Industry Leaders Develop Superior Method for Acid Number of Crude Oil and Petroleum Products

Metrohm (Switzerland) is pleased to announce that the ASTM has published method D8045 for the determination of Acid Number (AN) in crude oil and petroleum products. The new method describes thermometric titration and was developed by Metrohm together with industry leaders using the 859 Titrotherm titrator. Method D8045 demonstrates the superiority of thermometric titration for complex petroleum samples, as it provides for better reproducibility of results, is significantly faster, and consumes less reagent than the commonly used method D664.

Thermometric titration uses a highly sensitive, fast responding temperature sensor that detects the reaction endpoint based on the enthalpy change in the solution. This method requires no sensor maintenance aside from a solvent rinse, needs no hydration and requires no calibration. New chemistries used in ASTM D8045 significantly lower the cost per analysis as the new method consumes less solvent saving substantial costs for waste disposal.

Acid Number is a critical quality control parameter for crude oil and petroleum products. The accuracy of the AN results has a significant influence on the commercial value of crude oil and the profitability of a refinery. Moreover, acidic compounds lead to corrosion in petroleum refining and transportation infrastructure, therefore accurate AN measurements are necessary for safe operation. Given the commercial and corrosion impact of acidic compounds monitored by AN titrations, this new method is critical to quality control laboratories throughout the industry.

More information can be found at www.metrohm.com/ASTM-D8045. The method and its application to crude oil and petroleum products is described in Metrohm Application Note AN-H-141 and in more detail in Metrohm Application Bulletin 427. Method D8045 can be obtained from the ASTM website, www.astm.org