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Biodiesel => Chemistry and process => Topic started by: willbuild on March 01, 2014, 12:30:54 PM

Title: white layer in 50/50 test
Post by: willbuild on March 01, 2014, 12:30:54 PM
my feedstock was gloppy Chinese oil. I could not get a clear 3/27 pass with no fall out.
Kept adding Kohl with alittle methanol to no avail.
Added back first stage glyc did 5% pre wash left overnite, dropped glyc.
Moved to bubble wash tank and there was a thick layer of foam on the top that looked like expanding foam.
Skimmed of the top and left in a bucket for several hours still looked the same and did not break down.
I filtered the batch through j clothes then did several bubble washes till water was clear.
Left to settle for 2 weeks.
Now my 50/50 test shows a thin white layer and the water is slightly cloudy.
3/27 test not crystal clear.
Should i reprocess??????
Title: Re: white layer in 50/50 test
Post by: willbuild on March 01, 2014, 12:36:53 PM
And nothing in the bottom of selttling tank after two weeks
Title: Re: white layer in 50/50 test
Post by: Julian on March 01, 2014, 12:52:30 PM
Not had the problem myself, but I think it's been suggested in the past that oil from Chinese restaurants can contain a high percentage of mono sodium glutamate.

I've got a feeling that Tony may have had some experience with this.
Title: Re: white layer in 50/50 test
Post by: willbuild on March 01, 2014, 01:00:15 PM
They do "crispy fried seaweed" very popular. I think that seaweed has a high concentration of mono sodium glutamates, and my feed stock has a green tinge to it.
Title: Re: white layer in 50/50 test
Post by: Julian on March 01, 2014, 01:02:38 PM
This from wikipedia ...

Chemical properties

MSG is freely soluble in water but not hygroscopic and practically insoluble in common organic solvents such as ether.

In general, MSG is stable under the conditions of regular food processing. During cooking, MSG does not decompose: Like other amino acids, browning or Maillard reactions will occur in the presence of sugars at very high temperatures.


So ... if it's stable during cooking and not effected by ether it will probably survive transesterification, not too sure about the catalyst.  But then its water soluble it should wash out.

Wonder it it's worth trying a water wash on the oil before processing, a couple of Dr Peppers should give a good indication ... might make a great wiki page if it proves to be successful.

Title: Re: white layer in 50/50 test
Post by: Julian on March 01, 2014, 01:04:16 PM
They do "crispy fried seaweed" very popular. I think that seaweed has a high concentration of mono sodium glutamates, and my feed stock has a green tinge to it.

Wikipedia says it can be derived from seaweed, but isn't crispy fried seaweed really cabbage?
Title: Re: white layer in 50/50 test
Post by: willbuild on March 01, 2014, 01:08:28 PM
Am on good terms with them so i will ask.
Would not want to stop using there oil as its one of my main collections.
maybe i could do something to elimate the in the process??
Title: Re: white layer in 50/50 test
Post by: Jamesrl on March 01, 2014, 01:25:57 PM
I was under the impression that the white layer between bio and water in a 50/50 is mono and diglycerides, they're present due to the incomplete reaction.
Title: Re: white layer in 50/50 test
Post by: Julian on March 01, 2014, 01:43:19 PM
I was under the impression that the white layer between bio and water in a 50/50 is mono and diglycerides, they're present due to the incomplete reaction.

These appear after an acid wash.

We really need a communal infrared spectrograph.  I'm sure collectively we could make one ... how difficult could it be?

This one only has a dozen parts or so ...

http://upload.wikimedia.org/wikipedia/commons/1/17/IR_spectroscopy_apparatus.svg
Title: Re: white layer in 50/50 test
Post by: willbuild on March 01, 2014, 03:59:40 PM
I didt do an acid wash.
Am going to try dr pepper test on 1ltr  using 200ml methanol and 8grs? of Kohl
Title: Re: white layer in 50/50 test
Post by: Julian on March 01, 2014, 04:40:59 PM
Sorry, my mistake!

Could quite well be as Jim describes, he has been known to get things right in the past.

Jim, is there any provenance for the layer being mono and diglycerides?

Title: Re: white layer in 50/50 test
Post by: Jamesrl on March 01, 2014, 08:34:09 PM
Sorry, my mistake!

Could quite well be as Jim describes, he has been known to get things right in the past.

Jim, is there any provenance for the layer being mono and diglycerides?

