Stovers,
Excellent discussion. Jon's message below puts it into perspective. I
oversimplify what Crispin has said in the past: There are no bad fuels,
just bad stoves. (Exaggeration has its impact!! Basically, I agree
with Crispin.)
And Paal Wendelbo always says: Start with the fuel. And Jon points
out the abundant Jatropha seeds. I add that "abundance" in nature is
not the same as abundant in supply, meaning that it fuel needs to be
collected. So we have the chicken and egg problem of which comes
first. Leaving that aside, please note.
1. Jatropha and other oil-seeds not only yield pyrolytic gases and char
and heat, they also yield great amounts of vaporized oils that are
combustible. That difference is vastly important for the TLUD gasifier
(all micro-gasifiers) operations. That means, MUCH MORE SECONDARY AIR
is needed. It is not sufficient to simply turn down the primary air.
And on this basis, I believe that ONLY gasifier stoves are viable
candidates to have sufficiently clean combustion for Jatropha-seed fuel.
2. We cannot ignore the need for some chemical analysis of the
emissions from the stoves AFTER the good combustion of the gases. Can
any bad stuff survive the high heat of the combustion stage in a
gasifier stove?
3. Two known and proven and accomplished ways of successfully using
Jatropha (oil-seed) seed fuel in a TLUD stove. Natural draft (TLUD-ND)
is accomplished by the Jiko Safi by Jet City Stoveworks. It has a
central pipe for additional secondary air. More holes for secondary air
to mix into (with less distance to move horiziontally) the volume of
fuel rich gases. Someone suggested removing that central pipe. That
does not work. That was tried before the success came with the central
pipe. Step back for actual success, repeat what was not successful
earlier, and make no progress. Anyone is welcome to try it again.
4. TLUD-FA (forced air or fan-asssisted) with Jatropha seed fuel has
also been successful. It was done by Nathan Puffer and seen as
Gasifier/CHAB stove camp in 2010 at NESFI in MA. Done. It can be
improved. But there are no funds to undertake its refinement. And
then it has the higher price factor that puts these stoves out of
purchasing reach of those who need them. AND you have to get the fuel
supply chain functioning. Nathan (of New Hampshire) is active for a
couple of decades in Kenya, and his latest work is with the natural
draft TChar TLUD-ND in Kenya. Financial assistance would be appreciated
and appropriate. (I will be mentioning more about his TChar work in my
presentation at ETHOS next week. I might entitle my presentation:
"Unsung Heros of TLUD Stoves", but I cannot find many who have been "Sung").
Jonathan concluded:
The point of importuning my stove list colleagues on a fine Sunday
morning is to interest other stove makers to look at Jatropha and
other energy-rich seeds as a category of fuel worth consideration for
new stove designs. We are modestly pleased with the performance of
the jiko safi, but we also know that some of you with far deeper
understanding of gasification and far more experience in stove design
could produce a much better model. Anyone want to take up this challenge?
Yes, but there needs to be some financial support. Personally, I am
pressed too thinly for money and time to undertake anything without
serious co-workers/partners/associates/backers. Solutions that are
needed do not grow on trees (although the fuels do). So far I have not
seen any GACC funding that can be directed to the R&D efforts for stoves
such as Jatropha-seed TLUDs. That is NOT the mission of the GACC.
Other sources, maybe exist. On the other hand, GACC support for an
EXISTING product (the Jiko Safi) could stimulate sufficient business
that the owners can also do some refinements that would soon be evident
in the second wave of production. If we are going to get the NEEDED
stoves, we must acknowledge that there will be improvements on the
existing stoves. If that means R&D, then that must happen. But we
just need to have it done by companies that are sufficiently funded to
be successful enough to study, learn, and improve their stoves.
Summary: This topic keeps coming up, and it is time to do something
about it.
1. Support for Jiko Safi stove (Jet City Stoveworks -- the Otto
brothers plus)(Tanzania base)
2. I will assist, and can bring Awamu Biomass Energy Ltd (Uganda) into
participation
3. Nathan Puffer (focus on Kenya efforts)
4. Others (self-nominate here)
5. Some sources of funding (we do not know who you are, so please speak up)
6. Others (who will gladly join when some funding is available.)
Paul S. Anderson, PhD aka "Dr TLUD"
Email: [email protected] Skype: paultlud Phone: +1-309-452-7072
Website: www.drtlud.com
On 1/20/2013 8:23 AM, Jonathan Otto wrote:
Hey Richard,
Not sure why you feel my briquetting education has been neglected,
since that kind of fuel is not mentioned in any of my postings; but
I certainly subscribe to Dean's comment: we all have a lot to learn
about such alternative fuels. I would add: and the stoves that burn
them in a truly clean way. Which brings up the question: if a
briquette or pellet is burned in an open charcoal brazier, do we have
a clean energy source? To put in another way, there are no 'clean' or
'dirty' fuels; it's combination of fuel and stove that must be
evaluated together for emissions and other performance parameters.
My densified fuels question to Otto the Senior or anyone else who can
enlighten me concerning the logic of pelletizing Jatropha presscake.
If farmers grow their own energy-dense, uniform-sized fuel,
i.e., whole Jatropha seed, why complicate matters by processing that
ready-to-use fuel into another fuel? No matter how efficient the
pelletizing process, it must require time and energy. Why not burn
these seeds directly in a micro gasifier stove, such as our jiko safi?
Let me try to head off some likely comments. I know that there are
companies in many African and Asian countries engaged in commercial
scale production of Jatropha (and other biofuel crops) for export
of biodeisel. Land grabbing and other nefarious activities of some of
these players are obscene, as once again the global north exploits
tropical countries for cheap/free land and cheap labor to meet its
own needs.
Yes, those Jatropha oil export ventures produce presscake as a
by-product which they pelletize and market for fuel. And yes, some
smaller operations in a few countries like Uganda, are trying to make
a go of producing Jatropha-based biofuels for local and regional
energy markets. But for all the publicity, most of it appropriately
negative, in the 'food vs. fuel' analysis, there's a lot more to
Jatropha than current attempts to put the oil in European cars and jet
engines.
Far apart from all these recent commercial Jatropha ventures, many
of which are unprofitable for reasons we can discuss another time if
anyone's interested, are many millions of farmers in over 110
countries who use Jatropha as a living hedge and for medicianl uses.
Seems it's grown in every frost-free area of the world. I've found it
from Cuba -- it's native to the neo-tropics -- to Mali, which has
thousands of kilometers of hedges, to Bhutan where villagers were
obliged to pay a Jatropha tax to monks for lighting in floating wick
lamps.
My guess is that over 99% of all Jatropha seed fall to the ground and
rot, unused. (One study in a district of Tanzania where Jatropha seed
is a traded commodity found that only 6% of seed is harvested.) As we
all search for renewable, sustainably harvested biomass to fuel our
favorite stoves, can we afford to overlook seeds of this ubiquitous,
multi-use species?
The point of importuning my stove list colleagues on a fine Sunday
morning is to interest other stove makers to look at Jatropha and
other energy-rich seeds as a category of fuel worth consideration for
new stove designs. We are modestly pleased with the performance of
the jiko safi, but we also know that some of you with far deeper
understanding of gasification and far more experience in stove design
could produce a much better model. Anyone want to take up this challenge?
Over to you,
Jonathan
------------------------------------------------------------------------
_______________________________________________
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://www.bioenergylists.org/
