Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: Tony on February 25, 2013, 04:23:28 PM
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So we have a nice HMPEs page, but recent findings might suggest this page is not factually correct.
http://www.biopowered.co.uk/wiki/High_Melt_Point_Esters_%28HMPE%29
I think we might need to revisit this.
We know:
- that they give cloudy meth in a 3/27 test
- they form emulsions with water
- water washing seems to prevent it
- reprocessing it as part of another batch (while treating it as an inert component) produces fuel that doesn't have high melt components anymore
- WBD might(?) promote their formation in winter
The suggestion is that monoglycerides are the culprit as they have an elevated melt point, give the cloudyness to 3/27 and would wash out from a batch, which seems to fit the evidence.
Surely if they were just high melt FAME then reprocessing would not in any way shorten or dehydrogenate the fatty acids chains to reduce the melt point, so this seems the more likely explanation.
So should we rewrite the HMPEs page to be a "High melt point components" or "surviving winter" page, mentioning both feedstock related High Melt Point Esters (from Palm oil) and monoglycerides (from incomplete reaction or partial back-reaction)?
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I think you are right! The high melting or waxy stuff seems to have different properties with different brewers. The commonality seems to be it's appearance, consistency and the fact that they appear in the winter.
At some point we'll get a definitive answer as to what the stuff is - probably more than one thing. In the meantime describing it, along with it's typical characteristics and methods for dealing with it would be a sensible way forward.
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I think you are right! The high melting or waxy stuff seems to have different properties with different brewers. The commonality seems to be it's appearance, consistency and the fact that they appear in the winter.
At some point we'll get a definitive answer as to what the stuff is - probably more than one thing. In the meantime describing it, along with it's typical characteristics and methods for dealing with it would be a sensible way forward.
I'd go along with that train of thought. I've wondered for some time if we are all seeing the same thing, but giving what we see we give convenient label.
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So we have a nice HMPEs page, but recent findings might suggest this page is not factually correct.
http://www.biopowered.co.uk/wiki/High_Melt_Point_Esters_%28HMPE%29
I think we might need to revisit this.
We know:
- water washing seems to prevent it
Whatever I pull out with my Fuge at or around zero c is the same as Nathan pulls out, however he water washes and I do not. what we both pull out fits what has been called Hmpe's so I cannot be convinced that water washing does in all cases prevent it.
Having said that I would not be certain that what we pull out would cause a vehicle to break down unless the temp remained below zero for a sustained period.
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I think Tony's remark about water washing preventing "them" might be little enthusiastic. In all the tests I did what seemed obvious was that washing reduced but didn't prevent them.
There are folk who claim washing prevents the, based on experience, but that's a little like trying to prove a negative, especially as we are fairly sure they are feedstock dependant.
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Did you see the pic I posted yesterday? It kinda worried me a bit coz this time there was visual evidence of the stuff (unusual) - Could be be the longer duration in the cold or something else?
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I think Tony's remark about water washing preventing "them" might be little enthusiastic. In all the tests I did what seemed obvious was that washing reduced but didn't prevent them.
There are folk who claim washing prevents the, based on experience, but that's a little like trying to prove a negative, especially as we are fairly sure they are feedstock dependant.
If they were mono's / di's as a result of reverse reaction, then -
Water washing at a low enough temperature where the reactions would be slowed would not create them &
Water washing may then remove them, if they were formed.
It is strange how some people have so much issue with them, but others have none.
Currently, im removing the glyc at the end of s1 and then dosing s2 / going to bed / opening the venturi to vent to atmosphere all at the same time. (ie part batch WBD, if that makes sense?)
I leave the fuel in a settling drum for weeks though, so maybe i create them, and they form and drop with the soaps?
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That's certainly what happens with mine, it's a layer of cream over the settled (and usually solid) soaps. I top skim the bio through the drywash tower then pour the rest into another drum, accumulating this creamy stuff - which is what I used with the successful reprocess batch.
Even after drywashing I store the fuel in a 205l drum and if the temp drops sometimes I get more at the bottom of that, from the previously top-skimmed stuff.
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The only time I've been able to see them in the fuel is the last batch that had sat for four months prior to filtering. Normally they are not visible in the fuel - the bio looks visually really good and ready for use, yet they appear after filtering.
Does this suggest that there is a high distribution of very fine wax elements with a similar SG to BD which conglomerate whilst being spun which makes them drop out.
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Right then, here's a different take for you. I have only experienced this gel like cloud referred to as hmpes once in my production of bio. It happened this winter when using 50% rape oil and 50% KCT (soya.)
My usual feed stock would be mostly soya and some palm, which are both not seeds! I am sure that this gel like cloud is actual mucilaginous fiber. www.organicannie.com/Gel%20Seeds.pdf This link give a brief description.
As i have stated before we inadvertently us this in cooking to form emulsions in the forum of mustard seed and rape seed oil.
It is massively water absorbing, and in its raw refined state is a gel like substance used to aid digestion in oriental cooking.
Being a gel it would melt when heated and reform when cold.
Could it not be that water washing would help to remove this by flushing it out? More to the point could seed based oil feed stock be the problem?
