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Can't get clear water wash
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I've washed my 30gal of biodiesel with almost 400gal of water and it's still cloudy.
I first did bulk washing, then agitated (got emulsion I had to break with salt) then more washing with a hose, then the last 4 washes with a bubbler. The pH has now dropped to 5.5 but with the shakem up test I get separation in about 20 min but the water is always cloudy.

Any ideas? I'm using used canola oil if that helps.
 
Location: Kamloops | Registered: June 16, 2012Reply With QuoteReport This Post
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I think the pH of a distilled water wash of pure biodiesel should be about 7. What is the pH of the water you're washing with before you wash your biodiesel with it (about). I have only done 1/2 liter batches. I'm trying to get the bio pure and dry.
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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Seems your biodiesel is getting acidic? When I water wash I check the ph of the wash water before and after the wash, the wash cycles are complete when the ending ph is the same as the starting ph of the water. The more aggresive the water wash the less likely you are to see clear water at the end of the wash cycles. Soft or demineralized water will create emulsions faster than hard well water, the less mineral content in the water the more soap it will pick up causing easy emulsions, as well, hot water will collect more soap than cold water. If you are spray washing from a garden hose, turn the pressure down and set the spray to larger droplets. Using 7% (or less) water to oil volume for a wash cycle also makes it very difficult to create an emulsion.


" 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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My last wash before this one was a pH of 7.5 The wash water I start with is around that maybe slightly higer at 7.7
So the next wash came out at 5.5pH but I bubbled it for 13 hours at 48°c. I use city water which is soft water with not very many minerals in it.
I still get cloudy water on the rinses but now I'm scared I'm oxidizing it by running too much bubbles through it for so long at elevated temps. I've washed it enough now I'm not too concerned with emulsions but wonder if I keep washing if it will ever come clear?
 
Location: Kamloops | Registered: June 16, 2012Reply With QuoteReport This Post
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with an ending ph of 5.5 what is left to wash out, soap is caustic, don't wory about the water colour, pay more attention to the ph of the water after the wash. Stop washing when the ph gets to 7.0 - 7.5 at 7.5 the soap count will be slightly higher about 40ppm at least thats what it is for me. My water before washing is 7.8 and has 580ppm disolved solids.


" 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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Sounds like it was under reacted. Did you pass 3/27?


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Location: Seattle | Registered: January 06, 2009Reply With QuoteReport This Post



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Yes, it passed the 3/27 test but had some dandruff flakes in it after about 20 min. I also thought it might be an unreacted batch so I took 500mL's from the 30gal batch and reprocessed it. No glycerin what so ever fell out so I'm convinced it's pretty much fully converted.

So assuming all the soap is gone and I'm washing fully converted biodiesel but still have cloudy wash water. The shakem' up test takes like 20 - 30 min to separate. What should be my next move? Should I be worried about oxidation at this point (with my pH of 5.5)?
 
Location: Kamloops | Registered: June 16, 2012Reply With QuoteReport This Post
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dandruff flakes hmmm. did you have dandruff flakes after the reprocess sample? where they white or amber color? I have found that after reprocess the dandruff flakes vanish. Canola oil has a fatty acid that is harder to transeserfy, ifI remember correctly it is Alpha-Linolenic Acid, in a concentration of about 11%. soybean oil has 8% and all other oils have from trace to 1%. This oil processes better with a two stage process, I'm sure this will get rid of the dandruff. Having said that dandruff (white) can also be caused by oxidized KOH or NaOH


" 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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Well on my original 3/27 test it almost looked like a very small bead of oil but you had to look closely cuz it was about the size of a grain of sand. After I let the 3/27 sit for a while it was more like white dandruff flakes and no longer any sign of oil.

My original titration with the oil was 1.4 ml so it had a low FFA content.

When I reprocessed it I never did to a 3/27 and I've already discarded the sample.

I haven't done another 3/27 for a while. I could try again. Is it worth a reprocess if I get a grain of sand sized droplet?
 