It was  Mr GL himself  that informed the world as to what the white layer is, he also said that if you use distilled water for the test  it will enhance the result.
Title: Re: white layer in 50/50 test
Post by: Julian on March 01, 2014, 09:38:43 PM
Sounds quite plausible and I've every respect for Graham, an exceptionally clever man, but any idea where he got the information from?

The longer I play this game the more I'm starting think many of the "rules" by which we work seem to originate from the annals of history without any provenance.  A bit like the 3/27 test being cloudy or coloured.  It would be great to have definitive proof of some of these things and stick them up on the wiki.
Title: Re: white layer in 50/50 test
Post by: Jamesrl on March 02, 2014, 12:07:47 AM
Quote from: Julian link=topic=1871.msg22601#msg226011393709923
Sounds quite plausible and I've every respect for Graham, an exceptionally clever man, but any idea where he got the information from?

The longer I play this game the more I'm starting think many of the "rules" by which we work seem to originate from the annals of history without any provenance.  A bit like the 3/27 test being cloudy or coloured.  It would be great to have definitive proof of some of these things and stick them up on the wiki.

I believe Graham is well versed in chemistry and has a knowledge of the subject way beyond your average numb nut.
Title: Re: white layer in 50/50 test
Post by: willbuild on March 02, 2014, 10:50:33 AM
I didt do an acid wash.
Am going to try dr pepper test on 1ltr  using 200ml methanol and 8grs? of Kohl
checked this morning the test and had no glyc droping out, but clear pass on 3/27 test.
do i re process and should i use 20% meth.
the bio has changed from a light tan to a dark tan, is the glyc not droping?
Title: Re: white layer in 50/50 test
Post by: Julian on March 02, 2014, 11:24:35 AM
Possible.  Have you tried human centrifuging it?

http://www.biopowered.co.uk/wiki/Tips_and_wrinkles_1#Human_centrifuge
Title: Re: white layer in 50/50 test
Post by: willbuild on March 02, 2014, 04:54:58 PM
Did 5 mins of human centri and left for a few hours,still no split.
so took a 200ml sample, heated to 60c, added 10ml of water and mixed. 5% wash.
Within 5 mins bio had split, have now got 55ml of darkbrown glyc and light bio on top.
Should i assume that the 5% wash aids the splitting?
Title: Re: white layer in 50/50 test
Post by: Julian on March 02, 2014, 05:34:59 PM
Not sure what the mechanism was that made the water successful, but well done.  If it works on the main batch I think it would be worth documenting on the wiki.
Title: Re: white layer in 50/50 test
Post by: Julian on March 02, 2014, 05:45:43 PM
Should i assume that the 5% wash aids the splitting?

After my recent mishap doing a 5% wash, I just ran a batch which was demethed very heavily, without doing a 5 or 7% wash.  Although it split well, draining the glycerin was a nightmare, the stuff was so thick that it must have been sticking to everything inside the processor.  I had to drain it 5 times and even then I didn't get it all out.  With a 5/7% wash the stuff drains quite easily and gives a really clean split with the bio.

I don't think it necessarily aids splitting, I suspect some other dark forces are at play giving you the problem you had, but a prewash certainly makes life easier an, as Mark has documented, gets rid of a hell of a lot of soap.

Out of interest my last batch was way under dosed with NaOH, and after an overnight bubble in the settling tank has a soap ppm of 3600 and something.  In comparison bio from 3 batches ago which was acid washed and put through a dry wash tower, gave a soap ppm of 45.

Title: Re: white layer in 50/50 test
Post by: Julian on March 02, 2014, 05:57:27 PM
Quote from: Julian link=topic=1871.msg22601#msg226011393709923
Sounds quite plausible and I've every respect for Graham, an exceptionally clever man, but any idea where he got the information from?

The longer I play this game the more I'm starting think many of the "rules" by which we work seem to originate from the annals of history without any provenance.  A bit like the 3/27 test being cloudy or coloured.  It would be great to have definitive proof of some of these things and stick them up on the wiki.

I believe Graham is well versed in chemistry and has a knowledge of the subject way beyond your average numb nut.

Unfortunately I've only had brief contact with Graham by email, so wasn't aware of his expertise in chemistry.  I fully accept GL as good provenance.

It just worries me that you can get the "send 3s. 4d. we're going to a dance" syndrome, when so much of the info on which we rely is passed by word of mouth.

