Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: Tony on May 17, 2012, 10:33:51 PM
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Since it's summer I figured it was time to try and use the 60l of HMPEs I'd stored from winter.
They're all in a 120l barrel so I made a brew of bio and dumped in 40l at 90C and stirred the resulting mix (which must be about the 40C mark). Anyway, all the HMPEs have melted, so I'm bubbling and will see what happens. Hopefully I'll only be left with a smaller layer of stubborn HMPEs at the bottom. Fingers crossed!
Currently sipping some red Methanol antidote since I probably breathed a fair bit.
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I've just received a set of samples from Nige to test in the souped down freezer, along with three set of samples I've accumulated.
If you think it will reveal anything I'm happy to include some of yours too.
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Do you remember the HMPEs I brought to the BBB last year?
It was blazing hot and they were in a small plastic bottle looking like solidified honey!
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No, don't think I saw them.
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Ice cream anyone?
(https://lh5.googleusercontent.com/-2UTnIQwOznI/T7ahZSTdU4I/AAAAAAAAA6E/Gnv0y4i_qqE/s336/IMG_20120518_202229.jpg)
The liquid is quite thick now its cooled, I think they're reforming.
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I forgot to update this, the HMPEs did indeed reform. I wonder if I should've taken it up hotter (over 60C).
At any rate I'm getting HMPE formation in new batches back again now it's cooler, really very annoying!
Presumably the melt point is affected by hydrogenation of the fatty acid?
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Hi tony
How are you finishing your fuel is it water wash or de-meth settle
I have a bit of a idea but can't find the time to work on them can you message me with a contact number for a quick chat.
Paul
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Spoke to Paul and now have a few things to experiment with - cheers chap! 8)
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Any chance of sharing pre experimentation?
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Hi Julian
Drop me a message with a contact number so we can have a quick chat about some more trials before I go and put loads on the forum
Cheers
Paul
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I'm getting them on the last batch.
First time in 3+ years of demeth & settle.
I've never demethed over 75C until this batch, which I ran at 90C. This, of course, has been oft speculated before.
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I've never demethed over 75C until this batch, which I ran at 90C. This, of course, has been oft speculated before.
I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.
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It is going to be interesting to see if anyone who has adopted the titrated in-processor water wash process gets any problems with HMPEs.
I strongly suspect we wont (I certainly hope not)
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It is going to be interesting to see if anyone who has adopted the titrated in-processor water wash process gets any problems with HMPEs.
I strongly suspect we wont (I certainly hope not)
If my theory is correct then I think that they are a thing of the past for you ( let's hope I'm right )
Paul
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Sounds like I need to buy another temperature controller to run chilling tests in the spare freezer again.
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I have HMPE's forming in my drying tank (formally settling tank) that was cleaned out before I started titrated water washing.
Now this is only my second batch and I had problems with my first one (details allready posted),
but I still WBD at 85°c before washing.
Due to the recent drop in temps I can't say if there's more now than when I was settling .
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Hi mark
If your up for trialling something I have a idea that sould eliminate the hmpe's , I just have to get my head round wbd and water wash.
If I can get you to prevent the formation then you met not need to water wash.
Can I ring you in few days
Paul
I think the amount iproduced is down to the de-meth so we have to prevent them forming here
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You have a PM.
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My short journey into Whole Batch Demeth, especially when added to two stage no tiration processing was the only time I experienced significant HMPEs.
There seems to be something about the WBD process.
Glyc washing seems to be a far more energy efficient way of making use of the excess methanol without problems with HMPEs
I am now down to only 40 litres of methanol per 300 litre batch (using Sodium Methylate and Glyc wash) which means 1500litre of bio per barrel of methanol
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I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.
Well I won't be doing another WBD for a while. It was done mainly to test the speed / efficiency of the new coil in tank condensor.
Have none of the proper chemists put up any theories? I was trying to think and Google round it earlier and the best I could arrive at was:
WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!
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I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.
Well I won't be doing another WBD for a while. It was done mainly to test the speed / efficiency of the new coil in tank condensor.
Have none of the proper chemists put up any theories? I was trying to think and Google round it earlier and the best I could arrive at was:
WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!
Where did that bit of info come from?
He's (assume it's a he) mentioning things I've never even heard of before!
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WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!
[/quote]
Yer you know what he's probably right
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I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.
Well I won't be doing another WBD for a while. It was done mainly to test the speed / efficiency of the new coil in tank condensor.
Have none of the proper chemists put up any theories? I was trying to think and Google round it earlier and the best I could arrive at was:
WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!
Where did that bit of info come from?
He's (assume it's a he) mentioning things I've never even heard of before!
'He', Julian? I'm flattered.
Came across that stuff in one of those 40 page academic research papers. I remembered the 2 types from A level organic chemistry 30 years back.
I doubt it's that simple or the Industry would have a fix for 'bio from solids', instead of additives.
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A question
is WBD when u drain all the clyc and recover the meth from the whole batch before dumping out into a settling tank..
rob
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Hi Rob, welcome to biopowered.
