[Stoves] Comments about T-LUDs

[Jeff Davis]

Dear Kevin,

Good points! I’m sold on your definitions. But before I write the check
there is one issue that I’m struggling with: A gasifier has well defined
zones that our primary gas must pass through in an orderly fashion but
does an open-fire?

Jeff




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Kevin wrote:


Dear Paul

Thanks for the interesting comments on TLUD's...

To inquire further on one thought... "Is the J Stove a gasifier?"

In the past, effort was expended to define gasification and gasifiers, to
little avail. Biomass combustion is not possible without gasification. To
employ the terms "gasify", "gasifier". "gasification"  in connection with
"biomass combustion" is redundant, and therefore unnecessary.

The reality is that any stove is a gasifier stove, because they all employ a
process for conversion of a solid (or liquid) into a gas, so that combustion
is possible. A "wheeled automobile", a "winged aircraft", and a "gasifier
stove", would all seem to be in the same league. Are there any automobiles
that don't have wheels, aircraft that don't have wings, or stoves that are
not gasifiers?

In general, it appears that "gasifiers are devices that convert solids or
liquids into gases for consumption elsewhere." Clearly, Doug Williams
gasifiers are "gasifiers". One can ask the following questions about such a
gasifier:
" How is the gas going to be used? Is it going to be used for an engine, for
direct combustion, or as a feed to a chemical process?"
"How far will the gas be piped or ducted to the point of use?"

Similarly, an updraft gasifier producing a cold tarry gas suitable for
combustion in one or more burners is also a "gasifier". Since the gas is
very dirty, requiring extensive cleaning for engine use, and since it could
not be transported very far without plugging and maintenance problems, it is
clearly a different kind of gasifier. However, there is the clear and
distinct similarity that there is definitely a purposeful separation zone
where no combustion is taking place, and where combustion would be
detrimental to the intent of the device or system

On the other hand, it appears that stoves are devices that want to convert
the fuel into a gas, and complete the combustion process as quickly and
completely as possible.

Consider an open bonfire... it converts the fuel to a gas, and burns the
gases above the fuel bed. It could perhaps be defined as a "close coupled
gasifier combustion system." If a box was put around the bonfire, then it
could perhaps be called a "close coupled gasifier stove". However, the prime
purpose of both of these systems is immediate combustion, while true
gasifiers have remote gas utilization of the gas as their design intent.

The key differentiating issue between a "stove" and a "gasifier" would seem
to be: "Is the intent of the design to permit utilization of the gas at a
significant distance from the point of generation?"

If this is the key issue, then a "close coupled gasifier stove" is a stove
system, and not a gasifier system.

Does this hang together for you?

Best wishes,

Kevin


-- 
Jeff Davis

Some where 20 miles south of Lake Erie, USA