[Stoves] Cleaning Dung

Sat Mar 17 20:21:07 CDT 2012

Sarbagya and list: 

I tried googling for your project and found something almost a year ago from Josh Wilkey on this list. I think we can help you a lot more if your team has produced a report. Since you are doing CFD, it would be helpful to know what you have been learning from that. Have you optimized anything yet? 

Since you are using the Servals unit and only getting 12 minutes at a time, it is obvious that you need to densify. - which presumably means pelletizing. Since you are intending operations in Nepal, and maybe rural Nepal, maybe you have discarded that option . But I would look 

You scare me when you use a sentence like this (from below - and similar was used by Josh): 
" So what could be the heat output from burning 1 kg. of dung." 
Are you truly "burning" - which I take to mean no char output? 
Can you give us some more ideas on what you have already learned from your experiments? Are you getting (or could you obtain) about 25% char yiel 
You asked below about energy content of the dung per kg. I think it must be about 15-18 MJ - depending on the ash content. 

I worry a great deal about "burning" dung. The whole point of making char is to improve the soil and maybe especially in Nepal. But Char from dung can be of extra value - as proven in numerous soil experiments. Is you team into the soil side of char at all? I hope that the word "burn" is a misnomer. 

You asked about the flame temperatures. This will be strongly dependent on the excess air you are getting. Can you supply any data on the weight of a fuel load that lasts 12 minutes? What is the volume of the fuel space and the shape (and density) of that fuel. I would think your own tests could supply temperature data - using thermocouples. 

I would look closely at the Georgia Tech computations of the last few days on this list and see if they might not answer some of your questions. 

For others - the Servals unit is a nice looking commercial TLUD unit from Chennai India, developed with Paul Anderson. See 
http://servalsgroup.blogspot.com/ 
and 
http://www.slideshare.net/bitmaxim/servals-tlud-biomass-stove-deck 
(and there are more) 

I have seen some technical data in these, but assume there must be a good bit more. Paul? 

Ron 

----- Original Message -----
From: "Sarbagya Tuladhar" <sarbagya007 at gmail.com> 
To: "Paul S. Anderson" <psanders at ilstu.edu> 
Cc: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org> 
Sent: Saturday, March 17, 2012 5:37:57 PM 
Subject: Re: [Stoves] Cleaning Dung 

Hi Paul, 
Dung burning using TLUD as a project had been conducted by the final year students of uni of Adelaide of which I was lucky to be a part of. This project was conducted under the EWB Australia humanitarian undergraduate project. Excellent work was done on this. I would very much try to incorporate their findings in my report. 

Cheers 

Sarbagya 

Sent from my iPhone 

On 18/03/2012, at 7:00 AM, "Paul S. Anderson" <psanders at ilstu.edu> wrote: 

