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

[Kevin Chisholm]

Dear Jeff
----- Original Message ----- 
From: "Jeff Davis" <jeff0124 at velocity.net>
To: "Discussion of biomass cooking stoves" <stoves at listserv.repp.org>
Sent: Saturday, November 04, 2006 10:18 PM
Subject: Re: [Stoves]Understanding "charcoal making" stoves. Was: energy 
lost in charcoal making and briquetting


> On Saturday 04 November 2006 12:45 pm, Paul S. Anderson wrote:
>> To Kevin: I flatly reject the idea that all stoves are gasifiers.  All
>> biomass burning stoves do involve the gasification processes to turn 
>> solid
>> wood into combustible gases, but the "gasifiers" are the stoves that
>> separate the gas creation from the gas combustion, AND have some control
>> over both creation and combustion.  The "Burn-barrel demo" and the
>> Karve-Larson charcoal
>> making stoves
>> do not have that control, and to call them "gasifiers" would diminish the
>> descriptive value of all gasifiers.
>
> I just don't know Paul. Kevin has a good point. Lets take a candle and 
> blow
> out the flame, next place a lit match next to the smoke and the candle
> relights. No gas no flame.
>
> Not sure about (pure) charcoal stove.
>
> Maybe Kevin talks of microcosm gasification and Paul talks of macrocosm
> gasification.

Exactly the opposite!! :-) If we consider the T-LUD as a "total package" or 
as a "macro system", and draw an envelope around the system, the outputs are 
heat, charcoal,  and products of combustion. These outputs are what one 
would expect from a charcoal making stove. One expects combustible gas as 
the output of a gasifier.

As I see it, at a microcosm level, all stoves are gasifiers, but at a 
macrocosm level, no stoves are gasifiers. The purposeful provision of 
secondary air to permit combustion of the pyrolysis gases shows that the 
T-LUD device is a stove.

>From Tom Reeds www.woodgas.com site, we see that he clearly calls his T-LUD 
system a stove. Not a gasifier, but a stove. Tom designs and builds both 
gasifiers and stoves, so if he calls the device a stove, and not a gasifier, 
then there is a very good basis for accepting it as a stove.

"Three billion people in the world cook slowly on smoky, inefficient 
woodfires. We have developed a novel "WoodGas CampStove" that we believe far 
exceeds the performance of any other biomass cooking device because it first 
turns the wood to gas, and then burns the gas with the correct amount of 
air. It puts out up to 3 KW of heat, comparable to the big element on an 
electric stove, it burns only 10 g of fuel/min (40% efficient), and it can 
be used indoors with minimal emissions. We hope similar designs will be used 
in developing countries where the need is greater, but we want to develop 
our product first in the U.S., so we have developed a company to 
manufacture, market and distribute the stove. "

It sure looks to me like this system is a stove and not a gasifier.

Best wishes,

Kevin
>