Total Acid Number

Quality Specification:

The Total Acid Number (TAN) is a sum parameter for all acidic components to indicate the level of free fatty acids (FFA) and process acids present in biodiesel as well as organic acids that may be created over time as the fuel ages and oxidizes. TAN analysis is performed in accordance with ASTM D664 which requires potentiometric determination of the titration endpoint. High acid numbers have been linked to fueling system deposits and corrosion.

ASTM D6751 Requirement: a maximum total acid number of 0.50 mg KOH/g.