Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: Julian on December 28, 2012, 11:52:18 PM
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Ran my first ASM batch today. All went well up to demeth.
Titrated two stage ... titration of 1.25 using 0.1% NaOH and a base figure of 4.5. Gave me a figure of 2.7 litres ASM and 13 litres of Methanol for an 80 litre batch. Oil was very well dried by heating to 80°C and bubbling with a small compressor through the condenser.
Good separation of the sample at the end of processing and one of the clearest 3/27 I've ever had. Went on to demeth which I did for 4 hours at 75°C, recovering circa 4.75 litres. Stopped the pumps to allow glycerin to settle. Shed was at 20°C and the glycerin set in the pipe work after an hour. Quick warm with a blow lamp got it flowing and after a little glycerin ... jelly.
What the hell did I do wrong?
Has anyone else used WBD with an ASM batch?
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How did you get to 2.7L of ASM?
Calculation should have worked out to 2.3L using titration plus your base - 80 x 5.75 x 5
I don't think the WBD is the problem, but I'd say you have overdosed on the ASM. Without the water present, as you'd get with mixing NaOH and meth, you can use a base amount a lot lower than you're used to using. You could go down to a base of 3.5 or less and get a perfect pass with ASM.
I know you like to titrate, but try a titless batch and you'll be surprised how much less catalyst you'll need to use. As a comparison, I'd use a total of about 4g/l which would be 1.6L on your batch size.
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Ran my first ASM batch today. All went well up to demeth.
Titrated two stage ... titration of 1.25 using 0.1% NaOH and a base figure of 4.5. Gave me a figure of 2.7 litres ASM and 13 litres of Methanol for an 80 litre batch. Oil was very well dried by heating to 80°C and bubbling with a small compressor through the condenser.
Good separation of the sample at the end of processing and one of the clearest 3/27 I've ever had. Went on to demeth which I did for 4 hours at 75°C, recovering circa 4.75 litres. Stopped the pumps to allow glycerin to settle. Shed was at 20°C and the glycerin set in the pipe work after an hour. Quick warm with a blow lamp got it flowing and after a little glycerin ... jelly.
What the hell did I do wrong?
Has anyone else used WBD with an ASM batch?
What was your 10/90 result after stage one ?.
I only ever used 3.7 litres asm on a 180 litre batch for stage one.
more importantly have you managed to recover it ?
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I doubt overdosing ASM would cause a problem without water present somewhere, especially given the success of my deliberate overdose batches, which I've done quite a few of now. And I can't see WBD being the cause either (though removing Methanol will cause a jelly to form if there was water in there too - and adding it back would break the jelly).
I presume you don't have some of the originally dried WVO to do a hot pan test on? It may be one of those "we'll never know" situations. 80C and bubbling... maybe not enough? I take mine up to 105C to be sure.
How about the Methanol? Was it recovered from a previous batch (assuming it was if you're doing WBD). Do you have any to test with an alcohol hydrometer?
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When reading the opening post Julian my first thought was you have put too much ASM into the mix. My position is similar to Steve's where I use 3.0lts of ASM for my first stage titless with a further 0.5lts for stage 2. This is for a 150lt batch. The general consensus here is that you have used more than you needed to, but, it does not immediatly shed light on to your problem. This maybe a thread for the VOD where there are more ASM users and therefore more folk who are likely to have experienced the same issues.
On the other hand maybe the amount of meth recovered has had a detrimental effect on the chemistry. As Tony suggests it may be worth adding some of the recovered methanol back in.
It maybe time for you to try the titless method as well.
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I managed to make an almost jelly batch with ASM once (without demeth too) but that was because I was in a rush and the oil was too wet).
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My cure would be to add back in the glyc with 5% water mix for half an hour, settle and drain. take a sample and put it in the fridge. if all okay after half an hour dry the bio and all should be ok.
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Thanks for the replies. I'll post a picture of the samples and 3/27 test later when the camera battery has charged.
Logically there must have been water present and I'll recheck my sums for the ASM quantity.
