No Titration Method

[Jeff_Retired]

Hello all, new to this forum but have been reading for some time as a guest. Started making Bio a few weeks ago and my first batch was a single stage process. The second was the Titration 2 stage which resulted in more gel / soap than I was expecting. My oil titrated at .67 NaOH. At the end of the second stage, I demethed using the GL method. At the end I got a lot of foaming and the gel. My assumption was too much catalyst in the second stage.  I should have performed a 3/27 after stage one but I did not.
Given this experience, I am interested in trying the No titration 2 stage.  To this end, I made a spread sheet calculator. Compared my calculator to the one posted on this forum (Tools) and the first stage calculations agree, the second stage do not.
The data I used is as follows.
Batch 75.8 L
Base 3.5 NaOH
Methanol 20%
1st Stage Methanol 12.13L and 265gm NaOH. Agreement on calculated values.
2nd Stage assumed drop out. 0.5 ml
Methanol 20% 3.0L Tools calculator 2.5 L
NaOH  .5*3.5*75.8 = 133 gm. Tools calculator 44 gm.
Can anyone help explain the discrepancies?
Thanks Jeff

[Tony]

Hi Jeff, and welcome.

You say 0.5ml dropout - was that from 3ml of sample (3/27) or from a larger sample IE 5/45 or 10/90?

Lets assume you were doing 3/27, so 0.5ml of 3ml is 16.6% unreacted.

So for your 75.8 litre batch you have 12.6 of oil left to react.

Methanol at 20% ratio to 12.6l of unreacted oil gives 2.5 litres.  3.0 litres won't do any harm, of course.

Onto the catalyst, 3.5g/litre of 12.6l unreacted gives 44g.

I hope that helps.

I'm concerned that you got gelling with too much catalyst.  This tends to indicate the presence of water somewhere.  You can usually get away with too much catalyst if the oil is nice and dry.

[Jeff_Retired]

Thank you Tony. Your assumption of 3/27 is correct. Your math example now gives me complete understanding of the method. The No titration instruction on this forum could stand some clarification in my opinion for those of us just starting out.
On the gel issue, I use the home made carbide manometer and calibrated it to 500ppm. I had a reading of 197ppm after drying. I assumed this was dry enough. Maybe not.
Jeff

[Julian]

Thank you Tony. Your assumption of 3/27 is correct. Your math example now gives me complete understanding of the method. The No titration instruction on this forum could stand some clarification in my opinion for those of us just starting out.
On the gel issue, I use the home made carbide manometer and calibrated it to 500ppm. I had a reading of 197ppm after drying. I assumed this was dry enough. Maybe not.
Jeff

Hi Jeff, welcome to the wiki and forum, great to have members from overseas.

Sorry you found the no titration page confusing.  It's often quite difficult for someone whose been doing this stuff for years, not to make assumptions the everyone has the same level of knowledge.

As a newcomer it would be great if you could suggest changes to the page so it's more easily understood ... that's what the wiki is all about, after all!

You have the jump on most of us with your manometer ... I know KH on here made one, but he doesn't often refer to it ... do you use it regularly Keith?

I guess the way to see where you are with the ppm levels would be to buy a new bottle of veg oil or heat the b'Jusus out of some WVO and then test those.

[K.H]

I think Jeff is probably referring to the original manometer, my one uses calcium carbide but in a portable S Brae type set up, i think the one Jeff refers to is probably the most accurate of the three
http://www.make-biodiesel.org/Quality-Testing/testing-for-water-using-calcium-carbide.html

[Jeff_Retired]

KH is correct and the link he provided is exactly the one I followed to construct it and calibrate it. The calibration procedure assumes that there will be moisture even in new oil. His graphing procedure allows for the moisture in the new oil to be accounted for and removed from the final graph line. I simply calculated the slope of the final line 23.26 ppm/cm in my case. I use it all the time to test drying of oil batches. It is not an instant read out and takes 20 to 30 min of intermittent shaking to get a result. I have stick pins I place by the tube after each shake and when the amount of change essentially or almost stops, measure cm and calculate ppm.
I will take a look at the No Titration procedure page to see if I can help clarify.

Thanks Jeff