Hello David >Dear list experts, > >I note a good deal of information in the list about using Jatropha (J. >curcas) for biodiesel, and, mindful of repeated admonitions, I've looked >for information about the questions I have in the archives, but I've not >yet seen answers directly to my questions. My own background is in >biogas, and I have only recently started learning about biodiesel and >ethanol, so I'm an admixture of knowing and novice. May I ask a few >questions?
But of course. >(And Kieth, no doubt there are many gems in the archives >which of which you know, yet which I missed. Please feel free to educate >me regarding their nature and location.) I keep finding surprises there. There are 74,000 messages, 498.4 Mb of it, and that's in a compressed format, it's at least 500 books' worth. >I've been contacted about a project in south Asia which would involve >planting 600 ha to Jatropha, to produce 3,500 tonnes of biodiesel >annually. (Based on what I've seen about Jatropha, that may be >optimistic for yield, but I'm just presenting the information as given >to me.) > >Obviously then that also means either the use of a good deal of methanol >(as presently planned), or (as I have suggested), producing either >ethanol or butanol through fermentation and using one or more than one >together for separation. The oil cake resulting from oil extraction >would be feedstock for a biogas plant. The biodiesel plant is presently >being considered as a prototype for a number of such plants, and among >the key goals of the project are social and economic development, not >merely the production of fuel, and although the project expects a >profit, my impression is that things would be operated to produce a >balance of outcomes. I quite often hear of projects that sound similar (they often want advice from us). I'm always suspicious of the "best crop" or the "best technology" approach (see eg <http://journeytoforever.org/fyi_previous4.html#1511>Technology and the poor), and 600-ha monocrop plantations don't have a very good record. Why jatropha? Whose choice was it? On what grounds? Because there's a tax rebate for it in India? (There is still, isn't there?) Because it's hyped such a lot? I'm not being too sceptical, those are common reasons. If social and economic development are truly key goals, then the approach has to be bottom-up, not top-down. How are the local people to benefit? Did anybody ask them yet? There are other choices besides jatropha. The hype says the jatropha seedcake makes a great organic fertiliser, but the truth is that a non-poisonous seedcake that can be fed to livestock is generally much more useful - in fact it can make the difference to whether a project is feasible or not. Generating biogas from the cake first might make better numbers, but, again, how would the local community see it? What oil crops do the local farmers use, or know of? Wouldn't using mixed species something like J. Russell Smith's "Tree Crops" <http://journeytoforever.org/farm_library.html#treecrops> but with a bias towards oil production (easily done) be better? Such an agroforestry project, with intercropping, livestock grazing and so on, would seem to offer much more than a monocrop plantation could, and be more likely to be adaptible to local conditions, and the local community. Amid all the jatropha hype, this report is interesting, I don't know if you saw it, from GRAIN: Jatropha - the agrofuel of the poor? GRAIN July 2007 <http://www.grain.org/seedling/?id=480> That whole July 2007 issue of Seedling is worth a look: <http://www.grain.org/seedling/?type=68> >So, first question: Although I've reviewed the project overview, which >mentions that the biodiesel mixer will be batch loaded, as yet I have no >information about the size of the unit. What size would/should it be to >produce that much biodiesel annually? You could probably set the upper limit of what would qualify as DIY or homebrew or local coop or Appropriate Technology-level biodiesel production at about 1,000 gallons a day, which is about a tenth of what they're planning. They'll be wanting an industrial processor. If the biodiesel plant is to be a prototype for a number of such plants, they'll also be industrial processors. >Second, am I near the mark with suggesting that the project consider >producing ethanol (or butanol) rather than purchasing methanol? >Certainly it will provide increased challenges to use ethanol, and >perhaps even more to use butanol (in either case including adding >complexity to the process), but I would think for a plant this large, >with good access to land (albeit perhaps marginal land) and given the >low labor costs in the area, it may make sense, although one problem may >be training personnel. Yes? No? Nobody does it. A few homebrewers use ethanol, and they seem to be the only ones, virtually all or all commercially produced biodiesel is methyl esters, not ethyl esters. The ethanol biodiesel process is not easy, but the main problem is that it requires absolute ethanol, any water content and the process fails. Distillation can produce at best 96% ethanol, leaving 4% water, which has to be removed some other way, and it usually costs money and energy. India (if it's India) is ethanol-savvy, it should be easy to find out what producing absolute ethanol would entail to see if it's worth it - that is if they can handle the ethyl esters biodiesel process even with absolute ethanol. Nobody uses butanol either, not even home-brewers. Check United States Patent 5,713,965 <http://www.freepatentsonline.com/5713965.html> This is a method of using lipase enzymes with short chain alcohols (isopropanol or butanol) to produce branched alkyl esters, which have better cold-weather properties than mono-alkyl esters (normal biodiesel). I don't think it ever got further than the lab and the patent office. I know of a few people who tried it, and failed. Anyway, I strongly suggest you stick with methanol. >The Jatropha will almost certainly be planted in rows, ~3x2m per plant, >and it appears that the project developers are not considering using >irrigation. The area in which the plants will be growing has a rainy >season (June-September; 130cm rainfall), and a hot, usually dry season >(April-May, sometimes 40 deg C). What plants might be considered to >assist in producing ethanol/butanol, if they were interplanted with the >Jatropha? > >Glycerol/glycerine would be one by-product at perhaps 10% of the amount >of biodiesel (i.e. ~350 tonnes/yr?). Glycerol/glycerine plus soap, and it will take quite a lot of 85% phosphoric acid (not cheap) to separate the two, which would probably be advisable, unless you want a whole lot of powerful soap in the biogas digester, not sure it would like that. The H3PO4 splits the soap back to free fatty acids (which can be burned as fuel), leaving the glycerine, most of the excess methanol (in the glycerine portion), which can be reclaimed for re-use, and potassium phosphate, which can be sold or used as fertiliser. HCl can be used instead of H3PO4, it's cheaper, it doesn't work as well, and potassium chloride is not as easy to sell as potassium phosphate. >I know that depending on how one >handles this waste stream, it can be burned (at high temp), composted, >used in soap-making, used to supplement the oil cake for biogas >production, used in Clostridium fermentation to produce ABE, used to dry >ethanol (and butanol?), et al. Are there other options? Among those >possibilities, which might best serve the mix of goals? It depends whether you're talking of the raw by-product or the separated components. Did you read the Glycerine page at the Journey to Forever website? <http://journeytoforever.org/biodiesel_glycerin.html> Especially the bit on "Separating the glycerine" <http://journeytoforever.org/biodiesel_glycsep.html>. There are some decisions to be made. >Lastly, the information I have says that "Furthermore, the process to >manufacture biodiesel... has no waste at all [excepting the oil cake and >glycerol]. The process employed has no emissions and absolutely no >effluent treatment." I don't see how that can be correct. Can that be >the case? Did you add "[excepting the oil cake and glycerol]"? They're not wastes, or they shouldn't be, they're usually referred to as by-products or co-products. The process itself has no emissions, but the power supply used might have emissions. Would that be the biogas plant? There's also the water used for washing, but it can all be accounted for with no addition to the waste stream. I think that's all detailed at the Biodiesel section of the Journey to Forever website. HTH - best Keith >d. > >-- >David William House >"The Complete Biogas Handbook" |www.completebiogas.com| > >"Make no search for water. But find thirst, >And water from the very ground will burst." >(Rumi, a Persian mystic poet, quoted in /Delight of Hearts/, p. 77) _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (70,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
