GAS-L: Re: Gasifier terminology clarification

["Paul S. Anderson" <psanders@ilstu.edu>]

Stovers and Gasifiers

Tom's recent message did not go to the Stovers, so I have left it in the 
message below.

I have no problem understanding the term pyrolysis or pyrolyser or 
pyrolytic.  The problem come with the term "gasify" because it is so vague 
in general usage and (see below) used so specifically by 
professionals.  (see below)

At 01:17 AM 10/29/02 -0700, Tom Reed wrote:
>Dear Paul and aul:
>
>Concerning the choice of "pyrolyser" of "gasifier" or "pyrolytic gasifier":
>
>There are many kinds of gasifiers (>20,000 by my recent note).  ALL
>gasifiers (and combustors) by necessity include a pyrolytic stage as they go
>through the heating from 20-500C which releases volatiles and sometimes
>partially oxidized (to CH4, CO and H2) pyrolytic gases (in flaming
>pyrolysis).  Other gasifiers then (at higher temperatures) gasify the
>charcoal for a higher production of gas, less charcoal.
SOMEHOW, substitute a different word for "gasify" in the previous 
sentence.   OR give us a modifier (adjective) to refer to "XYZ gasify".   A 
generic word that means "to make into a gas" cannot also mean a SPECIFIC 
type of making into a gas.  Even "high temperature gasification" is inadequate.

It is better that the experts give us the defining terms (complete with 
adjectives or distinctive names for each "specific act of gasification") 
than to let the laypersons give those labels.

>So if we stop at the end of the flaming pyrolysis, Wendelbroe chooses to
>call it a pyrolyser. We are talking about the same reality.  These fine
>points are more than the average user can absorb, so  I choose to call it a
>gasifier.

I can accept it either way, with the understanding that if asked what kind 
of gasifier it is, we would need to say that it is a 
pyrolysis-gasifier   or a pyrolysis-based gasifier   or some other equally 
specific term.

Likewise, the big systems are also gasifiers, but if asked what kind of 
gasifier they are, then they are "full-system biomass-to-ash 
pyrolsysis-plus-XYZ reductive blah-blah-blah CO-generator 
gasifiers"  (shortened to be a "FSBTAPPXYZRBBBCG gasifier")   NOTE the 
humor intended, because this name is not user-friendly.

In other words, what do you call the type of gasification that occurs in 
the big gasifiers AFTER the pyrolysis process takes place?

Paul

>Only heavy duty steam reforming or oxidation can get rid of all tars, so all
>gasifiers produce some char, some tar and some gas.  Just a difference of
>proportions.  I suspect that the tars in our "inverted downdraft gasifiers"
>might be as high as 1% and I hope to measure them soon.
>
>~~~~~
>Sounds like Wendelbroe and company have lost interest, since I haven't heard
>since.  Please see if you can find Per S. Nielson at Danish Technical
>University and send him an Email.  I'm curious too.
>
>Onward,          TOM REED

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


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>