Re: fixing the mayonnaise in Tote #1

girl mark wrote:

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>Zac Imboden wrote:
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>>1) if not enough lye added to batch - pH below 8 (too acidic)
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You can have poor reaction AND a lot of soap at the same time. Several
factors influence conversion, and lye is only one of them. You can have

For example, if you have unreacted fuel, it could be caused by:
evaporated methanol
not enough methanol
not enough heat
not  enough mixing time
addition of methanol too rapid (resulting in methanol and oil not coming
into good contact) for the mixing time or for the particular equipment
not enough lye
too much water (destroys the catalyst AND helps make soap at the same time)
overly high FFA oil

As for neutralising the soap with acid, it turns it into free fatty
acids, which dissolve in biodiesel. You can't remove FFA from biodiesel
without re-reacting (which turns them back into soap), so most people in
homebrew biodiesel dont recommend it.
 FFA content is strictly limited by the ASTM specifications for
commercial fuel because there's been some evidence that it gums up some
fuel system parts (I got this info from the chairman of the ASTM
biodiesel committee a couple of years ago, but don't think the study is
published anywhere). In commercial biodiesel they sometimes do some
neutralising of excess catalyst, but their process is much quicker so
they're working with larger amounts of excess catalyst (ie they might
neutralise after an hour of settling, whereas we're settling longer
usually and much of the stuff they'd neutralise tends ot fall out in a
homebrew setup. Also, they tend to use a lot more catalyst to begin with).




>>
>>2) if too much lye added to batch - pH above 9 (too basic)
>>    you will get soap along with a liquid containing: oil, soap and
>>     biodiesel
>>    titrate sample of liquid with acid to get neutral
>>    add enough acid to neutalize the soap (bring pH to 7)
>>        Remove thick parts if possible (the soap)
>>        Take a homogenous 100ml sample of mayonnaise and test the pH
>>         with litmus paper.
>>        Add several drops of phenylphalein (pH indicator) to waste
>>         water. The solution should turn pink because its basic!
>>        In a DRY!! titration cylinder, put in 10 ml of 37% grade HCl.
>>         (Be careful with HCl- flammable and very stinky stuff! Check
>>         MSD sheet in Brew Book).
>>        Slowly add in HCl one drop at a time to mayonnaise while
>>         constantly stirring.
>>            Frequently test the waste water with pH litmus paper.
>>            Wait a full minute after each addition of HCL
>>        Keep adding HCl until the pink color goes away and the pH is 7.
>>        Amount of HCL used is per 100ml of mayonnaise.
>>        Multiply the amount of HCl used by the number of liters of
>>         waste water needed to be neutrilized.
>>        You might want to shave off .2-.5 ml of HCl per liter so that
>>         you avoid putting in too much acid. You can always add HCl in
>>         the end if the waste water is still too high.
>>        Test the waste water after treatment to make sure pH 7 was
>>         achieved.
>>
>>--------------------------------------------------------------
>>Zac Imboden
>>[email protected] <mailto:[email protected]>
>>1534 SE 35th Place
>>Portland, OR
>>97214
>>971-563-2477
>>
>>
>>
>>------------------------------------------------------------------------
>>
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