GAS-L: Biomass heats of combustion...

["Thomas Reed" <tombreed@home.com>]

Dear Arnt and all:

You said the heating value of bone dry wood is 18 MJ, but the HIGH heating
value is  22.21 MJ/kg (LHV 20.9) (average for most biomass, but varies +/-
2).  Trouble is you NEVER find bone dry wood, but it's easy to measure
moisture content and correct the heat values.  Typical here in Denver is 7%
moisture content.

There are major tables of these values in our book,

"Thermal Data for Natural and Synthetic Fuels", S. Gaur and T. Reed, Marcel
Dekker, 1998 and you can find tables at my site www.woodgas.com
both measured and predicted from the ultimate analysis.


         Dr. Thomas Reed
  The Biomass Energy Foundation
 1810 Smith Rd., Golden, CO 80401
303 278 0558; tombreed@home.com
----- Original Message -----
From: "Arnt Karlsen" <arnt@c2i.net>
To: <gasification@crest.org>
Sent: Sunday, August 12, 2001 8:36 PM
Subject: Re: GAS-L: Combustion Vs Gasification


> On Sun, 12 Aug 2001 17:44:49 -0500, Peter Singfield <snkm@btl.net> wrote
> in <3.0.32.20010812174243.00917740@wgs1.btl.net>:
>
> > At 11:07 PM 8/12/2001 +0100, you wrote:
> > >Heat value for bone dry wood is 18 MJ/kg. Vaporisation heat for water
is
> > >2.26 MJ/kg.  Where did the 20% come from?  18/2.26 yields that the
> > >theoretical moist level limit for combustion (gaining nothing in
exergy) is
> > >rather 800% (of dry weight).  Eight times as much water as wood? I
can't
> > >even imagine a piece of wood THAT wet.
> >
> > Yes -- I always mess up when it comes to counting wetness in terms that
can
> > be understood by all.
> >
> > "Whole" Green wood is slightly over half water -- half wood (55%).
> >
> > 20% as in 20% water and 80% wood per pound of whole wood.
> >
> > >
> > >Oh yes we have, several times. Fresh wood is no problem. Using fresh
> > >cucumbers or jellyfish would be difficult though.
> > >
> >
> > You know -- here in the tropics -- put up a tin shed and loosely stack
wood
> > -- dries to 20% in maybe one week or less when to sun shines.
> >
> > But talk about having 18 tons of biomass to dry every hour -- on the
fly --
> > is another problem. That takes one awful big tin roofed shed. Which --
by
> > the way -- only dries biomass when the sun shines. Not at night -- not
> > during heavy overcast -- and not during the rains.
> >
> > But now -- being as small is beautiful -- and I have two rabbit diesel
> > engines on the ground -- and would like to run one on wood gas to make
just
> > 3.4 kw power (the size of my present old Honda Genset -- converted to
run
>
> ..these I believe are designed for 10 kW to Dooms Day, and
> should do fine anywhere from your idle setting to ~25 kW.
> Above that, it time for supercharging and a few mean tricks.
>
> > on Butane gas -- which is very economic here in Belize) --
> >
> > Am prepared to mount a distributor (all Volks diesel have the "slot" in
> > place for the gas model distributer) and see no problem with adapting
the
> > injection hole for spark-plug.
>
> ..do.
>
> > Raising the head to lower compression is easy to -- as over head cam is
> > belt driven.
>
> ..shoot for a 13.5:1 compression ratio, lower it if you
> supercharge.  If you start grinding cams, try leaving
> the inlet open _long_, as in "way past half way up".
> Gives you a variable compression controlled by rpm and
> the inlet charge inertia.
>
> ..on my mums VW Beetle, 125 rpm idle, _prompt_omph_,
> about 100 kts (185km/h) rotation speed, (I caught it,
> gut told me _stomp_ the brake, as it started feeling
> like aquaplaning on dry asphalt,) and about 25 bikers
> tickets, (at 60 km/h I lifted my foot off, and let the
> green street light drag racing bikers catch up... and
> get caught... ;-) ...and a snapped drive shaft. :-( )
>
>
> > So --
> >
> > Should I run this on good charcoal only to avoid all the tar problems?
Or
> > make a copy of Arnt's gasifier in micro size and hope it does produce
tar
>
> ..after deciding and tweaking some, you may want to resize
> the gasifier's throat and nozzles a few times.
> A piece of 3-5' tall 12" dia 1" wall steel pipe should do
> fine for my gasifier proper shell, if you want to sneeze it.
> For preliminary sizing of the internal trim, chk Gengas or
> with me.  How much power etc., can/do/may/will you sell?
>
> ..when do you build this?  ;-)
>
> > free gas from 20% whole biomass? All that gas cleaning -- and
maintenance
> > of gas cleaners -- would so love to avoid it.
>
> ..I drew the hot gas thru a couple of barrels with about 10" of water
> in each.  Simply cool and filter the water, draining and adding more
> as needed.  Hot gas 2" piping enters each barrell tangentially, at
> the bottom of the side wall, "spinning" the bobbling water, and is
> drawn out of the barrel at the top center.  I used a cyclone inside
> the final bath exit.  An radiator the same size as the engine's
> radiator, and a water pump, and a water filter, valves, and a
> few transplarent hoses to show off color, "spin" rpm, pressures, temps,
> etc.
> A turbocharger can be also used to collect and condense water.
> Cat skin.
>
> > The advantage to charcoal is three birds with one stone. Moisture
> > conditioning, fuel size conditioning and less tars.
> >
> > Have on file the plans for that "Big-Top" -- great charcoal maker.
>
> ..url?  (as in "Did I miss this?")
>
> > And if I save the gas from that device during charcoal production -- the
> > volatiles -- can cook with it.
> >
> > The point being -- when going small -- easier to convert a motor laying
on
> > the ground than build a refrigerent cycle uniflow engine and boiler.
>
> .. ;-)
>
> > Peter in Belize
>
>
> --
> ..med vennlig hilsen = with Kind Regards from Arnt... ;-)
>
>   Scenarios always come in sets of three:
>   best case, worst case, and just in case.
>
>
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>
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> www.webpan.com/BEF
>
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> -
> Other Gasification Events and Information:
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> http://solstice.crest.org/renewables/biomass-info/
>


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

Gasification List Moderator:
Tom Reed, Biomass Energy Foundation,  Reedtb2@cs.com
www.webpan.com/BEF

Sponsor the Gasification List: http://www.crest.org/discuss3.html
-
Other Gasification Events and Information:
http://www.fsec.ucf.edu/bioam/
http://solstice.crest.org/renewables/biomass-info/gasref.shtml
http://solstice.crest.org/renewables/biomass-info/