[Stoves] "Young-adult" TLUD research Re: List of woods for TLUDs?

[Paul Anderson]

To all,                   29 April 2017     [This note contains some new 
content and explanations for the advancement of TLUD stoves.]

1.  Ron:    I and probably some others have successfully used dung as 
the input fuel into TLUDs.    I am not recommending dung, but if it is 
being burned, then a TLUD is preferred for cleaner burning.

2.  AD:   I agree with Ron that the TLUD stoves are better with both 
light and hard (heavy) wood than direct burning of them in any 
direct-burning (ICS) stove.

3.  Main point, to Neil and all:   TLUDs are not burning wood 
directly.   TLUDs turn wood into gases.   THEN the gases are burned.   
So poplar, maple, maize cobs, dung, etc. are ALL becoming gases first.   
THEN the burning of those gases might be somewhat different (but not as 
much as the direct burning of those diverse fuels).

TLUD stoves are just arriving into their "young-adult stage."   In 
contrast:  not infancy, not childhood, maybe still "youth", but 
certainly not full maturity, and a long way from  the "old age" of the 
ICS "Inproved or Inadequate" direct-burning cookstoves.  This is because 
we are still learning about better and better ways of mixing the 
combustible gases with  the incoming secondary air (SA)  (This is where 
the BURNING takes place to make the heat that goes to the pot.  TLUDs 
are DIRECTLY burning GASES, not solid fuels. ) (Please see my 
"Classification of Stove Technology and Fuels" documents (1-page and 
4-page versions) at 
http://www.drtlud.com/2017/04/11/classification-stove-technologies-fuels/ )

The _solid _wood and dung etc are an intermediate stage of the fuel.   
Sort of a "storage" stage.  Then pyrolysis "transforms solids into gases 
plus charcoal".  The created gases are then burned SEPARATELY (by 
centimeters and seconds, but certainly separately) from where the gases 
were created.  We do not have clear terminology for this, in layman's 
terms.  The closest might be "gas burning stoves that make their own 
gases."

So, what development is happening in the early "young-adult" stage? 
Control of primary air, learning about solid "intermediate" fuels, and 
improving combustion of the gases, as well as "new clothes" with sizes 
and mateials.

Consider this:  We have known of FA (forced air or fan assisted) TLUD 
stoves from the 1990s.  And there has been much progress.  But NO TLUD 
on the market has SEPARATE controls for "variable flows" of primary air 
(PA) and secondary air (SA).   THAT control is what will make the 
difference regarding Neil's initial question that pointed to differences 
in the initial fuels (and therefore differences in the resultant gases 
and quantities of gases that are being burned.)

Note that TLUDs can be made with different flows of PA ans SA by 
changing the sizes and number of holes.  That is a form of "tuning" the 
TLUD for a specific fuel.   This works great for one initial fuel, but 
only good but acceptable with other fringe fuels.  I am NOT referring to 
that work as being "variable flows".   I am referring to when the user 
can change the flows, even during one batch of fuel.

There has been some researach (mostly unreported and set aside) on 
variable control of primary and secondary air, using fans.  I have 
experimented several times.  The "million-dollar-grants" have had 
laboratory equipment with controlled and measured separate air flows.  
Nathan Puffer did it when we were looking at Jatropha SEEDS as a fuel.  
Seeds give off additional gases from the vaporization (not pyrolysis) of 
combustible vegetable oils (carbohydrates), which are much more 
plentiful in seeds than in stems and branches and leaves, thereby 
overwhelming the insufficient supply of SA in a "regular" TLUD-FA.

There is a good reason to not have separate control of PA and SA. That 
reason is the user, the cook.  To need to "dial-in" the right flow of SA 
(assuming PA flow stays the same) is, for the most part and for most 
non-scientist cooks, an extra task that could easily be done 
incorrectly.  And there are the financial reasons of increased cost and 
maintenance.

But with "separate air-flow control" (not an established term and NOT 
justifying an acronym like SAC, as in TLUD-SAC), Neil or anyone could 
put many very different initial fuels into a TLUD and have greater 
control of the burning of the gases.

More work is needed before TLUD stoves can reach their full potential, 
while growing in "young-adulthood".  Today (2017), maybe 40% of what can 
be known about TLUD stoves is now known (but not necessarily put into 
practice by stove manufacturers).

(This note is being placed at the EPosts section of my website 
www.drtlud.com   so that it can  be accessed continually instead of only 
one time on the Stove Listserv.)

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype:   paultlud    Phone: +1-309-452-7072
Website:  www.drtlud.com


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20170429/032d44dd/attachment.html>