with a high IV with one with a lower, should produce an average IV.
No Jan, that's not what I said, I don't think it will produce an average IV. An iodine test might give you an average result, but the makeup of the high IV oil will remain unchanged, and it will polymerise anyway. How can blending oils change their chemical characteristics? The double bonds will remain, though in the blend there will be fewer of them, only because there'll be less of that kind of oil. But it will still polymerise. I'm not sure about this, but it seems logical, and your explanation seems illogical - merely blending oils cannot change their chemical characteristics.
But in some course literature I read some time ago, it said that "oil spill from rape seed oil will leave you two months to wipe it up before it polymerizes, soy bean oil will leave you two weeks, and linseed oil two days. " From this way of reasoning one can conclude, when comparing the average IV values of each oil, that blending rape seed oil with llinseed oil to an average IV value of soybean oil, will produce an oil with similar polymerization properties as soybean oil.
I just don't see it - what effect can mixing rapeseed oil with linseed oil have on the double bonds of the linseed oil? There is no chemical reaction. The double bonds will still be there, unchanged, and will still polymerise.
And further- if producing of biodiesel out of high IV oils, will lower
Lower it yes, but not remove it as you recently claimed. Biodiesel made from high IV oils will also polymerise, but not as rapidly ast raw oil would.
the fatty acidsŤ ability to polymerize one can conclude that the first step of polmerization takes place within the triglyceride molecule, possibly with bridges of oxygen between the double bonds of different fatty acids. In methyl ester the fatty acids with the right will to polymerize have some difficulties finding each other and build bridges.
Some difficulties perhaps, but it will still happen. Best wishes Keith
Give me some input on this way of explanation ,Keith ! Best regards Jan Jan Warnqvist AGERATEC AB [EMAIL PROTECTED] + 46 554 201 89 +46 70 499 38 45 ----- Original Message ----- From: "Keith Addison" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, March 31, 2005 7:28 PM Subject: Re: [Biofuel] Re: soybeanoil a bad choice for BD making? > Hello DB and all > > >Anyone making bio-diesel should be concerned with the IV of the oil > >and the polymerzation of the engine. After a careful reading of the > >australian report "WVO as a Diesel replacement fuel" it is obvious > >that they are concerned with it's use as straight veggy oil and Not > >so much Bio-diesel.( I would be concerned too) Here is a direct > >quote from that report......... " Trans esterifying triglyceride > >oils and fats with monohydric alcohols to form biodiesel largly > >eliminates the tendency of the oils and fats to polymerization and > >auto-oxidation.." The base crop for european biodiesel being > >rapeseed with a IV of 98 is a reasonable goal to acheve. Most of my > >stock is soy oil and much of it is hydrogenated. I also get > >cottonseed and peanut oil along with canola (rapeseed) I no longer > >use straight soy oil and try to make a blend. In the past when I > >only had soy oil based biodiesel I would only run BD50. I an no > >longer worried about the IV of the oil and if you are then just run > >BD50.........Drive down the road > >Happy...............................DB ..PS. I have been making > >biodiesel since '02 and have made 1000's of gallons with zero > >problems. > > I agree, and thankyou, but I'm not sure I follow the logic of your > solution, attractive though it is. Does an IV value average out when > you blend different oils? Other things will, of course, like say FFA > levels, you'll end up with an average and that's that. But in a blend > with biodiesel made from a high IV oil with biodiesel made from lower > IV oils, while the proportion of high IV oil will be lower, what's to > stop it oxidising and polymerising just the same? Blending it doesn't > change its makeup. I'm not sure what effect blending it with > petrodiesel would have, but that wouldn't change its makeup either, > it still has its double bonds to be broken down and polymerise. All > you'd get is proportionately less polymerisation, no? So it'll take > longer to gunge up the engine. That doesn't solve the problem, just > mitigates it. Sorry, I don't know if this is right or not, just > trying to be logical - maybe it doesn't work like that, but I'd like > to know. > > Regards > > Keith
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