The water separation performance of marine medium speed diesel engine oil directly affects the efficiency of the oil-water separation system, which is related to the stable operation of the ship power system and the protection of the marine environment.
During the operation of marine medium speed diesel engine oil, cooling water will inevitably penetrate into the lubricating oil system. At this time, the water separation performance of diesel engine oil is particularly critical. Oils with excellent water separation performance can quickly and effectively separate from water to prevent the formation of difficult-to-handle emulsions. The formation of emulsions will not only reduce the lubricating performance of the lubricating oil, causing increased wear of engine parts, but also cause blockage of the oil-water separation system, affecting its normal operation. Therefore, designing diesel engine oil with good water separation performance is the basis for ensuring the efficient operation of the oil-water separation system.
The water separation performance of diesel engine oil depends first on the selection of base oil. Paraffin-based base oil has a regular molecular structure and is naturally hydrophobic. Compared with cycloalkane base oil, it has more advantages in water separation performance. The intermolecular force of paraffin-based base oil is weak and its affinity with water is low, making it easier to separate the oil and water phases. During the refining process, polar impurities in the base oil are removed through deep refining, which further enhances its hydrophobic properties and provides strong support for improving water separation performance.
Additive formulation is a key factor in optimizing the water separation performance of diesel engine oil. Demulsifier, as a core additive, can effectively reduce the surface tension of the oil-water interface. Demulsifier molecules have a special amphiphilic structure, one end is hydrophilic and the other end is oleophilic. They can be quickly adsorbed on the oil-water interface, change the interfacial properties, and make the water droplets in the emulsion collide and coalesce with each other, and finally separate from the oil phase. At the same time, the reasonable combination of additives such as antioxidants and detergents and dispersants is also crucial. While inhibiting the oxidation of oil products and dispersing pollutants, they will not have a negative impact on the water separation performance. Instead, they help maintain the overall performance stability of oil products and indirectly promote oil-water separation.
The compatibility of oil products and oil-water separation equipment has a significant impact on the operating efficiency of the system. Different types of oil-water separation equipment, such as gravity separators and centrifugal separators, have different working principles and separation efficiencies, and the requirements for the water separation performance of diesel engine oil are also different. For example, centrifugal separators use the centrifugal force generated by high-speed rotation to accelerate oil-water separation, requiring the oil to have good fluidity and rapid water separation capabilities to adapt to the high processing efficiency of the equipment; while gravity separators rely more on the oil-water separation characteristics of the oil itself. Therefore, when designing the water separation performance of diesel engine oil, it is necessary to fully consider the type of oil-water separation equipment equipped on the ship to ensure that the oil and equipment are optimally matched.
Operating conditions will also affect the water separation performance of diesel engine oil and the operation of the oil-water separation system. During the voyage of the ship, factors such as engine load changes, oil temperature fluctuations, and hull shaking will interfere with the oil-water separation process. Under high temperature conditions, the viscosity of the oil decreases and the oil-water separation speed is accelerated, but excessively high temperatures may cause the additives to fail and affect the water separation performance; at low temperatures, the viscosity of the oil increases and the difficulty of oil-water separation increases. In addition, hull shaking will destroy the stable oil-water interface in the oil-water separation equipment and reduce the separation efficiency. Therefore, the water separation performance design of diesel engine oil needs to take into account different operating conditions to ensure that efficient oil-water separation can still be achieved under complex working conditions.
Maintenance and monitoring are important links to ensure the continuous and efficient operation of the oil-water separation system. Regular testing of diesel engine oil water separation performance indicators, such as demulsification time and water separation index, can timely grasp the changes in oil performance. Once the water separation performance is found to be reduced, it can be adjusted by replacing the filter element, supplementing additives or changing the oil. At the same time, daily maintenance of the oil-water separation equipment, cleaning the sediment and impurities inside the equipment, and ensuring the normal operation of the equipment will also help improve the oil-water separation efficiency and form a virtuous cycle between diesel engine oil performance and equipment operation.
With increasingly stringent environmental protection regulations, the requirements for the water separation performance of marine medium speed diesel engine oil are also constantly increasing. In the future, it will become an inevitable trend to develop diesel engine oils with higher water separation efficiency, longer service life and more environmentally friendly. By introducing new additives, optimizing base oil formulas, and combining intelligent monitoring technology, real-time adjustment of oil performance and equipment operating parameters will further improve the operating efficiency of the oil-water separation system and help the shipbuilding industry achieve green and sustainable development.
