[Stoves] Understanding "charcoal making" stoves. Was:energylost in charcoal making and briquetting

[Kevin Chisholm]

Dear Paul

Subject: Re: [Stoves] Understanding "charcoal making" stoves. Was:energylost 
in charcoal making and briquetting


> Greetings Kevin, Jeff, and All,
>
> I have read all the messages on the above Subject through to AJH's 
> definition of
> a stove.  I will reply mainly relating to one of Kevin's messages, but 
> first
> point out the the World War II gasifiers were not top-lit updraft units, 
> as
> implied in one other message.


>
> Quoting Kevin Chisholm <kchisholm at ca.inter.net>:
>> If [we] consider the T-LUD or the IDD "devices" as a total package, we 
>> see
>> the following:
>> 1: A gasifier section
>> 2: Purposeful features for the provision of secondary air with the intent 
>> of
>> permitting complete combustion.
>>
>> it is clear that the intention of the device as a total package is for it 
>> to
>> be a combustion device, or a stove.
>
> In many messages, people use short names.  If I say "a T-LUD device",

I used the the description "T-LUD "device" as a neutral way of referring to 
the "device", without labeling it as a "gasifier", a "gasifier stove", a 
"stove", or something else.

> do I need
> to say every time "a T-LUD gasifier stove"?

In my opinion, "gasifier" is redundant. All wood stoves are gasifiers.

>  And would simply saying "a T-LUD
> gasifier" imply that I only mean the creation of the gases and NOT the
> combustion of those gases?

In my opinion, yes. With my previously proposed definition of a "stove", 
combustion is intended, and there is the purposeful provision of secondary 
air to make it a stove. If you don't have full combustion, you don't have 
secondary air, and thus the device would indeed be a gasifier.

  Let's not split hairs about these names
> having been
> written in short or long form.

With all due respect, one has to be true, correct, accurate, simple, and 
clear with ones definitions for the definitions to convey the same meaning 
to all readers. In my opinion, the definitions of "stoves", "gasifiers" as 
used on these Lists are at the loosey goosey level. In my opinion, the 
definitions are at the level where they mean what the presenter wants them 
to mean, rather than having an absolute meaning.

  The expressions "T-LUD stove"

In my opinion, a "T-LUD Stove" is a device whose purpose is combustion of a 
fuel to produce heat, as for space heating or cooking. A "T-LUD Gasifier" is 
a device whose purpose is to produce a fuel gas, for use in some other 
device, such as a stove, an engine, a mantle lantern, etc.

or "T-LUD
> technology" do have (for the most part) an understood meaning as in the 
> Reed,
> Anderson, Philips devices cited in a previous message.  If you want to 
> refer to
> the "top-lit updraft" as an air and fuel arrangement, then please do NOT 
> use the
> acronym of T-LUD or TLUD or tlud.  Write it out the long way every time if 
> you
> wish.  Or make up your own special designator.  But please stop trying to
> destroy a meaningful designation.  (Please read on.)

In my opinion, "top lit up draft" is a description of the operation of a 
device that could be a stove or a gasifier, in the same way that "bottom lit 
down draft", "bottom lit up draft", "top lit down draft", "side lit cross 
draft" also all produce wood gas for subsequent use. Thus, the acronyms 
"T-LUD", "B-LDD", "B-LUD", "T-LDD", "S-LCD" are excellent generic terms for 
describing basic gasifier technology. All solid fuel utilization processes 
start with gasification, and such designators do not limit or confine the 
use of the gas produced to any particular end use.
>
>> If the "combustion zone", was removable, then it would be a "gasifier 
>> with
>> an optional  top burner." However, the top burner or combustion zone is 
>> not
>> removable; it is purposefully built into the system, so that it can 
>> function
>> as a device permitting complete combustion of pyrolysis gases.
>
> But the top burner IS separate from the gas creation part in some of the 
> T-LUDs.

In my opinion, if the top burner is an integral part of the device, with the 
intent to burn the gas, then it is operating in  "stove mode". Secondary air 
is essential for combustion, and in my opinion, a "litmus test" to 
distinguish between a stove or a gasifier is whether or not secondary air is 
purposefully provided, or allowed to contact, the wood gases.  If the same 
gasifier section is built with no provisions for secondary air, then it is a 
gasifier.

> Just look at the Juntos B (See the middle pages of my 2004 publication on 
> the
> Stoves Internet site.)

I found a paper at 
http://www.repp.org/discussiongroups/resources/stoves/Anderson/GasifierLAMNET.pdf 
Is this the paper to which you refer?

 In the Juntos B (and in almost all of my prototypes
> that are not shown), the fuel container is removeable.

