Total Acid Number (TAN) Analysis

The total acid number (TAN, total acid number) is an acidity value determined by the amount of potassium hydroxide in milligrams required to neutralize the acids in one gram of fat. This value is an important quality measure of crude oil. The TAN value indicates the potential for corrosion problems in the crude oil refinery.

In general, the thermometric titration method is used for the simple and direct determination of the total acid number (TAN) in petroleum products. This method gives extremely accurate results compared to existing manual and potentiometric methods. The thermometric titration method uses a maintenance-free temperature sensor that does not require rehydration and is free from contamination and matrix effects. This procedure requires minimal sample preparation. The results are in close agreement with the results obtained from the potentiometric titrimetric procedure according to the ASTM D664 standard, but the thermometric titration method is far superior in reproducibility and analysis speed, and determinations are completed in a very short time.

Determination of the total acid number (TAN) is very important in terms of quality control in the petroleum industry, as is stated in many international standards. This value provides valuable information on oil degradation (oil aging) and corrosion promoting properties. It is usually determined by a non-aqueous titration with strong bases and is defined as the amount of potassium hydroxide consumed in neutralizing weakly acidic substances per gram of mineral oil.

In standard methods, endpoint detection is accomplished manually using the color change of an indicator (eg ASTM D974 standard) or instrumentally using a pH electrode (eg ASTM D664 standard). In manual methods, it is often not easy to observe a pale endpoint in a multicolored solution. In instrumental methods using a glass membrane pH electrode, it is not easy to work in an anhydrous environment. The new thermometric titration method overcomes these shortcomings. The procedure is very fast, robust and reliable. This method involves titration of weakly acidic species in anhydrous medium with sodium hydroxide solution in an alcohol mixture.

Our organization also provides total acid number (TAN) analysis services with its trained and expert staff and advanced technological equipment, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors.