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Recently started water washing and I'm running into a layer of white creamy soap looking stuff! I centrifuge before washing and soap is less the 100 ppm. I neutralize and use R/O water and still have the problem, any ideas out there?
 
Location: St Cloud | Registered: March 01, 2010Reply With QuoteReport This Post
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Sounds like a minor emulsion to me. Drain some into a jar, add some hot salt water and give it a gentle shake. If it separates and you get a layer of bio on top - bingo. If that's the case, stop draining when you hit that layer, it will wash out with additional washes.


2005 Duramax
 
Registered: April 09, 2012Reply With QuoteReport This Post
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By coincidence I was just about to post a question on the same topic. Every once in a while I encounter a batch with a emulsion layer between the BD and the glycerol/water layer at the first wash step. Background: Oil titrates at 2-4, process with 2x NaOH, monitor 3/27 until complete or just a trace, don't recover methanol, at the end of the last base treatment either quench with warm water or drain off brown gravy (recycle this to next batch). I have limited oil sources who are fairly consitent but the oil comes in the orginal plastic containers without the cardboard boxes so I don't know if they change their oil brands but suspect they do (either that or what foods they prepare.)
The problem is: If the final glycerol layer fails to seperate cleanly there is usually a large amount of "flocc" (a thin gel in the BD layer). Usually when this occurs I add two or three gallons of warm water down the side of the tank without stirring and much of the gel will dissolve and settle into the water resulting in a good separation. However sometimes a large layer of very fine emulsion forms between the two layers which accentuates with the first water wash. Quite often I must scarifice this layer to proceed with substantial loss in BD.

My only clue is that the methanol in the 3/27 test taken to monitor during processing is very cloudy, more so than usual (I think). In fact this time the unconverted oil layer in the 3/27 was itself a cloudy emulsion instead of the normal clear droplet. When this occurs I never can quite get complete conversion. Close but not perfect.

I suspect that there is some contaminate added by the cooking oil supplier such as a stabilizer, cheapener etc. My first thought is paraffin oil. Anyone have any ideas or experience?

The other thought is fish. Just as I was adding the methanol to the warm oil I had the distinct smell of fish instead of the usual beef/pork odor. Could this be fish oil which is known not to process well? Again, any ideas?
 
Registered: March 23, 2004Reply With QuoteReport This Post
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When I started with bio production I was water washing to and without the methanol recovery.

The problem is simple. When you process your bio and not evaporate the methanol out of your bio, the soaps are still present. If you water wash with misting head you will most probably not see any emulsion, if you agitate the whole mixture with water you will 100% get creamy stuff.

I prefer you wbd the batch and use some sort of drywash system.
 
Registered: April 04, 2011Reply With QuoteReport This Post
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Valdster, I am convinced that this is not soap. When I added the warm water to facilitate a phase break I did not stir on purpose, just poured it down along the tank wall. Usually the water will flow down the wall without much mixing and form a relatively clear layer into which the glycerol dissolves.
This time the whole batch almost instantly became a "thin" milky white color, not the usual thick mayonnaise emulsion of soap, BD & water due to over mixing. After a couple of quick test batches I managed to break this "thin" emulsion with salt water (quite easily) but interestingly there is very little soap in succeeding washes (as you might expect from the low initial titration).
This contaminate doesn't behave like soap.

Rfaloh, sorry I've highjacked your post but no I don't have any really good ideas yet, Was hoping someone else would.
 
Registered: March 23, 2004Reply With QuoteReport This Post
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you stated that the liquid in the 3/27 test was cloudy, in my experiance the reaction has not gone far enough. If this is the case you would have more monos and dys in the mix, when they mix with water they create emulsions. Water washing is always problimatic if the reaction is not complete. (pass 3/27 clear liquid)


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
 
Location: Manitoba Canada | Registered: March 24, 2009Reply With QuoteReport This Post



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I did water washing for a long time before switching to chips and resin. What you have is an incomplete reaction. The only time you will get an emulsion is if you allowed by-product to get into the wash cycle.

I water washed using a quite aggressive method of spray washing with hot water and the only time I ever got an emulsion was my own fault as I recycled cold wash water instead of draining and starting a fresh lot.

The triglycerides left un reacted will cause more trouble in the form of emulsions than simply aggressive water washing. Be very certain that no glycerine gets into the wash cycle though as these a re concentrated soaps and will give you headaches.

