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Thread: bio diesel wash

  1. #1
    Join Date
    Feb 2017
    Location
    portland oregon
    Posts
    1

    Question bio diesel wash

    I'm new to the forum so let me know if there is something you don't like. I have been making bio fuel for the company I work for in 35 gallon batches for about a year. In the early stages I had 2 large batches go bad. My question is if I have water washed fuel that has soap in it and it does not separate what can I do to recover the fuel. It partially separated but remains cloudy at room temp. PH is a little low. Any help would be appreciated.

  2. #2
    Join Date
    Dec 2007
    Location
    South Australia
    Posts
    1,150

    Re: bio diesel wash

    Sounds like you agitated it too much when washing. If you have the space just put it in some drums and leave it to settle, it may take months but it will settle. Then decant the good fuel off the top.
    Johnnojack
    4WD Isuzu Jackaroo 3.1 170,000km on WVO,(2017) 2 tank home built system 6 solenoids. Mk. 9 version. Improvements under investigation

  3. #3
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,172

    Re: bio diesel wash

    If you have the facility to do so, leave the drums in a warm place to assist the separation if the fuel and water.
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles in stable:
    '06 Musso Sports Crew Cab. Running on used cooking oil with 5% to 10% misfuel.
    '2014 Toyota Prius (on ULP)


    Previous Vehicles:
    '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup. Died when supercharger stuck at max boost for weeks. Stretched head bolts.
    '80 Mercedes 300D. 2 tank conversion [Sold]
    '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Donor for current Fatmobile coupe. (body parted out and carcass sold for scrap.)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
    '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
    Parts Car C220 1993 SOLD.
    '85 Mercedes Benz W123 300CD Turbodiesel single tank using 95% used cooking oil and 5% to 10% misfuel (where someone had filled diesel vehicle with petrol).


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  4. #4
    Join Date
    Nov 2010
    Location
    Fort Worth, Texas, USA
    Posts
    281

    Re: bio diesel wash

    If your fuel does not separate adequately, you can make the soap into free fatty acids and sodium or potassium acetate dissolved in water. Then the part of the liquid containing free fatty acids and methyl fatty acid esters (biodiesel) should float on the water with sodium acetate dissolved in it, when the two liquids can be separated. But the biodiesel will have some free fatty acids dissolved in it. Then magnesium silicate treatment with some heat, about 60 degrees centigrasde, will adsorb or absorb the free fatty acids onto the magnesium silicate (solid) that may be filtered out with about a 20 micrometer porus paper filter, after settling out the magnesium silicate that will settle out. I did an experiment with potassium or sodium soap. I put vinegar into a small beaker, added a little homemade sodium or potassium soap. The metal (sodium or potassium) switched its bond upon heating , to acetic acid (vinegar) and free fatty acids were released, floated up to the surface of the vinegar. So, sodium acetate or potassium acetate (water soluble) was formed producing the free fatty acids from the soap. This happened because acetic acid is a stronger acid than free fatty acids are. That is so because of molecular orbital is longer, bigger, with more electrons in the longer carbon chain. The oxygen on the carboxylic acid group have a high electronegativity forcefully pulling some electron density towards the oxygen, but the longer carbon chain allows the negative charge on the acid ion (the acid with the hydrogen detached) to be stabilized by electrons bonded to the hydrocarbon chain connected to the two oxygen bonded to one carbon , the longer carbon-hydrocarbon chain allows the electron density to spread out in the molecular orbital.. Formic acid with one carbon, two oxygen, two hydrogen is the strongest. Two carbon chain, acetic acid is next strongest. Acetic acid (vinegar) pulls the metal potassium, lithium, or sodium to it more forcefully than octadecane , a free fatty acid with an eighteen carbon chain length. The longer carbon chain makes a weaker acid, so the acetic acid ends up with the sodium or potassium metal, which will dissolve in water. Magnesium silicate (magnesol) made in Dallas , Texas, will remove the free fatty acids from the biodiesel. Magnesium silicate treatment was done by me to purify biodiesel. I heated the biodiesel to about 60 degrees centigrade after demething the biodiesel, then added magnesium silicate, stirred for maybe 30 minutes, allowed magnesium silicate to settle out, then vacuum filtered the biodiesel with an about 20 micron porus paper filter. You might separate your fuel that way. You could use salt sodium chloride also, but if you put salt into your wet biodiesel, you need to get it all out before using the biodiesel in an engine. You do not want salt in your combustion chambers.
    Last edited by WesleyB; 22nd February 2017 at 08:50 AM. Reason: didn't write it quite right

