Hello Keith, Zeke and all. If polymerisation is the issue should it be related to the oxidation stability of the BD. It should therefore be important to use anti-oxidants in order to improve the stability. The connection is higher pressure -> higher temperatures -> quicker polymerisation. And the higher the iodine number the lower stability. Sorry about that, ASTM. ----- Original Message ----- From: "Keith Addison" <[EMAIL PROTECTED]> To: <biofuel@sustainablelists.org> Sent: Saturday, October 17, 2009 9:09 PM Subject: Re: [Biofuel] Merceds-Benz
> Hi Zeke, Jan and all > >>Haven't really heard either way. I have heard lots of rumors about quite >>a >>few of the common rail diesel's having problems with biodiesel, due to >>polymerization of the biodiesel at extremely high pressures that those >>engines have, but I cannot remember any details or specific examples of >>any >>of them right now. > > Maybe they're just rumours, but I think DI diesels might indeed have > problems with polymerised biodiesel in the US. But is it because of > the high pressures? Can high pressure cause oxidation? I don't know, > but it's only from US sources that I ever hear that. > > Most biodiesel in the US is soy biodiesel, which doesn't need high > pressure to oxidise and polymerise, it's a semi-drying oil, it'll > polymerise anyway. The IV is well above the EU biodiesel standard > upper limit. (See "Iodine Values" > <http://journeytoforever.org/biodiesel_yield.html#iodine>, "National > standards for biodiesel > <http://journeytoforever.org/biodiesel_yield2.html#biodstds>.) The > biodiesel industry in the US seems to be more are less in denial > about this, but then the US National Biodiesel Board is a creature of > US Big Soy. > > Hm, I must check how the US-EU row over the US dumping cheap soy > biodiesel on the EU market is progressing. IIRC last time I looked > the US was accusing the EU of protectionism, on the basis of what > sounded like GMO-style "substantial equivalence" of America's soy and > Europe's rapeseed oil, though they're not equivalent when it comes to > iodine values and polymerisation. Rapeseed oil has a much lower IV > and is much less likely to polymerise. Nonetheless, a lot of > Europeans use anti-oxidant with their biodiesel, while very little > anti-oxidant is used in the US, by contrast. Also, in the US most > biodiesel is the NBB's commercial B20, a low blend with a lower risk > of polymerisation, so they have to care about it that much less. > > They're never going to accept that soy could be anything less than > ideal. I get the impression that, even if there is such a thing, > high-pressure polymerisation could be just a convenient scapegoat for > soy's shortcomings. > > Best > > Keith > > >>And I don't recall what sort of biodiesel and what >>iodine numbers they were running. >> >>Z >> >>On Sat, Oct 17, 2009 at 4:23 AM, Jan Warnqvist < >>[EMAIL PROTECTED]> wrote: >> >>> Hi all. Did anybody experience or heard of anybody experiencing severe >>> problems with MB CDI engines in connection with biodiesel ? >>> >> > Jan W > > > _______________________________________________ > 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/ _______________________________________________ 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/