> Sarbagya, 
> 
> I want to encourage your research on modelling cookstoves in Nepal. 
> 
> Please be aware of the Improved Cookstoves called TLUDs and the newest (and major) variation called TChar (TLUD top and Charcoal stove base). (TChar is described in 3 documents at www.drtlud.com and is the focal point of some stove initiatives in Uganda and Haiti.) Some studies of TLUD stove issues in Nepal have been conducted, with favorable results, but limited by lack of funding in the recent past. 
> 
> The TLUD stoves (including the TChar variation) can utilize dung briquette fuels very well. In India I successfully experimented with "dung tablets" that are easy to make in sizes such as rectangles that are 2 - 3 cm on each side and about 1.5 to 2.5 cm thick. 
> 
> I hope that your modelling will include the TLUD approach to using dung as fuel. 
> 
> Members of this Stoves Listserv would appreciate knowing more about you, your university, and objectives and methods. 
> 
> Doc 
> -- 
> Paul S. Anderson, PhD 
> Known to some as: Dr TLUD Doc Professor 
> Phone (USA): 309-452-7072 SKYPE: paultlud Email: psanders at ilstu.edu 
> www.gtz.de/de/dokumente/giz2011-en-micro-gasification.pdf (excellent ref.) 
> My website specific for TLUD information: www.drtlud.com = www.DrTLUD.com 
> 
> 
> Quoting SARBAGYA TULADHAR <sarbagya007 at gmail.com>: 
> 
>> Hi Stovers, 
>> 
>> I am undertaking my uni graduate project on the Use of CFD for the study of heat transfer and convection in a Dung Burning Cookstove. With this project, a heat transfer and convection analysis would be carried out using Computational Fluid Dynamics (CFD) for the optimization of dung burning cooktove that is currently being developed in Nepal. The analysis would involve simulation to predict the performance of the cookstove and would set up a benchmark for improved stove manufacturing in Nepal. This analysis would also assist in providing the experimental and the simulation results towards getting the stove certified as an ?Improved Cookstove?. 
>> 
>> However to simulate the dung burning I had to resort to using the fixed heat source instead as modeling combustion/pyrolysis of dung was beyond the scope of the project. So what could be the heat output from burning 1 kg. of dung. How mush heat would be released from this ? Is that the calorific value dung ? As I would be using a fixed temperature heat source, what could be that temperature ? 
>> 
>> Cheers 
>> 
>> Sarbagya Tuladhar 
>> 
>> On 13/02/2012, at 2:27 AM, Anand Karve wrote: 
>> 
>>> Dear Richard, 
>>> The undigested solid matter in the dung is in fact the lignocellulosic matter, However, in the case of ruminents, it is not in a fibrous form but in the form of particles due to the practice of chewing the cud. It is the dung of non-ruminents, like horses and elephants that has fibres. 
>>> Yours 
>>> A.D.Karve 
>>> 
>>> On Sat, Feb 11, 2012 at 11:30 PM, Richard Stanley <rstanley at legacyfound.org> wrote: 
>>> Ad, 
>>> 
>>> I don't personally think the solids would be of much value for a good briquette: What I would look for personally, is your lignocellulosic material, ( the more fibrous stuff) to encapsulate other more carbon rich salt free, materials sawdust charcoal crumbs/ dust, selected agro residues with aromatic-or non aromatic- considerations depending upon what kind of fuel aroma and duration of heat you desire. 
>>> 
>>> Richard Stanley 
>>> 
>>> 
>>> On Feb 10, 2012, at 9:36 PM, Anand Karve wrote: 
>>> 
>>> Cattle dung consists mainly of non-digestible lignocellulosic material, millions of micro-organisms, mucus produced by the animals and by the microbes, and some minerals. In fact it is the microbes and the mucus in the dung that yield biogas on anaerobic fermentation. A pressurised sieve, technically called a filter press, is the best device for separating the non-soluble solids from the fluids. If the fluids contained the microbes and the mucus, they should be subjected to anaerobic digestion before allowing them to be used as manure. Dung also has a very high ash content, because of which its calorific value is rather low. Dry dung has calorific value of about 3500 kcal/kg. Has anybody measured the calorific value of the solids in the dung, after removal of the fluids from it by using a filter press? 
>>> Yours 
>>> A.D.Karve 
>>> 
>>> On Sat, Feb 11, 2012 at 8:27 AM, Sarbagya Tuladhar <sarbagya007 at gmail.com> wrote: 
>>> Hi Boston 
>>> 
>>> 
>>> I volunteered with EWB Australia in Nepal working on a clean dung burning stove and thus worked with the dung as a fuel . Washing of the dung was done and briquettes which was a real success. Paper pulp used as a binder worked really well. Also the chloride contents of the dung which is responsible for watery eyes was removed on washing the dung which was proven by the copper wire test. We even fabricated a simple dung press for the same. The liquid portion of the dung was reutilised as manure in the fields. Thus the whole sceptism about "should" use dung as manure in the fields and not as a cooking fuel was somewhat solved. Did not test the NPK contents of the liquid portion though... 
>>> 
>>> Sarbagya 
>>> 
>>> Sent from my iPhone 
>>> 
>>> On 11/02/2012, at 2:06 AM, Boston Nyer <bostonnyer at gmail.com> wrote: 
>>> 
>>>> Hello, 
>>>> 
>>>> I'm looking to clean/rinse cow dung and do not have any experience doing so. Does anyone have any experience cleaning dung and would like to share? 
>>>> 
>>>> Thank you! 
>>>> Boston 
>>>> 
>>>> -- 
>>>> Boston 
>>>> Skype: BostonNyer 
>>>> Cell: (585) 503-3459 
>>>> www.burndesignlab.org 
> 
> 
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