Michael, thanx, In some research into used oil I have been perfoming, the source and use it has been put has a great bearing over the content. I noticed the supply of oil had come mainly from fish and chip shops. The oil may well contain an amount of more highly unsaturated fatty acid such as those derived from deep sea fish. The higher unsaturated nature is then capable of polymerizing, especially when there is no stearic hindrance occuring due to being held as a triglyceride.
The commercial cooking oils in Australia also contain other ingredients, being polymethylsiloxane (antifoam) and antioxidant. The antioxidant is most likely destroyed due to prolonged heating and rxn with water and amines etc. Therefore when the free pufa's are exposed to air, a very rapid rxn will occur. What I don't understand is, I separate the BD using a settling tank with conical base, and skim the good material from the top and drain the glycerol from the bottom. The first 60-70% BD from the top is very good, but it is the remaining BD that develops the skin. Maybe it's the prolonged contact with the water that causes this. I'll have to locate some bromine to test the saturation level. -----Original Message----- From: Michael Allen [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 11, 2002 7:43 PM To: biofuels-biz@yahoogroups.com Subject: Re: [biofuels-biz] skin on biodiesel Padraig, Thanks for the information. We have a locomotive in Thailand running 300 kilometres a day on a 50:50 blend of biodiesel:petrodiesel. The biodiesel in primarily methyl stearate because it is made from the waxy solid stearin/palmitin that separates out of the olein in the palm oil. We've even had it analysed by gel chromatography. In 1983, I had a student here in New Zealand making biodiesel from tallow (which is also primarily stearin). [Hey Keith! Perhaps I am the real "Father of Biodiesel in New Zealand"! Now what I need is a second-rate journalist to do my PR . . . . ] If there are any "drying oils" present in the oil (such as linseed, fish or flax-oil), oxidation of the relevant unsaturated fatty acids can be expected to form a polymeric film on the biodiesel/air interface. It reforms every time the surface is broken until it is all reacted with the air. I wonder if that could be an alternative explanation? Wendell, what do you think? Could there be any unreacted and unsaturated FFA present? Padraig! Glad to hear you got the paper OK! E-mail from southern Thailand was just slightly less reliable than it is from here in New Zealand. Regards Michael Allen 11/12/02 01:21:31, "goat industries" <[EMAIL PROTECTED]> wrote: >Michael Allen's question: What makes you so sure it is methyl stearate? Do >you have a reference for this perhaps? > >This conclusion is one of my own drawn through my own experiences with >making biodiesel from waste oil. There is no research reference that I know >of. What do you think it is? > >By the way, did you ever receive that paper I sent you entitled "Kinetics of >Palm Oil >Transesterification In a Batch Reactor" by D. Darnoko & Munir Cheryan ? > >Yes thanks! I did! > > > > > >Biofuels at Journey to Forever >http://journeytoforever.org/biofuel.html >Biofuel at WebConX >http://webconx.green-trust.org/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/ > > > > Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/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/ Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/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/
