Reinhard Henning wrote: >Albert Einstein often said: "Use the simplest thing that works, as >long as it's the best thing."
The proviso is critical, and in many cases it's context-sensitive - I believe this is the case with the biodiesel vs SVO argument. In the end it boils down to a matter of particular circumstances and individual preferences. >This in mind one should compare the two actual possibilities to use >plant oil as fuel: > >1) adaptation of the oil to the engine (bio-diesel, BD) >2) modification of the engine to run on pure plant oil (straight >vegetable oil, svo) > >Plant oil is pure stored solar energy in its densiest form (9,2 kg >/l). It contains only the elements carbon C, hydrogen H and oxygen >O. In the simplest way it is produced only by grinding of seeds and >pressing (ram presses, expellers) it. Purification by sedimentation >and / or filtration: Can somebody imagine a simpler method of >producing highly concentrated, environmentally friendly energy. > >In a short term planning, it is interesting to use biodiesel, >because you can use the already existing car engines. > >But in a longer perspective, it is more interesting to adapt the >engines to run on pure plant oil (SVO). And you have all the >advantages of an decentralized fuekl production. And you dont need a >chemical workshop to produce your own fuele at home. A ram press for >about 200 $ and some plastc barrel is all you need. That is not convincing Reinhard. In the future more diesels will probably be adapted to SVO use, but that will leave millions of vehicles all over the world not so adapted, bringing us back to the same choice between making biodiesel and rigging a two-tank system with heating etc to use SVO... on some vehicles, maybe not on others, whereas biodiesel will work in any diesel. There is also a shortage of good, long-term studies on the effects of using SVO, unlike with biodiesel, and no long-term studies on the use of WVO that I'm aware of. None of the European manufacturers of SVO systems covers the use of WVO, right? Biodiesel also gives you the advantage of decentralised fuel production. There is no need to have a chemical workshop to produce biodiesel at home. It is simple. $200 would more than cover the costs of everything needed to make biodiesel, and no need for a ram press. >For the mean time, you can convert your diesel engines into plant >oil engines (the still run on diesel). The conversion kits are not >expensive, but they are a bit different for one engine or the other. >(The Mercedes 123 engine doesn't have to be modified at all. You >just run it with SVO. If its cold, you add some diesel. Some kits are better than others. Some kits are not to be recommended at all. Some manufacturers claim their kits are suitable for any diesel in any climate, using WVO, and this is not true. But people buy these kits anyway, and there are plenty of stories of ruined pumps. Again, I know of no such stories with biodiesel use. And WVO remains a problem. If this valuable waste resource, used by many or most small-scale biodiesel makers, is to be used in straight SVO systems it has to be pre-treated, with not much less processing required than that needed to make biodiesel. And you still won't have the guaranteed results that biodiesel will give you. >In Germany, the producer of the tractors for agriculture are already >very interested to offer SVO-versions of their diersel engines to >the farmers (Deutz, John Deere). So in a short future, probably the >truck engine producers will do the same and later the car engine >producers. Which still leaves the older motors, especially in the Third World. >Another important argument for the use of SVO instead of BD is the >energy input for its production. With BD it is about 1/3, i.e. you >need about 30% of the energy of 1 litre of BD to produce 1 litre of >BD (in form of Merthanol or aethanol, chemicals, >destillation/purification). That depends very much on how it's done, and in what setting. >For the production of SVO you need only about 15 % (12 % for >agriculture, 3 % for oil extraction). If you use ecological advanced >production methods, you can reduce these 12 % considerably. Your second sentence applies to on-farm biodiesel production too. I have some arguments with Schrimpff's chart as well. >Ernst Schrimpff of the Tecnical College of Weihenstephan, Germany, >listed 8 parameters to compare SVO with BD. Here his list (partly): > >see also the attachment or: > >http://jatropha.org/p-o-engines/svo-bd-characteristics.htm > > Plant oil (SVO) biodiesel (BD) > >1) Physical characteristics: > >physical density 0,90 - 0,92 0,88 > >viscosity 60 - 80 7 - 8 > >ignition point > 220 135 > >2) Chemical characteristics: > >phosphate mg/kg < 15 < 15 > >sulphur mg/kg < 10 < 10 > >Chem. reaction neutral, very low > hygroscopic, solvent, fast reaction > >3) Production: > >principle decentralized small > central, big industrial units The biodiesel entry here is wrong - it should read the same as for SVO: decentralized small. > oil expellers >chemical compounds needed - > methanol, potassium hydroxyd > >energy input 12 % 29 % Questionable. >5) Transport / storage no risk small risk In the US, no risk. >6) Environment > >biol. degradation very fast delayed The EPA findings contradict this. You can find this information via the NBB site. >danger to water no small The EPA findings contradict this too. Biodiesel is used for remediating oil spills after all. Whereas rapeseed oil can be highly destructive in a water spill. >human toxicity regularly no toxic > (or small) Not so - biodiesel is non-toxic, again according to the EPA. >material circuit complete > difficult to realize > >7) Social acceptability > >strategy small, decentralized big, central Wrong: read "small, decentralized" for biodiesel. >logistics simple komplex Not so - the many thousands of people with no technical or chemistry qualifications all over the world who're successfully making their own biodiesel testify to that. And I reject the argument that they cannot make a quality product - they do make a quality product. >transportation short distances long distances Not so: read "short distances" for biodiesel. Should really be short or zero distance for both. >vulnerability small higher Based on what? >regional income high low >generation Not so - biodiesel is an excellent candidate for micro-regional production efforts, with great local benefits. >8) Costs > >fuel production 0,25 - 0,40 > 0,45 - 0,60 US$ > >fuel prices 0,45 - 0,55 > 0,70 - 0,85 US$ Neither of these apply to small-scale local brewers. This is perhaps a more useful (and simpler) chart than Schrimpff's: Needs processing Biodiesel Yes SVO/WVO Less Guaranteed trouble-free Biodiesel Yes SVO/WVO No Engine conversion Biodiesel No SVO/WVO Yes Cheaper Biodiesel Sometimes SVO/WVO Usually I've had this argument here before. I'll probably be accused of favouring biodiesel over SVO. In fact I favour neither, or rather both. As I said at the start, it depends on the circumstances and individual preferences. There are two pages at Journey to Forever where this choice is discussed - here: Three choices 1. Mixing it 2. Straight vegetable oil 3. Biodiesel http://journeytoforever.org/biodiesel_make.html#3choices ... and, in somewhat more detail, here, at the page you reffed below (thanks!): http://journeytoforever.org/biodiesel_svo.html Straight vegetable oil as diesel fuel: Guide to using vegetable oil as diesel fuel SVO systems References SVO vs biodiesel in Europe European SVO resources Diesel information Fats and oils I rather agree that SVO will probably be the fuel of the future, but I see that future as more distant than most SVO proponents tend to see it. I would say that SVO use is still at an experimental stage and needs quite a lot of further development. Most of all it needs long-term tests of various kinds, and, since some motors are more suitable than others (which is not the case with biodiesel), it needs quite a lot of different tests. So I'm very much in favour of SVO, but I think it's an exaggeration to pretend that it's a mature, assured technology, as many do. In fact I really reject this whole argument about biodiesel vs SVO. It's a choice, an informed decision to make, but there should not be any opposition, the two are complementary. There's a lot of unjustified biodiesel-bashing by the SVO camp in Europe especially, and I think it's ridiculous - it's ridiculous that there are two such camps. Perhaps it's because biodiesel is more industrialised there, as is also happening in the US - but that does NOT exclude small producers and home-producers. Biodiesel and SVO are in the SAME camp, please - it's the fossil-fuel interests that are in the opposite camp. Good heavens. Best wishes Keith Addison Journey to Forever Handmade Projects Osaka, Japan http://journeytoforever.org/ >Interesting links to this SVO - DB - discussion are: > >http://www.vegburner.co.uk > >http://www.pflanzenoel-motor.de (German) > >http://jatropha.org/p-o-engines/conversion-cars.htm > >http://elsbett.com/emotanfr.htm > >http://journeytoforever.org/biodiesel_svo.html > >Kind regards > >Reinhard Henning > > > >-- >bagani GbR, Reinhard Henning, Rothkreuz 11, D-88138 Weissensberg, Germany >Tel: ++49 8389 984129, Fax: 984128, e-mail: [EMAIL PROTECTED] >internet: www.bagani.de ------------------------ Yahoo! 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