Strangely enough I was thinking about making a post about this, you beat me to it Julian. So just to explain fully;
A friend of mine had this 'strange' oil offered to him. There was a total of about 17 IBC's. Not all full and some contained glycerol and very watery whites. I tested some of the oil via the Dr pepper method and couldn't get any dropout after adding methoxide. I titrated quite a few samples and got results between 9 and 13 (KOH) so After adding much stronger methoxide I did get some reaction although the yield was very poor as well as producing a lot of glycerol. 10/90 tests on the oil showed dropouts of between zero and 5mls
I phoned a well qualified friend (ex commercial producer) who had come across this before. This oil was 10 years or more old and kept in clear IBC's outside for all this time. He said the u/v had, over the years split the free fatty acid chains into shorter ones (so no longer ffa's) hence the reason why it was totally/partially soluble in methanol.
So even though I eventually got some reaction, what I made probably wasn't biodiesel (a fatty acid methyl ester) simply because I probably wasn't starting with ffa's originally.
I have since done a 100 litre process using a blend of 40 litres of this strange oil and 60 litres of my own 'fresh' oil. Even though blended some strange things happen. Glycerol seems to form much quicker after methoxide addition (like it turns dark within seconds) Yield is poor, probably some 10 litres below usual. It takes double the water washes to get clear water but no hint of a monoglyceride emulsion.
Anyway, I ran some of it in the Renault traffic van, Guess what............ ran completely normal!
So Julian, just blend it, I'm sure it will work.
This stuff really has me guessing, after the first few tests I was convinced it wasn't veg. I have tangled before with old oil (not as bad as this) and it always has that strange paint/turps smell to it.