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What is curious is why would making biodiesel (without washing, so no water present) from liquid feedstocks result in some solids? To me this suggests a chemical change rather than contaminants.
But, that said, it seems pretty certain there are several ways to end up with fuel waxing, and mucilaginous fibre may be one of them. The problem is distinguishing between them.
Is there any way to identify mucilaginous fibre? I'm thinking effect of acid, solubility in various solvents etc.
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Right then, here's a different take for you. I have only experienced this gel like cloud referred to as hmpes once in my production of bio. It happened this winter when using 50% rape oil and 50% KCT (soya.)
My usual feed stock would be mostly soya and some palm, which are both not seeds! I am sure that this gel like cloud is actual mucilaginous fiber. www.organicannie.com/Gel%20Seeds.pdf This link give a brief description.
As i have stated before we inadvertently us this in cooking to form emulsions in the forum of mustard seed and rape seed oil.
It is massively water absorbing, and in its raw refined state is a gel like substance used to aid digestion in oriental cooking.
Being a gel it would melt when heated and reform when cold.
Could it not be that water washing would help to remove this by flushing it out? More to the point could seed based oil feed stock be the problem?
Hmm, interesting theory. I can't start to understand the chemistry involved, but I have to admit the years when I experienced the biggest problems with "HMPEs" was when just about all my oil was coming from one supplier and they used exclusively non GM rape from Agri.
Trouble is it's often difficult to know the provenance of all the oil you collect.
I still have the redundant freezer and a new controller, if suitable samples can be obtained.
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What is curious is why would making biodiesel (without washing, so no water present) from liquid feedstocks result in some solids?
I posted a link up a while back (cant post it again, as who knows where it is!) that had the melting points of a triglyceride, and then the di, and mono.
IIRC the di and mono had really significantly higher melting points than the tri.
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Tony, The Solids or gel if you like can only occur if moisture is present the fibres we are talking about are tiny but they collectively have massive ability to absorb water (possibly from the air, condensation in cubies and containers is quite common.) hence the gel or solids forming.
This is all guess work based on observation of bio production and my own experiences with gels and emulsification agents used in modern cooking. I know for a fact that rape seed oil emulsifies very easily where as olive oil dose not. This is down to the presence of mucilaginous fibers from the rape seeds and their ability to retain water.
Probably all thoughts of an idiot but there they are!
Chris
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I know for a fact that rape seed oil emulsifies very easily where as olive oil dose not. This is down to the presence of mucilaginous fibers from the rape seeds and their ability to retain water.
Very interesting, I honestly did not know there was a difference!
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What is curious is why would making biodiesel (without washing, so no water present) from liquid feedstocks result in some solids?
I posted a link up a while back (cant post it again, as who knows where it is!) that had the melting points of a triglyceride, and then the di, and mono.
IIRC the di and mono had really significantly higher melting points than the tri.
Found it Julian
http://www.rikenvitamin.jp/int/emulsifier/spec/dmg.html
Though it does say "fully hydrogenated" which if I understand my chemistry rightly would increase the melt point as well, so can we say for sure a mono/di has a higher melt point than the triglyceride it came from (or the methylated esters)?
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Right then, here's a different take for you. I have only experienced this gel like cloud referred to as hmpes once in my production of bio. It happened this winter when using 50% rape oil and 50% KCT (soya.)
My usual feed stock would be mostly soya and some palm, which are both not seeds! I am sure that this gel like cloud is actual mucilaginous fiber. www.organicannie.com/Gel%20Seeds.pdf This link give a brief description.
As i have stated before we inadvertently us this in cooking to form emulsions in the forum of mustard seed and rape seed oil.
It is massively water absorbing, and in its raw refined state is a gel like substance used to aid digestion in oriental cooking.
Being a gel it would melt when heated and reform when cold.
Could it not be that water washing would help to remove this by flushing it out? More to the point could seed based oil feed stock be the problem?
Are we all talking about the same stuff? I'd not describe the wax cake that we are seeing as gel like, it like parafin wax. And I don't believe that you'd know you have it without filtering it out. As mentioned earlier in the thread, prior to filtering the fuel looks clear, bright and shiny and appears ready for use. It only appears as part of the filtering process. In the summer it doesn't form in the winter it does.
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Well for me this kind of thing appears without filtering, as a settled layer:
(http://www.biopowered.co.uk/w/images/f/f2/Hmpe1.jpg)
It was lots of this that was reprocessed successfully.
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mate, what are we looking at a skin on the surface or things floating? Can't quite make it out.
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Well for me this kind of thing appears without filtering, as a settled layer:
(http://www.biopowered.co.uk/w/images/f/f2/Hmpe1.jpg)
It was lots of this that was reprocessed successfully.
Geezus Tony, if I added up all my soapy/hmpe's stuff from the last 5yrs I wouldn't have that much.
WHAT are you doing to make that crap?
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It's a layer of bio and below it a couple of inches of creamy stuff. I collect it all together.
Never appear in summer but in winter I get a fair bit.
I've always followed the WBD process, though perhaps a little too enthusiastically on the Methanol recovery (usually take the batch up to 90C). Perhaps I get a reverse reaction into mono/diglycerides,though I never recover enough Meth to think that is the case. I'll take it a little easier on a batch I'm planning for this weekend.
