>When recovering the methanol, do you heat the whole batch after it >settles, or heat each part sepparately (biodiesel and glycerine)? > >Brent
Sorry Brent, you didn't get a response to this: Different schools of thought on this. Some people just heat the whole thing up a bit more after the process and recover the methanol there and then, which has some advantages - it doesn't take much extra heat, for instance, compared with heating all or part up again from room temperature. Here's one such: The touchless processor http://journeytoforever.org/biodiesel_processor.html#touchfree Others say the disadvantage of this is that removing the methanol makes the glycerine by-product much more difficult to process. The by-product is actually a mixture glycerine, excess methanol, soaps and catalyst, and it can be separated - the methanol content makes it easier to work with. Here the methanol will end up in the separated glycerine, and can then be recovered. See: Separating glycerine/FFAs http://journeytoforever.org/biodiesel_glycsep.html Others again say it's not worth trying to recover the excess methanol from the biodiesel as most of it collects in the "glycerine" layer anyway, so just heat the by-product. If you do want to recover the methanol content from the biodiesel, you have to do it before washing, which will remove all the methanol. There's quite a lot about this in the archives. Here are a few previous messages, these mostly on possible water content of recovered methanol: >I've used and re-used about thirty gallons of methanol so far using >my hot pink vacuum still. At first I was worried about recovering >water at the end of a run, so watched the condensate closely for any >sign of cloudiness. I've never seen any. I don't think water can be >recovered from the byproduct at anywhere near the boiling point of >methanol. > >Dale >Dale is right, recovered methanol is OK to re-use. I have found that >from biod made using 15% meth (v/v WVO), the glyc. yields 3% meth >(v/v WVO) and is well worth the trouble of simple distillation at 70 >deg C. Probably will use 20% in future for an easier life without >unnecessary loss of costly reagent. > >David T >Any water in the mix is either tied up in soap or, at the very >least, heavy in dissolved catalyst. Either will make the water much >more difficult to boil. I haven't taken my rig up to high enough >temperature to after methanol recovery to recover any water, so I >can't be sure at what temperature and pressure water recovery would >begin, but suspect it would be at a very high temp or low pressure. > >Dale >Sorry, I didn't make it very clear, did I? I've used much more than >30 gallons in processing fuel. In total, I have recovered and reused >about 30 gallons. > >Dale Which option you use is up to you really, depends what suits you and your set-up, the kind of oil you use, and your process. There are some further options too. One system constantly condenses off methanol vapours and recycles the condensate back into bottom of the mixing tank, then recovers all the excess at the end, seems very efficient. But I don't think that set-up is doing glycerine-FFA separation of the by-product. On the other hand, if it's good oil you're using with low titration results the by-product will probably stay liquid anyway and might be easy to separate even without the excess methanol. Best Keith ------------------------ 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/
