Hello Paul >----- Original Message ----- >From: Keith Addison <[EMAIL PROTECTED]> >To: <biofuel@yahoogroups.com> >Subject: [biofuels-biz] High FFA oils - another way ><snip> > > > I found an easier way though: two-stage base-base, only the first > > stage doesn't use methanol, it uses (horror!) water. > > > > Mix the titration amount of NaOH, in this case 9.15 grams per litre > > of oil, with 40 ml of water per litre of oil. > > > > Add the dissolved NaOH to the oil (room temperature), stir gently by > > hand until thoroughly mixed. > > > > Settle overnight. This leaves soapstock at the bottom and some gunk > > floating on the top. The water is apparently in the soapstock. > > > > Filter to remove soapstock and gunk - no need for fine filtering, > > fine steel mesh will do (like a fine tea strainer). > > > > Now process as usual for virgin oil - 3.5 grams NaOH per litre of > > oil, 20% methanol, 55 deg C, good and prolonged agitation as usual. > > > > Good product, production rate in this case 73%, slightly less than a > > normal single-stage, but it's a much easier process that won't go > > wrong, and it's nice not to have to make such strong methoxide as a > > straight single-stage process would require with this oil, 13.65 > > grams of lye per litre oil, or more like 14 grams (needs a bit of > > excess lye). ><snip> > >Slaked lime (CaOH2)can also be used to remove the FFA from WVO or high FFA >biodiesel rescued from overuse of NaOH (gel) with acetic acid.
You settle it with acetic acid? I think the resultant FFAs just dissolve back into the biodiesel then. >Mix the lime into the WVO/BD and heat with occasional stirring to 100 deg C. >The lime appears to dissolve in WVO as heated but is probably just held in >suspension. >Cool decant and filter. No problems with ammount of lime just use excess. Thanks Paul, I'll try that. But this caustic refining step is so easy I'm quite satisfied with it, and there's no need for heat, for filtering, or for anything you haven't already got. "... just use excess" - about how much per litre? >Would much rather go acid/base with feedstock with FFA content this high, Sure, as I said, but a lot of people don't do acid-base. Also, acid-base doesn't like this particular oil, it has a lot of salt in it (tempura oil). Hot pre-washing solves that problem, but that then makes the acid-base process a lot more trouble than this, and a lot more energy use, so you're left to choose between much more time and hassle for the acid-base advantages, or a quick and easy way like this, and there's not much in it. Especially since I think recovered FFAs are useful, not wastage. You're not using more methanol, the extra lye isn't expensive, so it's really just some extra phosphoric, no big deal, as against no sulphuric. >less wastage/recovery "It's an alternative - better than straight single-stage base for oil like this, and while it won't get as a high a production rate as acid-base, and it uses more catalyst and gives you more co-products, it's very quick and simple, and the product is good." >and acid stage allows alcohols other than methanol or >ethanol to be used. Isopropanol for instance has the potential to reduce >cloudpoint. Have you tried the acid-base process with isopropynol? That'll make branched alkyl esters, low cloud-point yes, but I don't know of anyone that's had any success with isopropynol or butyl other than with enzymes, though I do know people who've tried. Reference previously posted in "Cracking" thread, Foglia et al, for instance. Pressure maybe. Best wishes Keith > >Regards, Paul Gobert ------------------------ Yahoo! Groups Sponsor ---------------------~--> 4 DVDs Free +s&p Join Now http://us.click.yahoo.com/pt6YBB/NXiEAA/MVfIAA/9bTolB/TM ---------------------------------------------------------------------~-> Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://www.webconx.dns2go.com/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
