[Gasification] Biochar et al.

Paul A Judd paul.a.judd at pajeco.com.au
Sun Dec 8 16:11:46 CST 2013

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 Australiait 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 m^2 (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 _ab_sorb, it 
> _ad_sorbs 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 NO_3 .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 litterin 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 Nslowly 
> 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 

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

Local Australian groups:

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
     paul.a.judd at pajeco.com.au

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