HMPEs or monoglycerides?

[Tony]

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)?

[nathanrobo]

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. 

[Tony]

Well for me this kind of thing appears without filtering, as a settled layer:



It was lots of this that was reprocessed successfully.

[nathanrobo]

mate, what are we looking at a skin on the surface or things floating?  Can't quite make it out.

[Jamesrl]

Well for me this kind of thing appears without filtering, as a settled layer:



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?

[Tony]

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.

[Tony]

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.

[Jamesrl]

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.

[Tony]

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.

[Tony]

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).

[Tony]

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?

[Tony]

I take it from the stunned silence that no-one has any major objections then 

[Greenchef]

Look beautiful tony!

[Tony]

Look beautiful tony!

Is it my tights?    Oh wait, the page, right!

[kensterathame]

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?.