----- Original Message ----- From: "mark schofield" <[EMAIL PROTECTED]>
> Hi > > So after playing with the single stage for a > while, I have produced a good clear final > product. I have bought a hot plate magnetic > stirrer for $360 USD that has helped for > titrations etc. > > I have played with the two stage process and the > final product has turned to jelly. I have > followed the 2-stage instructions exactly - > timer, burettes, +/- 1mg weighing scale, 97% > H2SO4, hot plate stirrer with closed loop > temperature control and digit speed and temp > output. The chemicals are all analytical grade > and the oil requires only 0.1cc of 0.1M NaOH > solution to pH 8.5. > > I heat 1000cc of oil up to 35'C. I add 80cc of > 99.5% Methanol and stir for 5 minutes. I then add > 1cc of 97% H2SO4 and stir for 1 hour. I then cut > the heat and stir for a further hour. The mixture > does not separate but is left for minimum 8hrs > usually 12. I re-heat the still liquid mixture to > 55'C and add 3.5g NaOH and 120cc Methanol. I stir > for 1 hr and leave to settle. The final product > doesn't settle and congeals over time. > > Keith - I am lost. Some where along the line soap > is formed. I will re-run the experiment and > comment tomorrow. > > On a larger scale - could a 1um filter / > coalescer unit be used to pre-process heated oil? > > Regards > > Mark Hello Mark, With oil of 0.1ml 0.1M (0.4%) NaOH titration use of the two stage acid base method is not waranted. The aim of the acid stage is to esterify any FFA present. From your titration we can see that the oil has very little FFA in it to start with. It would be a better candidate for single base method. Very little would be happening in the acid stage, there is almost no FFA to esterify and acid catalysed transesterification is very slow. In this case all that is happening is that you are acidifying (with sulphuric acid) the oil/methanol mix prior to performing a base catalysed transesterification and not taking that acidity into account when choosing the ammount of NaOH to use. When you rerun the experiment try using a larger quatity of NaOH in the second stage. If you don't drain off the small ammount of acid/aqueous layer after the first stage some of the NaOH will be consumed neutralising it. Also current thinking is that more than 3.5g/l gives a better conversion. Both good reasons for using more than 3.5g/l in the second stage. Would suggest using this oil for single base method and finding some oil higher in FFA to trial the acid/base method. Regards Paul Gobert. > ------------------------ Yahoo! Groups Sponsor ---------------------~--> Get A Free Psychic Reading! Your Online Answer To Life's Important Questions. http://us.click.yahoo.com/Lj3uPC/Me7FAA/CNxFAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
