[Stoves] Spherical Cow Dung Balls for ND-TLUDs in Bangladesh

[Anderson, Paul]

Julien,     (and as a blind copy to Mahbul so that he might send a reply via you or me)

Very interesting.   You wrote:
>In India, the energy content of cow dung is higher than Bangladesh, because Indian cows eat plastic: http://www.karunasociety.org/the-plastic-cow-project

Where is the source of the energy content statement?   I assume that some plastic in very small pieces passes through the digestive tract of the cow.   But there is no mention in that linked article about plastic pieces being in the cow dung.   (Maybe in the 30+ minute video that I have not yet viewed?)

You also wrote that the spherical balls
>are made with 50% (w/w) cow dung and any chopped biomass.  Informal tests have been done using mustard husk, water hyacinth, rice husk, maize cobs, rice straw, tree leaves, sawdust.

On a weight to weight basis, I suspect some major variations.   Dung can be very wet or quite dried (but I do not expect the people to first dry it and then wet it to make the balls).   And some of the other ingredients are difficult to judge their weights, such as rice husk, straw, cobs, etc.   So I am probing here for more info about the actual “measurements” when making this dung-ball fuel.   Maybe some video clips or photos with comments about quantities could be provided.

1.  This dung fuel certainly does work for cooking with TLUD stoves.

2.  It is low-density (not mechanically pressed, not even by manual presses)

3.  It is by mixing biomass into dung, with corresponding variations of energy content (by final dried weight)
It is spherical by choice, not by requirement.

4.  Tablet shapes:  My work in India (about 2008) included such dung fuel that was mixed and laid out about 2-3 cm thick on flat sheets and while wet was scored (press-cut with a piece of metal like a license plate of a car) into approx. squares about 5 x 5 cm (plus or minus 2 cm).    Then sun dried, needing to be flipped over once to expose the underside.   The “tablet” shapes would stick together in groups of 3 to 8.   They would be broken apart into separate squares when placed into the TLUD stoves.

I call the tablet method to the attention of Mahbul and ask if that has been or could be tried by someone in his project.   The fuel is essentially the same, but the shape is different.  The issues are
A.  Amount of labor
B.  Appeal of spheres vs square with ragged edges
C.  Storage space, breakage,
D.  Cultural preferences and other factors.

Paul

Doc / Dr TLUD / Paul S. Anderson, PhD
Exec. Dir. of Juntos Energy Solutions NFP
Email:  psanders at ilstu.edu<mailto:psanders at ilstu.edu>       Skype:   paultlud
Phone:  Office: 309-452-7072    Mobile: 309-531-4434
Website:   www.drtlud.com<http://www.drtlud.com>

From: Stoves <stoves-bounces at lists.bioenergylists.org> On Behalf Of Julien Winter
Sent: Thursday, November 1, 2018 9:19 PM
To: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org>
Subject: [Stoves] Spherical Cow Dung Balls for ND-TLUDs in Bangladesh

Hello  Roberto et al.;

The spherical balls used in the Akha "Agriculture-Friendly Stove" (to use its full name) are made with 50% (w/w) cow dung and any chopped biomass.  Informal tests have been done using mustard husk, water hyacinth, rice husk, maize cobs, rice straw, tree leaves, sawdust.  I have seen a report from Pakistan were cow dung was 25% of a biomass brick.

Cow dung is quit high in ash.  Thirty-five percent ash is not uncommon, but it depends on what the cow has been eating.   In a ND-TLUD, the char yield can be as much as 50% of the original air dry mass of dung, because of the high ash content.  Mixing in biomass increase the energy content of the fuel.

In India, the energy content of cow dung is higher than Bangladesh, because Indian cows eat plastic: http://www.karunasociety.org/the-plastic-cow-project

Cow dung balls are being used in Bangladesh, because there is not enough fire wood to burn for cooking all year round.  Since ND-TLUDs require dense fuel, the cow dung balls augment the wood.

Bangladesh has two main seasons, a dry winter and a wet summer.  Rural people tend to burn sun-dried leaves and straw in the dry season, and conserve the wood for the wet season.

The Akha "Agriculture-Friendly Stove" burns about 35% less fuel than a traditional cookstove (that looks like a clay volcano, with a side port for stoking).  Any kind of compressed fuel will help to extend the use of the  "Agriculture-Friendly Stove"

We need to develop village-made compressed fuels in Bangladesh.  We have made balls with paper, but we are uncertain about the weather the ink dyes contain heavy metals.

Has anyone tried algae as a binder?

Baojun Yi, Qiaoxia Yuan, Hongliang Cao, Ming Wang, Wenjuan Niu, Shuiping Yan. 2018.  Combustion Characteristics of Densified Cattle Manure Briquette in an Isothermal Condition.  BioResources 13(2):3571-3584
can be downloaded from  http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_13_2_3571_Yi_Combustion_Characteristics_Densified_Cattle_Manure

Cheers,
Julien

--
Julien Winter
Cobourg, ON, CANADA
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