[Stoves] Calc. void space and pellet particle density
Frank Shields
frank at compostlab.com
Mon Mar 10 17:15:56 CDT 2014
Dear Ron,
The sand was needed in tests to determine void space around the particles
(in compost feedstock) to formulate the mix that permits air flow. Also in
erosion control berms to determine water flow.
Water is used in potting mixes and such to determine void space that holds
air IN (soaked) and AROUND the particles. The air for the plants.
I use acetone to determine particle density of small particles (less problem
with air) and to determine the skeleton particle density of chars. Heated
acetone will dissolve some tars and I can wash them out and add a new batch
and determine the skeleton particle density.
If the intent is to determine air flow I suggest sand. If you want to know
the air that is in the pile for combustion I think the water soak or acetone
soak to break apart the pellets.
My focus is now on Biochar and finding out what they can be used for and
quality determinations to help improve the making process. I am just
suggesting a method that might help others with a more focus on TLUD and
wood chip stoves. Like you Ron : ). I have more work than I can handle at
the moment.
At a past Stove Camp I left two glass BOD bottles for Dean's crew to
experiment with if they wanted. At that time I was trying to come up with an
easy method of determining the wood / char ratio on a mix of the leftovers
to calculate the WBT easier. My thinking was to determine the particle
density of wood and then char using acetone. Draw a line and plot the
findings of particle density of a ground sample that was left over. Further
experimenting here at the lab using known mixes I found it did not work well
enough. So it was back to the drawing board...
Regards
Frank
Frank Shields
Control Laboratories; Inc.
42 Hangar Way
Watsonville, CA 95076
(831) 724-5422 tel
(831) 724-3188 fax
frank at biocharlab.com
www.controllabs.com
From: Ronal W. Larson [mailto:rongretlarson at comcast.net]
Sent: Monday, March 10, 2014 1:58 PM
To: Discussion of biomass; Frank Shields
Subject: Re: [Stoves] Calc. void space and pellet particle density
Frank - see below:
On Mar 10, 2014, at 12:13 PM, Frank Shields <frank at compostlab.com> wrote:
Ron and all,
Seems a few years back there was a University (or some group) that was going
to assemble a collection of test methods for stoves? Was Tami involved? Did
anything come of that?
[RWL: Maybe there is a University that has been doing that, but I
would guess that Dean Still, of all on this list, would know best. Is a
consultant with GACC. I would also trust Jim Jetter of EPA, to know of
such. I don't.
Tami has an MS student, Ryan Thompson, doing tests on stove emissions,
but probably not on fuels or stove efficiencies.
More below.
See below:
From: Stoves [ <mailto:stoves-bounces at lists.bioenergylists.org>
mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Ronal W. Larson
Sent: Sunday, March 09, 2014 5:17 PM
To: Discussion of biomass
Subject: Re: [Stoves] Calc. void space and pellet particle density
Frank: (and anyone on list)
1. Would you be good enough to add a few more tests:
a. Measure (ml or gm) the amount of water (and/or acetone) you can add
to the container full of sand. (I see relative density of .785 for acetone)
[Frank >] I like acetone because water can have air bobbles when measuring
the density of grains of particles -like sand. So for particle density of
sand you fill a container with water to get volume. Then fill with acetone
to get the density of acetone. Then add sand and acetone together to get the
particle density.
[RWL: I like the idea of adding this as a standard test, but am also
asking you to repeat your earlier test with this use of sand and
water/acetone. Presumably the new weight will be 20-30% higher than with the
sand result you reported. I think that your method has not accounted for
the volume of air in either the sand or pellet case (no air volume of course
with water alone). Knowing this added sand/water and sand/acetone weight
results will, I think, decrease your reported void volume. Tightly packed
spheres get above 70% volume (air void space less than 30%). I think we
might get close to that with pellets.
I don't think I need the results with pellets and water or
acetone, but would be nice to have.
I think no issues with your other answers below, but the issue
with wax seems worth thinking more about.]
b. Same for sand replaced by pellets, even if the pellets are ruined
(but try to make the weight gain measurement as fast as possible (see how
much you can both add and drain). But perhaps they can be waterproofed with
only a gram or two of waxy material.
[Frank >] -Official tests for soil requires to coat with wax and use water.
Terrible - terrible. The wax leaks and add volume. The sand is better. The
sand changes in bulk density when shaken (a problem) but the item being
tested (wood chips, pellets, soil clod) do not change in particle size. So
my thinking is to decrease the sand / sample ratio as much as you can. That
is add the most pellets to the liter bottle as possible and get them to be
embedded into the sand.
c. Same when you mix sand and pellets (my preference is to start with
a liter of only pellets, then first see how much sand you can get in [by
shaking], weigh and then see how much water (and or acetone) can be added).
[Frank >] I do this for wood chips and suggest for large particles like the
cubes being talked about. Fill a container to the top to get bulk density
then pour in the sand with lots of tapping. Take out the wood pieces and
determine the reduction volume of the sand (= voids). But for smaller
particles I suggest embedding the particles in the sand to make sure there
are no big pockets of voids. If you keep tapping the sample will float to
the top. So for wood chips and sticks I add sand and chips together and make
sure there is plenty of sand on top. Then tap until I see the first sigh of
sample pocking through the top. Then I know the particles are all surrounded
with sand.
