Well i knew I'd have my first problem batch sooner or later.. I guess it's sooner.

rough process.. did AE process which dropepd my titration to 20 to 5 (this process was exactly replicated from the previous batch), transferred to methanol recovery tank and completed that step and then pumped into wash tank at 120F or so.. I washed immediately hoping the warmth would allow the wash to go quicker. But I got an emulsion. I washed 4 times and have almost a full batch of cloudy bio on top, with 3-4 inches of emulsion and then clear water... very clean separations. I separated the phases into 3 containers

Questions
1- The bio stil in the wash tank is lighter and looks creamier or thicker maybe than my previous batches... what do I do to this bio to fix it? Can it be saved to run in the new truck or am I better off sending it through my boiler at 20% instead?

2- Do i add salt to the bio too or just the emulsified phase?

3- would washing the bio when it's hot cause this, or was it another mistep along the way? I know it's not the wash process becuase that's been working great. So what causes emulsion other than vigorous washing?

4- I didn't try the 3/27 test on this batch (first time I skipped it of course!) Now that it's "wet" what happens if I run that test, or is it simply too late to do that?

thanks all...

the good news is that almost every problem batch can be saved. Your problem most likely comes from under reacted bio(lack of 3/27). Washing hot is the only way to go. I will never wash with cold bio again. You can add salt to the whole works. drying can be a problem now. mixing left over glyc may remove the last of it before reprocessing.


Mike

Some very hot salt water will break it, mist gently.

quote:

Originally posted by Raften:
Some very hot salt water will break it, mist gently.

X2 on that. Works for me. Just wash well after it breaks. When you think you're done, wash it two more times.

I had this problem & broke the emulsion by:
1 - warm the emulsion to @ 30 C
2 - put 3ml table sale per litre of emulsion into a bucket
3 - add hot water to the bucket to dissolve the salt
4 - make the salt solution upto 20 litres (I have 125 litres of emulsion)
5 - add salty water mix to the warm emulsion
6 - gently stirr for 30 seconds & leave for 3 to 4 hours

You can actually watch the emulsion break.

Good luck

Cool thanks.. I added 1/2 pound of salt to the emulsion phase and mixed and watched the magic happen.. then I let it sit a few hours and poured it back into the wash tank with the bio and bubbled overnight.. today all emulsion is gone and the bio looks normal again. It's washing now. And I'll rewash a couple more times.

Since all looks normal, what's the next step? Do I move on with the process after washing? Should I do a 3/27 test on it now that it's wet? Does the 3/27 test work on wet bio or do I have to dry it first?

#/27 will not work on wet bio. the water content will give a fail every time. Dry well then test.


Mike

I find myself disagreeing with a lot of the points made here. Hot washing, especially in the early stages of washing increases the risk of emulsions. Near the end of the washing a small amount of heat 30degreesC max, helps to dissolve the most obstinate soap.
While salt will certainly break an emulsion it contaminates the biodiesel badly and means that you must wash the biodiesel very thoroughly to get rid of it. Believe me you dont want salt getting into your engine or even your heating system. Glycerol byproduct breaks an emulsion just as well as salt and adds no new contaminant.
I test wet biodiesel with the 3/27 test regularly and it works perfectly. Since water is totally misible in methanol it should not interfere with the test. Methanol usually contains 1 or 2 % water anyway.

If you must use salt to break emulsions bear in mind that the normal indicator for when the washing is complete no longer applies, that is clear water with neutral ph coming out the bottom of the wash tank. Water containing salt is clear with neutral ph.
The best way to check whether you have finished washing is to test for salinity. Set a good quality digital multimeter to 200K ohm scale and tape the probe handles together so that the metal probes are about 1 inch apart. Switch on and immerse them in 1 litre of warm water, note the reading, mine reads 130 Now add 1 gm of salt to the water, stir thoroughly and take a new reading mine reads 25 , another gm of salt, 16, another gm of salt 13. You may get slightly different readings but you can see how this works.
To be sure that all the salt is gone from your biodiesel you must wash untill you get a reading of around 130 from the wash water. I have found that it takes 2 extra 12 hour warm bubble washes to achieve this.

Hello imakebiodiesel
It's funny you should say that heat can cause an emulsion.

I started washing my processors first batch a couple of days ago and didn't want to take any chances with emulsions so I mist sprayed about 8 litres of(quite warm) rain water over it before bubble washing,

Just to find that it caused a emulsion of about 10 litres at the bottom which I drained into cubbie and fixed it by mixing the emulsion with about the same amount of warm Glycerol,this started to fix the problem almost immediately.

I didn't know what caused it so I started I started mist spraying a small sample of bio in a jam jar with no problems and even violently shook a sample with the same amount of cold water just to find that it separated with no problems,
the only other thing else I could think off was the heat.

I'll never know,as I started washing the batch again before I read in your insructions about heat causing emulsions, so I couldn't test it.

Just recieved this information, and it my help here.
-soaps are symbolized as RCOO- Na+ in the soap molicule there are two polar parts: a negative RCOO and a posative Na. Soaps are soluable in water due to thier polar parts. Chemically related substances are soluable to each other, and not related are not. Water h2o is polar but mat better be written H-OH and thereby showing it's polar parts, H+-OH. So now you can see the chemical reaction between the soap and water. This form of water is called electrical bipolar form of water and has a tendancy to attract different negative ions in it's corners.this attraction is increased by heating the reactor (wash tank) or lowering the presure or a combination of both.
-What I get from this, and I my be wrong is that a hot wash has the ability to pick up MORE soap and glycerol than cold water, and this may well be the reason for an emulsion when using hot water. I have found that with the hot wash, the more water I use, the more apt I am to create an emulsion. The chemist that sent the above info, uses only 5% water in the wash and only washes 3 times for a 1500 ltr batch. Tom
-PS I have more wash chemistry if you are interested

I've noticed that washing with hot water does cause and emultion. I did it once when the BD was at room tempurature and other time when it was still warm from the reaction. The water was simply hotter.

The batch i have in now I pumped at 180 degrees F into the wash tank with room temp water already in the tank (about 1/2 the qty of bio) and just let it sit there (static wash) until the bio cooled to room temp. Then i drained and did a mist wash. First wash was pretty brown, but the second was almost clear. The third is basically clear... this wash used less water and took less time. No emulsion either. This was BY FAR the easiest batch I've done.

SO I'm trying to replicate the results with the next batch, but it would seem that heat is helpful as long as there is no agitation at first.

1st wash- Static- Hot bio and room temp water
2nd wash- mist 1/4 GPM - room temp bio and water
3rd wash- mist 1/4GPM and Bubble- room temp bio and water