Why is TAN (Total Acid Number) a critical parameter in crude oil characterization?

TAN, or Total Acid Number, is a critical parameter in crude oil characterization because it indicates the concentration of acidic components in the crude oil. These acidic components, primarily organic acids such as naphthenic acids, can cause corrosion in refinery equipment. The TAN value is defined as the milligrams of potassium hydroxide (KOH) required to neutralize one gram of crude oil. A high TAN value signifies a higher concentration of acidic components and, consequently, a greater potential for corrosion. Corrosion can lead to equipment failures, leaks, and unscheduled shutdowns, resulting in significant economic losses and safety hazards. Crude oils with high TAN values often require special handling and processing techniques to mitigate corrosion risks. This might involve using corrosion inhibitors, selecting specific metallurgy for equipment construction, or blending the high-TAN crude with low-TAN crudes to reduce the overall acidity. The TAN value helps refiners assess the corrosivity of the crude oil and make informed decisions about processing strategies and corrosion management. Monitoring TAN levels throughout the refining process is also important to ensure that corrosion is controlled effectively.