RE: GAS-L: Gasification = mass burn incineration?

["Weststeijn, Andries" <Andries.Weststeijn@essent.nl>]

Fernando,

Are you differentiating between toxic concentrations (in the product gas or
flue gas) and absolute quantities released?

Generally speaking, I could imagine that the toxic concentrations in the
product gas from oxygen gasification are higher than in the (diluted) flue
gas from burning. But also, that there could be an advantage in removing the
toxic components from the smaller quantity of higher concentrated product
gas.
I can see a parallel with sulfur removal after coal gasification: i.e.
removal of a higher concentration of sulfur from a smaller volume of coal
gas, than removing that same amount of sulfur from a higher volume of flue
gas from coal burning (diluted with lots of nitrogen from the combustion
air).

Your message quotes one specific project which intends to gasify selected
"cellulosic material with recyclables and plastics removed". Sounds pretty
clean to me! That for this project absolute emissions from this selected
cellulosic fuel would be "equal or greater than mass burn incineration"
doesn't appear to be logical. 

It looks to me that the key of your question is in the specific gasification
fuels chosen by USEPA for comparison with general mass waste incineration. 
Also, clearly, the technological level of gas and flue gas cleaning
considered (or predicted) by USEPA for each route is of importance.  

I could imagine the following sequence of comparisons:
1) compare landfill with mass solid waste incineration (combustion)
2) select certain higher potential waste fuels from incineration
3) optimize specific emissions controls going with the dedicated
gasification of these selected fuels
3) compare emissions of gasification of selected waste fuels with mass solid
waste incineration (not landfill).

best,
Andries

-----Original Message-----
From: Berton, Fernando [mailto:FBerton@CIWMB.ca.gov]
Sent: Monday, April 29, 2002 11:18 PM
To: 'gasification@crest.org'
Subject: GAS-L: Gasification = mass burn incineration?


This statement was recently made in a letter to the California Integrated
Waste Management Board (CIWMB) and I would like opinions from experts as to
the veracity if this claim.  The CIWMB has been interested in using
gasification of solid waste as an alternative to landfilling and is aware of
one facility in Woolongong, Australia that is in shakedown mode.  There is
one project proponent in California that would gasify cellulosic material in
which all recyclables and plastics have been removed.  Given this particular
feedstock, is the following statement accurate.
"One analysis by the US EPA would appear to suggest toxic air emissions from
gasification of solid waste equal to or greater than mass burn
incineration."
Another question:  What is the difference between starved air combustion and
gasification/pyrolysis.  My sense of the latter is that it is in an
oxygen-depleted environment thus not allowing combustion.  I liken it to
baking a lasagna instead of barbecuing a steak.  Is that an accurate
metaphor?   


-
Gasification List Archives:
http://www.crest.org/discussion/gasification/200202/

Gasification List Moderator:
Tom Reed, Biomass Energy Foundation,  Reedtb2@cs.com
www.webpan.com/BEF
List-Post: <mailto:gasification@crest.org>
List-Help: <mailto:gasification-help@crest.org>
List-Unsubscribe: <mailto:gasification-unsubscribe@crest.org>
List-Subscribe: <mailto:gasification-subscribe@crest.org>

Sponsor the Gasification List: http://www.crest.org/discuss3.html
-
Other Gasification Events and Information:
http://www.bioenergy2002.org
http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon