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Emulsion by bubbler?
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Newbie here. My last two batches have emulsified after I've left the bubbler on for about 6 hours. I'm using high quality dry canola. I've had either very little or no fall out. I'm manually adding hot water to the top of the bio and waiting at least 3 hours or overnight to drain water. I'm heating the bio each time before adding hot water. After the 2nd wash, things are looking good. The bio has a honey color. I run the bubbler, come back the next day, and it has emulsified. I have broken the emulsions with salt but I'm so new at this that I'm just confused about how it all works.
I've read about pump washing, bubble washing, static washing, mist washing...The bubbler seems like a great idea but I figured that after two washes it wouldn't have enough soap(or whatever it reacts with) to agitate and emulsify.
I'm using a small wooden block air bubbler and I can control the bubbles but after about 30 minutes it also starts pushing out large amounts of air. So even when I turn the bubbles down, those larger air pockets keep rising to the top. I'm not sure if that's enough to agitate. Maybe something is wrong with my bubbler.
I've attached pics of my wash water in case that helps.My first wash looked darker, not quite like bio but a bit brownish. The second wash was whiter. I'm also attaching a pic of the emulsification. Didn't look like it went all the way through in the tank to be honest, it was hard to see because of my white poly tank. The bio on top didn't look creamy but it wasn't the pretty honey color I had left it the night before. I broke the emulsion with rock salt and hot bio and hot water. I waited ten to fifteen minutes and could see it clearing up. I drained the water, added another 5% hot water, drained immediately and added another 5%. That is sitting in there right now.
Just wonder if anyone has any thoughts.


1997 Dodge Ram 2500


Imageshake_test.jpg (30 Kb, 8 downloads) Emulsification
 
Registered: November 13, 2014Reply With QuoteReport This Post
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Hi azjed,
Can you explain what you mean by "I've had either very little or no fall out"

Did you do a Warnqvest/ 3-27 test of your biodiesel before washing?
If so what was the results?






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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After the reaction I did the 3/27 test and had little to no fallout using that test.


1997 Dodge Ram 2500
 
Registered: November 13, 2014Reply With QuoteReport This Post
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Keep washing. You have excess soap and/or enough un-reacted oil to make the washing process more lengthy. You'll get there, it will just take longer. Allow plenty of time for it to settle between washes, otherwise you'll be throwing out emulsified biodiesel with the wash water.


Alvin
'01 F250 7.3 4x4 Lariat Crew
'95 Mercedes Benz E300 D
 
Location: Seattle | Registered: January 06, 2009Reply With QuoteReport This Post
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OK. I have built a heated misting system and used that the first time I got the emulsion. I thought maybe that was the culprit but now it's happened twice with the bubbler. I figured the static wash was less agitation but would you recommend the mister over the static. Seems like people recommend static for first or 2nd wash and then misting it.


1997 Dodge Ram 2500
 
Registered: November 13, 2014Reply With QuoteReport This Post
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What ever works for you. First couple washes need to be gentle to avoid creating emulsion early on, as you already know. I used to mist the first few, but now since I have so much time before it goes into a storage barrel, it often sits on water for a few weeks before I even get to it. By the time I do get to washing, most of it has dropped out anyway, and I can go directly to bubbling, with a few days settling time between water changes. A key thing early on is to get as much methanol out of it as possible, whether it be distilling it or washing it out. It will hold soaps in suspension and make washing take much longer as long as it's in there.


Alvin
'01 F250 7.3 4x4 Lariat Crew
'95 Mercedes Benz E300 D
 
Location: Seattle | Registered: January 06, 2009Reply With QuoteReport This Post



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azjed, Hi.
You will not get an emulsion however you water wash if the soap level is low to start with. Lets say below 400ppm.

All you need to do to achieve the lower soap is to de-meth the batch, leave it to stand @ 24 hours then you can wash as aggressively as you wish, pump washing is best.

With the present batch I have on the go I am just leaving it to settle after de-mething as I am doing some centrifuge trials.
After de-mething the batch (190 litres) then gentle bubbling for 12 hours, then left to stand overnight the soap level was 83ppm.

If you don't de-meth you are at the mercy of the soap. Fully converted, just processed biodiesel can contain 3000ppm soap or more.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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OK. thanks to both of you for your responses.
You both say 'de-meth'. I've only heard this used when heating glycerin so I'm not sure what that looks like after the bio reaction stage. So, there is still methanol in the biodiesel? And water washing gets it out or settling...or both?
Dgs, you mention simply letting it stand 24 hours. I did a 5% prewash and then let my bio sit more than that (36hrs last batch) after the reaction. I then did a first and second wash and then bubbled.

binuya, you say that after sitting for so long most of "it" has dropped out. "It" being soap? So with time, soap will also drop out?


1997 Dodge Ram 2500
 
Registered: November 13, 2014Reply With QuoteReport This Post
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Hi azjed,

quote:
Originally posted by azjed:
So, there is still methanol in the biodiesel?
Yes, there is still some methonal left in the biodiesel. Most will be mixed with the glycerine and as time goes by, if the biodiesel is in an open container, the methanol evaporates and the glycerine settles out taking soap and methanol with it.
Heating and bubbling air through the biodiesel will speed up the methanol evaporation which speeds up the glycerine/ soap dropping out.

quote:
And water washing gets it out or settling...or both?
Both
I used to water wash.
Now I bubble air through 180 litres for 6 or 8 hours and then pump the biodiesel into 205 litre sealed drums until needed.
Then I pump the biodiesel into 20 litre unsealed pails where it sits for a few weeks before using. More glycerine/ soap settles during this time.
At the present time I am using biodiesel made about 16 months ago with excellent results.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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azjed, even though you left to settle for 36 hours or so the soap level in the bio was still high (because of your emulsion when you bubbled)
Although you run the glycerol/water off you will notice after this pre-wash the bio is cloudy. It is this suspended water in the bio that now contains the soap.

A soap test kit would be a handy tool.

Soap and glycerol drop 'as one' from the bio. Most glycerol contains very roughly 30 to 45% soap.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs;
Most glycerol contains very roughly 30 to 45% soap.
I am curious where you came up with this percentage.
I know the "rule of thumb" is that there is about 79ml glycerol produced per litre of Oil reacted and about 2/3 of the excess methanol ends up in the glycerine layer but soap production is mainly a result of neutralizing FFA's with a small side reaction producing soap depending on the amount of water available.
I think you will find that with dry, low titration WVO there is actually very little soap produced.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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How did I know you were going to ask me that, Tilly.

From cracking glycerol, (de-methed) the top layer (ffa's) can be up tp 60% of the total volume. Titrating this layer gave me approx 120mls KOH which means about 60% of it was ffa's. So in that case the total soap would have been @ 36%. Agreed the soap and ffa's will not equate exactly to each other but pretty close.

The reason my commercial friend stopped producing bio from glycerol is that he suspected his glycerol source was watering it down. He started with a yield of around 45% ffa's and this reduced over the 2 years to about 25% (a point where he regarded the yield as no longer economic)

he used to have the glycerol delivered in tankers, 28000 litres.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post



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Hi Dgs,
A titration of 2 KOH means there is about 1% FFA (10ml) in each litre of oil that will be neutralized into soap.
Where does the rest of the soap come from?

I suspect most people on this forum do not have their glycerol delivered in 28000 litre tankers Wink






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Tilly, I'm really interested in how you clean the bio by bubbling. I would love to eliminate wash water simply for environmental purposes and time. I'm collecting it and have yet to attempt to neutralize it.

So you react your bio. Then you let it settle for how long? Then you drain the glycerin? Then you add the bubbler for 6-8 hours. With or without water? Just curious why you first pump it into sealed barrels. If you want the methanol to evaporate, wouldn't it be better unsealed and then into smaller containers?

I've heard biodiesel breaks down after sitting for some time so I wasn't sure if I could let it sit. The finished bio I have has dropped some glycerin. I just noticed it since it was the first time I got close to the bottom and it kind of freaked me out but I guess it's better there than in my truck.

Thanks for the info.


1997 Dodge Ram 2500
 
Registered: November 13, 2014Reply With QuoteReport This Post
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Saponification from water in the methoxide and water in the oil.

Some people will do base/base on much higher titrating oils, without glycerol washing.

If there was a very low soap in the glycerol then cracking it would not yeild the amount of ffa's that it actually does.

From memory my commercial friend (lets call him Russ) told me his yield from the glycerol was 44%

He used to use 2000 litres of concentrated sulphuric per week.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi azjed,

quote:
Originally posted by azjed:
So you react your bio. Then you let it settle for how long?
Typically overnight.


quote:
Then you drain the glycerin?
Yes


quote:
Then you add the bubbler for 6-8 hours. With or without water?
Yes- without water


quote:
Just curious why you first pump it into sealed barrels. If you want the methanol to evaporate, wouldn't it be better unsealed and then into smaller containers?
I do not have the facility to safely store large quantities of biodiesel in unsealed containers.
I do leave the biodiesel sit for another day or so in the bubbling tank after turning the bubbler off before pump into sealed tanks

quote:
I've heard biodiesel breaks down after sitting for some time so I wasn't sure if I could let it sit.
There is a lot of inaccurate information on the internet about producing biodiesel.
I have a 20 litre sealed pail of 12 year old biodiesel that still looked and smelled fine the last time I looked at it.


quote:
The finished bio I have has dropped some glycerin. I just noticed it since it was the first time I got close to the bottom and it kind of freaked me out but I guess it's better there than in my truck.
Yes, glycerine continues to drop out for some time. That is why I pump the biodiesel into unsealed pails a few weeks before I use it.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs:
From cracking glycerol, (de-methed) the top layer (ffa's) can be up tp 60% of the total volume. Titrating this layer gave me approx 120mls KOH which means about 60% of it was ffa's. So in that case the total soap would have been @ 36%.
I am trying to understand this.
If the top layer of FFA's was about 60% of the total volume, how did you arrive at the soap content being @ 36%?
Also 36% of what?






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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If the top layer (60% of the volume ) was 60% ffa's then the total ffa % is 36%, simples.

There is far more soap in glycerol than you realise. You have a go at cracking some and see for yourself. A good starting point is to add 4% conc sulphuric acid. Try to keep it warm for a couple of days, you can do it in a cubie, you will see what I mean.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post



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Hi Dgs,

quote:
Originally posted by Dgs:
If the top layer (60% of the volume ) was 60% ffa's then the total ffa % is 36%, simples.
How did you determine that the top layer which was 60% of the volume was 60% FFA's?


quote:
There is far more soap in glycerol than you realise. You have a go at cracking some and see for yourself. A good starting point is to add 4% conc sulphuric acid. Try to keep it warm for a couple of days, you can do it in a cubie, you will see what I mean.
I typically have a yield around 98%. Where is all the soap that you say is present coming from?

This message has been edited. Last edited by: Tilly,






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hi Dgs,

I have been doing a fair bit of research this morning and I think I am more or less up to speed on this.

quote:
Originally posted by Dgs:
From cracking glycerol, (de-methed) the top layer (ffa's) can be up tp 60% of the total volume. Titrating this layer gave me approx 120mls KOH which means about 60% of it was ffa's. So in that case the total soap would have been @ 36%.
I wonder how you titrated. I know that using the "normal" titration method after 20 it gets pretty hard to read the colour. I am not sure what a titration of 120 would look like.
So as I see it, your "worst case scenario" is a soap content of about 36% {assuming the titration is fairly accurate)and that is with the methanol removed.
My glycerine always falls out with lots of methanol in it as I am sure everyone else's does so that probably make it actually more along the lines of 30% or so, and that is your Worse Case situation.

My original concern was with your observation that " Most glycerol contains very roughly 30 to 45% soap" which is not supported by your own observation.
I am also aware that you often perform glycerine pre-washes which no doubt would have the effect of increasing the soap content EDIT Of the glycerine END EDIT which would not be a "normal" situation either.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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