Industrial oil purification

Mineral oil and other lubricants gradually undergo changes in their chemical properties over time, and their service life largely depends on the effectiveness of oil purification. The application of appropriate oil purification technologies allows these oils to be reused, while periodic treatment makes it possible to extend their service life. This is particularly important for hydraulic systems, gearboxes, and reducers, which rely on the consistent performance of lubricants for reliable operation.

Popularity of industrial oils

The evolution of machinery has led to the development of a vast array of specialized machines and mechanisms with each type requiring a tailored approach to oil purification. Selecting the right lubricant involves considering several criteria, including anticorrosion and antioxidation properties, acceptable operating temperature ranges, viscosity grades, the stability of oil-water emulsions, and the chemical composition of oil. Lubricants with an optimal set of properties for specific types of machinery are commonly classified according to their applications. These include industrial oils used for lubricating equipment, such as machine tools and gear mechanisms, turbine oils for stable operation over extended periods, and hydraulic oils for smooth operation of hydraulic systems. Other groups include oils specifically formulated to meet the particular requirements of their respective systems.

Turbine oils are designed to meet the unique demands of turbines, where they must maintain stability over long periods. Proper lubrication is essential for turbine longevity, as nearly a quarter of turbine failures result from inadequate lubrication. These oils shall resist oxidation, have minimum corrosive effects on components, and remain free from mechanical impurities and contaminating water. In some cases, turbine oils can undergo continuous reclamation to maintain their properties. However, in larger machines, this process often requires operation shutdowns, making it critical for maintaining the effectiveness of oil throughout the turbine's operational cycle.

Lubricating oils are classified by their origin into organic (derived from vegetable or animal sources), mineral, and synthetic oils. Among these, synthetic oils are the most advanced, as they are produced through the chemical synthesis of various substances, such as hydrocarbons and silicones. Although the production of synthetic oils is complex and cost-intensive, resulting in higher prices, their superior quality makes them indispensable for critical applications. One of the key advantages of synthetic oils is their enhanced stability, which significantly extends their service life. Furthermore, blending of synthetic and mineral oils results in semi-synthetic products that offer a balanced combination of cost and quality. Industrial oils are among the most widely used lubricants, primarily due to their ability to reduce wear and friction in machinery, especially in gearboxes (reducers) and other mechanical components. However, as a result of continuous contact with heavily loaded metal parts, these oils often become contaminated with mechanical impurities, including metal particles as well as fragments of seals made from rubber or plastics. Prolonged operation also leads to the accumulation of oxidation byproducts, which can compromise the oil effectiveness.

 

Impact of Contamination

During use, lubricants gradually lose their functional properties due to contamination or chemical changes in their constituents. Oils that are no longer suitable for use should be either disposed of or purified. Typical contaminants include:

• Water: accelerates oxidation, increases corrosion risk, and may lead to crystal formation at low temperatures, causing abrasive damage.
• Entrapped gases: air or reaction gases can chemically alter oil composition and cause cavitation.
• Solid particles: metal fragments or other solids exacerbate wear on machinery parts.
• Oxidation byproducts: acids, resins, and other compounds reduce oil effectiveness.

Water is one of the most hazardous contaminants, as it alters the physical properties of oil and may initiate oxidation processes. Water-contaminated oil also exhibits higher corrosion potential, and in low-temperature conditions, entrapped water can crystallize, causing abrasive wear on machine components. Furthermore, the presence of water can lead to electroerosion, a phenomenon where electrical discharges erode metal surfaces. Microorganisms may also thrive in water-contaminated oils, further degrading their performance.

Contamination with gases that often come from ambient air, or gases released during chemical reactions can also adversely affect lubricants. Depending on the chemical composition of contaminant gas, it may interact with oil constituents or generate foam, which disrupts the ability of oil to form a consistent lubricating film. This can result in reduced thermal conductivity of oil and lead to overheating of machine parts. Moreover, foaming can cause irregular operation in hydraulic systems, disrupting pressure control and causing mechanical failures.

Mechanical particles, such as metal shavings, dust, and wear debris from machine components, are another common source of contamination. These particles can act as abrasives, accelerating the wear and tear of moving parts. They also contribute to sludge formation, which can clog filters, oil lines, and cooling systems, ultimately reducing the efficiency and lifespan of the machinery.

Oxidation products shall mean byproducts resulting from the natural aging of oil. Over time, exposure to oxygen and elevated temperatures causes chemical reactions that lead to the formation of acids, varnish, and sludge. These substances not only deteriorate the lubricating properties of oil, but also accelerate corrosion of machine components. High concentrations of oxidation products can transform the oil into a thick, resinous substance, rendering it unsuitable for use without proper purification.

Process-related residues, such as emulsifiers and anti-wear additives, may also degrade over time or interact with contaminants to form stable emulsions or gels. These residues can compromise the effectiveness of oil in extreme conditions, including the high-pressure or high-temperature environments.

Complex Oil Purification with Fluidex Technology

Vacuum oil purification with the use of FLD-D systems provides an efficient solution for removing both moisture and solid contaminants from industrial oils. This technology is based on the extraction of water in the vapor phase rather than in liquid form, allowing for effective separation of water from oil regardless of the emulsification degree. Even highly stable emulsions can be treated to achieve complete moisture removal.

This approach differs fundamentally from conventional dehydration methods. By converting water into vapor under vacuum conditions, the process ensures efficient moisture removal, while simultaneous mechanical filtration enables the oil to reach cleanliness levels up to ISO 4406 class 16/14/11.

FLUIDEX technology is effectively applied to various types of industrial fluids, including:

• Lubricating oils: removes destructive moisture from lubricants used in technological systems across paper, steel, and aluminum production facilities, extending oil service life and improving oil performance.

• Hydraulic oils: provides enhanced protection against water contamination, safeguarding sensitive hydraulic components in power plants and industrial systems.

• Transformer oils: extracts harmful moisture to maintain proper cooling, insulation, and corrosion protection in transformers, thereby optimizing operational efficiency.

FLD-D systems offer significant advantages to industrial operators. A key advantage inherent to these systems is their ability to extend the service life of oil, reducing the need for frequent oil change. This results in lower maintenance costs, reduced environmental impact, and improved overall efficiency of equipment.