Location: Kamloops | Registered: June 16, 2012Reply With QuoteReport This Post
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I would use the biodiesel as is or mix it with petro diesel, In the future, don't go to the wash cycle until you're are sure the conversion is good, no dropout after 20 minutes at 68 - 70F. I'll probably take some flack for this but I do 4/27 as a minimum pass, if the reaction is really good you can do 6/27 without any drop out (there is no requirement to push the reaction this far), also, the higher the conversion the more clear the liquid is in this test, you should be able to read news print through it. I have to agree with binuya on this one, underreacted oil, this makes water washing VERY difficult! Tom


" 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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My 3/27 is as clear as water. I will do a 4/27 tomorrow. I might even try your 6/27 to see how much drops out for the hell of it. I'll post back and let you know exactly what I see after 20min.
 
Location: Kamloops | Registered: June 16, 2012Reply With QuoteReport This Post
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The original Jan Warnqvists Conversion Test which we call 3/27 used exactly 25 ml of well settled biodiesel in 225 ml of methanol. with this volume it is much easier to see the drop out. each ml of undesolved material = 4% by volume.


" 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 have also found that with water washing, it pays to drop out the wash water first, then the curdled looking soaps (don't discard this) and when the biodiesel starts to flow, only then stop and re-wash.
If you don't drop out the curdled stuff, you will keep on passing water through the soaps, and it'll take ages and much water to get rid if it.
The saved curdled stuff, if left for a while, will drop out the water and you will be able to recover the left over biodiesel to use in your next batch. Jim.
 
Location: Cape Town | Registered: May 17, 2006Reply With QuoteReport This Post
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Well I just completed the 3/27, 4/27 and 6/27 tests. All passed with flying colors. Even in the 6/27 it was a nice clear bright liquid with no fallout after 20min.
I also did the 25/225 test and again very clear liquid with maybe 3 or 4 specs of something in the bottom. These specs were so small I wouldn't even consider them fallout.

So I'm just working on the shakem up test. It turned to a cloudy emulsion right away and is very slow to separate. After about 5 min you can see it just trying to start to separate. It's been about 20 min now and the top layer (biodiesel) is cloudy whitish amber and the water on the bottom is cloudy. In between the two layers looks like to be a thin white layer. I have a sample I shook up a few days ago and on top it's clear bio and the water looks very slightly cloudy but it also has this interface layer that is white.
Any idea what this white paper thin layer between the two layers is? Should I be concerned? If I have fully processed oil why is it taking so long to separate after shaking?
 
Location: Kamloops | Registered: June 16, 2012Reply With QuoteReport This Post
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It sounds like the layer is soap.
 
Registered: September 14, 2012Reply With QuoteReport This Post
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Super,

What is the temperature of the wash water? If you have high meltpoint, high cloud point components in your BD they will crystalize when exposed to the cold water. Methyl Stearate has a meltpoint (mp) of about 101F while methyl eicosane's is at least 111F (variously reported 44-48 or 54.5C). Every time you wash with cold water you crystalize more. This would explain why your 3/27 is clear.
The pH of 5.5 is probably the result of overbubbing the wash water with air. Carbon Dioxide dissociates in water to form bicarbonate, CO2+H2O=H+ & HCO3-, the H+.
Warm a sample of BD and shake with a sample of warm water to see if the water is clear or cloudy. Clear would indicate that the high meltpoint components remain in the BD, cloud they crystalize out and settle in the water.
Hope this helps.
 
Registered: March 23, 2004Reply With QuoteReport This Post
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Originally posted by JimKohler:
I have also found that with water washing, it pays to drop out the wash water first, then the curdled looking soaps (don't discard this) and when the biodiesel starts to flow, only then stop and re-wash.
If you don't drop out the curdled stuff, you will keep on passing water through the soaps, and it'll take ages and much water to get rid if it.
The saved curdled stuff, if left for a while, will drop out the water and you will be able to recover the left over biodiesel to use in your next batch. Jim.


Can Attest to this. Origiannly tried to get get clear wash water from a city water source. No success, focus on your 3/27 test and pH in = pH out. Keep the currdled mix/emulsion. Mine usually breaks in a week and I recycle back to the start of the next wash cycle.
 
Registered: December 10, 2011Reply With QuoteReport This Post
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