A marine fuel oil purifier is essential for maintaining fuel quality and protecting engines on modern ships, as the shipping industry constantly requires large volumes of fuel. Modern vessels primarily use light diesel fractions of crude oil, blended with gas oils from secondary processing or vacuum distillates. Ensuring proper operation of a ship’s propulsion system requires fuels that comply with international standards such as ISO 8217:2017, which specifies limits for viscosity, density, sulfur content, ash, water, cat fines, and other properties before onboard treatment.
Shipowners and operators continuously face challenges related to fuel contamination, compatibility, and stability. Off-specification bunkers can cause engine failures, increased maintenance costs, reduced efficiency, and commercial losses. Proper sampling and detailed fuel analyses are critical, and a marine fuel oil purifier ensures removal of water, abrasive particles, and harmful chemical elements, protecting sensitive engine components and auxiliary systems. The ISO 8217:2017 standard specifies key fuel properties that impact engine performance, including:
- Viscosity
- Density
- Cetane index
- Sulfur
- Flash point
- Hydrogen sulfide
- Acid number
- Sediment and carbon residue
- Cold flow properties (cloud point, pour point, CFPP)
- Appearance
- Water and ash
- Lubricity
- Trace metals (vanadium, sodium, aluminium + silicon, calcium, zinc)
Water сontamination and marine fuel oil purifier
Water is commonly introduced into marine fuels due to poor housekeeping, faulty valves, or during fuel delivery. Water contamination causes sludge formation, filter blockage, corrosion of fuel injection equipment and exhaust valves, and fouling of turbochargers. Seawater contamination is especially critical because sodium compounds can react with vanadium in fuel, forming sticky, low-melting-point salts that adhere to exhaust valves and turbochargers, causing high-temperature corrosion. Freshwater contamination, while less severe, can still create emulsions and sludge, affecting fuel efficiency and system reliability.
Ships equipped with properly designed settling tanks and well-maintained separators can reduce water content to acceptable levels, even if initial contamination is as high as 3%. Advanced GlobeCore units like the CMM-1.0CF and CMM-2.0CF are capable of purifying fuels and oils with extremely high moisture content, up to 50/50% or more. Water removal is achieved through coagulation and filtration: water molecules form droplets on the filter element, which flow into a settling vessel and can be drained via a valve. Cartridge filters with 1, 3, 5, or 25 μm filtration fineness remove particulate matter. Processing rates for these units range from 1–2 m³/hour.
Cat fines, ash, and solid contaminants in marine fuel
Aluminium and silicon, commonly referred to as cat fines, originate from catalytic cracking during refining and are highly abrasive. These particles can severely damage fuel pumps, injectors, piston rings, and cylinder liners. ISO 8217 sets a maximum limit of 60 mg/kg for cat fines, but manufacturers recommend keeping levels below 10 mg/kg, with 15 mg/kg as a warning threshold. High ash content, including vanadium, sodium, calcium, and iron, can result from fuel contamination during storage and distribution. These elements contribute to fouling of turbochargers, exhaust valves, and boilers, reduce combustion efficiency, and accelerate engine wear.
A marine fuel oil purifier effectively removes these contaminants, protecting engines and auxiliary systems. Advanced units such as the CMM-4.0F are designed for on-site filtration of lube and dielectric insulation oils with viscosities up to 70 cSt, ensuring solid particles are removed before fuel injection.
Low-viscosity marine fuel polishing
Low-viscosity marine fuels, often used in medium- and high-speed diesel engines, resemble automotive diesel but have lower cetane numbers, higher sulfur content, and higher viscosity. Environmental regulations now require the use of low-sulfur fuels, which are more expensive and often require pre-treatment to remove harmful impurities. Methods such as filtration, gravity settling, and centrifugal purification remove water and mechanical impurities but are less effective against environmentally harmful substances.
The CMM-6RL unit from GlobeCore uses an adsorbent-based method to polish low-viscosity marine fuels. The unit contains six columns filled with natural adsorbent Fuller Earth; fuel passes through these columns, and harmful impurities, including aging compounds, are captured within the granules. The treated fuel meets environmental standards and is ready for use in marine diesel engines. A unique feature of this system is the on-site reactivation of adsorbent through controlled burning within the unit, eliminating disposal issues and allowing repeated use.
The CMM-6RL operates in sequential modes:
- fuel polishing (6 hours at 1.5 kW/h);
- adsorbent preparation (1 hour at 6.25 kW/h);
- ignition (1 hour at 17.5 kW/h);
- combustion (15 hours at 25.5 kW/h), refilling (0.5 hours at 6.5 kW/h).
This ensures continuous purification and reliable delivery of high-quality low-viscosity marine fuel.
Marine fuel oil purifier is vital for maintaining engine performance, reducing operational risks, and complying with international standards. Proper removal of water, cat fines, ash, and other harmful contaminants protects engines, improves efficiency, and prolongs service life. Advanced purification units, such as GlobeCore’s CMM series, provide efficient, reliable, and environmentally compliant solutions for modern shipping.