 and 7cms?
AJH
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_______________________________________________
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------------------------------------------------------------------------------
Am all ears Kevin & Andrew.
Clearly its not hydrated lime but rather directly powdered rock lime we are
seeing.
How would either variety, Hydrated or not effects the removal of shells off
the corn kernels --as done there in large 50 - 75 liter sized vats of hot water
is my question.
The efficient management of the partial decomposition of selected
agricultural residues makes or breaks a production activity from an economic
standpoint. In lieu of sophisticated machinery, it often comes down to finding
an efficient and locally managed method to accelerate the breakdown of the
plant material, preserving its fiber content while dissociating it from the
matrix material all left-still -, in a combustible state.
Its particularly, the loosened flexible ganglia of fibers, recombined in a
water slurry of other plant and granular combustibles, forms the kind of
tight, well infilled and relatively hot briquette that sells well, in the
local market.
If they don't have the fibers at work they can resort to paper if they have
it but paper is never going to burn like selected natural plant material which
they are familiar with and are best assured to be able to utilise on a
sustainable basis.
When it comes to practical briquetting based on traditional skills, there is
more collective wisdom in this truck than you can imagine. Its through these
incredible folks, and about 300 more, that the production trainers for the
region will soon emerge.
Am very busy learning from both ends of the candle here !
Your information could not be more timely:
Thanks again, Kevin and Andrew.
Richard Stanley
www.legacyfound.org
===========
On Aug 7, 2012, at 6:42 AM, Kevin wrote:
Dear Andrew
Very interesting possible explanation for why "spent agricultural lime" helps
with the anaerobic retting process!
While Ca(OH)2, or "Hydrated lime" can have a pH as high as about 12.5, and
is indeed very caustic, CaCO3 or "Limestone", "agriculture lime, "land lime",
has a pH in the range of about 8, which is not very caustic at all
Is there perhaps another possibility, that being that a marginal change in
alkalinity favours growth of different bacteria?
More specifically, is it perhaps the minor change in pH is "shifting the bug
balance", rather than making local chemistry harsher? In other words, are the
"retting fungus forms" more favoured with slightly higher pH, while the fungus
forms that consume cellulose are repressed?
Best wishes,
Kevin
----- Original Message ----- From: <[email protected]>
To: "Discussion of biomass cooking stoves" <[email protected]>
Sent: Saturday, August 04, 2012 2:04 PM
Subject: Re: [Stoves] material processing for briquettes few tips ontechnique
> On Fri, 3 Aug 2012 10:32:14 -0700, Richard Stanley wrote:
>
>> If processed correctly, natural fibers will flex and then tend to
interlock once blended with other materials in a water slurry.
>> One does not achieve this by simple chopping or even direct use of the
fiber without some form of softening (thru partial decompsition, in a hot humid
anerobic environment, (under such as a black plastic bag), or as we are
learning from our Mayan colleagues in Guatemala, use of agricultural lime
(which is traditionally discarded after its use in hot water to soften and
de-shell their corn kernals).
>
> As always I find your posts on briquetting educational.
>
> Alkalis, lime being calcium hydroxide, dissolve lignin and I expect
> this is what the bugs do in retting fibres out of the stem
> (simplistically wood rotting fungi can be classified into brown, white
> and soft rots, the white rots attack lignin and leave the cellulose,
> brown eat the cellulose and soft rots invade all the cells), it's
> lignin that hold all the stringy fibres together. So I can see how
> lime would separate out the fibres.
>
> Your observation that the bugs work better in anaerobic conditions
> may be that this is what favours a white rot. Flax sheaves where laid
> in a water filled ditch to ret.
>
> I may have missed something in Rok's post: Rok mentions 16cms diameter
> briquettes with a 5 cms hole, I take it it is the length he is varying
> between 3-12 cms and favouring a length of between 5 and 7cms?
>
> AJH
>
>
> _______________________________________________
> 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://www.bioenergylists.org/
_______________________________________________
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
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for more Biomass Cooking Stoves, News and Information see our web site:
http://www.bioenergylists.org/
------------------------------------------------------------------------------
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
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to UNSUBSCRIBE or Change your List Settings use the web page
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for more Biomass Cooking Stoves, News and Information see our web site:
http://www.bioenergylists.org/
_______________________________________________
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
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for more Biomass Cooking Stoves, News and Information see our web site:
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