[Stoves] (no subject)

Sun Jan 23 01:00:01 CST 2011

What is the composition of Jatropha seedcake? Probably traces of oil, 
how about water? A high ash content?
If no water and low ash, it might be the shape of the seedcake, too big, 
relatively little surface area per volume.

Just a thought.

Peter Verhaart

On 21/01/2011 06:39, 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 <mailto: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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