Hi Paul, Christian Christian, my apologies - I know you addressed the question to me, but I'm a bit sporadic these days, otherwise occupied, and didn't manage it. I was glad Paul picked it up - I think I said previously I hoped someone else would chip in rather than your getting advice only from me.
Paul, your black oil is interesting, I had some stuff like that, yuk - 9.6 ml titration. I wanted to ask the restaurant customers how they liked the food but they were all dead. (Joke.) (I think.) One thing you might try is to warm it a bit and then pour at least an equal quantity of boiling water onto it, shake it up, let it settle out, the water should take some of the FFAs with it. Somebody reported success with this, but I haven't managed to try it yet. Ken's method works well: http://groups.yahoo.com/group/biofuel/message/10378 Another point, as you surmised, is the conc aqueous NaOH solution. It's certainly a convenient way of mixing it, though there are others - see: http://archive.nnytech.net/index.php?view=12986&list=BIOFUEL It's interesting to know that it can be done, a useful option. But I do have reservations about it - adding even that little water won't help the process, though it might not hinder it, depending, but then again it might. I think it adds a variable, which for tests is perhaps to be avoided - you want as few variables as possible. Well, that's my view at any rate. Also, for someone who's learning it might be an unnecessary complication, especially as there are other ways of doing it. Another reservation is the use of PET bottles. I think it's been established that shaking it initially and then leaving it won't guarantee maximum completion. You can still be left with unreacted TGs, and di- and mono-glycerides. Water and/or too much lye will make soap, and if there's anything more than minimal MGs, you'll certainly have trouble washing it. Very gentle washing methods like misting might get round that, but the MGs will still be left in the final product, and you don't want them in your motor. Todd said some things about this which I think are worth repeating. One was that you should be able to subject the processed product to a really fierce wash in a blender, without creating a frothy mess. "As little as 1% mono-glycerides can lead to enormous wash emulsions... If no emulsions form under conditions of wild agitation the fuel can be counted on as being a completed product." I think that's right. By the way, this was among the early feedback on Aleks's update of the Foolproof method: "... Just started the wash - and it looks stellar. No soap at all, just water and oil." That's as it should be. Todd also posted this advice on shaking: "I would encourage anyone to shake vigorously for 30 seconds every half hour for about two hours in a one gallon environment... Anything less than such levels of agitation invite incomplete reactions." I'd do the same with a PET bottle, or more. Shaking it more and processing it for longer certainly can't hurt it, and might help a lot. These are only test batches anyway, nobody's going to get into making their fuel supply in a PET bottle. Well, nobody in their right mind anyway. So the longer time and a little more work shouldn't matter. Incomplete reactions are the devil of home-brewing and I reckon it's worth a little more bother to make sure. Regarding Christian's soap problem, it seemed to be rather high-quality feedstock he used, low titration. I doubt his titration was that inaccurate that he's having a high-FFA problem. Christian, I think you should just keep going, you'll get better at it, more accurate, and your results will improve. You're doing fine, you just need some more practice. Regards Keith >----- Original Message ----- >From: "Christian" <[EMAIL PROTECTED]> >[snip] > > > Anyway, if too much lye forms that sticky gel and too little forms a third > > layer of unreacted WVO, then if I only get a layer of glycerine and a >layer > > of WVO, my proportions should be right, right?. >[snip] >Not a definitive guide as to the quality of the BD. >As an example made two batches of BD from some really well used oil. >(More about this oil in a few days when I do more tests, get more >imformation from the distributers.) >The oil titrated at 9.0ml, pretty well used. Tried neutralising some of the >acidity with lime but this oil refused to transesterify after the treatment. >Titration was definitely lower but even using levels of NaOH appropriate for >the titration on the origional oil, the treated oil/ methoxide mix remained >in one phase. >Going back to the origional oil I made two 1L batches. Both used 250ml of >methanol. >Batch A/. 15ml of conc aqueous NaOH added to methanol, Batch B/. 20ml added >to methanol.Shaken in 2L bottle, set aside. In half an hour both batches had >settled nicely. >The origional oil is almost black, BD/glycerine interface difficult to see >in A/., easier to see in B/. (BD in B lighter in colour) > >Yield. A/. 810ml BD, 450ml glycerine. > B/. 710ml BD, 500ml glycerine. > >Glycerine from both batches drained off easily at 25 deg C. >Batch A/. glycerine was still liquid when last seen 6 hours later. >Batch B/. glycerine set after four hours, setting seemed to occur from the >top down even though the beaker was sitting on cold tiles. >From past experience expect both SG and viscosity of Batch B/. to be lower >than that from Batch A/. > > > > And very little whit residue (soap?) is left on top of the glycerine >layer. > > However, the first wash is very dirty (white, milky cloudy almos foamy). >So > > what should I change to get less soap formation? > >Use an oil with less FFA. >Neutralise the FFA in the oil you use. >Titrate your oil and use the ammount of NaOH indicated by the titration. >The oil used here titrated to 12.5g NaOH/litre. >Batch A/. used the equivalent of 12.5g and Batch B/. 16.7g >Better to err on the high hide than the low side especially if you are >processing animal fats or the oil you are using has beef tallow residues in >it. >Use 250ml methanol per litre of oil. > > > Can I wash indefinitely (say, three or four times) to remove all soap? > >By all means. Make sure that your initial washing is not to vigorous though >as it is easy to loose BD through emulsification in the presence of soaps. >Mist washing combined with prolonged settling works well. Usually only the >emulsion layer between the BD and the wash water requires prolonged >settling. > >Would be good to see others have an input to this as these observations are >from processing using conc aqueous NaOH to make the methoxide. >Whilst this method works well for me and the GC results have been >favourable, its not a method which has acheived universal acceptance. > >Accounts of others experiences in these areas would be appreciated. >More on that "Black Oil" later. > >Regards, Paul Gobert. ------------------------ Yahoo! Groups Sponsor ---------------------~--> Kwick Pick opens locked car doors, front doors, drawers, briefcases, padlocks, and more. 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