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Safe Methoxide-Diluted Batch Removal/Seperation

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October 24, 2014, 03:22 PM
Justin McCarty
Safe Methoxide-Diluted Batch Removal/Seperation
Methoxide was added to a batch of biodiesel for reprocessing without first heating the oil. Of course, no heating can occur at this point given that the batch is now diluted with methoxide. At this point, I'm thinking that our only option is to dispose of the batch if we can't somehow separate the methoxide from biodiesel. Does anyone have any suggestions for either safe disposal or separation of the methoxide from the diluted batch?

"It is easier to ship recipes than cakes and biscuits." -Keynes
October 24, 2014, 03:53 PM
Hi Justin,
As long as everything remains liquid in the reactor, the temperature of the reaction is not a limiting factor to the eventual quality of the biodiesel.
In other words, as long as everything is still liquid in the reactor just keep mixing and the reaction will continue, just at a slower rate.

The rule of thumb is that for every 10deg C the temperature is reduced, reaction time doubles.
Assuming everything else is normal and you have an adequate reactor, reaction times would look something like this.

50deg C- 1 hour for the reaction to complete
40deg C- 2 hours
30deg C- 4 hours
20deg C- 8 hours

October 24, 2014, 04:31 PM
I have processed and re-processed many batches to full conversion at between 20 and 30 degs C

The conversion time in practice does not take as long as suggested in the previous post.
October 24, 2014, 04:49 PM
Hi Dgs,

Originally posted by Dgs:
The conversion time in practice does not take as long as suggested in the previous post.
That is likely to be the case. The times I posted above are for a single stage reaction from start to finish and then they would only be approximates.
When reprocessing, about half the oil remaining to be reprocessed is already partially converted into mono and diglycerides.

Also, if you are using the Warnqvest test to determine the amount of chemicals to use in the reprocess you end up using a large excess of chemicals in the reprocess which will likely accelerate the rate of the reprocess.

In your experience, how long should he mix before doing his first Warnqvest test to check the progress of the reprocess?