Dear Keith and Prof. Allen, I am still fixing some details to start my project on a small pilot plant (100 l) to produce ethanol based biodiesel. I have read a lot of information in the archives and the Journey to Forever site about of troubles when dealing with ethanol and the same old question is back: if ethanol is used, it is better to change the catalyst from NaOH to KOH. However, even in this case, success is not guaranteed as the separation between glycerine and ester may not occur. The tips given by Ken Provost do not help a lot, since at the end even he says that it is like lottery (matter of good luck and fervent prayer). There is no clear explanation about why glycerol does not separate well or what can be done to avoid it (without mixing methanol). I cannot get reproducibility in my lab tests. Sometimes it works and sometimes not, as he said. The same recipe! Does anybody know a paper which explains in details the chemical reasons of separation problems (or any additive to help it). I have in hands a brazilian handbook to produce biodiesel from several brazilian vegetable oils. It was written in 1985!!! In all recipes, biodiesel is successfully made by mixing reactants in the following proportions:
600 g refined oil (for soy oil, 0.2 acidic index) is firstly treated with 1.5 g of CaCO3 at 120¼C and filtrated. Then 182 ml anhydrous ethanol previously mixed with 2.5 g NaOH is added to the oil. After 20 min mixing at 60¼C, 3.5g of NH4Cl is added (catalyst poison). Then filtration of the precipitate and addition of 17 ml of HCl (36%). Then settling for a couple of hours, separation and washing with water + bicarbonate. The authors say that the HCl acid is added to enhance settling of glycerol. Does anybody know the basis of this method? Is it a too old method? Thank you for your future comments. Murilo D.M. Innocentini Group of Engineering and Microstructure of Materials Department of Materials Engineering Federal University of Sao Carlos Via Washington Luiz, km 235 13565-905 Sao Carlos - SP - Brasil Tel. 00 55 16 260-8253 Fax. 00 55 16 261-5404 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/
