Corrosion Monitoring: New ASTM Method to be Released Soon!

A new test method for the determination of napthenic acids in crude oil and petroleum refinery intermediates and products is under active investigation by ASTM (ASTM WK48004). Thermometric Endpoint Titration (TET), developed by Metrohm (Switzerland), is superior to ASTM D664 (potentiometric titration) at all levels: it is more accurate, more robust and and more reliable. Moreover, it is significantly faster than the ASTM D664, and because it uses much less solvent, reagent and waste disposal costs are much lower.

The TET method utilises the same titrant (0.1 mol/L KOH in 2-propanol) as ASTM D664. Instead of using a potentiometric probe (which is liable to fouling of the membrane and clogging of the reference junction after only a couple of determinations), the endpoint is detected using a highly sensitive, fast responding electronic thermometer.

This probe (Thermoprobe) requires essentially no maintenance aside from a solvent rinse, needs no hydration, requires no calibration and is ready for use 24/7.

It can be used by operators as a «walk-up» method, or fully automated with a sample changer in the laboratory. Because TET is so fast, corrective response to deviant process conditions can be much faster, with consequent savings to equipment and process running costs.