>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.
Thankyou Jan. >And the higher the iodine number the lower stability. Sorry >about that, ASTM. :-) Best Keith >----- 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/