BUT, why did I only get jelly after removing the Methanol? Usually if soap is going to form it happens when you add the catalyst. This batch processed normally up until the removal of the Methanol.
Unfortunately I drained the glycerol, what there was of it, into saw dust, so I can't reuse it. Would Glycerin from another batch help with the recovery?
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Gly from another batch has got to be worth trying, do it in a sample just in case.
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I did a standard batch (160) recently that was fine till demeth then after settling the glyc kept coming and coming about 120L! On close examination it was jelly. I left it in cubbies intending to heat it and get it back into the processor but, over several days, it separated or the jelly liquified whatever, I ended up with most of the bio back and more than usually glyc. I think it was because I was rushing and did not add enough meth and possibly the oil was wet.
It might be worth letting a sample sit and see what happens.
Dick
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Dick, that's exactly what's happened, except I don't think I have enough glycerin (although the 3/27 was excellent). This morning I managed to get the processor contents circulating and took a sample, then the main circuit blocked with residual glycerin and not even the Mono on the secondary circuit would shift it. So I've spent most of the day dismantling and clearing pipe work.
The glycerin is defiantly glycerin with attitude, the bloody stuff is like solid rubber! Now I've finally got circulation on both circuits, I'm heating everything up while running the pumps to get the glycerin remnants in suspension, ready for a quick drain.
However, the sample I took this morning started out looking like viscous bio, rather than thin soap that it did last night, has cleared to quite clear looking bio with a fluffy layer at the bottom ... most strange. Looks like I might get a part yield from this batch but I still can't fathom out exactly what's happened because of the point at which the soap appeared.
I'll get some pics. up after I've had a nice cup of Earl Grey and tidied up a bit!
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Dick, that's exactly what's happened, except I don't think I have enough glycerin (although the 3/27 was excellent). This morning I managed to get the processor contents circulating and took a sample, then the main circuit blocked with residual glycerin and not even the Mono on the secondary circuit would shift it. So I've spent most of the day dismantling and clearing pipe work.
The glycerin is defiantly glycerin with attitude, the bloody stuff is like solid rubber! Now I've finally got circulation on both circuits, I'm heating everything up while running the pumps to get the glycerin remnants in suspension, ready for a quick drain.
However, the sample I took this morning started out looking like viscous bio, rather than thin soap that it did last night, has cleared to quite clear looking bio with a fluffy layer at the bottom ... most strange. Looks like I might get a part yield from this batch but I still can't fathom out exactly what's happened because of the point at which the soap appeared.
I'll get some pics. up after I've had a nice cup of Earl Grey and tidied up a bit!
I have had jelly on 3 occasions when I first started using NAoH and was doing Titrated 2 stage (this was before testing dropout after stage 1) . It happened as soon as I had demethed
This was when I worked out that a base of 3.5 was where we were working from with 2 stage.
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Here are the photos ...
(http://www.palmergroup.co.uk/Bio/ASM soap.JPG)
From right to left ...
3/27 (still no dropout after 24hrs)
Sample taken at the end of processing, clear bio, no sign of soap.
50/50 mix of soap and methanol ... what looks like glycerin at the top is quite liquid (no idea what's going on)
50/50 with water, nice emulsion!
(http://www.palmergroup.co.uk/Bio/ASM soap 3 samples.JPG)
Again from right to left ...
Sample from 10 litres drained last night
Sample taken after reheating this afternoon
Sample taken this morning. Bio quite clear with a relatively small amount of soap at the bottom.
(http://www.palmergroup.co.uk/Bio/ASM soap 2 samples.JPG)
Comparison of this mornings sample, left and a very soapy one this afternoon, right.
(http://www.palmergroup.co.uk/Bio/Glycerol with attitude.JPG)
Glycerol with attitude ... it took quite a force to break the worm appart!
I can't have dried the oil properly, despite this method having worked fine for tens of batches now. I didn't do a HPT because, having fitted her a new kitchen bio is now banned in the kitchen. So I need a new means of doing HPTs ... something on which I've been working.
