[Stoves] Ph.D. Thesis on TLUD Stoves.

Alex English english at kingston.net
Sun Jun 30 20:35:14 CDT 2013 

What do you think the maximum service temperature of SS 304 is in a 
stove environment?

Alex

On 30/06/2013 9:22 PM, M. Nurhuda wrote:
> Paul and all,
>
> I agree with you. The char combustion is very dangerous to the plat
> material of burning chamber. My experiences, the combustion chamber will
> be damaged within 2-3 months if it is long exposed in a strong char
> combustion mode, even the plat material is SS 304.
>
> Moreover, to be wise is a better way to conserve nature. The soil has
> right to get biochar in term of combustion residue to maintain the soil
> fertility. This, not only good for soil, but also for CO2 reduction.
>
> Regards
> M. Nurhuda
>
>
>
>> Varun,
>>
>> You say that with the Oorja, 70% of the total energy is delivered in
>> flaming mode and 30% in char mode. But would this not apply to all TLUDs?
>> In my case, if I leave the fan on after the flaming mode is finished, a
>> char mode begins. As the char is combusted, the temperature within the
>> unit
>> climbs incredibly (dangerously) high.
>>
>> This leads me to ask: why consume the char? Why not stop the process when
>> the flaming mode comes to an end? There is an inefficiency that kicks in
>> when char is consumed, since this takes place at a considerable distance
>> from the pot.
>>
>> Thanks.
>> Paul Olivier
>>
>>
>>
>>
>> On Sun, Jun 30, 2013 at 8:28 AM, Varun ShivaKumar
>> <varun at cgpl.iisc.ernet.in>wrote:
>>
>>>   Dear Paul,
>>>
>>> Oorja is exactly TLUD. 70% of the total energy is delivered in flaming
>>> mode which involves migratory pyrolysis front (or flame front as
>>> discussed
>>> in chapter 5). Only 30% energy in the left over char is delivered in the
>>> char mode in the manner described by you. You are correct in saying that
>>> it
>>> is not TLUD in this char mode (in fact it is co-current in char mode as
>>> opposed to counter-current in flaming mode) . But in flaming mode it is
>>> exactly TLUD. I kindly request you to take this into account when you
>>> discuss this at Aprovecho.
>>>
>>> Varun
>>>   ------------------------------
>>> *From:* Stoves [stoves-bounces at lists.bioenergylists.org] on behalf of
>>> rongretlarson at comcast.net [rongretlarson at comcast.net]
>>> *Sent:* Sunday, June 30, 2013 3:17 AM
>>> *To:* Discussion of biomass cooking stoves; Paal Wendelbo
>>>
>>> *Subject:* Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>>>
>>>    Paal and list.
>>>
>>>       The thesis was inspired by the  Oorja, and helped to improve it,
>>> but
>>> the thesis itself is much more general.  The word "Oorja" rarely
>>> appears.
>>>
>>>      Does anyone know if there have been any Oorja test results reported
>>> by
>>> any of the major stove testing labs (Aprovecho, EPA, etc)?
>>>
>>>
>>> Ron
>>>
>>> ------------------------------
>>> *From: *"Paal Wendelbo" <paaw at online.no>
>>> *To: *"Discussion of biomass cooking stoves" <
>>> stoves at lists.bioenergylists.org>
>>> *Sent: *Saturday, June 29, 2013 1:18:21 PM
>>> *Subject: *Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>>>
>>>   Ron and Paul O
>>>
>>> Into the advertising leaflet of the Oorja stove is written “at end of
>>> flame very little aches is left” and I have tested the stove and can
>>> confirm it is right. I could see sparks up in the air above stove. The
>>> grid
>>> of cast iron 10 mm thick was white yellow about 900-1000ËšC and quite
>>> dangerous to handle to take out some few char left.
>>>
>>> With regards Paal W
>>>
>>>   *From:* rongretlarson at comcast.net
>>> *Sent:* Thursday, June 27, 2013 10:51 PM
>>> *To:* Discussion of biomass cooking
>>> stoves<stoves at lists.bioenergylists.org>
>>> *Subject:* Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>>>
>>>   Paul etal:
>>>
>>>      I should have added there are some good discussions of the same
>>> stove/cylinder (glass) with numerous types of fuels.  And he shows they
>>> obey the same laws - can predict performance (front velocity, power
>>> level
>>> (?)  - given the superficial velocty.)
>>>
>>> Ron
>>>
>>> ------------------------------
>>> *From: *rongretlarson at comcast.net
>>> *To: *"Paul Anderson" <psanders at ilstu.edu>
>>> *Cc: *"Discussion of biomass cooking stoves" <
>>> stoves at lists.bioenergylists.org>
>>> *Sent: *Thursday, June 27, 2013 2:44:07 PM
>>> *Subject: *Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>>>
>>> Paul:
>>>
>>>       I know very little on the Oorja stove.  But the thesis is mostly
>>> (entirely?) on a packed bed, top lit.  It is on the migratory pyrolytic
>>> front (MPF) - so should be applicable to all TLUDs.   I would like to
>>> hear
>>> from any/all on whether I am getting the right reading about NOT
>>> consuming
>>> the char.
>>>
>>> Ron
>>>
>>> ------------------------------
>>> *From: *"Paul Anderson" <psanders at ilstu.edu>
>>> *To: *"Discussion of biomass cooking stoves" <
>>> stoves at lists.bioenergylists.org>
>>> *Cc: *rongretlarson at comcast.net
>>> *Sent: *Thursday, June 27, 2013 2:12:57 PM
>>> *Subject: *Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>>>
>>> Ron,
>>>
>>> I am in Uganda now and have not had a chance to see the thesis.   Thank
>>> you for the comments.
>>>
>>> About #3, the Oorja stove is rather heavy for turning over, has a
>>> smallish
>>> fuel chamber meaning not much char and only short TLUD burns, and has a
>>> loose cast iron cup in the bottom that would fall out if the unit is
>>> tipped
>>> over to remove the char.   It is designed to NOT be tipped over for
>>> saving
>>> char.
>>>
>>> It is intentionally designed to have continuous burning with the fire in
>>> the bottom consuming char.   And when doing that, the Oorja is NOT
>>> operating in the TLUD mode which is specifically characterized by the
>>> migratory pyrolytic front (MPF), but the Oorja is not with MPF after the
>>> rather small initial load of fuel has been pyrolyzed.
>>>
>>> Therefore, the Oorja (and most others with forced air FA) essentially is
>>> NOT a TLUD because it is operated without the MPF except for the initial
>>> batch of fuel.
>>>
>>> I will be addressing this topic more at the Stove Camp at Aprovecho on
>>> 22
>>> - 26 July.
>>>
>>> Paul
>>>
>>> Paul S. Anderson, PhD  aka "Dr TLUD"
>>> Email:  psanders at ilstu.edu   Skype: paultlud  Phone: +1-309-452-7072
>>> Website:  www.drtlud.com
>>>
>>> On 6/27/2013 2:43 PM, rongretlarson at comcast.net wrote:
>>>
>>> Julien  and list
>>>
>>> 1.  Thanks very much for providing this cite.   I have read most and
>>> find
>>> it to be a well done thesis.   I wish we had more like it.
>>>
>>> 2.  The concepts of char and TLUDs are in here thoroughly.  But nothing
>>> on
>>> the idea of a stove designed to make char.  All char is presumed and
>>> desired to be consumed.
>>>
>>> 3.   My conclusion (would like to hear more) is that a good case is made
>>> (not intentionally) for NOT consuming the produced char in a TLUD  (this
>>> one fan-powered and widely sold in India as the "Oorja"  (started by
>>> BP)).
>>> Very little gain in overall efficiency as the char is consumed.
>>>
>>> 4.  A major advance was his study of the importance of ash in this
>>> "char"
>>> period as a poor radiator - thereby responsible for (undesired) high
>>> char
>>> temperatures.
>>>
>>> 5.   Most everything shown as a function of superficial velocity (Vs) -
>>> with 16-17 cm/sec shown as key dividing point in stove behavior..  Above
>>> which velocity one swtches from char production to char consumption.   I
>>> have not seen this before.
>>>
>>>      For his highly automated fan system, measuring Vs was apparently not
>>> so difficult.  Anyone able to give a way to get an easy estimate of Vs,
>>> when there is only natural draft?
>>>
>>> 6.  Quite a bit on the importance of low emissions of CO.
>>>
>>> 7.   Good information on both the experimental and computational side of
>>> top-lit (packed bed) stoves.  Not much here for rocket stoves.
>>>
>>> Have I got #3 right?
>>>
>>> Ron
>>>
>>>
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>>
>> --
>> Paul A. Olivier PhD
>> 26/5 Phu Dong Thien Vuong
>> Dalat
>> Vietnam
>>
>> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
>> Mobile: 090-694-1573 (in Vietnam)
>> Skype address: Xpolivier
>> http://www.esrla.com/
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