hey guys im new to acid esterification but im trying to figure it out. Now im basing my numbers off of "A PILOT PLANT TO PRODUCE BIODIESEL FROM HIGH FREE FATTY ACID FEEDSTOCKS M. Canakci, J. Van Gerpen"

There is a section where they do an acid esterification using wvo titrated at 9% ffa, ive titrated my oil to 9.5% so im just using their numbers in my first batch cuz i was curious as to how the layers would split. I got pictures but i forgot my cam at home so those will be coming soon. Anyway i used 750ml non dewatered WVO, 187.5ml Methanol, and around 1.635 ml of Sulfuric acid @ 93% (66 deg baume).
Added MeOH+H2SO4 mix to wvo, stirred on hot plate at 120-130deg F for about an hour and a half, let settle overnight at about 70-75 degF.
Anyway next morning, there were 2 layers, methanol (or meth/biodiesel mix) on top, watery WVO on bottom, drained off the WVO, heated to 112 deg C, for 15 min, drove off the water. Tested pH was down around .8, but could have been higher like 1 or so. Anyway did a titration, added half a ml of 0.1M NaOH and it rocketed to 10.7, i added it way too fast cuz i was expecting to use way more than half a ml.

So im thinking its really low ffa oil? havent done calc yet, going to do more titrations using a 0.1% NaOH and again with the 0.1M with a slower addition.

This message has been edited. Last edited by: AZBiodsl,

made a mistake on first titration starting pH was around 3.7, the actual pretreated oil itself was around 0.8-0.1 pH

The oil has to be close to bone dry for acid estrification to work well, if you are measuring the ph of oil you are getting the ph of the water in the oil, as far as I am concerned ph has little to no utility in bio production.

ok here is a pic of it separated out...notice the top layer, that is what i am assuming is methanol/biodiesel mix, bottom layer i am assuming is wvo & water

also fab, i didn't de water the wvo before acid pretreatment, however i did de water it after at 112 deg C for 15 minutes...

0324090941a.jpg (16 KB, 92 downloads)

also notice how much darker it is compared to 5 minutes after addition of methanol/acid mix.
maybe this is due to carbon-sulfur byproducts? any thoughts?

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