[Stoves] Characteristics of biochar was Re: [biochar] grassifier & cedar chip char

[Alex English]

Crispin, Tom,
http://www.ithaka-journal.net/certificate/european-biochar-certificate-v4.2-final2012.pdf
This document  includes a lengthier discussion of PAHs in char, 
including how some chars are used to bind them in soils, and that 
current methods for testing are problematic.

We have test results from chars that could be called ' wood 
gasification' char at levels below the 4mg/kg limit for 'premium biochar'.

The high PAH levels >1000mg/kg in wood gasification chars mentioned 
below needs a further explanation of the production method. Wood 
gasification is to vague.

Are there any PAH tests results for TLUD rice hull chars?

Alex



On 06/02/2013 2:35 PM, Crispin Pemberton-Pigott wrote:
>
> Dear Tom
>
> Thanks for that:
>
> http://www.bacatec.de/dl/Ge09_Glaser-Steiner_engl.pdf
>
> "A further criterion for the quality of biochar is the lack of 
> contamination with both inorganic
>
> (e.g. heavy metals) and organic contaminants (e.g. polycyclic aromatic 
> hydrocarbons (PAH),
>
> dioxins etc.). In this study, we could only evaluate polycyclic 
> aromatic hydrocarbons (PAH,
>
> Fig. 4). Although chars from wood gasification are within the 
> elemental composition and the
>
> black carbon thresholds, they exhibit extremely high PAH contents 
> (Fig. 4). Therefore, they
>
> are not suited for soil amendmentand thus, they cannot be classified 
> as biochar. Surprisingly
>
> high PAH contents were also measured in the barbeque charcoals (Fig. 
> 4) while all other
>
> investigated chars had low PAH contents (Fig. 4)."
>
> Well, there's a kick in the head. Why not? Because of chemicals 
> manufactured in the process that were not there in the original fuel. 
> That may explain a lot to some experimenters.
>
> Regards
>
> Crispin
>
>
>
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