[Gasification] Gasification Air/Fuel Ratio

[Greg Manning]

Greetings Brennan and list members.

Brennan, some light on interpretation, page 24 I do not know the tables, but
the pages in the PDF document are in volume as a ratio. if it was mass, the
amount of air consumed would be astronomical.

Any gasifier (up/down or fluid) has a very small output, compared to the
same physical size equipment dealing only in combustion.

Gasifiers are NOT combustors, rather, they are thermally driven matter
reformers. One can substitute an external source of heat, in lue of the
small portion of combustion within a gasifier, and run the gasifier in this
mode, however, the amount of external heat needed to produce the reaction,
out weighs the result.

Air is needed for partial combustion, leaving a pipeable gas that can be
used "un-coupled" (loose coupled) from the gasifier (referring to close
coupled dual combustors, vs. gasifiers). after the initial combustion for
the required heat to drive the reaction, air is NOT required (or wanted) at
later stages of gasification (thermally driven chemical reduction).

Do NOT compare combustor levels of air needed, to gasifiers, this will
confuse even me.......(not that I know much, in the first place).

Your best answers would be to ask Mr. Tom Reed, as I believe they are his
articles in the first place.

Greg Manning,
Brandon, Manitoba, Canada



-----Original Message-----
From: gasification-bounces at listserv.repp.org
[mailto:gasification-bounces at listserv.repp.org]On Behalf Of Brennan R
Henderson
Sent: Tuesday, November 14, 2006 8:25 PM
To: gasification at listserv.repp.org
Subject: [Gasification] Gasification Air/Fuel Ratio


Dear Listers,

After a long break I am continuing construction on my conventional
updraft gasifier. I am getting close to trying it out but I have some
questions about
the air/fuel ratio.

On page 24 of the book "Handbook of Biomass Downdraft Gasifier Engine
Systems" on table 4-2 it states:"Air Ratio Required for Gasification:
2.38kg wood/kg air (lb/lb)" (Moisture and Ash Free Basis)

Then on this link: www.woodgas.com/EquivalenceRatioDiagram.pdf, it
states that an air/fuel ratio for conventional gasification should be
1.5/1 (Moisture and Ash Free Basis). With an equivalence ratio of .
25. In this instance, are they speaking in terms of mass?

I must be missing something here, If someone could point me in the
right direction that would be very helpful.

Also on page 32 of the book "Handbook of Biomass Downdraft Gasifier
Engine Systems" it states " The updraft gasifier throughput is
limited to about 10GJ/h-sq.m. (1MBTU/h-sq.ft.). When speaking about
hearth load,
are the authors refering to the energy of the wood that passes
through the
hearth in an hour or the gas that is produced in an hour?

Once again any information would be very helpful.

Thanks in advance,

Brennan Henderson













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