[Gasification] The New New Fuel

[Greg Manning]

 Greetings Toby, Bob, and list members.

 Can I offer this one extra point ?


 Toby, while oak and yellow pine might have higher heating potential (mass
based), I do agree with your "field of hay" as well, but here's the point...

 The hay or lighter trees (willow, poplar, etc.) while less dense, also grow
4 times as fast, (grasses even faster). I would not want to promote a "Grab
all the hardwood first" mind set, simply from the regrowth time needed to
replenish the original source.

 while oak and such are great for testing, I think, I myself, will continue
my endeavors on fast growing sources, rather than denser ones.

 Greg Manning,
Canadian Gasifier Inc.

Brandon, Manitoba, Canada





-----Original Message-----
From: gasification-bounces at listserv.repp.org
[mailto:gasification-bounces at listserv.repp.org]On Behalf Of Toby Seiler
Sent: Saturday, November 10, 2007 7:49 AM
To: bobstuart at sasktel.net
Cc: gasification at listserv.repp.org
Subject: [Gasification] The New New Fuel


Bob,

  Go to http://vtwoodsmoke.org/pdf/Hill-79.pdf  and look at page 22.  The
values given are on a dry basis.  Compare a cord of oak to a cord of white
cedar.  Since the btu per pound is near the same (about 8,500-9,000 btu/lb),
the difference is in the water content of the fuel (that is removed).  A
cord of oak is twice the weight of a cord of cedar, thus cedar is carrying
more lbs water until it is dried.  I point this out because one has to
handle twice the volume of cedar to get equal heat value with oak.  And the
weight then of the water removed is correspondingly higher in the cedar,
placing a much greater load on any drying system for the cedar.

  Fuel moisture content is the single most important factor in pyrolysis.
But since woods are harvested in the nearly saturated state (about 80%
m.c.), there is a lot of water that must be dealt with.  I see no reason to
think that grasses or hay would be any different.  This then seems to make a
case for growing the highest density woods so less water will be handled.
It seems unrealistic to intentionally ignore the water content, because of
the significant burden in drying it.

  But then the issue of growth rate comes into account.  I don't have those
numbers at hand but will be looking for them.  Growth rates in your location
are based on the availability of sun, water and nutrients.  Some high water
content woods may grow more biomass (even after drying).  In my example,
Osage orange is the highest density wood that I know grows in North America,
thus less handling of water would occur in the harvest for energy.  If the
drying of a fuel is natural or air dried, these differences are less of a
factor, but if one is using energy from the system, drying of less dense
fuel will rob the energy away from productive uses (because the volume of
water to be gotten rid of, is greater).

  Note the difference in yellow pine and white pine.  Yellow pine has nearly
twice the btu in a dry cord than white pine.  Is this a case for growing
yellow pine over white pine?  The answer would appear to be in the growth
rates and water removal system, including handling.

  This then comes back to my point that a planned approach to fuel growth
will take into account both growth rates and the amount of water that must
be removed.  Just because a fuels annual growth appears high, the net heat
gain should take into account the method of drying and that less dense woody
plants will require twice or more volume (handling) to achieve the same heat
output.

  As for your area, look to the density of woods, hay, etc and determine
what weight is water.  If you purchase the material "wet", extract the cost
to dry it and look at the "net" energy gain.  My belief is that the denser
woody plants are a better feedstock unless your well equipped for solar
drying (giving field dried hay an advantage if it does not get rewetted).

  Sincerely,  Toby Seiler




 __________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
_______________________________________________
Gasification mailing list
Gasification at listserv.repp.org
http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org
http://gasifiers.bioenergylists.org
http://info.bioenergylists.org

No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.503 / Virus Database: 269.15.33/1133 - Release Date: 11/15/2007
8:57 PM

No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.503 / Virus Database: 269.15.33/1133 - Release Date: 11/15/2007
8:57 PM