Hey Richard, Not sure why you feel my briquetting education has been neglected, since that kind of fuel is not mentioned in any of my postings; but I certainly subscribe to Dean's comment: we all have a lot to learn about such alternative fuels. I would add: and the stoves that burn them in a truly clean way. Which brings up the question: if a briquette or pellet is burned in an open charcoal brazier, do we have a clean energy source? To put in another way, there are no 'clean' or 'dirty' fuels; it's combination of fuel and stove that must be evaluated together for emissions and other performance parameters. My densified fuels question to Otto the Senior or anyone else who can enlighten me concerning the logic of pelletizing Jatropha presscake. If farmers grow their own energy-dense, uniform-sized fuel, i.e., whole Jatropha seed, why complicate matters by processing that ready-to-use fuel into another fuel? No matter how efficient the pelletizing process, it must require time and energy. Why not burn these seeds directly in a micro gasifier stove, such as our jiko safi? Let me try to head off some likely comments. I know that there are companies in many African and Asian countries engaged in commercial scale production of Jatropha (and other biofuel crops) for export of biodeisel. Land grabbing and other nefarious activities of some of these players are obscene, as once again the global north exploits tropical countries for cheap/free land and cheap labor to meet its own needs. Yes, those Jatropha oil export ventures produce presscake as a by-product which they pelletize and market for fuel. And yes, some smaller operations in a few countries like Uganda, are trying to make a go of producing Jatropha-based biofuels for local and regional energy markets. But for all the publicity, most of it appropriately negative, in the 'food vs. fuel' analysis, there's a lot more to Jatropha than current attempts to put the oil in European cars and jet engines. Far apart from all these recent commercial Jatropha ventures, many of which are unprofitable for reasons we can discuss another time if anyone's interested, are many millions of farmers in over 110 countries who use Jatropha as a living hedge and for medicianl uses. Seems it's grown in every frost-free area of the world. I've found it from Cuba -- it's native to the neo-tropics -- to Mali, which has thousands of kilometers of hedges, to Bhutan where villagers were obliged to pay a Jatropha tax to monks for lighting in floating wick lamps. My guess is that over 99% of all Jatropha seed fall to the ground and rot, unused. (One study in a district of Tanzania where Jatropha seed is a traded commodity found that only 6% of seed is harvested.) As we all search for renewable, sustainably harvested biomass to fuel our favorite stoves, can we afford to overlook seeds of this ubiquitous, multi-use species? The point of importuning my stove list colleagues on a fine Sunday morning is to interest other stove makers to look at Jatropha and other energy-rich seeds as a category of fuel worth consideration for new stove designs. We are modestly pleased with the performance of the jiko safi, but we also know that some of you with far deeper understanding of gasification and far more experience in stove design could produce a much better model. Anyone want to take up this challenge? Over to you, Jonathan
From: [email protected] Date: Sat, 19 Jan 2013 20:46:53 -0600 To: [email protected] Subject: Re: [Stoves] Jatropha fruit as fuel? Dear Ottos, Seems you both need training in briquettemaking . Jon you know where to go in nchi yeti but Otto, where are you based? Seriously, the blends you are finding smelly smokey etc suggests that you get in touch with any of hundreds of others who can train you. Richard Stanley Monte Rico, Guatemala Sent from my iPhone On Jan 19, 2013, at 18:10, Otto Formo <[email protected]> wrote: Josh and Jonathan (Otto), Yes, we are talking about the presscake of Jatropha and it was processed into pellets localy in Zambia, quite easily and with "simple" tools - (no waste of energy) We had the same experience as your colleagues using briquettes made out of ricehusks and sawdust. They even started to glow like charcoal early in the gasification process and produced smoky and smouldery combustion. Thast why we prefer to use pellets of best possible quality. I hope you are correct about the gasification of jatropha pellets will destroy the phorbol esters and other problematic compounds instead of emitting them. Iam a bit worried about the forced draft units, while they seems to blow some parts of the ash and gases into the open air or room. May be the char from Jatropha could have a pestecide effect as well? Otto Date: Sat, 19 Jan 2013 18:23:35 -0500 From: [email protected] To: [email protected] Subject: Re: [Stoves] Jatropha fruit as fuel? Otto - FYI jatropha presscake (the mealy material left over once oil has been pressed out of the seeds) can be directly pelletized without further processing. It's pretty easy to pelletize, even with a small, cheaper (e.g. benchtop) pellet press. The mealy presscake still contains some of the oil (think coffee grounds) and it pelletizes well without worry over moisture content or having to use a binder. The pellets burn in a TLUD similar to wood or other pellets, at least by visual observation and temperature recording. I have colleagues that have tried to make cooking briquettes with jatropha seedcake and had a very smoky, smouldery combustion. I believe there are concerns of some potentially toxic emissions (phorbol esters, other compounds?). I have not tested the emissions from TLUD charring jatropha pellets, but there was no visible smoke and the gasifier seemed to operate fine as it does with other types of pellets. It would be