Total Acid Number (TAN)

Description

Measures the concentration of acidic compounds in oil, serving as the main indicator of its oxidation, aging, and corrosivity toward metals.

Oil aging is inevitable, but it shouldn't be a surprise that destroys your budget. The Total Acid Number (TAN) is the pulse of your industrial, hydraulic, compressor, and turbine systems. Under the influence of high temperatures, oxygen, and water, oil degrades, forming organic acids. These acids not only aggressively corrode metal parts (causing copper and steel corrosion) but also lead to the formation of thick sludge that clogs filters and valves. TAN analysis from RENA will allow you to catch the moment when the oil stopped protecting the equipment and started killing it. The test is performed by the precise potentiometric titration method (ASTM D664) on an automatic Metrohm titrator. A precisely weighed oil sample is dissolved in a special solvent (a mixture of toluene, isopropyl alcohol, and a small amount of water), which extracts all acids from the sample. Next, highly sensitive glass and reference electrodes, which measure millivolts, are immersed in the solution. The instrument begins to add an alkaline reagent (an alcoholic solution of potassium hydroxide - KOH) into the solution in micro-doses. The alkali enters into a neutralization reaction with the oil's acids. The microprocessor constantly builds a titration curve (potential change versus the volume of alkali added). As soon as all acids are neutralized, a sharp jump occurs on the curve (equivalence point). The instrument automatically calculates how many milligrams of KOH were consumed to neutralize the acids in one gram of oil.