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Thread: Can I reprocess if failed 27/3 test?

  1. #1
    Join Date
    Dec 2007
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    Quakers Hill
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    Can I reprocess if failed 27/3 test?

    I recently did a batch of BD that failed the 27/3 test.
    I really only want to use high conversion fuel.

    Is it ok to titrate and reprocess?

    Or would it be better to just mix the underprocessed BD in with a batch of oil before I titrate that batch?

    Cheers,
    George

  2. #2
    Join Date
    Apr 2008
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    Perth
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    Re: Can I reprocess if failed 27/3 test?

    I would re-process using roughly 50ml/litre Methanol mixed with another 1 gram/litre Catalyst then remove the extra glycerine and then check it again with your 27/3 test.

  3. #3
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    Sunshine Coast, QLD
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    Re: Can I reprocess if failed 27/3 test?

    I've always been troubled by reprocessing as there doesn't seem (to me a dumb a$$) to be any scientific way of determining how to properly reprocess.

    A titration may be scued by the acidity of the methanol, so may not be accurate. And with no real accurate amount in mind how can we calculate how much meth we need?!?

    I wonder if the ol' method of lining up 10 bottles on a wall with varying amounts is best, using glycerine "drop out" as a benchmark?

    Any one think they have it stitched up?

  4. #4
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    Re: Can I reprocess if failed 27/3 test?

    I have reprocessed in the past on several occasions using this method and it worked ok. Besides, Tilly taught me and his advise is normally pretty good.

  5. #5
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    Re: Can I reprocess if failed 27/3 test?

    Ok I will give that a try out tomorrow and see how it goes.

    Thanks

    Cheers,
    George

  6. #6
    Join Date
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    Location
    Armidale NSW Australia
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    Re: Can I reprocess if failed 27/3 test?

    Really keen to see how you go with that rerun George. Please be sure to post your results mate.

  7. #7
    Join Date
    Sep 2005
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    Re: Can I reprocess if failed 27/3 test?

    There is no value in a titration of a failed batch where the amount of caustic added is at least in the same order as was required. This is because the caustic will have saponified the FFAs and there should be no FFA remaining in the failed batch. eg, If 8g/L NaOH was needed and only 5g/L was used, all of the FFA should have been neutralised by the 5g/L.
    In this case, it may be possible to reprocess using 5 g/L or less NaOH. A series of small batches to determine the correct amount of caustic to use will minimise the amount of soap produced in reprocessing the full batch.

    If the amount of caustic was vastly under supplied, eg 5g/10L, there would be FFA available and a titration would show its presence. In this case, you should reprocess as for used oil, using the catalyst amount plus the titration amount.

    In either case, if the batch has remained sealed and little or no methanol has been lost by evaporation, the caustic should be dissolved in a reduced amount of methanol to minimise the amount of methanol needed for the reprocessing.

    Just some thoughts on this topic.

    Hope this helps,
    Tony

  8. #8
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    Re: Can I reprocess if failed 27/3 test?

    An addition to the thoughts

    There is no simple test that will tell you how much NaOH is required in a reprocess.
    Neutral's recommendatiion was that if you had made your biodiesel to a formula that should have passed Warnqvest but did not you should start with 1g NaOH mixed into 25ml methanol per litre of biodiesel being reprocessed if the biodiesel is unwashed and 1g NaOH mixed into 50ml methanol per litre of biodiesel being reprocessed if the biodiesel is washed and dried.
    Do several test batches until you get the results you want.

  9. #9
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    Dec 2007
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    Re: Can I reprocess if failed 27/3 test?

    Thank you gentlemen.

    All good, I reprocessed with 50ml methanol (it was washed already) and 1gram of NaOH per liter of under processed BD.
    It separated out just fine, I re washed and dried.

    I am now looking at a very clear 27/3 test.

    Once again thanks for you input.

    Cheers,
    George

  10. #10
    Join Date
    Apr 2008
    Location
    Armidale NSW Australia
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    Re: Can I reprocess if failed 27/3 test?

    Good on you George.

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