Water occurs as a contaminant in virtually all petroleum products. It reduces lubricant properties, promotes microbial oil degradation, leads to sludge formation in the tank, and promotes corrosion of ferrous and nonferrous metals.
While at higher temperatures water boils and contributes to a partial degreasing, temperatures below freezing point lead to the formation of ice crystals and a rapid decrease in lubricity. In addition, insulating and transformer oils used in highvoltage engineering become electrically conducting and are therefore rendered use less in the presence of water.
In view of this, knowledge of the water content in petroleum products is of prime importance. Karl Fischer titration, owing to its excellent reproducibility and accuracy as well as its ease of use, numbers amongst the most important water determination methods and accordingly figures in numerous international standards. Measure ment can occur by volumetric or coulometric Karl Fischer titration. Because of the low water content in petroleum products, KF coulometry is usually applied.
ASTM D6304 states that its aim is “Standard Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric Karl Fischer Titration, and the new 917 KF Coulometer from Metrohm is the perfect instrument to satisfy this method.
The 917 KF Coulometer from Metrohm is the perfect instrument to satisfy ASTM D6304.
The 917 Coulometer is a compact titrator for coulometric water determination according to Karl Fischer. ”Reduced to the max” – operating module, stirrer and pump are integrated in the 917 Coulometer for rapid reagent replacement. This saves a great deal of space on the laboratory table.
Recommended measuring range: 10 µg – 200 mg absolute water.
Coulometry is the ideal method for the determination of trace water in liquids, solids and gases. In addition, coulometry is an absolute method and thus no titer determination is necessary.