Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: countrypaul on May 30, 2022, 03:56:03 PM
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Normal process with 125L UCO and ASM, got about 75% conversion on the first stage, glycerol dropped normally and was removed. On the second stage, again ASM but slightly less methanol than normal (I couldn't be bothered opending another 25L container. After 30 mins processing I took a sample (about 500ml) and left it to settle before testing. After 20 minutes there was just a visible trace of glyc on the bottom of the glass jar when I expected 5-6mm. I did a 27/3 test and it came out slightly cloudy (not unexpected) so I put the results of the test in with the main sample with the intention of adding back to the processor. Within a few seconds of adding that small amount of methanol large globules (esitmate about the size of a drip of water) of glycerol started dropping out from almost from the surface of the bio. With a couple of minutes most of the glcyerol had dropped out and there was the expected 5-6mm in the bottom of the jar.
I've not seen this behaviour before, and wondered if others had observed it?
I did not have time to carry out any experiments or look into why this happened, but wonder if maybe a lower than normal amount of methanol meant the glycerol did not want to precipitate out and adding that test sample of methanol simply triggered things. Even so the way in which it dropped out intrigued me - and made me wonder if it would have eventually dropped.
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I've batches where there has been no drop out. The jug fix has always been addition of more methanol but never seen glycerol visably forming before my eyes. Must have been an extraordinary thing to witness
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Almost like 'seeding' an over saturated solution.