Richard was right, I made a silly mistake in my sums. My ASM figure should have been 2.3 litres. But next time I'll use a lower base figure too.
I think that a large amount of soap was produced, so much that when draining the glycerol followed by a large amount of soap, I assumed the whole batch had turned. In fact I must have drain off most of the soap, leaving reasonable bio in the processor and this is what I sampled this morning.
Although Steve seems to have had a similar experience, I still can't see why the soap is only obvious once the Methanol is removed, didn't you think that strange when it happened to you, Steve?
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Just been thinking (an exercise which is getting more difficult) ...
I dried the oil by heating and bubbling with large volumes of air from a small compressor. In this very dank, damp weather perhaps that's not such a good idea. I have coalescing filter on the air line but that didn't collect any water.
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What we do know is soap will remain suspended until the meths is removed,
I wonder if you had produced that much soap that even when some meths was still pressent there wasn't enough meths to keep it all in suspension.
It's only a stab in the dark, but there could be something in it.
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I'd have thought that Methanol would only hold trace amounts in suspension, not bucket fulls!
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I've never produced bucket fulls so I can't comment on that.
Before you say it, I know, I've produced a reactor full, twice.
It's still sat in drums and one day I'll get around to slowly mixing it in with my future batches.
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So, on these two batches of soap when did the soap first appear?
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Hi Julian
This is my take on things , as any soaps or excess base is soluble in meth then while there is plenty of meth then the batch would look ok regardless of how much of the soap/ base is in the the batch and on testing would still give good results.
On removing the meth then things become apparent with physical problems. This was the good thing about a open top reactor , being able to do visual inspections to see what's going on.
If you have all the gloop out and can finish the batch then I would save the gloop for the next batch and put it into the feed stock before a Glyc wash, this way you get to use the base chem's but if it is soap (I'm not convinced that its soap and think its excess base ) then the Glyc wash after will remove the water thus releasing the base chem's.
This is just a quick jot on things inbetween a million other things going on. Plus as on iPhone can't see picks.
Phons on tomorrow if you want a chat
Paul
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Although Steve seems to have had a similar experience, I still can't see why the soap is only obvious once the Methanol is removed, didn't you think that strange when it happened to you, Steve?
I did think it strange but put it down to overdosing as I was glyc washing too (possible partial reaction) and my research at the time was "jelly" meant overdose with NAoH whereas KoH was tolerant of overdosing.
At the time I went on to mixing the full 100% of Methoxide, using 80% for stage 1 and then doing stage 2 with a further 5% at a time. Never actually used the last 10% and got a clear pass. This 10% went in with the next glyc wash and so I got to a point where I was not using hardly any of the stage 2 amount so started doing a 45/5 after stage 1 to calculate stage 2 amount.
Not long before I stopped Titrating ! And realised that actually the JTF 3.5g base was actually accurate if you did it this way. Lots of dribs and drabs came out on VOD, most getting stamped on in some way lol.
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About 10 mins after the methoxide was introduced, the pump started to sound very labored so I took a sample,
the sample was stringy as it came out and formed a skin very quickly, soon after it was sold.
I now know this was down to wet feed stock.
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Hi mark
With regards to your 2 bucket fulls we can sort them easly in 1go much better than waiting to put bits into other reactions and maybe complicating future reactions
Paul
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Hi mark
With regards to your 2 bucket fulls we can sort them easly in 1go much better than waiting to put bits into other reactions and maybe complicating future reactions
Paul
No, no, I do bucket fulls. Mark does whole reactor fulls!
I'm guessing your next post will involve acid.
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Paul, the two bucket fulls are actually over 400L of solid creamy coloured stuff, rich in meths.
My thought were to stick say 10% of the batch size in before gly washing.
What do you have in mind ?
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I had the same thing on my second ever batch. The guy I got my machine from said I sould bury it in the garden.
3 months later I converted it to bio
I wasn't using acid at this stage so can still be sorted without acid.
Mark I will try and give you a ring tomorrow , when would be the best time.
Paul
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I'm at work today, so some time after 6:30pm, I'll pm you home number.
Thanks mate.