Trevor,<br><br>You are right about the fixed carbon content of rice hulls at about 15%.<br>If the ash content is 20%, then this leaves a volatile matter content of 64%.<br>This calculation is on a dry weight basis.<br><br>
If we gasified all volatile matter, <br>the fixed carbon content of the char would rise to about 43%,<br>and the ash content would rise to about 57%.<br>But typically rice hull biochar has an ash content of about 40%.<br>
This means that there is still a lot of volatile matter that remains in the biochar.<br><br>In the case of rice hulls,<br>the amount of volatile matter that remains in the biochar is determined by the rate of gasification.<br>
At times the yield in rice hull biochar by weight is as low as 30%.<br>
At times the yield is as high as 50%.<br>If the rate of gasification is high, high temperatures within the reactor are reached.<br>With high temperatures, more volatile matter is gasified.<br><br>We need operating temperatures well beyond 1000 C before fixed carbon gets gasified.<br>
In my opinion it makes little sense to gasify fixed carbon.<br><br>Thanks.<br>Paul<br><br><div class="gmail_quote">On Thu, Oct 13, 2011 at 3:53 PM, Trevor Richards <span dir="ltr"><<a href="mailto:febiochar@gmail.com">febiochar@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Tests I've seen on rice husk char showed 15% fixed carbon. <br>I do not recall seeing a biochar definition, specifying a minimum fixed C.<br>
How low could the C% be & still be defined a biochar?<br><br><div class="gmail_quote">
On 13 October 2011 03:00, <span dir="ltr"><<a href="mailto:stoves-request@lists.bioenergylists.org" target="_blank">stoves-request@lists.bioenergylists.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Today's Topics:<br>
<br>
1. Re: burning rice husk (Crispin Pemberton-Pigott)<br>
2. Re: burning rice husk (Crispin Pemberton-Pigott)<br>
3. Re: burning rice husk (CHRISTA ROTH)<br>
4. Re: burning rice husk (Frank Shields)<br>
<br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Wed, 12 Oct 2011 11:19:02 -0400<br>
From: "Crispin Pemberton-Pigott" <<a href="mailto:crispinpigott@gmail.com" target="_blank">crispinpigott@gmail.com</a>><br>
To: "'Discussion of biomass cooking stoves'"<br>
<<a href="mailto:stoves@lists.bioenergylists.org" target="_blank">stoves@lists.bioenergylists.org</a>><br>
Subject: Re: [Stoves] burning rice husk<br>
Message-ID: <037501cc88f2$500af3e0$f020dba0$@<a href="http://gmail.com" target="_blank">gmail.com</a>><br>
Content-Type: text/plain; charset="us-ascii"<br>
<br>
Dear Christa<br>
<br>
<br>
<br>
There are other initiatives to make stoves based on the approach Alexis has<br>
taken. Paul has other models that show some promise as well.<br>
<br>
<br>
<br>
The Mayon Turbo Stove is not perfected yet and I don't think much is being<br>
invested in trying. It holds promise from the point that it does not require<br>
a fan. I worked on one here (in Waterloo) earlier this year together with<br>
two interns from REAP. We doubled the overall efficiency but created new<br>
problems that it got too hot. It needs additional work to keep the fuel<br>
cool. There are of course other ways to burn the fuel with natural draft.<br>
Maybe with the advent of cheap power from TEGs we will all make fan stoves<br>
and not worry about natural draft any more.<br>
<br>
<br>
<br>
The MTS has the important advantage that is can be refuelled continuously at<br>
your convenience. It does not need to be loaded in batches.<br>
<br>
<br>
<br>
Regards<br>
<br>
Crispin<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
+++++++<br>
<br>
<br>
<br>
The best rice-husk burning stoves I know of are the ones based on the<br>
tremendous work of Alexis Belonio. Paul Olivier' s work in Vietnam has taken<br>
rice-husk burning stoves in the household-size range to another level,<br>
uncomparable with natural-draft stoves like the Mayon Turbo, LoTrau or<br>
whichever. Paul has generously shared a lot of his work on this list in the<br>
