[Stoves] Plastic in briquettes, and potential new stove brick design. (declassified ? )
Rok Oblak
rok.stoves at gmail.com
Mon Jul 14 02:33:46 CDT 2014
Hey all,
interesting sketches for the expandable stove, as Richard said, we did some
similar designs in Malawi, having 3,4 or 5-sided stove. Here is only a
version with 4 but you get the idea
http://holeyroket.files.wordpress.com/2009/07/img_62071.jpg
it was made out of clay, mixed with sawdust+ashes+sand and thrown in a
wooden mold
http://holeyroket.files.wordpress.com/2008/06/img_58971.jpg
later we found out its better to glue the walls together - for the
durability purposes
http://holeyroket.files.wordpress.com/2008/06/img_60181.jpg
I found the biggest issue was how to accomodate different pot-sizes to
provide a snug fit. Then again, the 5-sized stove didnt work so well with
briquettes as the briquette-stove fit needs to be well tought-through
depending on their size. In this case we had bigger briquettes (cca 16cm in
diameter), so 4-walled stove worked best
other issues i though about with this design:
- is the user the one that modifies the size or there are different 'fixed'
versions to buy (and the design serves just for economized manufacturing
purposes);
- static durability - is the stove strong enough to hold aggressive
nsima-mixing for instance;
- how to attach the modules together - chemically or phisically (in this
concept for mdula, we had different solutions, one being wrapping it with a
wire, than surrounding it with clay, where the walls serve as an insulator,
then 'gluing' it with clay while the modules are semi-dry. also wrapping
them with a metal cilinder (or any kind of recycled metal structure that
holds the parts together) as you also suggest there if i get it right
as for the plastics in briquettes - do you have any information what
temperature is needed to burn plastics in briquette-formation well? Would
be interesting to check out if the roket-stove model as Joshua developed
contributes to cleaner burning of plastics comparing to regular
briquette-burning in an open fire or other stoves like the jiko. my tests
showed significantly lower CO emissions for the elbow/roket construction
for briquettes with a hole, but i never tried to test burning plastics :)
good luck to all!
Rok Oblak
On Sat, Jul 12, 2014 at 11:57 PM, Richard Stanley <rstanley at legacyfound.org>
wrote:
>
> Paul,
>
> Thanks for the info about the use of PET plastics in briquettes and Kens
> and Robert briquette bricks
>
> We had an interesting discussion about four/ five years ago in this group
> about the use of plastics in briquettes: Kevin Chisolm and others had
> reported on the issue of combusting at least, polyethylene as a short
> chained hydrocarbon. Studies from Scame out o the UK and Sweden,
> concerning the wiso dom of burning it instead of burying it.
>
>
>
> Turns out that this type of plastic is relatively "clean burning" and it
> turns out to also be the main constituent in those ubiquitous whispy two
> to five (??) liter sized shopping bags. These bags comprise the majority
> of the very blight we see in all too many depressed economies globally.
> (They are sarcastically termed the national flower of many developing
> nations).
>
> As applied to low pressure, wet process of biomass briquetting, about
> one typical bag (weighing 6 to 8 grams (size wise it would hold two to
> three liters ) is abou all that can be used per one 130 gram briquette (
> 10cm Ø x 7cm height before one begins to encounter binding issues and
> drying problems. Thats fine though, because two and a half of such
> briquettes are required per the avdrage family member per day while the
> average family of 6 such average persons only consumes about two to four
> bags per day. Using them in briquettes would actually tend to clean up the
> neighborhood "for free".
>
> In using the bags however , one needs to really shred them into whispy
> shards ( with a mean Ø of ≤12mm (½") --with torn edges of stringy
> ganglia-like fibers.
>
> Anything more solid much less larger or in the case of chopped pet bottles
> more resistant to deformation, and they will tend to seariously block the
> migration of moisure out of the briquette in the drying process. I think
> taht in the case of utilising the PET bottle in said briquetting process at
> least, it would require chopping grinding them into ≤ 2.5mm (⅛') Ø
> granules --- much like the feedstock for plastic injection machines---and
> using them as a granular additive much like rice husks sawdust etc
> etc..before they could be found useful at least in the low pressure wet
> process. I can only speculate that if used in higher pressure briquetting
> operations, they may well melt and flow interstitally, thus acting as a
> very durable binder…
>
> I will be interested to read the study when you / Robert gain access to it.
>
> Re the adjustable briquettes for stove wall design, I would ask Rok Oblak
> to please comment on his earier design out of Malawi as well as Brian and
> Nancy Davis to comment on the evolution fo same for their COCI Nica stove
> as it is emerging rapidly in Nicaragua.
>
>
> Thanks again,
>
> Richard Stanley
> ----------
>
> On Jul 11, 2014, at 8:18 AM, Paul Anderson wrote:
>
> Stovers and briquette folks,
>
> I thank my infrequent correspondent Robert Haston for an exceptionally
> informative message that he allows me to share with all of you.