2. I agree with Andrew Heggie that a void space of 52% sounds high. Can
you specify the diameter of the pellets and an average pellet length.
Manufacturer? Any spec on source material?
[Frank >] This was a quickly conducted test using a real sample but without
all the QC usually done for the sole purpose of showing an example of how to
do the test.
3. If you have to start over, let's use a volume of "exactly" 1 liter
(water weight = 1 kg), for all cases (to simplify the computations).
[Frank >]
<http://www.novatech-usa.com/Products/Glass-BOD-Bottles>
http://www.novatech-usa.com/Products/Glass-BOD-Bottles
<http://www.hach.com/disposable-bod-bottles-300-ml-100-cs/product?id=7640237
102>
http://www.hach.com/disposable-bod-bottles-300-ml-100-cs/product?id=76402371
02
One liter volumetric flask is not easy to use for such tests. Nice to fill
to top and determine that volume. I like BOD bottles for using with acetone
or water for testing the particle density of very small particles. Eye
dropper removes the excess to exact. I use glass but they are expensive. The
disposable ones are made of a plastic and I will work for water but may
not(?) with acetone (or other solvents).
I use imhoff cones for wood chips and sticks. Add sticks or chips to a
couple inches from top. Pour in sand and tap, tap, tap until the chips poke
out of the surface. See total volume from marks on side. Pour out the sand
and collect. Dump wood. Pour back sand, tap, tap, tap and see volume of
voids.
<http://www.coleparmer.com/buy/product/56354-imhoff-settling-cone-plastic-ea
ch-w990800.html>
http://www.coleparmer.com/buy/product/56354-imhoff-settling-cone-plastic-eac
h-w990800.html
4. We should be able to get the same answer for pellet density regardless
of how hard we try to increase the bulk densities (Alex' point).
[Frank >] Pellet density but not necessarily pellet bulk density. Depends on
packing.
Thanks in advance.
Ron
On Mar 8, 2014, at 3:53 PM, Frank Shields < <mailto:frank at compostlab.com>
frank at compostlab.com> wrote:
1555.68
sand
1053.17
water (vol)
671.78
pellets
152.47
pellets used
1539.82
Pellets + Sand
0.637865
Bulk density Pellet
671.78/1053.17
1.47714
Sand bulk density
1555.68/1053.17
1387.35
Sand used when mixed with pellets
1539.8-152.47
168.33
Sand not used
1555.68-1387.35
113.9567
Vol sand not used
168.33/1.477
1.337965
pellet density
152.47/113.95
502.091
pellet vol in bottle
671.78/1.337965
551.079
void space
1053.17-502.091
52.32574
% voids
551.079/1053.17*100
Tare a glass narrow neck bottle
Fill with sand -weigh
Fill with pellets weigh
Fill with water - weigh (vol of glass jar)
Calc bulk density of sand and pellets
Weigh a handful of pellets
Add sand > sprinkle in pellets > add sand > sprinkle in pellets until all
pellets are in bottle and topped off with sand
Weigh sand + pellets mix
Calc sand in mix
Calc sand NOT in mix
Calc volume of sand NOT in mix using sand bulk density
Calc. particle density of pellets from wt hand full of pellets / volume of
sand not in mix.
Calc pellet volume in liter bottle when filled with pellets
Calc. void space in bottle left
Calc percent voids from void / total vol of liter bottle X 100
I fill with sand then tap twice on the counter then top off with sand.
This is a sample from a local US pellet source. The bulk density is 0.638
g/cc and the particle density of the pellets is 1.338 g/cc
Void space for air movement in a TLUD filled with these pellets is 52.3%
Instead of sand one can use water or acetone for other materials. The
particle density of sand (or like) I find best done using acetone.
Hope the calcs are correct. : )
Regards
Frank
Frank Shields
Control Laboratories; Inc.
42 Hangar Way
Watsonville, CA 95076
(831) 724-5422 tel
(831) 724-3188 fax
<mailto:frank at biocharlab.com> frank at biocharlab.com
<http://www.controllabs.com/> www.controllabs.com
From: Stoves [ <mailto:stoves-bounces at lists.bioenergylists.org>
mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Dean Still
Sent: Thursday, March 06, 2014 11:21 AM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] Cuber and size of densifying machines. (no longer Re:
The wood and char and fuel "debate" )
Hi Tom,
In Uganda the pellets were too dense and were hard to light. Do you know the
density of USA heating stove pellets?
Best,
Dean
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
<mailto:stoves at lists.bioenergylists.org> stoves at lists.bioenergylists.org
to UNSUBSCRIBE or Change your List Settings use the web page
<http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylist
s.org>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
for more Biomass Cooking Stoves, News and Information see our web site:
<http://stoves.bioenergylists.org/> http://stoves.bioenergylists.org/
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
<mailto:stoves at lists.bioenergylists.org> stoves at lists.bioenergylists.org
to UNSUBSCRIBE or Change your List Settings use the web page
<http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylist
s.org>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
for more Biomass Cooking Stoves, News and Information see our web site:
<http://stoves.bioenergylists.org/> http://stoves.bioenergylists.org/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20140310/4feceeeb/attachment.html>
More information about the Stoves
mailing list