Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: Julian on November 13, 2012, 12:35:17 PM
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Having recently collected some ASM from Nige ... thanks Nige, I had a read of the ASM page.
I'll go back and reread 'cos I usually miss things, but there doesn't seem to be a factor in the calculations to take account of the ASM strength.
Both chemistry and sums have never been my strong points, but I'd have thought that ASM strength should somehow figure in the calculations.
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I didn't come up with the calcs - I just made the page using them - jamesrl is your man for the history behind the calcs.
I have used them with the Trinity 28% stuff and NigelB's 30% stuff and both work fine.
At the end of the day - there is not a huge difference - it's not like using 20% and 50% afterall.
If you are doing a two stage no titration then the first stage will just sort itself out anyway, presumably slighlty better conversion than would be the case with 28%
It is only the second stage where there is any difference and the volumes of methylate used in that are small, therefore the difference between the amounts of 28% and 30% would be tiny.
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Thanks, Jules. I thought as much as I've only seen 28% and 30% figures banded about. I'll contact Jim, but I think we ought to at least make mention that the calcs are based on 28/30%, just in case someone comes up with an obscure supply ... remember the wiki is internationally visible.
For my part, I've not been that impressed with no titration, largely due to my plant being very easy to mix methanol and catalyst and a pain to make up small, second batches. Hopefully the situation will be different with ASM so I'll give it another try on a future batch. I'll stick with two stage for my first batch, making too many changes at once always strikes me as an invitation for problems!
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I see the formula is a general rule that can be tweaked to suit your process. I have used a base of 4 for all of my current ASM batches but now feel with Jim's advice that it could be trimmed to 3.5 for stage 1. I'll see what happens when I brew again.
Nige
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Exactly right Nige - everyone has different oil, different drying processes and different processors.
As such, it is a safe starting point that should get a decent pass with no real dramas.
I have got away with 3.5 and 3.5 but that was with very good oil, well dried (it could have been used as WVO really rather than making into bio) and with a decent glycerol wash which would have imparted some methanol and reduced the acid value to some degree