This is getting tedious, I'm simply reporting what I found. I followed the acid base recipe and got a low calorific value fuel. After the acid was neutralised and allowed to settle, I ran the 1.5g of NaOH as per the recipe. This did not transesterify all of the oil. I therefore repeated the base reaction with more methoxide at 1.5g of NaOH per litre of oil.
The changes I had to make showed that my oil has less FFA to be reacted by the acid than Alecs would normally have. He agreed that this would happen with lower FFA oils. A titration would have shown that, but I was following the recipe and experience told me that it had not completed. As I used a large excess of methanol I washed the product with 4 water changes. Wasteful, but I did not want the methanol reducing my fuel's CV. My result was a low Calorific Value fuel. Why? Idea 1 Acid burnt oil? Maybe, but would that reduce the CV? I would expect any unreacted glycerol to hold up the energy value. Idea 2 Some oxygens were lost - they help to maintain the miles per litre if not the measured Calorific Value. Idea 3 Maybe the FFA was stripped of any remaining glycerols, but not turned into methyl ester. Clean FFA has a lower CV than methyl ester. BTW Martin was told by Tegasc that acid/base reacted biodiesel is "not as good" as purely base reacted biodiesel, but the details were not quantified. We need some proper research on this - not simply me messing about with home-brew. Somebody else please try the acid/base recipe with heavily used oil and then do some miles per gallon comparisons with purely base reacted ester. Hopefully both will be the same, but I'm sceptical. Dave --- In [EMAIL PROTECTED], Keith Addison <[EMAIL PROTECTED]> wrote: > Hi Dave > > >Hi Keith, > > > >Alecs does qualify that in his recipe's. He means that the process > >reaches an equilbrium before all of the oil is converted. > > He says: "Esterification is followed by transesterification, but > under acid conditions it's much slower than under caustic conditions > and it won't do a complete oil-to-methyl ester conversion as the > reaction is much more equilibrium-sensitive. Without methanol > recovery, the alcohol overdose required would make the price of your > fuel jump, and even with recovery it would still be much more > expensive. Hence the second base-stage." > > That doesn't mean the process reaches an equilibrium before all of > the oil is converted, it means what it says: the first stage won't do > a complete conversion, hence the second stage. > > >In theory > >you can never get to 100% conversion to ester etc. He also hates to > >not convert the FFA to ester. While I agree it's wasteful to dump the > >FFA, I'm not convinced FFA can make DIN 51606 standard ester. Clean > >FFA can be used in blends for low speed site plant or heavy oil > >generator engines. > > > >That said, Energea use an acid pre-reaction for >8% FFA feedstock and > >they deliver DIN standard fuel, so it can be done. I'd like to > >compare calorific values (per litre) of ester from high FFA feedstock > >and new oil. > > Methinks Teagasc also do it. There are quite a lot of people making > it and using it in their cars and reporting no problems; some report > improvements, smoother running. It checks out as high-quality. Simple > comparative tests find it's the equal of commercially produced biod > from Austria. Why relegate it to low-speed gear and generators? What > are your doubts based on, exactly? Anything concrete? > > >A single stage (base) reaction with new oil might make biodiesel > >which is less than 2.5% oil, but 10% unreacted oil is more likely > >especially with RVO. Reacting in 2 stages gives a good chance that > >the ester is more or less fully converted. You react with 2/3 of your > >methoxide and allow it to settle. Then draw off the byproducts and > >react again with the remaining methoxide. This polishes the ester. > >Shorthand is base/base process. > > So, to answer my question, your "normal base-base process" is Aleks's > two-stage process. He'd certainly be surprised that this is what gave > you sloppy biodiesel, the usual result is high quality. > > >I think Energea plants do three reactions to make absolutely sure > >they are within the standard. Unused methanol is recovered so there's > >no waste. > > Some plants do more than three reactions. > > >When I followed Aleks Kak's "Foolproof Process" my waste oil was not > >as overcooked as he uses so I needed to do two base reactions. It was > >really an acid/base/base. > > So this wasn't according to Aleks's methods either. No wonder you're > having strange results. > > >Incidentally, our Ace Biodieseler friend from Manchester has managed > >to reuse the stage 2 byproduct as part of another batch, indicating > >that his first stage came fairly close to full conversion. [Camillo > >I'm not suggesting that's OK for commercial operators :) ] > >What a shame he's not got a personal Gas Chromatograph. He could move > >small scale techniques forward no-end. > > In think he already does, doesn't he? > > Best > > Keith Addison > > >Regards, > >Dave > > > >--- In [EMAIL PROTECTED], Keith Addison <[EMAIL PROTECTED]> wrote: > > > Hi Dave > > > > >You mentioned biodiesel you made with "the normal base/base process", > >which, according to your results with it, Aleks says is sloppy > >biodiesel. I don't know what the normal base/base process might be. > >Which process did you use exactly? > > > > > > Best > > > > > > Keith Addison Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://www.webconx.com/2000/biofuel/biofuel.htm 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/
