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

[Tom Miles]

Alex,

 

I haven't seen any complete TLUD char analyses. The Glaser groups seems to
be making their gasification char in the Pyreg gasifier.

 

Tom  

 

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of
Alex English
Sent: Saturday, February 09, 2013 4:41 PM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] Characteristics of biochar was Re: [biochar]
grassifier & cedar chip char

 

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 amendment and 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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