Marine medium speed diesel engine oil needs to have good antioxidant properties under the complex working conditions of ship engines to ensure long-term stable lubrication. The realization of its antioxidant properties is the result of the comprehensive effect of multiple technical means. First of all, the selection of base oil plays a decisive role in the antioxidant properties of marine medium speed diesel engine oil. High-quality base oil is the cornerstone of good antioxidant properties. Hydrofined or synthetic base oil is often used. Hydrofined base oil removes a large amount of impurities such as sulfur, nitrogen, oxygen and unstable components such as aromatics in crude oil through deep hydrogenation process, making the molecular structure of the base oil more regular and saturated, thereby significantly improving its antioxidant ability. Synthetic base oil, such as poly alpha-olefin (PAO), has excellent chemical stability and thermal stability. Its molecular structure is highly regular and it is more difficult to undergo oxidation reaction under high temperature and oxygen environment, providing an excellent antioxidant foundation for diesel engine oil.
Efficient antioxidant additives are the key to improving the antioxidant properties of marine medium speed diesel engine oil. Antioxidant additives are mainly divided into primary antioxidants such as phenols and amines and auxiliary antioxidants such as metal passivators and antioxidants and corrosion inhibitors. Phenolic and amine antioxidants can capture free radicals generated during the oxidation process, interrupt the oxidation chain reaction, and thus prevent the oxidation of oil products. For example, hindered phenol antioxidants can quickly react with free radicals in the early stage of oil oxidation, converting them into stable compounds and delaying the oxidation process. Metal passivators can effectively inhibit the catalytic effect of metals on oil oxidation. Metal parts in ship engines, such as copper and iron, will accelerate the oxidation of oil products. Metal passivators form a protective film by chemical adsorption or chemical reaction with the metal surface, reducing the catalytic activity of the metal. Antioxidants and corrosion inhibitors can not only resist oxidation, but also form a protective film on the metal surface to prevent metal corrosion, further enhancing the antioxidant and anti-wear properties of oil products.
Detergents and dispersants also play an important role in improving the antioxidant properties of marine medium speed diesel engine oil. During the oxidation process of oil products, colloids, asphaltene and other oxidation products will be produced. If these substances are not removed in time, they will further accelerate the oxidation reaction and will also be deposited on the surface of engine parts, affecting engine performance. Detergent dispersants can disperse these oxidation products into fine particles, suspend them in the oil, and filter them out through the oil filter to keep the engine clean. In addition, detergent dispersants can neutralize the acidic substances produced during the oxidation process, prevent the acidic substances from corroding the metal parts of the engine, and indirectly improve the antioxidant properties of the oil.
Optimized production processes also help to achieve the antioxidant properties of marine medium speed diesel engine oil. In the production process, it is crucial to accurately control parameters such as blending temperature, time and stirring speed. Too high blending temperature may cause unnecessary chemical reactions between base oil and additives, reducing antioxidant properties; while too short blending time or insufficient stirring will cause the additives to be unable to be evenly dispersed in the base oil, affecting the overall performance. Through advanced production equipment and precise process control, ensure that the base oil and various additives are fully mixed to form a stable and uniform system, so that the components can synergistically play an antioxidant role.
The storage and transportation conditions of oil products will also affect its antioxidant properties. Marine medium speed diesel engine oil should be stored away from direct sunlight and high temperature environments to prevent premature oxidation of the oil. At the same time, the storage container should be kept clean and sealed to prevent moisture, impurities and oxygen from entering and affecting the quality of the oil. During transportation, avoid severe vibration and collision to prevent oxidation of the oil and precipitation of additives. Good storage and transportation conditions can maximize the antioxidant properties of marine medium speed diesel engine oil and ensure that it performs best when used.
Regular oil testing and maintenance are important links to ensure the antioxidant properties of marine medium speed diesel engine oil. By testing the viscosity, acid value, oxidation stability and other indicators of the oil, the degree of oxidation and performance changes of the oil can be understood in a timely manner. When the oxidation index of the oil is detected to exceed the specified range, the oil should be replaced in time to avoid damage to the engine due to excessive oxidation of the oil. In addition, according to the actual operating conditions and use environment of the ship engine, it is also an effective measure to maintain the antioxidant properties of the oil to reasonably adjust the oil replacement cycle.
With the development of the shipbuilding industry and the improvement of environmental protection requirements, the research on the antioxidant properties of marine medium speed diesel engine oil has been continuously deepened. Researchers are committed to developing new additives and improving formulas to further improve the antioxidant properties of oil products. For example, new composite antioxidant additives are studied to enhance the antioxidant effect through the synergistic effect between different additives; the application of nanomaterials in diesel engine oil is explored, and the special properties of nanomaterials are used to improve the antioxidant and anti-wear capabilities of oil products. These research results will provide new directions and technical support for improving the antioxidant properties of marine medium speed diesel engine oil.
