[Gasification] Biochar et al.

Oscar Jimenez oscar at cubaenergia.cu
Mon Dec 9 08:52:44 CST 2013


Dear David.

 

.I think that it is a very good point when you highlight..that.." Depending
on the soil analysis a good soil doctor would produce a prescription
biochar, which would mean different temperatures etc, etc."

 

Kindest regards.

 

Oscar.

 

 

 

De: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] En
nombre de David Murphy
Enviado el: Sunday, December 08, 2013 9:25 PM
Para: Discussion of biomass pyrolysis and gasification
Asunto: Re: [Gasification] Biochar et al.

 



Greetings Paul !

No problem with your criticism/correction.     But as I understand it (and
I'm no expert) "oils ain't oils" and Biochar ain't just biochar".
Depending on the soil analysis a good soil doctor would produce a
prescription biochar, which would mean different temperatures etc as you
descdribe.     The topic is complex and I certainly can't describe it in a
few linesand neither am I qualified to.   It's a bit like worms.  Some
people say to me "Tell me all about worms".  I've written 3 books (Best
Sellers) on the topic and haven't  covered it properly yet.

DJM.



On 09/12/2013 10:16 AM, Paul Judd wrote:

On 07/12/13 09:00, David Murphy wrote:


Greetings Biochar/Gasifier people !

Everybody & his dog seems to have something to say about
charcoal/biochar/biochar-compost mix and so on.    Well, here's another dog
to bark his piece ! 



Biochar is often seen as the great agricultural panacea, but it is not.
Biochar is a name given to plain ordinary charcoal to indicate that it is
destined for use in soil improvement, but basically it is still plain
ordinary charcoal, just crushed into smaller particles.  In some
circumstances it is a very beneficial tool but it is not magical as some
proponents seem to think.   Just remember, all charcoal has a bio-origin -
wood. 



In some Ag. trials in Australia it significantly improved crop volume
(treble in one case) but in other instances, nothing worth writing home
about.  It depends on what the soil is like to start with. 



Charcoal is stable.  That means it does not take part in any composting
system (which is one primarily of bacterial digestion) and it is
indigestible so that when offered as a dietary supplement (in poultry food
for example) it passes through the digestive system physically unchanged but
will adsorb a high proportion of the gases and some toxins produced in the
process of digestion, because that is what charcoal does.    For this
reason, it's adsorption capability, poultry will generally do better on a
little charcoal. 

Quite a few pages could be filled on the beneficial services provided by
charcoal as it travels through the digestive system, but it does it as
charcoal only and as nothing else.   By all means use a little in the feed,
you can only benefit.    

The only physical way to change the nature of charcoal is to burn it.
That is why it lasts in soil (or wherever it is) for thousands of years.

It has an incredibly high surface area of 360 m2 (varies) and is a mass of
minute tunnels which in turn means a very high volume and gases become
trapped in these tunnels.  It does not absorb, it adsorbs and traps only.
The difference between absorb and adsorb is the same as the difference in
liquids of suspension and solution.  Clay particles will be in suspension,
sugar and salt go into solution. 



Charcoal is useful in an aerobic composting system because again of the
entrapment of air in the tunnels.   A composting system goes well if there
is enough oxygen bearing air available to the bacteria which are a
significant part of the system.   The more air, the higher the population of
bacteria (other factors being OK).    The charcoal itself is inoperative,
and doesn't change, nor is it a catalyst, it simply provides a service.   It
will only provide a haven for soil benevolent bacteria if there is something
trapped in the tunnels which the bacteria can eat. 



Charcoal is a good adsorber of gas and liquid simply because that is what it
does.   Zeolite on the other hand, can have an even higher surface are per
gram and has a propensity to entrap gases, most particularly nitrogen in
it's various forms - as gas - ammonium for example - and in liquids as a
salt of NO3 .   It actually draws them in (like a magnet attracts ferric
objects) where charcoal just takes it as it comes.    It is easy to see also
why charcoal is so effective as a filter, but if you have a solution rich in
nitrogen, run it through Zeolite and the N will be removed.  Add some to the
litter in poultry grower sheds, there will be fewer mortalities because the
ammonia which sometimes will asphixiate small birds will be absorbed.
Zeolite will take N out of solution, charcoal will not.    There's 40
natural forms of Zeolite and more than another 150 can be synthesised, so
choose carefully for the one most appropriate to your problem.    Zeolite
can perform an amazing range of actions.    Once used and applied as
fertiliser, Zeolite subsequently will release the N slowly and remain in the
soil as a balancer of N.  Too much, it will take it in (so that the soil pH
is not lowered) and release it as required.



Charcoal's great stuff though, it's easy to make and holds answers to a lot
of problems - but not all !

David Murphy. 




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BioChar is not "ordinary charcoal".
Charcoal is usually made at temperatures above 1000C and all volatiles are
removed.
Bio-char is made a lower temperatures, 400~600C just above spontaneous
combustion temperature of organic material (wet or dry). It contains tars
and a different structure withing the hollows than `ordinary charcoal`. It
is the structure and the tars that make a good home for soil micro
organisms. It also holds water and minerals better than charcoal. 

See  http://www.biochar-international.org/ for more detailed information and
projects.

Local Australian groups:
http://biocharproject.org/
http://www.bioenergyaustralia.org/




-- 
Paul Judd B.App.Sc. Secondary Metallurgy, Dip Electrotechnology Renewable
Energy,  Dip Sustainability
Trainer and Sustainability Advisor
    PAJeco    Sustainable Education
    Sustainability: Learning to live today but leaving enough to live
tomorrow
    http://www.pajeco.com.au
    paul.a.judd at pajeco.com.au
    +61415518134






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