The lubricant temperature of typically 50-90 °C already intensifies oxidation processes and the degradation of antioxidants, but impurities such as wear particles (Fe, Cu, Al, Zn etc.), soot and water accelerate these processes many times over. Important additives such as wear and corrosion protection additives, detergents and dispersants, and acid-neutralizing additives are consumed much faster. Emulsified water washes the additives out of the oil.
The degradation of the base oil and the additive depletion means that the viscosity and acidity of the lubricant increase and the lubricating effect can be lost. Aggressive acids, due to blow-by gases, intensify acidification. The ingress of blow-by gases is inevitable whether you’re running the marine diesel engine with heavy fuel oil, marine diesel or gas oil, distillates, blended or residual fuel grades, dual-fuel or natural gas (LNG).
Therefore, for lube oil filtration, you should rely on a solution that removes all impurities — particles, water, oxidation products and acids.