[Stoves] Jatropha and its future

Wed Aug 10 18:33:45 CDT 2011

Jan and list: 

Thanks for the detailed responses. I hope you can continue to supply good photos like those we have seen. Very helpful in figuring out how to make pyrolysis stoves move faster. I think the central secondary air post has a lot of promise. I believe a combination pot and stove combination could give high efficiency with where you are heading, since you already have a convective shield geometry. As said earlier, I think a control over primary air is important and will prove valuable in more than the shutdown operation 
The use of the full jatropha seed seems to be a good solution where rural folk need propety boundaries. In reading about jatropha, I see there are big gains to be made in seed production through proper pruning (same as for almonds) - so your stove system could have a bigger supply than now being planned for and can maybe get to more urban folk as well. 

Ron 

----- Original Message -----
From: "Jan Bianchi" <janbianchi at comcast.net> 
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org> 
Cc: rongretlarson at comcast.net 
Sent: Wednesday, August 10, 2011 2:14:47 PM 
Subject: RE: [Stoves] Jatropha and its future 

Ron 

Thank you for your questions about the Jiko Safi, the jatropha seed stove that Jet City StoveWorks is currently testing. I apologize for the delay in response, but I had to pass the questions on to our developers as I am not technically competent to answer all of them. 

Why use jatropha in the Jiko Safi? Why whole seed? 

Frankly, we got involved in developing a jatropha seed stove because it hadn’t been successfully done. Past efforts resulted in a very fast, smoky burn. Jonathan Otto, who has been working in East Africa with farmers engaged in jatropha production, knew about the past failures and jatropha’s abundance there and urged us to try. One of our developers, Dave Covert, is an emeritus research professor in Atmospheric Sciences from the University of Washington and the other, David Otto, is a contractor/ tinkerer extraordinaire in Seattle. They had not traditionally been “stovers,” but they are now. 

As you know, jatropha is a very common tropical and sub-tropical non-food plant with high energy content, available from Haiti to Bhutan to Indonesia. It can be easily cultivated as a hedge row and on land not suitable for other crops. In many areas of the world we have reached 'Peak Wood." Things will not change for the better as population expands. One estimate suggests less than 4% of the jatropha seed is harvested. We believe this largely unused rural energy source has potential as an alternative to tree burning stoves, both charcoal and wood. We believe that “there is no food security without fuel security” and jatropha can be a secure fuel. Our hope is to make the alternative stove available to the people who are now walking for hours past jatropha on their way to a diminishing supply of trees. We expect that eventually jatropha seed will also be available on the street corners in villages and urban areas just as the much more expensive charcoal and kerosene are now. 

In several places around the world, there are experiments going on with jatropha seed cake and rice hull blends where seed is purchased from the farmer then transported to a center with the electricity necessary to run three machines: an extractor that removes about 95% of the oil, a hammer mill processes the seed cake with the rice hulls and other ingredients, and a pelletizer to form the material in a way it can be burned. Finally the pellets are transported back to the farmer/cook. This approach to using jatropha could prove to work well in areas that have the machinery and the electricity. 

In the meantime, Jet City StoveWorks is focusing on a whole seed as a fuel for its simplicity, availability and very small carbon footprint as well as putting the farmer/ cook in charge of her fuel. It is a natural pellet stove. 

How did this stove come to have a central air duct, a chimney, no port adjustment equipment, the amount of secondary air holes etc.? 

We started with several specific goals: 

(1) The stove was specific to jatropha with its high energy content. Other seeds with high oil content may work: castor, croton and sunflower seeds come to mind, though some have competing uses. We will be testing them in time. 

(2) The stove must be direct, intuitive and simple to use, requiring only a demonstration of how to light a TLUD stove. 

(3) The stove will operate with natural draft: without fan if possible and without moving parts--the bane of all machines in developing areas. 

(4) The stove must be designed to have the lowest possible emissions and remove whatever pollution that is created away from the cook and her family. 

(5) The stove must be durable and long lasting. 

(6) The stove's truly important field test is its success in meeting the cook's needs as she prepares daily meals because only then will it be used. 

The stove evolved over the past twelve months to its current form. Starting with TLUD principles (e.g. seeking the correct balance of primary and secondary air, thank you Paul Anderson), we then made rough calculations of the energy captured in the seed and started building and modifying in a typical iterative process. Typical stove designs all had too much primary air and often a promising design would work well in some respect but not all. For example, we had one model that would boil water like crazy but the temperature just above the fuel was over 1100 C. When the central air duct was added in a week long testing at the wonderful facility at CREEC in Uganda, the opposing secondary air currents brought the turbulent flame down to a flat, reliable pattern. We are experimenting with an adjustment that allows the primary air to be shut off at the end of a burn to cut off the smoke that usually occurs at that point. We are currently doing pollution testing, advocate open source principles and so will be posting information at our new web site which is currently under construction. http//jetcitystoveworks.com 

The Jiko Safi is currently being manufactured by metal workers in Arusha, Tanzania, who we have assisted in the financing of the tools and jigs necessary to produce the stove within the tolerances required. That is the model we expect to use wherever we introduce the stove so there will be local economic development opportunities as well as someone available to repair the stove, if necessary. It is currently designed to be used only outside. We hope that kitchen testing will tell us whether it can be used indoors as long as the chimney is ventilated to the outside. 

The testing and manufacture is under being done with the assistance of the Department of Agriculture, Partnership for Development, JANI, (Jatropha Agriculture and Nutrition Initiative in Tanzania, and Pamoja, Inc. 

Thanks for your interest and questions. We welcome suggestions. 

