[Stoves] Char

[Tom Miles]

Ron,

Frank seems to say that bagasse chars while composting at 70C. It is clearly not just heated to 70C but undergoes biological degradation at the same time. apparently the higher temperature biological conversion creates a char that resists degradation. I assume that there is a loss of carbon in the process.

Is this "biothermal carbonization"? It could prove to be an interesting technique for rural applications.  

Tom     

-----Original Message-----
From: stoves-bounces at lists.bioenergylists.org [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of rongretlarson at comcast.net
Sent: Saturday, May 28, 2011 1:58 PM
To: Discussion of biomass cooking stoves
Cc: Biochar-production
Subject: Re: [Stoves] Char

Tom and Frank:, stoves list (and adding "biochar-production" ) 

1. To Tom: Are you asking if one gets better compost at this higher temperature? 

2. To Frank: This is the first time I have heard of "char" being produced at anything under about 300 C - usually 400 C and above. Can you clarify? I would think this dark product would disappear from the soil about as fast as any other compost. Even Torrification requires temperatures well above 70 o C. Although it would be great to hear more on this material in any case - which is maybe what Tom is asking. 

One exception is that HTC (hydrothermal carbonization) (maybe called hydrochar) occurs at 230 o C (with corresponding high pressure, and a catalyst) - but might not be so recalcitrant either (recently reported - not sure) . 


Ron 

----- Original Message -----
From: "Tom Miles" <tmiles at trmiles.com>
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
Sent: Saturday, May 28, 2011 1:14:09 PM
Subject: Re: [Stoves] Char 

Frank, 

Is there any benefit to the composting to char or heat part of the bagasse first? 

Tom 

-----Original Message-----
From: stoves-bounces at lists.bioenergylists.org
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Frank Shields
Sent: Saturday, May 28, 2011 11:53 AM
To: 'Discussion of biomass cooking stoves' 
Subject: [Stoves] Char 


Stover's, 

Perhaps of interest, we test products for the Biodegradable Products Institute and some are made from bagasse. When composted at low temperatures < 45 deg C these products break down easily. But when composting temperatures go to 70 deg C the bagasse chars and they remain as the same structure (only darker) as the product we put in the compost. Proof that charring is resistant to biodegradation. 


Frank 





Frank Shields
Control Laboratories, Inc. 
42 Hangar Way
Watsonville, CA 95076
(831) 724-5422 tel
(831) 724-3188 fax
frank at compostlab.com
www.compostlab.com 




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