[Stoves] Misuderstanding of TLUD stoves Re: Refuelable TLUD Coal Stove developed in Mongolia that is not a batch process.

Paal wendelbo paaw at online.no
Mon Mar 7 07:19:04 CST 2011 

Sorry, I can't partrisipate.
Regards Paal Wendelbo
----- Original Message ----- 
From: <kchisholm at ca.inter.net>
To: "Discussion of biomass cooking stoves" 
<stoves at lists.bioenergylists.org>; "Paul S. Anderson" <psanders at ilstu.edu>
Cc: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
Sent: Sunday, March 06, 2011 4:46 AM
Subject: Re: [Stoves] Misuderstanding of TLUD stoves Re: Refuelable TLUD 
Coal Stove developed in Mongolia that is not a batch process.


> Dear Paul and Ron
>
> Quoting "Paul S. Anderson" <psanders at ilstu.edu>:
>
>> see below
>>
>> Quoting Ron Larson <rongretlarson at comcast.net>:
>>
>>> Paul and ccs:
>>>
>>>   I had not realized that your Chip Furnace operated in the manner  you 
>>> describe below.  Am I correct then in assuming that the word  pyrolyzer 
>>> (which you didn't use) would be inapproproriate - and  that char 
>>> production is minimal?
>
> # I would propose for your consideration the following definitions:
> 1: PYROLYSIS is destructive distillation, yielding a pyrolysis gas,  and a 
> char. There are two basic methods for PYROLYSIS:
> a: The RETORT method, where additional energy required for pyrolysis  is 
> provided through the walls of the retort, and
> b: additional required thermal energy is provided by partial  combustion 
> of the pyrolysis gases and/or char through addition of air.
>
> 2: GASIFICATION is a process where a solid feedstock is substantially  all 
> converted to a gas.
>
> It would thus appear that a device that produces significant  quantities 
> of char, whether by accident or intent,  would be a  PYROLYZER and not a 
> GASIFIER.
>>
>> Char production is controlable by the operator.  With fast  throughput, 
>> we could extract chars with many volatiles and some  torrified fuel.
>
> It is my understanding that this would not be a controllable process. 
> Have you actually been able to produce charcoal AND torrified wood at  the 
> same time in teh same reactor, OR was the product a mixture of  char plus 
> partially charred wood?
>
>   With very slow throughput, it could output only
>> ash/minimal char.  The control also allows for use of different fuel  in 
>> the same device (but not at the same time).  Chip Energy furnaces  make 
>> char if (and how) you want it.
>
> # A FURNACE is NOT a "GASIFIER" or "PYROLYZER". A FURNACE is a device 
> whose intended purpose is the release of heat through combustion of a 
> fuel.
>>>
>>>   But also that much of your other writing is on char-making stoves  of 
>>> a batch type and that you would then not use the term "gasifier"?
>>
>> "Gasification" to the majority of readers includes making gases via 
>> pyrolysis and/or by char-gasification.
>
> # A PYROLYSER produces a fuel gas PLUS a char product. A GASIFIER is 
> intended to convert all, or substantially all, of the feedstock into a 
> fuel gas for subsequent use elsewhere. If you gasify char, then it is  a 
> gasifier. If you produce char, it is a pyrolyser.
>
>> A gasifier can pyrolyze.
>
> # True, but a GASIFIER does not have CHAR as a desirable end product.  A 
> device that has CHAR as a desirable end product is a PYROLYZER. It  stops 
> the pyrolysis at the char stage, and does not continue on to  gasify the 
> char.
>>>
>>>   I have not heard whether Nat Mulcahy demonstrated at the Ethos 
>>> meeting that he could add extra fuel at the end of a run - and that 
>>> TLUD was therefore Inappropriate for his design.
>>
>> Nat did not operate any of his stoves at ETHOS.  He did explain why  he 
>> does not consider his stoves to be TLUD technology.
>>>
>>>   I believe (perhaps like Crispin) that a BLDD could produce char -  and 
>>> could add extra fuel at the top - and hope that someone will  report on 
>>> that pair of desirable characteristics in a collating.
>
> # Definitely. A "Stratified Downdraft Gasifier" can be operated in a 
> manner where biomass can be added continuously and char can be  produced 
> continuously, and a fuel gas can be produced continuously.  There is a 
> requirement for continuous removal of char.
>>
>> Good luck.  I too await such a report, but that technology works  against 
>> the creation of char.
>
> # If the desired objective is char production, then it is basically a 
> PYROLYSER. If the desired production is a fuel gas, then it is  basically 
> a GASIFIER. If the desired production is HEAT, the it is a  FURNACE.
>
>
>  Meanwhile, I have a char-making device
>> in the form of the Chip Energy Biomass Furnace and (as of this past 
>> month) the Chip Energy "Dragon" (shoots out fire or combustible  gases to 
>> the user-provided destination/application - US$15,000 with  variable 
>> configurations.)
>
> # Does it burn gases to completion? What is the heat output rate? What 
> percentage of the energy in the input fuel shows up as heat, and what 
> percentage of the input fuel energy shows up in the char? Can the 
> "Combustible Gases" be piped elsewhere for use?
>
> Best wishes,
>
> Kevin
>>
>> -- 
>> Paul S. Anderson, PhD
>> Known to some as:  Dr. TLUD    Doc    Professor
>> Phone (USA): 309-452-7072   SKYPE: paultlud   Email: psanders at ilstu.edu
>>
>>
>>
>>
>>>
>>> Ron
>>>
>>>
>>>
>>> Sent from my iPad
>>>
>>> On Mar 3, 2011, at 12:30 PM, "Paul S. Anderson" <psanders at ilstu.edu> 
>>> wrote:
>>>
>>>> Quoting Crispin Pemberton-Pigott <crispinpigott at gmail.com>:
>>>>   snipped
>>>>>
>>>>> A TLUD is just a down draft built upside down. They can be  refuelled 
>>>>> continuously but if the desire is to get char out, that  could be a 
>>>>> problem.
>>>>>
>>>> This is a very common misunderstanding that was even promoted by  Tom 
>>>> Reed who initialy call it "inverted down draft" gasification.
>>>>
>>>> In a true downdraft gasifier, there is a hot zone that stays at  the 
>>>> bottom all the time, and the fuel moves downward to it,  becomes char 
>>>> and is later subjected to char gasification.  The air  flow is also 
>>>> downward.
>>>>
>>>> In a TLUD, the hot zone starts at the top, but then the hot  pyrolysis 
>>>> front migrates downward until reaching the bottom of the  fuel pile. 
>>>> That is FUNDAMENTALLY DIFFERENT from the downdraft  gasifiers.
>>>>
>>>> Furthermore, after the pyrolysis front reaches the bottom, the air 
>>>> flow still continues to be updraft.  Placing a significant amount  of 
>>>> fuel onto the top of the fuel bed can cause variations in the  gases 
>>>> created (initially much water vapor while the fuel is  drying, then the 
>>>> pyrolytic gases start later).
>>>>
>>>> Note:  In the case of the Chip Energy Biomass Furnace 
>>>> (www.chipenergy.com) which is a true updraft gasifier with  continuous 
>>>> operation (and the hot zone is at the bottom where the  air is 
>>>> entering), the new fuel enters in small amounts, avoiding  the problem 
>>>> mentioned in the above paragraph about water vapor.
>>>>
>>>> I hope this helps explain what is happening in the TLUDs
>>>>
>>>> Paul
>>>>
>>>>
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