[Stoves] gasifying sawdust

Sat May 23 13:12:20 CDT 2015

Thanks Ron. I posted a few photos here: https://plus.google.com/photos/112929397141178613286/albums/6074575146282561169 <https://plus.google.com/photos/112929397141178613286/albums/6074575146282561169>.

Sorry, I don’t have metrics or performance data. Pressure drop through sawdust can be considerable, so particle size matters. Planer shavings are easier than coarse sawdust. Fine sawdust (e.g. from sander or finish work) is all but impossible. Moisture content was very high (as are most things in the humid tropics!). I recall running exhaust from my Dodge truck through the load to heat-dry it to the point where it could sustain a flame. 

The big TLUD It was used to dry/prime an even bigger retort kiln (4M³) filled with damp coarse (up to 30cm dia.) forestry residues, so after pyrolysis we kept the blower going and oxidized the carbon as well, to wring all the heat out of it that we could. When the big retort finally took off, it was pretty amazing. Boys building things and burning stuff…

We recently looked at reviving the TLUD design to fire ceramic water filters for CATIS-Mexico (CATIS-Mexico <http://catis-mexico.org/>), but couldn’t fit the TLUD into our budget, so we’re going to fire the filters in a ceramics kiln chamber using a sawdust blower-burner.

Rob 
~~~~~~~~~~~~~~~~~~~~~~~
Robert A. Lerner
Mexico cell: 415-101-4591
U.S. direct: 619-618-1248
Skype ID: bajarob
Rob's Biochar TED talk <http://www.youtube.com/watch?v=SgwwV6YrWb0>
Board member CATIS-Mexico <http://www.catis-mexico.org/>
~~~~~~~~~~~~~~~~~~~~~~~

> On May 22, 2015, at 10:16 PM, Ronal W. Larson <rongretlarson at comcast.net> wrote:
> 
> Rob and list:
> 
> 	Sounds like an important advance.  Congratulations
> 
> 	I’ll bet most on the list would like to see your pictures.
> 
> 	What weight of sawdust?   The fuel bed height?  Times for the pyrolysis front to reach the bottom and for total combustion?   Have to change to lots more “primary” after you had made the char?  Can you guesstimate the several butterfly ratio settings?  Power for the fan/blower?  Might you have been able to save the sawdust char if the  4 m3 wood was dry?  Any way to describe cleanness of the burns?
> 
> Ron
> 
> 
> On May 22, 2015, at 6:06 PM, Robert Lerner <bajarob at gmail.com <mailto:bajarob at gmail.com>> wrote:
> 
>> We built a big (1M dia.) fan-forced sawdust TLUD gasifier in Costa Rica, designed by Nikolaus Foidl.
>> 
>> Used one blower with two butterfly valves—one to balance primary:secondary air ratio, and the other to adjust total airflow. 
>> 
>> Worked great, though we combusted the char too, because were using the TLUD to dry & prime a 4M³ retort kiln filled with high MC wood. I have pictures.
>> 
>> Rob Lerner
>> ~~~~~~~~~~~~~~~~~~~~~~~
>> Robert A. Lerner
>> Mexico cell: 415-101-4591
>> U.S. direct: 619-618-1248
>> Skype ID: bajarob
>> Rob's Biochar TED talk <http://www.youtube.com/watch?v=SgwwV6YrWb0>
>> Board member CATIS-Mexico <http://www.catis-mexico.org/>
>> ~~~~~~~~~~~~~~~~~~~~~~~
>> 
>>> On May 22, 2015, at 12:00 PM, stoves-request at lists.bioenergylists.org <mailto:stoves-request at lists.bioenergylists.org> wrote:
>>> 
>>> Message: 1
>>> Date: Thu, 21 May 2015 11:11:33 -0700
>>> From: Tom Reed <tombreed2010 at gmail.com <mailto:tombreed2010 at gmail.com>>
>>> To: "stoves at lists.bioenergylists.org <mailto:stoves at lists.bioenergylists.org>"
>>> 	<stoves at lists.bioenergylists.org <mailto:stoves at lists.bioenergylists.org>>
>>> Subject: [Stoves] Sawdust Gasification
>>> Message-ID: <3B3D1B5B-91C0-408B-8FBE-38ADAE3896A2 at gmail.com <mailto:3B3D1B5B-91C0-408B-8FBE-38ADAE3896A2 at gmail.com>>
>>> Content-Type: text/plain;	charset=us-ascii
>>> 
>>> Dear List
>>> 
>>> One of the benefits of the TLUD stove working on wood chips is that it produces 20% charcoal, which can be sequestered, removing 38 tons of CO2 from circulation for each           ton of wood gasified (20% due to formation of charcoal from the lignin and using the gas from the cellulose (renewable) in place of propane, natural gas of coal gas.  
>>> 
>>> If we could gasify sawdust, it would bring another, typically dry, source of fuel into the picture.  However, the particle size of sawdust does not permit TLUD operation.  Does anyone have a suggestion of how to gasify sawdust?
>>> 
>>> TOM REED 
>>> 
>>> Thomas B Reed 
>>> 280 Hardwick Rd
>>> Barre, MA 01005
>>> 508 353 7841
>> 
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