New source of oil, did all the usual but failed the 27/3 test. Question for Tilly or anyone else in the know. When Tilly says use 1gr per L does that mean a "total of one", or does that mean 1gr plus the base of 5 using KOH? I am drying the batch now and after cooling I will rerun it. Thanks

When I last did a repro I used 1g per llt of oil total(this was before washing)
If your using KoH with a base of 5 for regular processing,this is very low on modern thinking-I think you will find most are using 7g or above and then adjust for purity-this maybe why you have failed your 27/3

If you are using a base of 5 plus T you are more than likely way under reacted. I use 9 plus T and most use at least 7 plus 10% for purity correction which totals 7.7gr / liter.

Norman

Sorry all, I meant 7 plus T. My oil titrates at 8 and I use a total of 15g. The failure was ever so slight but a fail is a fail so I will redo. Thanks

Before you reprocess do another 3/27 making sure of quanties and temp. Can't hurt and the slight fail might not show up the second time.

Will
-I use 10 ml methanol and 1 gr koh per ltr of oil. if the fail is real bad, you my have to do this a couple times. Drop the byproduct prior to repo. tom

I make 40 gallon batches with Naoh. When I have to reprocess I draw off the glycerol from the initial reaction and reporcess with:

2 Gallons of Methanol (5% of batch)
151g Naoh (1 gram per liter)

I have had to do it twice and both times after two hours of reprocessing I passed 3/27.

Hope that helps. Good luck.

I have always used the following for reprocessing.

1g NaOH/liter or 1.4g KOH/liter with

50ml/liter of MeOH for dried/washed biodiesel

35ml/liter of MeOH for unwashed biodiesel.