HTH



** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.


 
Location: :-) Great White North eh ? | Registered: December 10, 2004Reply With QuoteReport This Post
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monoglycerides in the biodiesel will cause emulsions. and it doesnt take much. i see more emulsions with biodiesel that is in the 0.15-0.20 total bound glycerol range than fuel that is in the 0.05-0.15 range

most notably the washed biodiesel doesnt want to drop the water, even if all the soaps are neutralized

the difference between having to dry material that is <0.5% water vs >1% water
 
Registered: July 06, 2004Reply With QuoteReport This Post
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Thank you for the post everyone! Let me see if I can explain a little better. once the reaction is complete I remove the glycerin with 2-sharple 15K centrifuges. I check for soap by water shake test and soap test with regent. This time there was 975ppm before transfer to the wash tank. The water shake test sample was a little turbid with only a small white layer between the water and bio. Now once washing starts only misting, there comes gallon and gallons of a white creamy emulsion. I tried neutralizing with acid with no success and just tried the suggestion by

MarquisVII
Sounds like a minor emulsion to me. Drain some into a jar, add some hot salt water and give it a gentle shake. If it separates and you get a layer of bio on top - bingo. If that's the case, stop draining when you hit that layer, it will wash out with additional washes.

The emulsion remained the salt test improved it a little and there is no bio that comes out of this stuff. One thing is for sure those 15K centrifuges strip off the glycerin and even the methanol. I have attempted to demeth after centrifuge and not even on ounce came out! So there is no methanol before washing. Is it possible that this could be some form of shorting/oil? The post by

Simple Fuels is making sense, I had to wash/dry in two batches and the first one was dried to 250 degrees and pumped into the storage poly storage tanks. It was dry but now is seeing moisture in it!
 
Location: St Cloud | Registered: March 01, 2010Reply With QuoteReport This Post
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Okay so from reading all the post it makes sense that the reaction was not complete! I drew a sample of the emulsion and added a small amount of sodium hydroxide/water solution and it cut the emulsion by 90%. This must mean that there is under-reacted oil parts that are now soap! I'm going to mix a 1g per leader solution with water and mix it into the wash. This should react any remaining oil/parts and allow the washing to continue! What do you think?
 
Location: St Cloud | Registered: March 01, 2010Reply With QuoteReport This Post
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Well it worked instantly! I mixed a gallon of water with 15 grams of sodium Hydrox. and agitated the bio and WOW "the creamy white stuff was gone". That means it was an incomplete reaction and the solution reacted with it converting it into a small amount of soap which is almost washed out! Thanks for the help everyone! Good one to write down in the journal...
 
Location: St Cloud | Registered: March 01, 2010Reply With QuoteReport This Post
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quote:
Originally posted by Biotom:
you stated that the liquid in the 3/27 test was cloudy, in my experiance the reaction has not gone far enough. If this is the case you would have more monos and dys in the mix, when they mix with water they create emulsions. Water washing is always problimatic if the reaction is not complete. (pass 3/27 clear liquid)


I would agree with you, Biotom except for the fact that 3/27 following the 2nd stage base showed only about 3% unconverted, initial base reaction went very smoothly with very nice seperation and until I went to quench the 2nd stage base reaction I thought everything was going great. My previous experience (over the past 8 years) has been that if the 3/27 shows complete or almost complete (less than 3% unconverted) I have very little trouble with emulsions. Something was different and the difference was indicated by the extreme cloudiness of the methanol portion of the 3/27 test and the abrupt formation of the milky (but quite thin) biodiesel layer.

It is possible that you are correct since when I cleared the biodiesel layer (not exactly collapsed the emulsion) with brine the subsequent water washes were almost soap-free judging from the clearness of the wash water. This would imply that once the methanol content of the BD decreased following the first water wash the mono & di glycerides dissolved in the BD and were stable there.

Once I get the batch dried I plan to re-react a test sample to determine if I can recover additional glycerin.
 
Registered: March 23, 2004Reply With QuoteReport This Post



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quote:
Originally posted by Rfaloh:
Well it worked instantly! I mixed a gallon of water with 15 grams of sodium Hydrox. and agitated the bio and WOW "the creamy white stuff was gone". That means it was an incomplete reaction and the solution reacted with it converting it into a small amount of soap which is almost washed out! Thanks for the help everyone! Good one to write down in the journal...


This is an interesting idea, How long did you allow for the saponification reaction? How did you agitate the batch? Do you have any sense of how much unconverted oil you converted into soap? Was you final yield decreased by much?

It is definitely something to think about.
 
Registered: March 23, 2004Reply With QuoteReport This Post
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