Title: Re: white layer in 50/50 test
Post by: willbuild on March 02, 2014, 08:42:05 PM
will try and re process tomorrow, 18% meth and 5gr Kohl.
Am not sure if 18% meth is to much?
Title: Re: white layer in 50/50 test
Post by: Jamesrl on March 02, 2014, 08:45:26 PM
I've never heard of the 3/4d syndrome.

There are those who speak with such an air of authority about a subject that you accept what they say without question, Graham is one of those people in my mind.
Title: Re: white layer in 50/50 test
Post by: Julian on March 02, 2014, 09:05:12 PM
I've never heard of the 3/4d syndrome.

There are those who speak with such an air of authority about a subject that you accept what they say without question, Graham is one of those people in my mind.

You were probably too old to be actively involved in the war, but it was an example of how messages got bastardised whilst being passed from one person to another ...  "Send reinforcements we're going to advance" became "Send 3/4 we're going to a dance".

Title: Re: white layer in 50/50 test
Post by: Julian on March 02, 2014, 09:08:35 PM
will try and re process tomorrow, 18% meth and 5gr Kohl.
Am not sure if 18% meth is to much?

If it's passed a 3/27, and you've discovered a way of forcing the glycerin to drop, why are you looking at reprocessing?
Title: Re: white layer in 50/50 test
Post by: willbuild on March 02, 2014, 09:18:19 PM
I didt do an acid wash.
Am going to try dr pepper test on 1ltr  using 200ml methanol and 8grs? of Kohl
it was the above sample that gave me the 3/27 pass and went on to drop the glyc when i did the 5% wash.
I've got 60 ltrs of it that leaves a white layer in the 50/50 test, this is what i want to reprocess
Title: Re: white layer in 50/50 test
Post by: Julian on March 02, 2014, 09:54:28 PM
Ah, got it, sorry.  I must try and keep up.

You could probably get away with less methanol, but it won't do any harm to overdose.
Title: Re: white layer in 50/50 test
Post by: Jamesrl on March 02, 2014, 10:21:11 PM


You were probably too old to be actively involved in the war, but it was an example of how messages got bastardised whilst being passed from one person to another ...  "Send reinforcements we're going to advance" became "Send 3/4 we're going to a dance".

Ah, right, I've always known that as Chinese Whispers.
Title: Re: white layer in 50/50 test
Post by: Julian on March 02, 2014, 10:38:20 PM
Me too, but I thought that one was a well known example ... wrong again!
Title: Re: white layer in 50/50 test
Post by: Chug on March 04, 2014, 09:29:01 AM
I was gonna make a new thread but it's related to this one, so what do folks reckon?

http://www.vegetableoildiesel.co.uk/mybbforum/showthread.php?tid=36081

Title: Re: white layer in 50/50 test
Post by: Julian on March 04, 2014, 11:15:29 AM
Is that from one of the US sites, Chug?
Title: Re: white layer in 50/50 test
Post by: 1958steveflying on March 04, 2014, 11:14:13 PM
Is that from one of the US sites, Chug?

Maybe Nigel or others who have soap test capabilities can verify or refute this info I found on infopop.
Title: Re: white layer in 50/50 test
Post by: Julian on March 04, 2014, 11:27:25 PM
Is that from one of the US sites, Chug?

Maybe Nigel or others who have soap test capabilities can verify or refute this info I found on infopop.

I've got one of Nige's soap test kits.  Was that meant to be a link to infopop?  If so it's not working, can you repost pleas?
Title: Re: white layer in 50/50 test
Post by: Chug on March 05, 2014, 09:22:41 AM
http://www.vegetableoildiesel.co.uk/mybbforum/showthread.php?tid=36081
Title: Re: white layer in 50/50 test
Post by: willbuild on March 06, 2014, 07:25:30 PM
will try and re process tomorrow, 18% meth and 5gr Kohl.
Am not sure if 18% meth is to much?
Did batch using 18% meth and 5gr per litre and got a instant clear 3/27 pass.
5% pre wash left to settle overnight, drained off glyc then demethed and spray bar overnight.
Next a gentle bubble wash.
I had a creamy layer between water and oil that i drained off (Hmpes?) three more washes then dried.
Did a 50/50 test after 12 hours of settling and have a very thin line of white between water and bio and very little cloudiness in the water.
I think it will be ok to use in a few days time, thank you to everyone for there help.