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

[Kevin Chisholm]

Dear Paul
----- Original Message ----- 
From: "Paul S. Anderson" <psanders at ilstu.edu>
To: "Discussion of biomass cooking stoves" <stoves at listserv.repp.org>; 
"Steve Taylor" <Steve at thetaylorfamily.org.uk>
Sent: Monday, November 06, 2006 10:39 PM
Subject: Re: [Stoves] Understanding "charcoal making" stoves. Was:energy 
lost in charcoal making and briquetting


>
> Quoting Steve Taylor <Steve at thetaylorfamily.org.uk>:
>
>> Kevin Chisholm wrote:
>>> I would suggest that the above definition is a good definition of a
>>> gasifier.
>>>
>>
>> Aha ! Agreement. Lets mark that one up then. Gasifier. Defined.
>
> Nice try, Steve and Kevin.  But agreement by 2 people does not constitute 
> an
> acceptable definition to be used by hundreds.   :-))

OK... If you dislike it, what would you propose as a definition of a 
"Gasifier"?
>
> There is some agreement that GENERALLY a stove is a device that gives 
> usable
> heat, but there are also furnaces and boilers and other things.  I like 
> the
> definition that Tom copied from the Stoves Internet site.

What would you propose as a definition of a "Stove" that would get more than 
"some" agreement?
>
> Now, about gasifiers.  Kevin wrote about "combustion" being the ending
> action of
> a stove before the heat goes to the pot.  Seems reasonable.
>
> And he also mentioned that there can be the creation of gases BEFORE the
> combustion,

More specifically, there MUST be gasification of wood before combustion. 
Recall that I made you an offer of a box of beer is you could burn wood 
without first gasifying it. :-)

> and that if there is not an associated combustion of the gases, it
> would be a gasifier.  But if those gases were combusted, it would be a
> stove.

Yes. (Or also a boiler, furnace, oven, kiln, etc)

Therefore, it follows that the "gasifier" (that specifically
> makes gases
> without associated secondary air for combustion) can be "INSIDE" or part 
> of a
> stove.  That means there can be "gasifier stoves" and "non-gasifier 
> stoves."

ALL wood stoves gasify wood. If the gasifying section is inside a stove, and 
the gases are burned, then it is no longer a "gasifier" but a "stove", in 
that it meets the posted definition of a "stove." Could you please give an 
example of a "non-gasifier stove" where wood is not gasified?
>
> Note that I wrote "gasifier" (that physical device that makes gases
> separately)
> and did not write "gasification" (the chemical processes necessary for all
> stoves to make heat from dry biomass).
>
> Therefore, if the gas-making component can be identified and operated
> separately
> from the combustion, then that could be called a "gasifier stove", with 
> the
> designation of "stove" indicating that the gases are combusted in a 
> context
> reasonably but directly associated with the gasifier.

I have suggested that if the device produces a fuel gas, it is a gasifier, 
but if there is the purposeful addition of secondary air is is a burner, and 
burners are not gasifiers.

Note that you and I seem to have relatively fixed positions on what is a 
"gasifier", what is a "stove" and if it is meaningful to use the term 
"gasifier stove." Only 3 other people have added comments to this thread, 
one expressing regrets, one expressing confusion about definitions to date 
not being helpful, and one expressing likely futility at the taxonomy 
exercise. :-) There are about 550 people on this list... perhaps the other 
545 could offer some suggestions?
>
> But if the gasification processes cannot be confined to some physical
> component
> of the whole device, then the whole device can be a "stove" but is not a
> "gasifier stove."

As suggested before, draw a box around the device in question: if a 
combustible gas comes out, then it is a gasifier, but if products of 
combustion come out, it is a stove.
>
> And that is the case of Crispin's Vesto.  It does (at least at certain 
> times)
> create gases that can be visually observed, but it does not allow the 
> separate
> control or containment of the gasification processes.   I believe that a
> correct
> clasification would be a "quasi-gasifier stove", related in processes
> but not in
> design to the quasi-gasifiers seen in China.  I believe that 
> "quasi-gasifier"
> devices have great merit and can indeed be better (lower emissions) than 
> the
> stoves with the "standard combustion" as seen in a match or a flaming 
> stick of
> wood.  (I did not attempt to compare the emissions of the quasi-gasifiers 
> and
> the various gasifiers.  Please change the Subject/thread if you want to 
> enter
> into that topic.)

Crispin's Award Winning Vesto Stove provides for the purposeful addition of 
secondary air, and gives off products of combustion. It is clearly a stove, 
and is termed a stove. I don't know anything about "quasi gasifiers" Could 
you please define or describe the difference between a "quasi-gasifier", a 
"real gasifier," and a stove?
>
> Kevin gave us a list of seven criteria that could be used to classify
> stoves.  I
> counter by saying that EACH of the seven can serve as one way to classify
> stoves.  But to combine them into some giant matrix does not constitute a
> meaningful classification, but does yield a complex "description" without
> classification.

I believe it was Steve who listed these seven features.
>
> Consider that JUST for the criteria of "heat creation" ("burning" or
> "combustion"??) we need some identifying "labels" that do not overlap
> too much.

> Note that I wrote "heat creation" and not "combustion" because converting 
> dry
> biomass to heat involves the creation of the gases and the oxidation 
> (commonly
> called combustion) of those gases.  It is not appropriate to use a word to
> define itself, especially if multiple components are involved, with ONE of
> those components having the same name as the full term that is being 
> defined.
>
You lost me there.

> In other words, it does make sense to call something a "gasifier stove" to
> distinguish it from other types of stoves.
>
Perhaps things will become clear when you describe a "non-gasifying" wood 
stove. Also, you win a box of beer for showing how to burn wood without 
first gasifying it. :-)

> I will need to be careful to always say "T-LUD gasifier stove" when
> referring to
> the Reed and Anderson and Philips devices.  They cook, they have a 
> gasifier
> component/stage, and they have top-lit updraft operation.

As noted previously, the gasifier descriptor in "T-LUD gasifier stove" is 
redundant, in that all wood stoves have a gasifier component.
>
> Concerning what started this whole discussion, namely the Karve and Larson
> charcoal makers, I accept to call them "T-LUD stoves" or even "T-LUD
> quasi-gasifier stoves" or "T-LUD not-gasifier stoves" or (probably best)
> "Karve-Larson charcoal making stoves".

Obviously, you are free to accept whatever you want to accept. For others to 
accept your opinion, it would be helpful if you provided criteria that would 
enable them to do their own evaluation fo similarities and differences.

Best wishes,

Kevin
>
> Paul
>