in the article of Micheal J. Haas of USDA, He suggest that
1- SS has to be saponified prior to Acidulation by alkali-hidrolysis (adding solid NaOH into SS bringing PH >:11,6 there is no temperature data)
2- Acidulation of Saponified soybean based SS must be made by adding concentrated H2SO4 (Injecting H2SO4 steam into Soap bringing PH: 1,6 and then removal of water)
3- Esterification at 65 C, at 1/1,8/0,17 Molar ratio (SS/methanol/H2SO4) If we asume that FFA is enterily composed of stearic acid where is molar wegiht is 284 gr/mol and Density 0,8 gr/mol- approximately molar ratio in liter is equal to 1000 ml SS/ 218,4 ml-methanol/27,60 ml H2SO4
NOW; The MOST INTERESTING POINT IS that Volume of 27,60 ml H2SO4 IS'nt THAT)
Up to now, We knew that in order to bring High FFA acid value to acceptable limit (FF%: 0,5) for FAME reaction, we always use 1-2 ml H2SO4.

any comments for this matter, I would be very appreciated
bye for now
erdem

Erdem
I don't think there is anything wrong with the ratios you get. I worked it out and got similar. The final concentration of sulphuric calculated is approx. 2%-3%, which agrees with everything I've read. Where did you get the figure of using 1-2ml/litre, that gives a concentration of 0.1-0.2%? I've never seen acid esterification using such a low acid concentration.

ive seen it. in fact it works fine if only about 3% - 8% of your oil is ffa (up until the point you you can still get the glycerol layer to drop). lol - where do you think he got it?
btw you don't need to do base step even if you oil isn't 100% ffa.

btw #2 i dont think i could help either lewis or erdem my "soapstock" experience is limited to forgetable moments i had before i swore off using base forever. i now prefer acid in limited doses with a high level of alchohol kick behind it.