Understanding the Impact of Free Acids in Diesel Oil

Free acids in diesel oil are undesirable contaminants that can cause significant problems in diesel engines and fuel systems. These acids are typically weak organic acids, but their presence can lead to harmful reactions, especially with metal components.

When diesel oil containing free acids is stored, these acids come into contact with the metal surfaces of the storage tank. Metals, particularly the steel commonly used for fuel tanks, are susceptible to corrosion when exposed to acids. This leads to the gradual degradation and weakening of the tank walls, potentially causing leaks and contamination of the fuel with rust particles.

Similarly, when this acidic diesel oil is used in a diesel engine, it flows through various metal parts of the fuel system and the engine itself. These parts include fuel pumps, injectors, fuel lines, and potentially parts of the combustion chamber. The free acids can corrode these metallic components. Corrosion can lead to:

• Wear and damage to precision parts like fuel injectors and pumps, affecting fuel delivery and engine performance.
• Blockages in fuel lines and filters due to corrosive deposits and rust particles.
• Potential damage to cylinder walls or exhaust system components over time, although the primary and most immediate damage from free acids is typically corrosive attack on the fuel system and tank.

Therefore, the presence of free acids in diesel oil directly contributes to the corrosive deterioration of both the fuel storage tank and the engine's internal components, leading to damage in both areas.