Julien,
If you bottom light the 30 gal with straw and some vertical passages, be
aware that the initial heat energy goes into drying any of the straw
above it. That means much moisture (and little chance of it igniting)
in the first minutes. You will probably get the firemen to visit
you. Be careful.
Your trial with a single central air column is the same as the well
known packing of sawdust into a similar arrangement.
The above are not my specialty, so I have little else to add.
For TLUD trials, straw that is cut and kept straight (not crushed and
matted) and placed vertically in a TLUD should work. But the issue is
how much pushing together can be done before the needed primary air flow
is uniformly blocked (which is not bad if then use a fan to power the
air through it, as done with rice husks), OR if it is blocked is some
places and somewhat open in others (which is bad because the fire will
channel down to the bottom.)
I suggest you try the vertical straw rather loose. Expect a short
burn. Note: Make the bundle tight with a string, insert, and remove
the string so that the bundle expands to fill the whole diameter of the
fuel chamber. That is what Paal Wendelbo taught us to do with the more
"reedy" grasses.
Good luck and let us know what happens.
Paul
Paul S. Anderson, PhD aka "Dr TLUD"
Email: [email protected] Skype: paultlud Phone: +1-309-452-7072
Website: www.drtlud.com
On 4/9/2013 4:03 PM, Julien Winter wrote:
Lanny Henson Tue Apr 9 12:58:26 MDT 2013 wrote:
Julien,
Have you tried top lighting the 30 gal drum of straw?
Do you have problems maintaining an open, central, air flow, pathway?
Lanny
Lanny;
I did not try top lighting the 30 gal drum with a hollow core in the
bed of straw. That is probably worth trying, but the paint can tests
suggest that it may not work if the reaction is in TLUD mode.
I have not had trouble with the central hole in a bed of straw
collapsing during a burn. Gasified straw maintained its structure,
even though it had lost ca. 80% of its mass.
I think my next move is to bottom light a 30 gal bed of straw
containing multiple vertical holes, to see if I can shorten the path
length for the convection of gases and heat. If I can get that to
work, I will try top lighting it as a TLUD. I like the TLUD process
in theory, because the oxygen is used up in the descending ignition
fire, and not in ashing charcoal, as occurs with bottom lighting.
However, I will not be running any more trials for a week, because we
have rain and possibly snow in the forecast.
I find that a paint can reactor is a fairly good model for a 30 gal
drum reactor. I can easily test equipment designs, fuels and
procedures. I can run several trials in an hour and not use too much
feedstock, and I can run replicates to be sure. I can also run
special photo-ops, such as in the dark. If a paint can trial is a
failure and I have to put it out, I don't have to dispose of much
waste straw. By contrast, a run of the 30 gal reactor can take a
couple of hours, plus, if it goes really badly and I create heaps of
smoke, I could be visited by the city fire brigade. Alas, I am not
working in a farmyard, but in a suburbia. One-upon-a-time, my family
used to collect cows, but not any more.
Thanks to all for the input,
cheers,
Julien.
--
Julien Winter
Cobourg, ON, CANADA
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
[email protected]
to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
for more Biomass Cooking Stoves, News and Information see our web site:
http://stoves.bioenergylists.org/
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
[email protected]
to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
for more Biomass Cooking Stoves, News and Information see our web site:
http://stoves.bioenergylists.org/