  5. #5
    Join Date
    May 2008
    Location
    Hobart TAZ
    Posts
    75

    Re: bio diesel wash

    When I have this happen I chuck a litre or 2 of vinegar in the mix and that soon sorts things out

  6. #6
    Join Date
    Dec 2016
    Location
    York UK
    Posts
    116

    Re: bio diesel wash

    The disadvantage with using acid is that it converts the soap into FFA's. If the starting soap level is unknown then so are the levels of FFA's that are formed. The use of acid also 'splits' any monoglyceride emulsion formed when water washing agressively, leaving the mono's in the biodiesel. This increases the temperature at which the bio will mist/gel (a problem here with cold UK Winters)

    The use of acid also leaves the biodiesel slightly darker in colour. I try to avoid using it whenever possible.

  7. #7
    Join Date
    Apr 2007
    Location
    numurkah
    Posts
    550

    Re: bio diesel wash

    Oh no we have a new member with the user name smithy thats going to cause some confusion
    smithw

  8. #8
    Join Date
    Dec 2016
    Location
    York UK
    Posts
    116

    Re: bio diesel wash

    lol, I hope not.

  9. #9
    Join Date
    Nov 2010
    Location
    Fort Worth, Texas, USA
    Posts
    281

    Re: bio diesel wash

    Someone wrote , using acid. A distinction ought to be made, strong (mineral) or weak (caroxylic, organic, vinegar or acetic). When the free fatty acids are produced when vinegar and a little heat, with stirring, the weak acid, free fatty acids have a polar end on the long chain molecule. These weak acids, free fatty acids in biodiesel stick to, adhere to, absorb or adsorb onto magnesium silicate (Magnesol?) , so the ffa's can be removed by treating the liquid with the solid magnesium silicate, then filtering out the magnesium silicate solid with ffa's stuck to its surfaces. The issue of monoglycerides was mentioned. Monoglycerides are an ester of glycerine, that's three carbons single bonded to each other with a hydroxide group bonded to each of the three carbon atoms in the molecule, but one of the hydroxide groups was previously reacted with an organic, carboxylic acid group minus one water molecule. That leaves three of the glycerine carbons bonded to a fatty acid through an oxygen atom (an ester), but the other two carbon atoms on the three carbon chain glycerol back bone have hydroxide functional groups bonded to them that are polar, being polar they will stick to , adhere to , absorb onto ,or adsorb onto the surfaces of magnesium silicate and then filter out the solid magnesium silicate solid that has the impurity stuck to it, leaving a purer biodiesel product. Using magnesium silicate treatment I've got my potassium soap content in biodiesel down below 20 parts per million. The stuff works. In the past a company in Dallas Texas manufactured Magnesol (brand name) which was used to clean up fry grease (vegetable oil) in restaurants by removing break down products from the frying oil.

  10. #10
    Join Date
    Dec 2016
    Location
    York UK
    Posts
    116

    Re: bio diesel wash

    Thanks for the info Wesley. I have used Magnesol in the past with generally excellent results. After reading your post I'm wondering if the slightly darker colour left in the bio after an acid wash is simply due to the mono's being left in the mix.( the reason I say this is that after emulsifying the mono's during water washing , then removing this layer and splitting with acid the monoglycerides are much darker than the resultant biodiesel) If the magnesol really does remove them, could this be one of the reasons that the use of magnesol slightly lightens the colour of the bio.

    The reason I stopped using Magnesol was the worry that a small amount could be left suspended in the bio even after filtering through a 1 micron filter, in fact after doing a 50/50 shake up with my finished bio (zero soap by titration) I got a milky water layer and I am still convinced that this was due to some suspended magnesol.

    I now centrifuge my finished bio, so may give the Magnesol another go and see if the centrifuge removes anything.
    Last edited by smithy; 26th February 2017 at 08:13 PM.

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