[Stoves] Fuel Testing

[Paul S. Anderson]

Stovers,

I just finished reading about 8 messages with great comments about fuel 
testing.
Observations are:

1.  Frank, please do not leave the Listserv.

Quoting AJH <list at sylva.icuklive.co.uk>:
> Mass of oven dry fuel minus ash times 18.6 gives
> the energy content for most biomass and subtract from this 2.7MJ/kg
> for every kg of water in the wood.

2.  If a kilo of wood has 10% moisture, then 0.27 MJ must be subtracted.
0.27/18.6 = 0.0145 = 1.45 %.  Seems like a mighty small amount.  Did I miss
something?

3.  Frank gave a detailed discussion on making measurements, that I think are
rather complex.  Instead, I have started doing something more simple.  Granted
that I have a clearly defined size of fuel container in the T-LUD units I am
using.  (The stove unit is provisionally called "Juntos B+" because it is a
slightly modified version of the "Juntos B" gasifier that is described in the
LAMNET article (Chile 2004), seen at Bioenergylist  website.)

     a.  Fuel chamber size is 10 cm diameter and 14 cm height of fuel.  Surface
area of 78.5 cm2.  times 14 = 1099.5 cm3.   Call it 1100 cm3 or 1.1 liters.

     b.  For each fuel sample (I have done only 2 so far, but expect to do
many), I obtain the weight of the fuel that fits into the fuel chamber and the
weight of the remaining char + ash after the pyrolysis phase has ended, giving
total used fuel weight:  sum of pyrolyzed material + whatever char was also
consumed during pyrolysis + water (moisture).  (Note:  I have not yet made any
measurements of moisture content, and I might only make estimates after I know
my fuels better.)

     (1).  Wood chips sundried:   200 g start - 28 g char+ash = 172 fuel used

     (2).  Fireballs (paper)(from Jeff):  170 g - 28 g = 142 g fuel used

    c.  Each test is conducted in identical conditions of 7 liter SS 
pot holding
5 liters of water.  Starting temperatures are recorded, and temps recorded at
intervals   0,  2.5 min,    5 min,   10 min,  15 min,  end time.

Both tests were conducted with about the same settings on the blower.  The
objective was consistent moderate flame, neither trying for high heat for
fast-boil nor for low heat for slow-simmer.  Such testing experiences 
will come
later, I'm sure.

The first tests were practice and will be repeated, so please do not be 
quoting
these numbers.  Both fuels raised the temperature of the 5 liters of water by
43 or 44 deg C., in 17 minutes for the woodchips and 14 minutes for the
fireballs.

I must say that I am quite impressed with the paper fireballs!!!  Credit for
those goes to Jeff!!!!

More results later, probably in an item for the Bioenergylist website plus a
note to the Stoves listserv.  Right now, constructive comments about this
method to test fuels would be appreciated.

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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