I'm not too bothered by having to collect them up beyond the extra bit of hassle. At least I know they won't get wasted now, as they can be reprocessed.
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OK so last batch I did I took the WBD up to 95C and left demething for a couple of hours. This is much, much longer and hotter than I would otherwise WBD.
The settled batch is about 1/3 by volume "creamy stuff". I think this also points to the reverse reaction case.
I'm doing a batch now, I'll go especially easy on the WBD and see how that turns out.
Then suck in these creamy bits for a bit of reprocessing.
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OK so last batch I did I took the WBD up to 95C and left demething for a couple of hours. This is much, much longer and hotter than I would otherwise WBD.
The settled batch is about 1/3 by volume "creamy stuff". I think this also points to the reverse reaction case.
I'm doing a batch now, I'll go especially easy on the WBD and see how that turns out.
Then suck in these creamy bits for a bit of reprocessing.
I remember saying in a post quite some time ago that I reckoned what we call HMPE is a sign of a reverse action.
I drop WBD as the weather cools and have nothing that even resembles the dreaded stuff.
I also said that Stoich should be set at 13 - 14% as against the generous 12.5% suggested by Chug.
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OK so last batch I did I took the WBD up to 95C and left demething for a couple of hours. This is much, much longer and hotter than I would otherwise WBD.
The settled batch is about 1/3 by volume "creamy stuff". I think this also points to the reverse reaction case.
I'm doing a batch now, I'll go especially easy on the WBD and see how that turns out.
Then suck in these creamy bits for a bit of reprocessing.
I remember saying in a post quite some time ago that I reckoned what we call HMPE is a sign of a reverse action.
I drop WBD as the weather cools and have nothing that even resembles the dreaded stuff.
I also said that Stoich should be set at 13 - 14% as against the generous 12.5% suggested by Chug.
I'm keen to get to know how to avoid them in winter in order not to be unwittingly making them in summer, where they will remain liquid and appear OK, if that makes sense?
I agree that stoic should be treated as higher, I think the 12.5% was an average with some bracketing either side depending on feedstock.
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Just dried some more oil, sucking in the creams for go at reprocessing to see if it works again. Expect it will - though if there is anything anyone can think of to try as an experiment now would be a good time to mention it (probably will run the reprocess batch an evening this week).
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I've done a rewrite - please comment!
http://www.biopowered.co.uk/wiki/Winter_waxing
(Using the word "wax" to cover both possibilities).
Not mentioned greenchef's theory on the page yet - footnote required?
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I take it from the stunned silence that no-one has any major objections then ;)
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Look beautiful tony!
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Look beautiful tony!
Is it my tights? 8) Oh wait, the page, right!
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One of my collections last week had what looked like parafin wax settled on the bottom of his unused KTC Soya.
There was about 0.5L in each of his cubbies. Could it be this that appears in the Bio?.
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One of my collections last week had what looked like parafin wax settled on the bottom of his unused KTC Soya.
There was about 0.5L in each of his cubbies. Could it be this that appears in the Bio?.
hmm not sure! A clear 10/90 should show a near 100% reaction. There's something happening post reaction. I've had the stuff from very clear / runny feedstock as have others.
Sooner or later, somebody with some decent lab test kit will put us all out of our misery!
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One of my collections last week had what looked like parafin wax settled on the bottom of his unused KTC Soya.
There was about 0.5L in each of his cubbies. Could it be this that appears in the Bio?.
Firstly welcome to the forum :)
Does he keep the oil somewhere cold?
All oils contain triglycerides with all manner of melt points, some of them do indeed wax before others. Turning such a thing into biodiesel normally elevates the melt points such that at the same temp, this waxing is not seen. I was of the impression that biodiesel conversion raised the waxing temp by 5-10C or so.
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I wonder if the likes of Chemiphase or Trinity could look at their winterising formula to solve this problem?
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One of my collections last week had what looked like parafin wax settled on the bottom of his unused KTC Soya.
There was about 0.5L in each of his cubbies. Could it be this that appears in the Bio?.
Firstly welcome to the forum :)
Does he keep the oil somewhere cold?
All oils contain triglycerides with all manner of melt points, some of them do indeed wax before others. Turning such a thing into biodiesel normally elevates the melt points such that at the same temp, this waxing is not seen. I was of the impression that biodiesel conversion raised the waxing temp by 5-10C or so.
The oil is kept in a warm room. I brought some home to test. It is hard, white, gritty and melts into a clear liquid. Could this be the antioxidants used in ktc.
Ken
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Just got an inverted 750cc rotor fuge for feedstock. I'm going to experiment and see if there are improvements with very clean oil vs. just strained and glyc washed.
Off to see JRL for a tank to do this next week, should have the new processor in a week or so too, so I'll any findings.
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One of my collections last week had what looked like parafin wax settled on the bottom of his unused KTC Soya.
There was about 0.5L in each of his cubbies. Could it be this that appears in the Bio?.
If the establishment uses frozen chips what you could be seeing is palm oil residue.