I saw a Bio_Pro demo a couple years ago and remember they used sulfuric acid in the beginning of the process but doon't remember if any methanol was used until the base process was started.

4 gallons of methanol are used in the acid method
6 gallons of methanol are used in the base method

-Graydon

quote:

4 gallons of methanol are used in the acid method
6 gallons of methanol are used in the base method

These are the amounts for a Bio pro 190(190 liters or 50 gal.)? I saw some biopro chat about using 190 ml. acid and that using 360 grams of KOH will cancel out the effects of the acid. One brewer states that the acid doesn't effect titration . This is what I'm seeing with the little AE I've tried, but the opposite of some other chat.

It depends on when you introduce the Sulfuric & KOH.

The Sulfuric, if introduced at the right time (first, and with 4 gal of methanol), can effectively reduce the titration because of something called acid esterification.

The details on why this works are here:
http://biodieselcommunity.org/acidbase/

Basically, the sulfuric acid modifies free fatty acids so that they can be converted into Biodiesel.
Convert enough of them and your titration will go down (titration is just measuring how many free fatty acids there are in the oil).

However, if your oil isn't all that acidic to start with, then you're right, excess KOH will neutralize the sulfuric if it isn't used in the first reaction.

Yep. 190 mL Sulfuric
190 liters is roughly 50 gallons, hence the BioPro 190 name...

-Graydon