>
> Biggest news (to me) is about the study of the inclusion of plastics
> (including PET water bottles) into biomass fuel briquettes!! Link is
> given to a scientific study done in Greece. I hope our briquette and
> emissions gurus will be making comments.
>
> I ask Robert to please help find out from his Greek contacts about the
> testing of these briquettes in OTHER stoves. I hope that will include the
> TLUDs.
>
> See also the attached about making stove structures. Reminds me of the
> low density bricks by Ken Goyer and others that come together for a hexagon
> shape, but for only one size of stove. Robert's design is expandable.
> Robert, please revise with your suggestion of possible "lockable angles"
> (by having specific short straight segments instead of smooth curve on the
> ends.) I like it!!!!
>
> Robert, thanks again for providing this info. This could be discussed
> at Stove Camp starting 10 days from now.
>
> If replying to Robert, note that he probably does not subscribe to the
> Stoves Listserv, so be sure to include his email address in
> the recipients. "Haston, Robert E LTCOL USAF (US)"
> <robert.e.haston.mil at mail.mil> <robert.e.haston.mil at mail.mil>
>
> Paul
>
> Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
> Email: psanders at ilstu.edu
> Skype: paultlud Phone: +1-309-452-7072
> Website: www.drtlud.com
>
>
>
> -------- Original Message -------- Subject: Paper/biomass fuel, cooking
> fuel - terrorism link, potential new stove brick design. (UNCLASSIFIED) Date:
> Tue, 01 Jul 2014 17:58:40 +0000 From: Haston, Robert E LTCOL USAF (US)
> <robert.e.haston.mil at mail.mil> <robert.e.haston.mil at mail.mil> To:
> psanders at ilstu.edu <psanders at ilstu.edu> <psanders at ilstu.edu>
>
> Classification: UNCLASSIFIED
> Caveats: NONE
>
> Dear Dr. Anderson,
>
>
>
> You might remember me sending you an email about mixed plastic/biomass
> (i.e. waste from remote military bases) as cook stove fuel.
>
>
>
> Since then the university of Athens expanded on the ASU Biodesign’s meta
> study. They did burn tests that proved the concept.
>
>
>
> Converting Biomass and Waste Plastic to Solid Fuel Briquettes.
> http://www.hindawi.com/journals/jre/2013/360368/
>
>
>
> Once again I am deployed overseas (Djibouti Africa). The smoke from poorly
> operated waste incinerators/open burn pits (which always seem to get
> installed upwind) is the worst I have ever experienced.
>
>
>
> The latest twist here is this: Illegal Charcoal Trade Funding Somalia's
> Al-Shebab. http://allafrica.com/stories/201406261350.html You probably
> already know about the expanding deforestation due to the growing charcoal
> trade south of here.
>
>
>
> Miniaturizing the waste to fuel process seems reasonable once you get past
> misplaced fears of burning plastic. The process is straightforward: pick
> the cleanest plastics, combine them in the optimal ratio, and form them
> into briquettes or pellets designed specifically for “mini-incinerator
> stoves”. This sure looks cleaner than the “certified safe” burn pits on our
> bases. Instead of EPA standards, you only have to beat the emissions of an
> sheep dung fire.
>
>
>
> I guess the next step would be to work on designing and lab testing custom
> designed fuels for different stove types. Aside from the size and shape, I
> guess the only other factor is whether it would be best to incorporate the
> plastic in the pressing or to hot coat the briquettes/pellets afterward.
> This would increase their water resistance.
>
>
>
> Of course getting the military behind this would require some expert bona
> fides. This is a pretty good location to field something. Our hanger sits
> right next to the Army Civil Affairs Company. KBR just got another 53
> million dollars to run the camp. I am sure they are interested in ways to
> fix their waste stream problems and polish their tarnished reputation.
> Unlike Iraq or Afghanistan, this base is expanding.
>
>
>
> Also, I was thinking of making an expandable cook stove – like adding
> rocks to make a campfire bigger. I came up with a design for cove and bead
> bricks that you can strap together like barrel staves. The design (along
> with a matching pedestal brick) eliminates the need for mortar.
>
>
>
> I attached a simple sketch of a top-down view. It would probably have a
> base molded to accept the bricks. I figure you could add some features
> (bumps, tabs, pins, etc.) to lock the bricks at 45 and 60 degree angles. I
> am probably missing something, but it looks like an extremely useful design
> to me. It would sure be cool to see it adopted.
>
>
>
> Feel free to forward this to your cohorts.
>
>
>
> Thank you for your consideration and all your great work.
>
>
>
> Lt Col Robert Haston
>
> 303rd Expeditionary Rescue Squadron
>
> Camp Lemonier, Djibouti Africa
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> Classification: UNCLASSIFIED
> Caveats: NONE
>
>
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> 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/
>
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> 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/
>
>
>
--
*Rok Oblak, MAA Design*
rok.stoves at gmail.com
briquettestoves.com <http://www.holeyroket.com/>
Gregorciceva ulica 5
4224 Gorenja vas
Slovenia
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20140714/beadda04/attachment.html>
More information about the Stoves
mailing list