[Stoves] Correcting a misconception that approaches myth status

Dean Still deankstill at gmail.com
Tue Dec 16 15:00:22 CST 2014


Dear Paul and Crispin,

My hope is that someone will do the experiments to detail how the work with
TLUDs, etc has resulted in progress and publish the results in a peer
reviewed journal. It might take a while but it's a job worth doing. Maybe
find an interested student or professor to instruct?

Best,

Dean

On Tue, Dec 16, 2014 at 7:42 AM, Paul Anderson <psanders at ilstu.edu> wrote:
>
>  Stovers,
>
> This is about Crispin's story and showing slow progress, but it is
> progress.
>
> On 12/16/2014 12:51 AM, Crispin Pemberton-Pigott wrote:
>
>
>
> There are dozens of ways to make a stove work improperly. Paul and I have
> tried all of them, I think. Paul told me that a TLUD fuelled with wood
> could not be refuelled. We were on the back patio of my home in Ezulwini
> Valley in Swaziland and he went off to do something, leaving a small TLUD
> can-stove running,. I fed in some wood vertically and it worked just fine.
> I continued to do so and it continued to run long after it should have gone
> out. Thus I proved to myself (and Paul) that TLUD’s can be refuelled but
> not too much at a time. OK, that was valuable and contradicted received
> wisdom.
>
> His story is correct.   I remember it well (now that I have been
> reminded).   But it also tells us something about the progression of our
> science.
>
> Back then, the importance of the MPF (Migratory Pyrolytic Front) had not
> been realized.   What Crispin did then in 2002 was what BP-Oorja, Biolite
> and Philips and others did years later.   They were all trickle feeding
> additional fuel into the TLUD well above the pyrolytic zone.   Heat from
> below was (and still is, if you do it) sufficient to pyrolyze the new fuel
> by heat WITHOUT the small flames of the pyrolytic front at that fuel.   The
> char can be fine, but probably a little different (not made at the higher
> temperatures of the MPF).
>
> And when the MPF reached the bottom, and with new fuel placed on top of
> the char (not into the hot zone), the unit switched over to operating with
> Bottom Burning (BB) as a rather normal UpDraft gasifier.   And that leads
> to higher temperatures in the bottom (air coming onto charcoal) and the
> need for the different materials (cast iron, ceramics, special metals) to
> protect that hot zone.
>
> As I have written in "Micro-gasification Terminology: An Instructional
> Summary of MG", available at my website.   See:
> http://www.drtlud.com/wp-content/uploads/2013/11/micro-gasification-terminology-14nov2013.pdf
>
>
> Therefore, there are actually two types of TLUD (device name) gasifiers,
> one being TLUD-MPF and the other being TLUD-BB. The two types are quite
> distinctive in operation, and deserve separate recognition and study. The
> common usage of the “TLUD” name today means more than the TL of “Top-Lit”
> can signify. ...... snip ...  In essence, TLUD is a name for the small
> updraft gasifier processes/stoves and is not a description of what process
> (MPF or BB) is actually happening. However, we expect that in common usage,
> the TLUD name will designate TLUD-MPF, unless the UD-BB mode is specified.
>
> However, many people continue to ignore the transition from MPF to BB.
> Back in 2002 I had no clue about this.   Now I consider it essential
> knowledge for understanding the variations within micro-gasification
> technology.   (Note that I wrote "micro-gasification technology" and not
> "TLUD technology.")
>
> I repeat:
>
> However, we expect that in common usage, the TLUD name will designate
> TLUD-MPF, unless the UD-BB mode is specified.
>
> Of course I can only suggest and request.   People will do what they want
> to do, sometimes unfortunately.
>
> 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
>
>
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