Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: Dickjotec on September 15, 2013, 10:35:50 AM
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Also posted on vod
First time ever I have a jelly batch in the processor. 6 years processing and never had it before and don't know the best way forward.
Normal process. For me
34l meth 1100 NaOH
Suspect wet oil
It is still liquid in the processor at 65 degrees.
What is the best way forward.
Help Dick
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I've recovered a couple of jelly batches and done some successful tests on some Womble gel.
Try a sample first ... just add more catalyst and methanol incrementally. If you study things closely it should change to a clear stage and you should get a small temperature rise of a degree or two. With a little more catalyst and methanol go cloudy . At this point you should see glycerin start to drop.
I run my entire batch like this now and it works well for me.
My guess is that gel is the result of insufficient catalyst (for whatever reason).
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On my way to try
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Good luck.
This is a photo of the stages I found when recovering from a gel.
(http://www.palmergroup.co.uk/Bio/Three%20stages%20plus%20water%20wash.JPG)
A more expansive explanation is in this thread ... http://www.biopowered.co.uk/forum/index.php/topic,1264.15.html
Post up if it works, it may be worth adding to the wiki page.
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Looks promising.
Did a test, 2g NaOH 50ml meth 1l from processor. Some splitting. Upped the meth and looks OK.
I have added 400g NaOH to 9 L meth and processed for an hour at 65c . Several samples have split and settled so it is all now settling for an hour then we will see!
I don't think I will WBD this batch I case it goes T up again.
Thanks for the advice.
Dick
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Once you've got glycerin to drop, you should be able to treat it as normal. The only difference may be slightly more soap than normal.
Any idea what the cause may have been ... high titrating oil, wet oil, miss calc. on quantities?
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Once you've got glycerin to drop, you should be able to treat it as normal. The only difference may be slightly more soap than normal.
Any idea what the cause may have been ... high titrating oil, wet oil, miss calc. on quantities?
A combination I think. The oil was high tit though I didn't titrate it but it always is from one supplier and I usually use that for other things as it is very clean but I needed a top up. It was also wet. One of the pickups must have left a lid off or dumped washing water in the drum. I dry by heating and draining over a number of days and that has always done the job before but this time I got out more free water and the oil must still have been wetter than I thought. Unfortunately I didn't have any gly to wash it but then I rarely do. All my vehicles would run on veg so I don't normally go for a full conversion anyway.
I have drained the glyc and got more than normal and the bio is now demething. I will give it a couple of hours then settle and see what it is like. At least I will have some liquid glyc to wash the next batch! (After my usual WBD is sets like stone as I don't usually prewash before demething to keep the meth pure and the glyc solid for disposal)
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I have trouble believing the ammount of methanol you've used on this batch Dick. Quite shocking really. For a 160lt batch you've used 34lt in the initial batch and a further 9lt in the recovery process......43lt for a 160 batch. It's not Trinity meth is it?
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I have trouble believing the ammount of methanol you've used on this batch Dick. Quite shocking really. For a 160lt batch you've used 34lt in the initial batch and a further 9lt in the recovery process......43lt for a 160 batch. It's not Trinity meth is it?
No but only 29l is fresh meth from Basic and I have run a number of batches with the same fresh meth. I will try using less next time, I have to confess that I don't change the process except if I have an experiment like two stage etc but I will cut down the meth next time, promise!
I have already got 12l back from the bio.
Dick
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Next stage of saga. Demeth going fine then foam! So I now have bio contaminated meth.
The rest is in the settling tank with a good 'head' of foam. Will it be jelly when it cools. Time will tell.
I have flushed the processor with clean oil so, hopefully, it won't have any blockages!
Now for a shower and glass, or two, of wine.
Dick
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Don't worry about the foam, it just shows you've got the Methanol out of your biodiesel. Leave it to cool/settle then either scoop the foam off or stir it in (it'll sink).
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Tis morning the samples that were liquid yesterday were jelly. A shake made them liquid. The settling tank was a bit jelly at the top but liquid at the bottom so it is all back in the processor warming up. I have put a bit of the reclaimed meth back in and taken samples. The Venturi gauge shows full suck so it can't be too thick.
What to do next?
I will give it till tomorrow in the processor to see what happens to it and the samples.
