[Stoves] Questions on coal-burning possible TLUD

[Paul S. Anderson]

Crispin and all,

Good explanation and thanks for the photos.  Certainly seems like a  
reasonable heater and stove.

1.  I will distinguish the "Silver" stove based on it being a coal  
burner.  I have not spent much time regarding coal and  
micro-gasification.  John Davies opinion would be greatly appreciated.  
  I believe the Silver is substantially larger in diameter of fuel  
chamber than is John's.

2.  In what way would the Silver NOT be accomplishing what we all seek  
(especially Crispin) as a coal-burning heater/stove appropriate for  
Mongolia or even the High Veldt of South Africa where coal is  
abundant?  This is VERY important and I hope we can address it.

3.  This Silver stove needs further study, meaning access to the  
devices.  We want to see and know that the top-ignited fuel does  
create a migrating pyrolysis front (MPF for short, not as a name).Much  
more about its emissions needs to be promptly known and, if low, be  
recognized.

4.  Would this Silver unit function with dry biomass?  If not, why  
not.  If yes, then has it been done?  And if successful, why does it  
take until 2011 to recognize this, but NOT use it with wood anywhere?   
Have the 53 years of users been somehow missing such an observation?

5.  Who, what and where (Turkey) is the company that makes this  
device?  What is its price there (not the USA price)?

VERY interesting!!!   We should not drop this topic.

-- 
Paul S. Anderson, PhD
Known to some as:  Dr. TLUD    Doc    Professor
Phone (USA): 309-452-7072   SKYPE: paultlud   Email: psanders at ilstu.edu



Quoting Crispin Pemberton-Pigott <crispinpigott at gmail.com>:

> Dear Paul
>
> Thanks for picking up on the obvious implications, including the statements
> in Christa's recent publication.
>
> Your question and my statement are not on the same page, however: I said
> they have been making top-lit updraft stoves since 1958.  You are referring
> to TLUD "gasifiers" which are sometimes discussed as a completely different
> device, sometimes not. You also referred to TLUD with a link - I didn't
> check the link, I am providing the info I have. I think the design
> originates from an even earlier Russian stove.
>
> The company is called "Silver". Photos of one of their products are
> attached.
>
> All coal fires are gas fires. In some cases (fluidised beds) they operate in
> a manner that is clearly different from a batch-loaded stove, even if
> periodically refuelled. The stove I referred to is not a fluidised bed
> combustor. It is batch loaded and lighted on top.
>
> The Silver Stoves pyrolyse the fuel in a downward moving pyrolysis front
> de-volatilising the fuel until it is charred. It then continues to burn the
> char which in the case of coal has a name of its own: coke.
>
> I don't think there is anything all that unusual about this. It is a batch
> loaded stove that works as you describe.  So I am not propagating a rumour,
> I am reporting on an old product. They have something like a dozen models.
> The company is 53 years old.
>
> The stove consists primarily of a vertical round container with a controlled
> air supply at the bottom (a rotating 'flower' at the back), a grate at the
> bottom that can be dumped by rotation around a horizontal bar, and the
> ability to shake the grate axially to create air space for primary air to
> travel upward if it gets blocked (something missing from John Davies' TLUD
> packed bed gasifier).
>
> The operating method includes filling it, placing ignition fuel on top,
> igniting it, opening a top access hole (see photo) for air to get the fire
> going, then closing that hole to limit top air and to draw pyrolysing air
> through the fuel (using heat in the chimney instead of a fan), the charring
> of the fuel creates a combustible gas of volatiles at the top which burns
> into a heat exchanger then vents gases up the chimney. The switch from a
> 'coking mode' to a 'char burning mode' is by opening the bottom air supply
> following which the char is consumed. I didn't check to see if it is from
> the bottom up or the top down or the whole thing slowly at once.  It is
> purely a batch stove with a burn max of about 12 hours.
>
> The descending pyrolysis front dehydrates then devolatilises the fuel
> progressively, something clearly seen in a plot of the dilution of the
> combustion gases by water vapour. Bottom-lit stoves tend to dehydrate all
> the fuel at once (and make a great deal of smoke in the process).
> Batch-filled cross-draft stoves are just TLUD's on their side.
>
> So it sounds a great deal like a TLUD gasifier to me so I am modifying my
> statement to include 'gasifier' as the combustion type, as it is one.
> Perhaps you can point to a significant difference that would put this stove
> in a category of its own. It is basically larger version of the Davies
> packed bed gasifier made from cast iron with a pretty shell. It is pretty
> clean burning (see attached chart) though the CO can be reduced with a small
> change to the over-air supply.
>
> Incidentally the thermal efficiency is about 90% on a non-condensing mode.
> Quite an achievement.
>
> Regards
> Crispin
>
> ++++++++
>
> I respectfully request proper and adequate documentation to support your
> statement.
>>> There is a company in Turkey called SILVER that makes TLUD stoves and
>>> has been doing so since 1958.
>
> I found something that might relate, but certainly does not substantiate
> being TLUD combustion technology:
>
> http://www.alibaba.com/countrysearch/TR/solid-stove.html
>
> As the "unofficial self-appointed historian of all things TLUD", I state
> that data is needed not only of what those stoves are actually today, but
> what they were in the pre-1985 period.
>
> We will gladly acknowledge prior-art (so far, nothing before 1985), or truly
> independent development (as is the case with Paal Wendelbo's Peko Pe), but
> only when the evidence is in hand.
>
> We are all busy, and I do not expect a fully researched response
> immediately, so in the mean time let's not propagate rumors or incomplete
> analyses.
>
> Note:  The defining characteristic of the TLUD gasifiers is the "migrating
> pyrolysis front" (could be called the MPZ), and not the fact that some stove
> has upward moving air (most do) and the initial fire is at the top of the
> fuel pile (as could be done in many common stove devices, but with poor
> results on emissions).
>
> --
> Paul S. Anderson, PhD
> Known to some as:  Dr. TLUD    Doc    Professor
> Phone (USA): 309-452-7072   SKYPE: paultlud   Email: psanders at ilstu.edu
>
>
>> On Jan 18, 2011, at 7:03 PM, Crispin Pemberton-Pigott wrote:
>>
>>> There is a company in Turkey called SILVER that makes TLUD stoves
>>> and has been doing so since 1958. I am in fact reprocessing a test
>>> done in December on one of them, not the smallest version. It peaks
>>> three times at 24 kW during the burn. It behaves badly and needs
>>> better secondary air which I found easy to add. They it was really
>>> good.  I think they had never had a test done before, certainly not
>>> one with gases and PM.  Lots of potential with small modifications.
>>>
>>> So TLUD is not all that new I guess. It keeps getting rediscovered
>>> because it is a good system at least for some applications.
>
>



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