Thanks ever -so- much for letting me join your organization. I've just processed the first batch of wvo with KOH (1.5 kilo) and of course methanol at 21% into 100 litres oil. I was quite pleased with myself when I drained the dark brown glis off & saw that it had seperated quite well. I ran the high output heating pump that circulated the fluids at 57 C for an hour but would like to ask the question did I perhapse stop the circulation too quickly???
because when I did the 3 /27 test all the 25mm oil did dissolve apart from a minute amount of what appear to be quite clear minute crystals which formed at the bottom of the clear glass jar. At first however I noticed at the surface
edges around the jar there appeared to be a small amount off slightly opaque residue clinging to the jar which stirred into the methanol. A day later and I thought Id better do the water test. To my apprehension there is an emulsion middle layer which represents about a third the thickness of the bio deisel above. Please may I ask your advise- Do you think I should put the whole back in my processor & re heat & re settle before carrying out your careful wash proceedure ???? Kind regards Mick

Good day to you too old chap (from another Pom, who hasn't quite got this Aussie accent sussed yet )

I hour at 50C is enough to make a complete reaction, so as long as the temp stayed above that for the whole time you were mixing then that would have been enough. FYI I usually react mine for 1.5 hours, not strictly necessary but a bit of extra safety margin.

As for the 3/27 test that can fail due to a variety of reasons, such as water or other contaminants in the oil "using up" some of the methoxide, causing an incomplete reaction. Or you didn't use enough KOH possbily by titrating inaccurately or not using enough base.

You can try increasing the base KOH from 7 to 8 or 9 and see if that helps. The only problem with that is it increases the chances of an emulsion during washing, as you've already experienced. Just do the first couple of washes very gently, or hot water will decrease the chances of an emulsion.

As for the existing emulsion I would drain as much water off as possible, then take the good biodiesel off the top and deal with the emulsion layer separately, with heat, time or various other methods as described elsewhere (use the search).

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Sean

I use a very simple forumula to determine my mixing time, for every 50ltrs of WVO I mix for one hour. It's always produced good bio for me.

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Maverick
Canberra

Thanks for the good advice. This mornig at room temp the jar I have the sample in I notice now has the emulsion layer very much reduced to almost nil & I think given a little more time it will deminish altogether. I went onto the USA site & saw a guy called antifuel 1' letter in that forum & he seems to have a method whereby he uses sulphuric acid in the first stage. It seems he does this to reduce the soap content. I feel although my titration at 7 does not seem to show my various oil collections are too bad but I'm wondering if I try the acid method it may help the end product. He does not state if he uses KOH (as I do) however & it seems he clears his product to completion by settling and then filtering but not by washing. I hope he's going to send me some useful instructions soon. Thanks so much. best regards

OPE,
Google the "FATTA Method", which is a 2 stage (Acid then Base) process where the FFA in the oil are converted directly to biodiesel then the remaining acid is neutralised and sufficient caustic added to catalyse the triglycerides into biodiesel.
The additional work may be worth it if your oil is titrating high. How high justifies the FATTA methiod? I don't know. Perhaps other members would care to comment.

Tony

Thanks for all the good advice. After all my first batch of fuel didn't end up too badly. Its now washed ok after I did a very slow job with it. It's a good job I re-read instructions by USA's biolyle who gives classes re biodiesel & makes plant etc. I was going to fine spray water onto the top of the fuel ('oops') which is in a conical HDPE container but he said he puts his water in at the bottom & then bubbles it gently for the first wash. I did as instructed with warm water (5%) which was very milky when drained & proceeded for three more washes & the last was virtually clear. I'll let it sit now as he says & then perhapse heat it to dry it (in case) & then hopefully it will be usable... Best regards Mick

Tony thanks again for the info - I've not stopped looking at this site & have looked at a guy called D Kenny biodiesel forums eve comunity (USA) his method is similar to Fatta in fact on the same sheet on their site or a link to it the fatta method is first on the page & D Kennys method is just below it. I've just used his method & I'm quite chuffed that it turned out right first try. I was very apprehensive about the acid but needn't have been although you can see a slight mist over the hdpe carboy opening when you put the acid in although in my case the oil titrated at 9 KOH
so I added 6 gms /Ltr hoping that the titration after the acid base would be 3 but it stuck on 4 so I just added another grm per litre & started the second reaction. Mr Kenny says I may have had water in the oil but I did not check this so I'd better do this next time. He says the water stops the reaction of the acid. when I worked it out it only cost another 37pence to process the 150 litres but I'm pleased I condisended to try the acid method -it worked for me.. Thanks & Regards Mick in the UK

Tony - This is a P.S. to my posting with thanks.. regards the titration level before acid. It appears in the USA the commercial producers use the acid method whatever the titration of the oil. There was one producer that stated he uses the acid method down to 1 Titration. I suppose they consider the maximum yield of usable fuel to outlay.It seems the reasoning behind this process method is that it reduces soap in the reaction. I see dkenny has helped folks thru processing fat of 80 titration!!!!!It's all very interesting isn't it.. Regards Mick In the UK

I am happy that you have had success with the processing of your oils using this technique.

The main issue with the acid stage, as you have indicated, is the water which is released in esterifying the FFAs. The water stops the reaction as the concentration increases, stopping the reaction eventually. For very high titrating oils you will need to change the acid possibly several times to lower the titration to an acceptable level.

I have not researched the amount of titration reduction each acid stage provides.
Perhaps this is something you can document.

Another issue is the disposal of the wet acid. Have you found any way of removing the water from the acid to allow you to re-use it?

Regards,
Tony

Tony When the process was finished after the second stage I checked the bio with a test strip and it showed that the acid had been neutralised so I hope there was no residual acid left in the whole of the liquid. However I think I started to wash this batch too soon after processing because I read on the net that a Mr Lyle waits for at least three days to let it settle before washing commences. too anxious to get it washed it has turned cloudy so I'm going to look into making filters to filter it dry. Thanks Regards Mick