Obviously, I cannot coment on prototypes that are not shown. The 
removability of the fuel container is not a determining factor in the 
definition of whether a device is a gasifier or a stove.

 Is that the "gasifier"
> part?

The "gasifier part" is where the primary air is reacted with the fuel to 
produce a gas.

 If so, than simply a tin can with holes in the bottom is what really
> constitutes the T-LUD technology?

Agreed.

 To me, a MEANINGFUL "gasifier" should be
> more than a container with smouldering biomass, even if the gases are able 
> to
> sustain a weak flame.

In my opinion, "smouldering biomass" would suggest a "charcoal producing 
gasifier."  There can be all degrees of success in a gasifier, from partial 
to complete, yet they are all gasifiers. A gasifier that produces a gas that 
is only able to sustain a weak flame suggests that there was too much pre 
combustion of the gas, as a result of excessive superficial velocity. Such a 
device would be a "poor gasifier", and also a "poor stove", in that it does 
both jobs poorly.
>
> With due respect, Dr. Karve and Dr. Larson have upward-moving air through
> biomass

This would therefore be an "Updraft" device."

> in a container that they ignite generally at the top,

This would therefore be a "Top-Lit" device.

> but they are not
> very worried about the flame dropping down to the bottom because there is 
> not
> much draft and they are mainly motivated to produce charcoal.  Their 
> physical
> devices are so different from the Reed, Anderson, Philips (and other) 
> devices
> that merit the specific distinction of T-LUD.

The only fundamental difference I see between the Dr. Karve and Dr. Larson 
(K&L) device and the Reed, Anderson, Philips (and others) (RAPO) devices is 
that the K&L device is natural draft, with low superficial velocity, while 
the RAPO device is forced draft, with high superfical velocity. Both are top 
lit up draft devices
>
> What is important is that TAKEN TOGETHER, the pieces of the T-LUD devices
> constitute meaningful stoves that can serve needy people.
>
> Gasification refers to a process.
>
> Gasifier refers to a device.
>
> Just because gases are created (as in a flaming or smoldering match stick) 
> does
> not qualify every such gas-making arrangement to be called a "gasifier."

In my opinion, if wood is gasified with secondary provided, or allowed, to 
access the wood gas, then teh device is a "combustion system". If secondary 
air is not provided, or purposefully excluded, then the device is a 
gasifier.

  At
> least not if you want to give any respect for the useful and functional
> gasifier devices that range from Doug's large units down to Reed's Woodgas
> Campstove.

Using the "litmus test", the absence of secondary air clearly definines 
Doug's devices as gasifiers, and Reed's Woodgas Camp Stove as a stove.
>
> Let's go one step further:  Under a cylinder, place some wood on a grate 
> and
> allow air to come in from the bottom.  Light the wood (Bottom-lit, not
> top-lit).  Let the flames go up the cylinder.  Would you call that a 
> bottom-lit
> up-draft gasifier, (meaning simply a traditional up-draft gasifier)?   I 
> think
> Kevin would.  And to be a stove, a pot could be supported above the flame.

Again, using the litmus test, if secondary air is provided, it is not a 
gasifier.
>
> Well, what is described above is the essence of a Rocket stove and several 
> other
> types of stoves.  And take away the cylinder, and it is a grated-3-stone 
> fire. I would not call such an arrangement "an up-draft gasifier."

Using the litmus test, we are able to come to agreement. :-) I wouldn't call 
a "grated three stone fire" an "up draft gasifier" because there is 
provision of secondary air.

  And I am sure
> that Larry Winearski would agree with me, (and Larry created the Rocket 
> stove
> after many years of work on traditional gasifier systems, so he knows the
> difference).

You can see clearly that he, and Tom Reed, call their systems "stoves", and 
they both have the addition of secondary air.
>
> People can debate until the cows come home as to whether any or all of 
> these
> arrangements are gasifiers or have gasification processes or are even 
> "stoves".

If you apply the "Stove or Gasifier Litmus Test", (SOGALIT :-) then this 
ends opinionated debate that is  not supported by science or fact. :-)

> I'll read the messages, but I have stoves to build and test.  Some good 
> things
> are coming soon, and they are clearly "Reed and Anderson style T-LUD 
> pyrolytic
> gasifier stoves."  Or should I call them "R&AST-LUDPGS" devices?  At least
> there is no confusion about what that means!!!!!

No problem with that at all, whatsoever! That is a descriptive way to tell 
people that the device is made by Reed and Anderson, it is top lit and burns 
the gas in a stove. This is important to distinguish your product from the 
products of others, who also use top lit up draft technology for their 
purposes and markets.
>
> (end with a smile)   :-))
>
Best wishes, indeed, in our search for truth, clarity, fact, and science, so 
that we can minimize opinion and eliminate debate. :-)

Kevin
>