[Stoves] Jatropha and its future

Boston Nyer bostonnyer at gmail.com
Wed Aug 17 10:30:12 PDT 2011


Jan,

I also agree that it is not accurate to imply that the Hoffenheim folks
oppose these efforts to use Jatropha as a fuel (nor do I).  However,
*I*believe that we must act responsibly.  To the best of my knowledge,
nor they
or anyone else has tested the level of toxins in the emissions from any J
stove (if anyone knows otherwise, please share with us!).  We simply need to
do our due-diligence.  That said, I do not think it is responsible to simply
brush-off these concerns with parallels to toxins in wood.  You are not just
playing with your own life...

Anyways, that is just one opinion of many varying perspectives.

Thanks for the good conversation.
Boston



On Wed, Aug 17, 2011 at 10:19 AM, Jan Bianchi <janbianchi at comcast.net>wrote:

> ** ** ** ** **
>
> Dear ****Boston********
>
> ** **
>
> Thanks for your cite.  Professor Makkar’s studies have focused on how to
> detoxify jatropha seeds to make them edible for animals.  One of the
> projects that he and his colleagues are working on is the use of jatropha
> oil in cookstoves.
> http://ec.europa.eu/research/agriculture/pdf/events/4jatropha_en.pdf   I
> don’t think it would be accurate to imply that he opposes these efforts.
> ****
>
> ** **
>
> As an amateur woodworker, I am also well aware that wood is full of
> toxins.   See this list for a start.
> http://www.dave-wilcox.com/Woodturning/toxics.aspx.  I choose to build
> furniture nevertheless.****
>
> ** **
>
> Interestingly, both the curcin and the phorbol esters in jatropha seeds can
> have a tumor-inhibiting impact too. ****
>
> ** **
>
>
> http://www.academicjournals.org/ajpp/pdf/%20pdf2009/November/Balaji%20et%20al.pdf
> ****
>
> Phorbol****
>
> esters are co-carcinogens which themselves do not induce****
>
> tumors but promote tumor growth following exposure to a****
>
> subcarcinogenic dose of carcinogen [13]. Apart from the****
>
> co-carcinogenic activity, many phorbol esters (reported****
>
> from other plant source) also exert beneficial biological****
>
> effects without tumor promotion, such as prostratin [75].****
>
> Some naturally occurring phorbol esters are reported to be****
>
> tumor inhibitors [76] and Phorbol 12-tigliate 13-decanoate****
>
> has been shown to be active against the P 388 lymphocytic****
>
> leukemia in mice [77, 78].
> https://jatropha.uni-hohenheim.de/uploads/media/7--diterpene_review_02.pdf
> ****
>
> ** **
>
> ** **
>
> Just a reminder about how complicated this all is.  As with many things, it
> is a matter of degree.  None of these articles address either degree or how
> these properties may behave in smoke.  Therefore, the need to study this
> further.  You are absolutely correct that the testing needs to include smoke
> at all stages of the burn.****
>
> ** **
>
> Jan****
>
> ** **
>  ------------------------------
>
> *From:* stoves-bounces at lists.bioenergylists.org [mailto:
> stoves-bounces at lists.bioenergylists.org] *On Behalf Of *Boston Nyer
> *Sent:* Tuesday, August 16, 2011 10:53 PM
>
> *To:* **Discussion of biomass cooking stoves**
> *Subject:* Re: [Stoves] Jatropha and its future
> ****
>
> ** **
>
> FYI: In addition to being toxic when ingested (as previously discussed),
> some phorbol esters can activate tumors.  Although compounds may break down
> during the normal cycle of the stove, they may not when it is being lit.
> When testing the toxicity of emissions from J stoves, we must test at the
> various times during pyrolysis.  In my opinion we should be extremely
> cautious regarding the toxicity before promoting this stuff.  If you are
> interested in literature on the toxicity of Jatropha, Harrinder Makkar at
> the ****University** of **Hoffenheim**** has published a significant
> amount.
>
> ****Boston****
>
> ****
>
> On Tue, Aug 16, 2011 at 10:11 PM, Crispin Pemberton-Pigott <
> crispinpigott at gmail.com> wrote:****
>
> Dear Roger****
>
>  ****
>
> >I am curious if this "log" was an extruded or pressed product. ****
>
> It is a pressed/extruded log (same thing) using no binder save the lignin
> in the material. The diameter is about 110 mm and the length about 250/300mm
> – will check.****
>
> The colour is ‘pine’ so I would say, golden.****
>
> >…The moisture content is known to be about 8%. ****
>
> It varies with storage. The production process dries the wood almost
> completely (hot) and it picks up some moisture after that.****
>
> >It is approx 8500 btu/lb, ****
>
> That would be 8500 x 1055 x 2.2046 (lbs/kg) = 19.8 MJ per kg which is
> definitely a ‘dried’ energy content.****
>
> With 8% moisture it is about 17 MJ/kg for typical hardwood.****
>
> >…and gives a burn time of up to 12 hours (in our stove) ****
>
> It is important that you express this burn time together with a kW rating
> (or BTU if you can work that out instead).****
>
> A couple of contributors explained this before but here is a repeat:****
>
> 8500 BTU’s / lb in the 2.2 kg log.****
>
> That is 8500 x 1055 x 2.2 = 43,493,000 Joules total heat content (43.4 MJ)
> ****
>
> One Watt is 1 joule per second of energy.****
>
> 12 hours = 12 x 60 minutes x 60 seconds = 43,200 seconds.****
>
> 43,493,000 Joules / 43,200 seconds = 1007 Watts average heat output on a
> continuous basis. That is the same as saying ‘the power output is 1 kW’
> average.****
>
> >Funny thing is I get more smoke at a higher heat output than the medium
> to lower end. ****
>
> That has to do with the availability of secondary air and the combustion
> environment (including its physical size).****
>
> >Estimated [heat] output at 27,000 high, 5,000 btu low output. ****
>
> Per what? Per hour? Per day? It is not clear. 5000 BTU’s is 5.275 MJ. If
> that was per hour, it is 1.465 kW. The 27,000 = 7.9 kW. If it takes 12 hours
> to burn the log, (and in fact there is still some coals left) it averages 1
> kW heat output average.****
>
> An earlier point I was making about Mongolian space heating is that the
> homes need between 4 and 12 kW on a continuous basis. We would need to burn
> at about your ‘medium’ power level continuously to keep the place warm. The
> largest stoves we work with in homes are 20 kW, equivalent to about 1.3 kg
> of wood per hour (depending on the moisture content).****
>
> Any stove sold there has to be able to cook a 16 inch diameter wok, and to
> boil 9 litres of water (in the wok) in less than 1.5 hours from ignition (or
> it won’t be considered at all for the programme). Some stoves can boil it in
> 30 minutes, but 90 is the upper limit. Mass production facilities are
> available. It has to retail under $150.****
>
> Good luck with the EPA testing and alla that. Please keep us informed about
> how it goes.****
>
> Crispin****
>
>
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