[Stoves] jatropa does not burn well for us ....but it probably has for others, somewhere

Thu Jan 20 16:27:15 CST 2011

Boston, 
I would toss this question out to the combustion experts on the stoves and biomass lists...here.

I have not tried it out but I know that others must have by now. The idea is to get behind the reason for poor combustion Crispin if I have him correctly implies that there is  no poor biomass fuel, only poor stoves...Thats one avenue which the stoves group is particularly good at. 

The larger question is: What is missing by this process: What is missing is the 90% of the rest of us in the inquiry. I'm referring to the faceless bystanders you see as CNN rushes to its big story in the so called developing world.  

People have been sorting undesired elements out of biomass for as long as we  have had fire-- probably before that: Indeed the fire must have excused lots of pre processing.   Bio-matter has been is washed/soaked/dried/winnowed/beaten/buried/ and blended for specific culinary or health applications for centuries...
That we notice one kind of biomass which burns badly and therefore has to be especially processed lest it not pass the test of our western  intellectual inquiry-- is not necessarily a definitive test of its potential suitability at all.  It merely reflects the fact that the "we" are probably in need of going  out amongst the rest of us to find out, the why, how and the what--- the rest of us  have been doing...  
It may be that no one has ever successfully burned jatropa...but, personally,  I would not bet on it.

If you like coffee, take a read of this example. The Inca's had perfected a simple method of soaking the roasted ground beans in cold water then draining off the liquid after a certain time period (~12 hrs) to  separate out the oil and acid from the real coffee "caffeol" element. The oil and acid remained bound to the roasted grounds,  while the pure coffee element nicely disburses into the water as a concentrate--for use with then Hot water or cold to make a really good cuppa java! Even the cheap sawdust the discount houses offer as coffee grounds will make a really good cup (Starbucks beware). 

The Incas may have evolved this procedure for coffeemaking, more out of necessity than for the inherent pursuit of the perfect cuppa joe,  because in the altiplano at least, they lived on- or above- tree line ~9,500 ft where fuelwood consumption for cooking is about 3 X greater than at the more common sea level to say 4000 ft  elevations. 

The result was however, that the resulting coffee came out with far less oil and acid with greatly reduced chance of the associated stomach and heart burn (which we try to mask with sugar and cream nowadays).  

The incas mastered  this process  several hundred years ago, well before the process was "discovered" by two young scientists from xyz university en el norte, as the  story goes, "working in their garage, etc., etc"... You can read about the new cold brew process at ( www.toddycafe.com ) but if you ever venture into a coffee shop in Cusco Peru, you may find small cups of concentrated liquid coffee made by the same process.  It was well established before I ever set foot in the altiplano of Peru,  ten years ago.   

Sure it has since been analysed, packaged and widely sold in the states now--we are very good at that part--but in all honesty it began far before we even set eyes upon the notion.. 

The point of this digression is this:  I have little doubt that if you were to venture out into the jatropa-using world (not just the development project world or institutional research world)  but the user-on-the-ground world, you will probably discover how somebody somewhere has figured out a way to process it as fuel...

The ideal is to do this and to frame your scientific investigations at the same time: to run the "field" investigation in parallel and collaboratively with the lab analysis. Then you get not only the best of both worlds as information and data sources: You form a link to-- and directly or indirectly- help to empower those who can not only benefit from  the results but who can become teachers of others for the future. 

Then publish it with all your collaborrants, for the rest of us. It  will be a great contribution ! 

Pressing on,

Richard Stanley
www.legacyfound.org 
Ashland Or. 

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On Jan 20, 2011, at 12:39 PM, Boston Nyer wrote:

> Hi Richard,
> 
> I have a related question to this discussion, which I think is interesting.
> 
> At CU, we have a Jatropha project that you fielded some questions about a few months ago.  As I'm sure you've heard, Jatropha seedcake does not burn well, not even close.  So, one of our questions now is:  what can we do with this waste stream this is both useful and desirable?
> 
> One approach we will test is to carbonize the material and for biochar briquettes (and a water filter media, etc.).  However, I wholeheartedly agree with your sentiment on biochar briquettes.  What is your opinion if the ag-waste doesn't burn well normally?  It still seems a bit contrived, eh?
> 
> I'm looking forward to hearing your perspective.
> 
> Cheers,
> Boston
> 
> 
> 
> 
> On Thu, Jan 13, 2011 at 2:13 PM, Richard Stanley <rstanley at legacyfound.org> wrote:
> Jessica, 
>  Me again, I answered some of these questions to you in a post directly to you (as that one  came directly from you) --a few minutes ago, but 
> let me add a few comments in reponse to your other questions here...( am responding in-kind below...)
> 
> On Jan 13, 2011, at 12:33 PM, Jessica De Clerck wrote:
> 
>> Hello,
>>  
>> I am looking for some insight into an array of issues around fuel briquettes and stoves.  I apologize for the long list!  I am hoping Crispin, Dr. TLUD, Richard and others can answer some of these.
>>  
>> Burning Stalks
>> At Stove Camp 2010, we used TLUDs to burn what I recall were maize stalks in Dr. Anderson’s TLUD. It worked great.  However, if maize or sugar cane stalks can be burned for fuel, why are people not already using this fuel in three stone fires, or are they?  I did not see this in Uganda, but I do not know about Haiti or elsewhere (where I will be working soon).  I understand that a TLUD or other stoves would do a better job of cleaning up emissions. -But if a person had access to free fuel in their fields, I would think they must have a good reason for not burning it, even in an open fire.
>>  
>> Does the fact that it burns quicker than wood deter people because it requires more effort to feed it constantly into the stove?  Or does it not burn as cleanly as wood?
>>  
>> Consumption Rate
>> Does burning fuel in a TLUD or other stove slow down the rate at which fuel burns as compared with fuel burned in an open fire?  It seems to me it would because the airflow into the fire would be more controlled in a stove.
>>  
>> Density
>> This also brings up the question of the density of a fuel briquette.  What difference does density make?  It seems like we pay a lot of attention to this, but to me it seems the only difference is that the less dense the briquette the quicker it will burn. Does a less dense briquette burn hotter (assuming identical material is used in each briquette)?
> It burns quicker but not necessarly hotter. Density is roughly equivalent to duration assuming same blend and stove . Greaster density also equates (ex any special starters) to harder start with above assumptions also in effect. You 'pays yer money and takes yer choice', eh ?  
> 
>>  
>> Briquette Stoves
>> I have recently built another RokStove or Holey Rocket –the side fed rocket stove for holey briquettes out of clay and sawdust.  I made it to the best specifications I could come up with after considering rocket stove principles, which was 9” long, 15” tall, and 5” in diameter both in the feeding area and combustion chamber. Once the stove has been fired, these dimensions will have shrunk approximately 10%.   This will leave a gap between the stove and my 4”x 2” holey (1” hole) briquettes.  I would like to know if anyone else has had experience in building or using these stoves so that we may share lessons learned.  I already speak with Rok and he’s a great help.
> Rok is  the guy for this. He speaks of the need to think a lot about internal hole size to regulate primary air volume and via my own insight gained through such Stoves group luminaries such as Crispin here, temperature...The annular space between the OD of the briquettes and the ID of the feed tube, is also important. 
> 
>>  
>> What other stoves have been tested and are recommended for burning holey briquettes?  I am assuming unless the hole is used as an air channel as in the RokStove, the hole in the briquette makes no difference (for example if the briquettes are just put in a pile, or used in a gasifier, because otherwise a briquette can be broken into pieces if too large).
> 
> Rite-e-o on that one, save the one fact that the hole greatly acceletates --and makes more consistent-- the drying rate. Add too, the effect of the hole in burning them up right, in the three stove open burn situation. ie., ex any stove surround structure. 
>>  
>> Green Charcoal vs. Uncarbonized Briquettes
>> Lastly, has anyone done a study of the emissions from making “green charcoal”?  I see what Amy Smith is doing with the kilns to make charcoal and the Adam Retort and there seems to be a ton of smoke coming off the kilns in the process of making the charcoal.  I understand it is an improvement from traditional charcoal making, but I wonder if anyone has measured the emissions so that I can compare it to other processes.
> Shhh. you are unveiling the big secret  of the carboniser school  here !!! We don't want to talk about the smoke and energy losses due to carbonisation..not as they occur in the user site and all conditions they live with...and after the techies have left and the ted talks and photo op's wither from our memories. 
> 
> But why carbonise at all if you have access to the charcoal crumbs and fines and dust found around every charcoal sellers stall everywhere in the third world...?  Thie waste accounts for between 15 and 20% of the lump charcoal being brought into the stall and sold through it...You blend that amount into the briquettes and you double the market for the seller or proportionately reduce their demand on charcoal while earning them the same income... but I'm being a bi facetious: It makes sence where there is no charcoal dust--I guess...
> 
>>  
>> Does anyone have recommendations on what raw materials ought to be burned in a retort vs. crushed and made into uncarbonized briquettes? I’m thinking coconut shells and other hard materials that cannot be crushed easily, but I would appreciate more input.
>>   
>> Thank you all for you time.
>>  
>> Jessica De Clerck 
>>  
>> 
>> 
>> 
>> 
>> 
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> -- 
> Boston Nyer
> Graduate Student
> Department of Civil, Environmental, and Architectural Engineering
> University of Colorado at Boulder
> (585) 503-3459
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