interesting to know if firing jatropha pellets in a TLUD destroys the phorbol esters and other problematic compounds instead of emitting them. I first tried to char un-pelletized jatropha seedcake in the TLUD - because it is mealy like coffee grounds no draft could get through and it was a total fail - lots of smoke poured out! This brought the fire department to our Colorado backyard during a fire ban. Whoops. Also FYI char made from TLUD jatropha pellets performed similar for herbicide uptake from simulated natural water as chars made in the same way from pine pellets, bagasse pellets, and bamboo pieces. Josh On Sat, Jan 19, 2013 at 12:29 PM, Jonathan Otto <[email protected]> wrote: Otto, Whole Jatropha seeds can be picked from hedges on-farm and used directly in our jiko safi gasification stove without any further effort (except maybe for some sun drying if harvested during a damp season) … the most decentralized, efficient sustainable fuel system I can imagine. Sure, urban jiko safi users will need to buy their fuel seeds, so a commercial system for transport and retail sale of seed will be needed eventually, likely mimicking some aspects of the charcoal trade. But it’s just whole, unprocessed seed. Concerning pelletized Jatropha fuel, I would like to understand the advantages you find in going through the costs and effort (including energy losses) of processing seeds to expel the oil, then probably milling the press cake and shells (?) to uniform size/texture, then extruding or otherwise forming the mixture into pellets, and finally distribute the fuel, some of which will go back to the same farmers that grew the Jatropha seed in the first place? I know there are technical advantages to gasification of uniform-sized pellets, but it seems to me that round or ovoid shaped seeds like Jatropha, castor (I know, more poisons!), shea or croton megalocarpus provide this same advantage, without going through the pelletization process. What am I missing? Otto, the minor P.S. It's too late for me to retire 'on time' From: [email protected] To: [email protected] Date: Sat, 19 Jan 2013 17:23:37 +0100 Subject: Re: [Stoves] Jatropha fruit as fuel? Jonathan, We have got some samples of pelletized jatropha shells and seeds from Zambia, after the oil has been extracted and we feel that is the way forward. We will update you on the progress, so you will be albe to retire "on time".................:) We are not so worried about PM in natural draft gasifiers, but thanks for the concern. Otto........................ From: [email protected] To: [email protected] Date: Sat, 19 Jan 2013 09:03:35 -0500 Subject: Re: [Stoves] Jatropha fruit as fuel? Otto- You 'would guess' wrong. 'We should be very careful advising people' about such unsupported conclusions. The challenges of gasifying oils found in seeds, notably the oils of Jatropha seed, in a cookstove are far different from working with most pellets formulations. I keenly look forward to news of your all-fuel stoves that will handle J seeds, and the results of your tests. I sincerely hope you develop this soon, so I can finally retire in peace. Oh, and when you do tests, please include particulates in your emissions testing, so we can finally end all this hand wringing about 'these types of fuel'. >From the cheeky other Otto, Jonathan From: [email protected] To: [email protected] Date: Fri, 18 Jan 2013 23:23:48 +0100 Subject: Re: [Stoves] Jatropha fruit as fuel? Dear stovers, I would guess that "any" gasifier will burn jatropha seeds or pellets cleanly and efficient, as long as the moisture content are less than 10%. We have in the pipeline to test a new design of natural draft gasifiers, using jatropha seeds and pellets, for emmissions and toxcic fumes. We should be very carefull adviceing people using these types of fuel, before it has been carefully tested by independent institutions. Have a nice weekend. Otto (not the famous one..........:) From: [email protected] To: [email protected] Date: Fri, 18 Jan 2013 10:19:11 -0500 Subject: Re: [Stoves] Jatropha fruit as fuel? Dear Jonathan I am interested in the general layout and dimensions of a stove that will burn the seeds well. Are you sharing at this time anything regarding the design? Thanks Crispin ++++++++ Dear Joyce and stovers all, My regrets for not responding to this request 6 months ago. I admit that it got lost in my messy inbox which I have now reduced from 6000 messages to a mere 2400, and in the process uncovered Joyce's email. Burning Jatropha seeds whole or in briquettes in open cooking arrangements is a bad idea. It produces a smoky, smelly fire and probably exposes cooks to toxic emissions. I even question burning Jatropha oil in lamps in enclosed areas for the same reason. Maybe others know of emissions studies. [snip] _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] 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 [email protected] 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 [email protected] 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 [email protected] 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 [email protected] 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/ -- Josh Kearns PhD Candidate, Environmental Engineering University of Colorado-Boulder Visiting Researcher, North Carolina State University Director of Science Aqueous Solutions www.aqsolutions.org Mobile: 720 989 3959 begin_of_the_skype_highlighting 720 989 3959 end_of_the_skype_highlighting Skype: joshkearns _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] 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 [email protected] 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 [email protected] 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/
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