[Stoves] [biochar-production] Re: Stoves Digest, Vol 14, Issue 17

Fri Oct 28 11:45:46 CDT 2011

Tom,

My main disagreement is the term Fixed Carbon and that it means the total
weigh DAF where it should be a measure of carbon in that fraction. I will
need to get over that. 

The IBI has some good test methods that I am now using. Measure pH, salts,
etc on diluted samples are a few I have changed to. Methods for metal are
acid digest and is what I have been doing along with most others. The CEC I
would like to change to an AOAC procedure for peat. And the butane activity
is left out. Going to iodine. I have been doing 450 deg for calcining temp
but now raised it to their 600 deg as that is where I have found the butane
activity is highest (600 to 650 deg C) for most biochar when plotting
curves. But the loss in weight seems to stabilize at ~450 deg C. I was
thinking if activity was not that important the lower temperature is all
that is required.   

They use a C/H ratio to determine if the biomass is sufficiently charred
where I was measuring loss in weight after re-charring at 450 deg C. My
procedure has some real problems and was looking for other ideas. I think
theirs may be better but still we need to keep looking as I am not sure it
will weed out tars that would be removed in my procedure and different
feedstocks may end up with different C/H ratios even when fully charred. So
on it goes. 

I was looking into a TGA to do the testing but after sending in samples to
Leco I was not real happy with the results. This can determine moisture then
switch over to nitrogen atm and char at predetermined temperature then add
air and ash at predetermined temperature all in one unite and cycle. This
should work well. I had them char in nitrogen a sample at different
temperatures thinking I would get a value that leveled off at 450 deg C as
what I have found in my pipe system. But my pipe system seems to work
better. Not sure if air was in their system when they ran it after drying or
if biomass does change in weight more than I found over temperature
differences with my pipes. 

Thanks

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

  _____  

From: stoves-bounces at lists.bioenergylists.org
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Tom Miles
Sent: Thursday, October 27, 2011 12:29 PM
To: 'Discussion of biomass cooking stoves'
Subject: Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14,Issue
17

Frank,

Test methods. Many oof the ASTM methods for biomass are coal methods that
have been adjusted for biomass. Usually the calcining temperature of a
sample for biomass has been reduced by ASTM fro the 900C used for coal to
550C or 600 C for biomass. 

Tom

From: stoves-bounces at lists.bioenergylists.org
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Frank Shields
Sent: Thursday, October 27, 2011 12:06 PM
To: 'Discussion of biomass cooking stoves'
Subject: Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14, Issue
17

Dear Paul,

The way I look at it; 

Biochar is not needed by the plant anymore than peat moss, perlite, sand,
lime, gypsum etc. These are all materials used to change the texture of the
soil. Better drainage, hold more water, make water more available, adjust pH
that changes availability of nutrients, added porosity, add microbes that
regulate the nutrients etc. If the biochar product adjusts one of these
components to make the required constituents (water, nutrients, temperature
etc) more optimum for the plant you will see a benefit. A lot of silica (as
in rice hulls) may very well be the component that makes the change and the
carbon fraction has nothing to do with it. Or it could all be from the
carbon fraction or mixture of both. IMO it is important to determine the
condition change that has created the increase in plant response. And the
constituent of the biochar that has done it. Then we can determine the
biochar quality that should be used on that specific site. 

But I think we can agree that it's the carbon component we regard as
important when talking biochar. If it's the silica in rice hulls making the
difference we could just add something like sand. Being carbon as the
important fraction biochar quality should be rated based on the carbon
component. Not only carbon concentration but also the carbon structure (or
we could just as well add organic matter).  Carbon comes in a range of
biological activity. Very reactive like green grass, sugars, oils,
vegetative materials. Semi-reactive materials like wood chips, stabilized
compost, biosolids and organics from aeration ponds, finished septic systems
etc and very stabilized like plastic, biochar.  Available carbon increases
microbes. That in turn uses a lot of oxygen making soils anaerobic creating
lots of problems.  The reason we compost and have septic systems before
letting high reactive organics into the environment.  Because biochar claim
to have a very stabilized carbon (non-available to microbes and oxidation)
we need to measure to the degree the carbon is stabilized in addition to the
concentration to rate and compare biochar products. Rice biochar has low
carbon (not good) but likely high stability (good). And a unique structure,
that in the right locations and soil type, could make all the difference. 

It's the test methods that work best to determine the carbon concentration
and properties that we need to sort out.  Not an easy task thanks to people
wanting to use coal testing methods for biochar.  We need our own methods
manual.

Regards

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

  _____  

From: stoves-bounces at lists.bioenergylists.org
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Crispin
Pemberton-Pigott
Sent: Thursday, October 27, 2011 6:56 AM
To: 'Discussion of biomass cooking stoves'
Subject: Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14,Issue
17

Dear Paul

Do you know if the char has been characterised well, or is it from the smoky
stacks you described earlier?

Thanks

Crispin

++++++

Frank,

Rice hulls biochar makes as excellent soil amendment, as numerous test have
shown.
Yields on rice, water spinach and other plants have increased roughly 3-fold
in the trials that were done in Vietnam and Cambodia.
If it is not the best biochar, I would be truly exciting to find something
better.

Paul Olivier

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