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Run it through another demeth cycle.
I've found that if you have a lot of soap, jelly will form as the methanol evaporates - but only as long as some methanol remains. If you remove all the methanol, you get biodiesel and soap as usual.
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I don't think it is meths remaining as I understand foaming is a sign that all the meth is out?
Update. It is a very thin jelly this morning. It pumps (tam105) and samples liquefy with a gentle shake. The glyc which was not demethed has set solid. Usually if I don't wbd demeth then it stays liquid for guide a while.
One of the test tube samples I took yesterday cleared nicely with an obvious layer of soap at the bottom but that is also jelly.
I have emptied the processor and have 150 ish of jelly bio in cubies. It has not fully reacted but I am loath to add more NaOH incase it makes it worse it has already had 1600g!
I think I will mix it in with the next few batches and reclaim it that way.
Thanks for support
Dick
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Feeding it intro the next few batches should work out OK. Don't forget it may still contain water but that should come out if you mix it with the oil before dewatering.
Personally I'd have added more catalyst and tried to fully convert it, then deal with the soap ... possibly an acid wash.
Which ever way you go, glad to hear that you managed to recover it.
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I don't think it is meths remaining as I understand foaming is a sign that all the meth is out?
Some of the meth is out - enough to start the soap precipitating. What remains in solution is what causes the jelly. You're on the limit of what can stay in solution.
But of course, while it's jelly, it's more difficult to evaporate the remaining methanol resulting in a sort of catch-22.
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I will have an experiment on on of the cubies. A bubble for 24 hours with it warm and liquid should get any remaining meth out.
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I have tried fully demething jelly (in a pan) and my findings were that the jelly reformed on cooling.
Hence, that it was *not* just the meth holding the suspension.
I then tried multiple heating / cooling cycles, without agitation, and that did not work either.
My best solution to date has been to can the product, forget about it, and then come back a long time later, when, eventually, about 2/3 seems to split to clear bio, leaving a layer at the base (which can go in with the glyc wash on a new batch)
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No problem to leave it but it is fascinating. In a test tube it looks clear but sets to a very weak jelly. If not handled gently it becomes liquid again. I have bubbled the first cubie out of processor all day and it seems very liquid. I have taken samples to see what happens overnight. It is still bubbling. The other cubies seem liquid but time will tell.
Out of interest I added miss fuel to a sample (well it stops gelling in winter!) no difference.
I will try mixing 50/50 with bio tomorrow and see if that makes any difference.
Will try heating to boil off any meth or water as well.
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Well the previous solution to that has been to mix with glyc to slurp out the remaining water and then separate and demeth as per normal.
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It would seem Julian and I disagree on this one.
I'll be interested to hear how your cubbie does.
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It frothed over well and, so far, a sample has not jelled but I won't know till tomorrow. Hope to have more time to play at the we. 60l back in processor with some good oil ready to process. Will do a glyc wash first then see how we go on a two stage. Heating up ATM.
Dick
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It would seem Julian and I disagree on this one.
Disagree seems too strong a word!
I have no doubt in the slightest that you have had success with your method.
However, i tried it on my product, and did not meet with the same success.
No one method suits every situation - if it did, we would never even need to talk about Jelly in the first place : )
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Unfortunately the only glyc I have got is from the jelly batch. I assume this will already be saturated? I can try a mini batch reintroducing the glyc if it is thought the glyc will be dry enough to suck any water out
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Dick, I can drop you off some glyc on my way to Cardiff on Sat morn if you want? no demeth or pre-wash water been near it.
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That's a kind offer but I have a plan. The glyc from the Sunday batch will give me some 'clean' glyc to try on the remaining jelly.
Have a good wild camp
Dick
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Dick - just a thought.... was this a batch using the latest meth we purchased? I've not used mine yet but my next batch will and now I'm having nightmares about jelly!
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Yes it was but don't worry it is the third with that meth, the others were fine. It was caused by laziness on my part in not drying the oil properly. It was very grotty oil that I thought would be ok as I have never had jelly before.
Hope that puts your mind at rest.
Dick
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Disagree seems too strong a word!
Yes, it does a little doesn't it. Maybe just that we've had differing experiences?