|
Dear Paul and All:
We are in a morass of terminology and ineveitably
we will each develop our own subset.
However, to me "Flaring" has two bad
connotations. The "flare" at a refinery is typically a visible waste of
energy that could be used for other purposes. In any case, it is a
diffusion flame, since no air has been mixed with it to make it a clean flame,
so it is filling the air with particulates and more.
In our WoodGas stove we have solved two
problems.
1) Making a combustible gas from
wood
2) Sufficient turbulent mixing of that
gas with air to maximize heating rate and minimize emissions.
So we call it a WoodGas CookStove and I hope to
post an invitation to those who would like to try it on my website this
month.
Your
pal,
TOM
REED
BEF STOVEWORKS
----- Original Message -----
Sent: Wednesday, June 26, 2002 1:58
PM
Subject: Re: GAS-L: Small Scale Gasifiers
Defined
Patrick and all,
Your explanation is excellent.
Because your message did not make it through to the "Stoves list serve", I am
including it below.
However, I must disagree with your
conclusion. You wrote:
Most lay people do not consider
this close coupled system a gasifier. Therefore while we could call it "Staged
Gasification" or a "Close Coupled Gasifier", we have elected to call it staged
combustion.
Except for one year on the Stoves list serve, I am
about as much of a "lay person" as can be found. I definitely want the
word "Gasifier" or "Gasification" into the title because the word "Combustion"
is where the confusion takes place. The word "combustion" is a lot like
the word "burn". Neither "combustion" nor "burn" assists the lay person
to appreciate what is happening when the process of gasification becomes
identifiably distinct from simple "burning."
Yes, I like your
explanation and I like the use of the word "staged" or the words
"close-coupled", (or perhaps "closely staged"). But we do need to be
sure that anyone reading about these small "combustion chambers" (the name I
use to avoid calling them "stoves" that implies cooking) realizes that
gasification occurs, and that is "closely coupled" or "staged" with whatever
happens next.
And herein lies the problem. What would you call
the "whatever happens next" when the gases are mixed with air and
"consumed."??? We cannot use the word "combustion" because it is
too vague. Patrick's full message (below) has a definition for
"combustion" that somehow is not the same as what happens to the gases
after they are produced.
I am just the interested lay person, so my
next suggestion might be useless: Could we call that "consuming of
the gases" to be considered as "flaring" (or perhaps "flaming")????
If
so, does that lead to the name of "combustion chamber for gasification
followed by close-coupled flaring"??? Or it could be a "gasifier
with close-coupled flaring" I think that captures what we
have been calling "small scale gasifiers". I suspect that there
are some large gasifiers what have close-coupled flaring.
Whatever happens about the final terminology, this discussion has been
helpful to me. It has also helped clarify the fairly wide gap between
those who do "big gasifiers" and those who do "small gasifiers" (meaning the
REALLY small ones.)
I look forward to future sharing of gasifier
knowledge with you all.
Paul
At 10:24 AM 6/26/02 -0700, Pat
Travis wrote:
Dear Tom and GAS-L
subscribers,
When defining or putting a
"label" onto a process such as gasification there are two distinct audiences
that must be considered from a commercial standpoint. The first is the
regulatory and technical community and the second is the general
public.
EPI uses 3 terms for our energy
systems. The first, "Combustion", is very straight forward and covers
projects utilizing standard fluidized bed combustors which generate heat for
process or power applications.
The second,
"Gasification", is used when we produce a low Btu gas (LBG) in an
oxygen deficient atmosphere and burn the LBG in a second piece of equipment
utilizing a specially designed LBG burner, such as a gas boiler, or by
injecting it directly into an existing coal fired boiler as a reburn gas. In
either case, the LBG is transferred to a separate piece of equipment for
combustion. This is done without cooling the LBG, therefore radiant losses
from transporting the LBG between the gasifier and the end use device is the
only energy loss. This type of two part process is easy for the public to
understand and the one I typically find associated with gasification. The
same definition applies to processes where the LBG or MBG is cooled prior to
use, such as in an engine or turbine.
The
third, "Staged Combustion", is used to describe what some people may
consider a close coupled gasifier. In this process we combine a fluidized
bed gasifier bottom with the upper section from a combustor. We generate LBG
in the lower portion of the vessel and when it reaches a specific elevation
above the gasifier section, combustion air (including dirty process exhaust
gases with a high VOC content) is injected and the LBG is ignited. This
provides energy for process applications and/or for power production. Most
lay people do not consider this close coupled system a gasifier. Therefore
while we could call it "Staged Gasification" or a "Close Coupled Gasifier",
we have elected to call it staged combustion.
I leave it to those better qualified than myself to set the legal
definitions.
Patrick
Travis Energy Products of Idaho
(EPI)
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 -
7/00
Rotary University Teacher Grantee to Mozambique >10 mo of
2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360;
FAX: 309-438-5310 E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
|