The answer to your question is No and Yes!
With WBD, once you have a 3/27 pass, you go straight into demething the whole shooting match, both Glycerin and Bio. The original method devised by Chug, advises to only recover Methanol down to the stoichiometric quantity, ie leave enough Methanol in the batch to prevent a reverse reaction.
In reality, many people have taken demething further with no reported ill effects.
The wiki page covering WBD is here ... http://www.biopowered.co.uk/wiki/Whole_Batch_Demeth
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I ended up with about half a bucket full of HMPE's from two batches last winter during the cold snap when it went below freezing, I kept them to one side and they all melted back to liquid bio and were used up by the end of May.
I WBD and go up to 85-90°C when demething and don't get any HMPE's until the temps drop below freezing when I would naturally expect to have them drop out at as the temp falls below their relevant melting points.
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Hi Rob, welcome to biopowered.
The answer to your question is No and Yes!
With WBD, once you have a 3/27 pass, you go straight into demething the whole shooting match, both Glycerin and Bio. The original method devised by Chug, advises to only recover Methanol down to the stoichiometric quantity, ie leave enough Methanol in the batch to prevent a reverse reaction.
In reality, many people have taken demething further with no reported ill effects.
The wiki page covering WBD is here ... http://www.biopowered.co.uk/wiki/Whole_Batch_Demeth
Thanks Julian, its rob from the other forum, now as im more bio, ive joined this one too.
ok, so Paul if you are seeing this, then it looks like i dont do a WBD, as i drop all the clyc after my 10/90 and then demeth..
so the experiment you want me to try may not work..
rob
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As I read it the Author of this is actually saying
1."WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type."
2. "But that happens with hydrogenation"
3. "whereas during WBD the bio gets pumped full of air which is the opposite"
4. "I'm out!"
So he is still saying it does not make sense to him ! !
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[quote ]
ok, so Paul if you are seeing this, then it looks like i dont do a WBD, as i drop all the clyc after my 10/90 and then demeth..
so the experiment you want me to try may not work..
rob
[/quote]
Hi rob
It's not just wbd that get hmpe's , and the experiment will be a lot easer on just bio de-meth than it would be in the whole batch , if it sl goes well then I will start work on the wbd method.
Paul
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I've had HMPE's (if that's what they really are) after very thorough mist washing, but they have only occurred at very low temps (I guess -5 deg and worst). PF, do you think that what's dropping out at higher temps are different to what's dropping out at very low temps.
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well, im just emptying a batch i made about 6 weeks ago into cubies, this was a mixture of fats, but mostly peanut oil , my god, i have a big load of HMPE's or whatever, i reckon 40 litres of the stuff, luckily this is going to spain to get filtered and used...
will post pic
im in the process of making another batch, but no experiment as yet, just the usual with 100% rapeseed, usual 180, titless, clyc wash, 24.5l meths, 760 of sodium,
now waiting for the clyc to drop, 8 hrs at least, but have 2.5 dropout, 10/90, so mixing ready to go 7L,meth and 270 of sodium
will drop most clyc tonight, then the remainder in the moring, before i run up again..
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I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.
Well I won't be doing another WBD for a while. It was done mainly to test the speed / efficiency of the new coil in tank condensor.
Have none of the proper chemists put up any theories? I was trying to think and Google round it earlier and the best I could arrive at was:
WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!
Can you elaborate on wbd upsetting the equilibrium please? what do you mean by this?
and how would a wbd batch get pumped full of air?
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Presumably upsets it because the Methanol is removed while the catalyst is still present.
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ok, I understand that theory of no meth left so catalyst starts attacking the bio but maybe what I should have asked is what is this equilibrium?
and is there an equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio
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I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.
Well I won't be doing another WBD for a while. It was done mainly to test the speed / efficiency of the new coil in tank condensor.
Have none of the proper chemists put up any theories? I was trying to think and Google round it earlier and the best I could arrive at was:
WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!
Can you elaborate on wbd upsetting the equilibrium please? what do you mean by this?
and how would a wbd batch get pumped full of air?
Meth removed = possible reverse reaction is what I meant.
I run a venturi on demeth, that's where the air's introduced.
They were just some ideas, so one for chemists like I said.
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Aha I see it was thrown up possibility/theory ...sorry
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I've had HMPE's (if that's what they really are) after very thorough mist washing, but they have only occurred at very low temps (I guess -5 deg and worst). PF, do you think that what's dropping out at higher temps are different to what's dropping out at very low temps.
Mate I think maybe yours is at a much lower temp than others because you do tend to speed wash... what I mean by that is not worry too much about settling times which means you drain of a fair bit of milkier stuff with each lot of water, lowering your yield slightly. Could this milkier stuff ( ie: the last bit that wants to split ) be what turns out to be the higher temp Hmpe's in the finished Bio.
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In the colder months like now I stop recovering methanol and instead prefer to 5% pre-wash, drain glycerol, bubble and settle as I find this reduces hmpe's. I've no idea why but it's significantly better I've noticed.