[Gasification] close coupling, Paul Anderson

Mon Oct 9 15:15:25 CDT 2006

Paul,

  I ask a question when the subject of "clean" gas was recently brought to the gasification list but may not have stated it correctly.  My interest is not making gas for use in internal combustion or turbine direct firing, but creating a cleaner burn in a secondary burn catalyst and recovery of the energy in a boiler.  I hope to be efficient in infrared transfer because of the high delta t.. High temp combustion is desired without high flow.  

  The question that I have is; is it advantageous to uncouple gas production from secondary burn and clean it up?  Is condensing out non-combustion matter before a secondary high temp combustion going to lower emissions or acid condensation in the stack condenser?  I'm not a chemist but wonder if "clean" gas is better (and worth the effort) than "dirty" gas!  Please help me decide wether I am a clean or dirty gasifier enthusiast.

  Toby J. Seiler

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Today's Topics:

1. Comments about T-LUDs: Close combustion (Paul S. Anderson)

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Message: 1
Date: Sun, 08 Oct 2006 12:15:09 -0500
From: "Paul S. Anderson" 

Subject: [Gasification] Comments about T-LUDs: Close combustion
To: english at kingston.net, GASIFICATION - Listserve

Cc: stoves at listserv.repp.org
Message-ID: <20061008121509.jealbq22v40808gs at webmail2.ilstu.edu>
Content-Type: text/plain; charset=ISO-8859-1; format="flowed"

Alex,

Your comments to the Stoves Listserv are much appreciated and relate 
not just to
T-LUD gasifiers. Therefore, I am taking this Subject also to the Gasification
Listserv where it may or may not have gasification discussion. For the Stoves
Listserv, let's keep to the topic of T-LUDs, and leave the big-size gasifiers
to the Gasification Listserv discussion. (Please do not cross-post unless you
are sure that both lists would want your reply.)

Quoting Alex and Christine English :
>
> ... the latter senario [with combustion within two feet of the 
> creation of the gases] appears to yield significant reductions in 
> emissions,
> comparable to systems with greater and more destinct separation 
> between the zones
> of fuel and burnout.
>
> Ironicly, the makers of combustion "gasifiers" have suffered some 
> loss of business by
> being confused or associated with the poor record of many gasifiers 
> built for engine
> and turbine use.

At the risk of being too general in these statements below, Paul replies:

1. The closer the combustion to the gas creation, the emissions are cleaner.

2. The gasifiers for "combustion" (meaning thermal applications) should be
evaluated differently (and clearly identified) from the gasifiers for engine
and turbine use.

3. The gasifiers for engine and turbine use can, in general, be called CHP
systems, for Combined Heat and Power. But it is the quest for the P
(electrical or mechanical power) that dominates the CHP systems. The H (heat)
is a by-product (a very valuable by-product, but still very much in second
place to the P of power).

4. Because the CHP gasifiers (for engine and turbine use) must include
components that will cool the gases, the distance to the final usage of the
gases must be greater than is the case for the thermal-application 
gasifiers. Cooling implies risk of condensation of tarry materials, and 
therefore cleaning
becomes an essential issue. To avoid the cleaning, the "answer" is to create
the gases without any significant amounts of impurities. A few seem to have
accomplished this.

5. There is much gasification action in India currently. But I suspect that
the issue is to create installations (with much cleaning of the gases) and not
how to create gases that need minimal cleaning. See:
http://biopact.com/2006/09/biomass-gasification-systems-to-power.html
THIS topic is for GAS-L and not for Stoves Listserv.

6. For the Stovers, the T-LUD gasifiers are about as close-coupled as you can
get and still be a gasifier device. For low emissions (among the lowest ever
tested in small stoves), The T-LUDs show clearly that burning the tarry gases
well is one way to succeed.

Paul
-- 
Paul S. Anderson, Ph.D., Geography professor - Emeritus
Telephone: USA-309-452-7072 (residence and office)
Internet site: www.ilstu.edu/~psanders
For my gasifier stoves info, go to:
http://bioenergylists.org/contributors#Paul_Anderson

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End of Gasification Digest, Vol 4, Issue 7
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