last days, so you can look more details up from the links provided there or<br>
consult the section on rice-husk burning gasifiers, pages 43-48 of the<br>
manual microgasification<br>
<a href="http://www.gtz.de/de/dokumente/giz2011-en-micro-gasification.pdf" target="_blank">http://www.gtz.de/de/dokumente/giz2011-en-micro-gasification.pdf</a>,<br>
<br>
it contains all I found as per last year. If anybody knows of models that<br>
are not included there, please let me know, so that they can be included in<br>
the next update.<br>
<br>
regards<br>
<br>
christa<br>
<br>
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<br>
Message: 2<br>
Date: Wed, 12 Oct 2011 11:19:02 -0400<br>
From: "Crispin Pemberton-Pigott" <<a href="mailto:crispinpigott@gmail.com" target="_blank">crispinpigott@gmail.com</a>><br>
To: <<a href="mailto:rajan_jiby@dataone.in" target="_blank">rajan_jiby@dataone.in</a>>, "'Discussion of biomass cooking stoves'"<br>
<<a href="mailto:stoves@lists.bioenergylists.org" target="_blank">stoves@lists.bioenergylists.org</a>><br>
Subject: Re: [Stoves] burning rice husk<br>
Message-ID: <037f01cc88f2$53782e30$fa688a90$@<a href="http://gmail.com" target="_blank">gmail.com</a>><br>
Content-Type: text/plain; charset="us-ascii"<br>
<br>
Dear Rajan<br>
<br>
One stove that burns whole rice hull efficiently is the Mayon Turbo Stove.<br>
<br>
Regards<br>
Crispin<br>
<br>
<br>
+++++++<br>
<br>
I do not know whether a stove can efficiently burn rice husk.<br>
<br>
But it seems rice husk can be burnt efficiently in FBC ( fluidised bed<br>
combustion ) boilers. There are several medium sized FBC boilers operated<br>
all over India. So the fuel need not go waste.<br>
<br>
Regards,<br>
<br>
<br>
Rajan<br>
<br>
<br>
<br>
<br>
------------------------------<br>
<br>
Message: 3<br>
Date: Wed, 12 Oct 2011 17:39:49 +0000<br>
From: CHRISTA ROTH <<a href="mailto:stoves@foodandfuel.info" target="_blank">stoves@foodandfuel.info</a>><br>
To: Discussion of biomass cooking stoves<br>
<<a href="mailto:stoves@lists.bioenergylists.org" target="_blank">stoves@lists.bioenergylists.org</a>><br>
Subject: Re: [Stoves] burning rice husk<br>
Message-ID: <<a href="mailto:B4B60F1C-E72F-44B4-8B49-6B22E3F30982@foodandfuel.info" target="_blank">B4B60F1C-E72F-44B4-8B49-6B22E3F30982@foodandfuel.info</a>><br>
Content-Type: text/plain; charset="windows-1252"; Format="flowed";<br>
DelSp="yes"<br>
<br>
Crispin, see below:<br>
Am 12.10.2011 um 15:19 schrieb Crispin Pemberton-Pigott:<br>
<br>
> There are other initiatives to make stoves based on the approach<br>
> Alexis has taken. Paul has other models that show some promise as<br>
> well.<br>
CR: Which Paul do you mean? I was talking of Paul Olivier below, who<br>
has taken Belonios concept to a new era.<br>
<br>
><br>
> The Mayon Turbo Stove is not perfected yet and I don?t think much is<br>
> being invested in trying. It holds promise from the point that it<br>
> does not require a fan. I worked on one here (in Waterloo) earlier<br>
> this year together with two interns from REAP. We doubled the<br>
> overall efficiency but created new problems that it got too hot. It<br>
> needs additional work to keep the fuel cool. There are of course<br>
> other ways to burn the fuel with natural draft. Maybe with the<br>
> advent of cheap power from TEGs we will all make fan stoves and not<br>
> worry about natural draft any more.<br>
><br>
> The MTS has the important advantage that is can be refuelled<br>
> continuously at your convenience. It does not need to be loaded in<br>
> batches.<br>
CR: But the disadvantage I noted is that it needs a lot of attention:<br>
we had to tap the stove every two minutes last year in Belchertown<br>
with the colleagues from REAP to assist gravity and make the rice<br>
husks fall down, otherwise there was no continuous feed adn the fire<br>
would go out. Maybe that 'spoonfeeding' can be reduced with skills and<br>
acquired habits, but as an unskilled user I found it rather<br>
inconvenient.<br>
><br>
> Regards<br>
> Crispin<br>
><br>
><br>
><br>
> +++++++<br>
><br>
> The best rice-husk burning stoves I know of are the ones based on<br>
> the tremendous work of Alexis Belonio. Paul Olivier' s work in<br>
> Vietnam has taken rice-husk burning stoves in the household-size<br>
> range to another level, uncomparable with natural-draft stoves like<br>
> the Mayon Turbo, LoTrau or whichever. Paul has generously shared a<br>
> lot of his work on this list in the last days, so you can look more<br>
> details up from the links provided there or consult the section on<br>
> rice-husk burning gasifiers, pages 43-48 of the manual<br>
> microgasification <a href="http://www.gtz.de/de/dokumente/giz2011-en-micro-gasification.pdf" target="_blank">http://www.gtz.de/de/dokumente/giz2011-en-micro-gasification.pdf</a><br>
> ,<br>
> it contains all I found as per last year. If anybody knows of models<br>
> that are not included there, please let me know, so that they can be<br>
> included in the next update.<br>
> regards<br>
> christa<br>
> _______________________________________________<br>
> Stoves mailing list<br>
><br>
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> site:<br>
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------------------------------<br>
<br>
Message: 4<br>
Date: Wed, 12 Oct 2011 09:27:59 -0700<br>
From: "Frank Shields" <<a href="mailto:frank@compostlab.com" target="_blank">frank@compostlab.com</a>><br>
To: "'Discussion of biomass cooking stoves'"<br>
<<a href="mailto:stoves@lists.bioenergylists.org" target="_blank">stoves@lists.bioenergylists.org</a>>, <<a href="mailto:rajan_jiby@dataone.in" target="_blank">rajan_jiby@dataone.in</a>><br>
Subject: Re: [Stoves] burning rice husk<br>
Message-ID: <EF2941FD30314943BF1939C78F58E7CE@cl.local><br>
Content-Type: text/plain; charset="us-ascii"<br>
<br>
Stovers,<br>
<br>
I was talking to a rice grower in Northern Calif. and found out that Wild<br>
Rice has much less silica in the hulls than White Rice. I haven't tested<br>
wild rice hulls to confirm.<br>
<br>
Frank<br>
<br>
Frank Shields<br>
Control Laboratories, Inc.<br>
42 Hangar Way<br>
Watsonville, CA 95076<br>
(831) 724-5422 tel<br>
(831) 724-3188 fax<br>
<a href="mailto:frank@compostlab.com" target="_blank">frank@compostlab.com</a><br>
<a href="http://www.compostlab.com" target="_blank">www.compostlab.com</a><br>
<br>
<br>
-----Original Message-----<br>
From: <a href="mailto:stoves-bounces@lists.bioenergylists.org" target="_blank">stoves-bounces@lists.bioenergylists.org</a><br>
[mailto:<a href="mailto:stoves-bounces@lists.bioenergylists.org" target="_blank">stoves-bounces@lists.bioenergylists.org</a>] On Behalf Of Crispin<br>
Pemberton-Pigott<br>
Sent: Wednesday, October 12, 2011 8:19 AM<br>
To: <a href="mailto:rajan_jiby@dataone.in" target="_blank">rajan_jiby@dataone.in</a>; 'Discussion of biomass cooking stoves'<br>
Subject: Re: [Stoves] burning rice husk<br>
<br>
Dear Rajan<br>
<br>
One stove that burns whole rice hull efficiently is the Mayon Turbo Stove.<br>
<br>
Regards<br>
Crispin<br>
<br>
<br>
+++++++<br>
<br>
I do not know whether a stove can efficiently burn rice husk.<br>
<br>
But it seems rice husk can be burnt efficiently in FBC ( fluidised bed<br>
combustion ) boilers. There are several medium sized FBC boilers operated<br>
all over India. So the fuel need not go waste.<br>
<br>
Regards,<br>
<br>
<br>
Rajan<br>
<br>
<br>
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End of Stoves Digest, Vol 14, Issue 17<br>
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</blockquote></div><br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Paul A. Olivier PhD<br>27C Pham Hong Thai Street<br>Dalat<br>Vietnam<br><br>Louisiana telephone: 1-337-447-4124 (rings Vietnam)<br>Mobile: 090-694-1573 (in Vietnam)<br>
Skype address: Xpolivier<br><a href="http://www.esrla.com/" target="_blank">http://www.esrla.com/</a><br>