Jan 

From: rongretlarson at comcast.net [mailto:rongretlarson at comcast.net] 
Sent: Monday, August 08, 2011 8:21 PM 
To: Discussion of biomass cooking stoves; Jan Bianchi 
Subject: Re: [Stoves] Jatropha and its future 

Jan and list 

This is to better understand your nice Jet City stove .(for non West Coast USA readers - that means Seattle - which has a lot of Biochar activity) 

1. How did you happen to center on Jatropha? Have you experimented both with whole seeds and the residue after pressing and how does stove operation differ? Have you tried anything like wood chips? 

2. I think the flame pattern in your stove is wonderful. As you say, very compact and obviously very turbulent - which must be desirable. I am pretty sure the idea of central secondary air has been mentioned n the past on this list as a possibility - but I don't recall ever seeing it in practice. Can you describe a bit how you came to the present dimensions ? 

3. I worry that you may now have too much secondary air - as the flame seems to only be holding near the bottom row or two. Have you any way of knowing what the dilution factor is? Tried operation with a smaller number of interior holes (just plugging some progressively)? 

4. The central "column" (maybe with a different height) looks like it might be able to hold a pot of the right size - since you would then already have the "convection shield" that gives considerable efficiency improvement. And you could retain the chimney height needed to get your desired air flow and power level. Ever been tried? 

5. I have felt that controlling primary air supply to be an important feature of pyrolysis stoves (TLUDs). It seems your bottom set of holes could receive a rotating or sliding (or up and down) plate to accomplish that. Has that ever been tried? (This being accomplished nicely with a blower in the "Paul Olivier design also being discussed today.) 

Best of luck with what you are doing. Nice work. 

Ron 

----- Original Message -----

From: "Jan Bianchi" <janbianchi at comcast.net> 
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org> 
Sent: Monday, August 8, 2011 9:56:48 AM 
Subject: Re: [Stoves] Jatropha and its future 

Roger 

That stove in the ETHOS pictures was a prototype version. The stove is now made from steel. 

Jan 

Sent from my iPhone 

On Aug 8, 2011, at 8:51 AM, Fireside Hearth < firesidehearthvashon at hotmail.com > wrote: 

Good morning.... 

I am curious about a couple of the pictures of the stove by Otto....do I see galvanized sheet metal used in area's of high heat? the text talks about 800deg C. (1472 f.) if there is galvanized materials in contact with these temps it is quite possible that galvanic poisoning could kill the operator. A friend of mine was welding inside a galvanized pipe (large culvert for water drainage) when his oxygen mask failed and a green colored gas entered his lungs causing him some of the most horrible pain and near death experience imaginable. The other question I have is the material thickness. It does not look like this will withstand these temperatures for long. What is the life expectancy of this unit when exposed to these temps. Does it make sense to build something a bit more stout and send less of them to the land fill as the "burn out" too quickly with these exposures. Not all ways can we value things simply on "cost per unit" but "cost to the environment" should be taken into account. After looking at the industrial area's of northern China it seems to me that it is the environment which is paying for our "cheap" flat screens. 

From: janbianchi at comcast.net 
Date: Mon, 8 Aug 2011 08:08:37 -0700 
To: stoves at lists.bioenergylists.org 
Subject: Re: [Stoves] Jatropha and its future 

Jet City StoveWorks is currently conducting kitchen tests of the jatropha seed stove Marc refers to in Tanzania. 

Jatropha grows wild throughout the tropics as well as recently as biodiesel crop there. Alternatively, and more productively, it can be grown as a hedge around land holdings so it need not displace land for food production. That produces enough seed to fuel the family cookstove for a year as well as have some left over to sell into the Jatropha market. It costs at least four times less than a comparable burn time for wood and six times less than charcoal. 

We are continuing CO and PM testing and hope to have our test results online by next month. We had a stove at Aprovecho's stove camp couple of weeks ago and will have one at Paul Anderson's TLUD camp in MA in August. 

Sent from my iPhone 

On Aug 8, 2011, at 2:10 AM, Marc Pare < mpare at gatech.edu > wrote: 

Crispin, re exisiting Jatropha stoves: 

There was this one at ETHOS this year by J. Otto and friends: 

http://www.vrac.iastate.edu/ethos/proceedings2011/OttoOttoCovert_JatrophaSeedCookingStoveDevelopmentPromotion.pdf 

and a quick picture of it running outside in Kirkland: 

http://smallredtile.tumblr.com/post/3246717546/marc-in-the-wild-there-were-many-arguments-about 

It burns whole seeds in a natural draft TLUD. Draft is augmented by an inner air pipe (lots of pictures of the assembly in the ETHOS presentation) 

Marc Paré 
B.S. Mechanical Engineering 
Georgia Institute of Technology | Université de Technologie de Compiègne 

my cv, etc. | http://notwandering.com 

On Mon, Aug 8, 2011 at 1:36 AM, Crispin Pemberton-Pigott < crispinpigott at gmail.com > wrote: 

Dear Friends 

I am not sure how many stove are being worked on as Jatropha seed or oil or cake burners, but my understanding was the main thrust was to put to use some of the leftovers from biofuel production, especially that was the focus in Tanzania. 

It seems those farmers who invested in Jatropha production lost about $65 per ha http://pubs.acs.org/doi/full/10.1021/es201943v so my question is whether or not there is much point in working on (perhaps) whole seed stoves. Perhaps if the J-oil industry suffers a quick death there will still be a meaningful supply of oily seed fuel that can be burned relatively easily with a decent performance and controllability. At least until they go back to sunflower which looks a lot more promising. 

Has anyone made a sunflower seed burning stove? The oil runs up to 49% on some varieties. 

Always looking for new ideas… 

Regards 

Crispin 

_______________________________________________ 
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://www.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://www.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://www.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://www.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://www.bioenergylists.org/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20110810/24905eff/attachment.html>