Diesel generator sets serve as critical backup and primary power sources, widely used in overseas engineering projects, mining operations, communication base stations, and island power supply systems. Sea transportation is the principal delivery method for cross-border shipments; however, the marine environment—characterized by high salt spray, high humidity, and significant temperature fluctuations—poses serious corrosion risks to the metal components, electrical systems, and surface coatings of generator sets. A scientifically designed and comprehensive anti-corrosion protocol is essential to ensure that equipment arrives at its destination in perfect condition and is ready for commissioning.

1. Corrosion Risks in the Marine Environment

1.1 Salt Spray Corrosion

Marine air carries large quantities of salt particles such as sodium chloride, which settle on equipment surfaces. Salt absorbs moisture to form an electrolyte film, accelerating the electrochemical corrosion of metals—particularly steel, copper, and aluminum commonly used in generator construction.

1.2 High Humidity and Condensation

During sea voyages, day-and-night temperature swings are substantial, and relative humidity inside shipping containers often exceeds 80%. Condensation readily forms on metal surfaces. Since moisture is a prerequisite for corrosion, prolonged high-humidity conditions lead to rust, mold growth, and degraded electrical insulation.

1.3 Sulfur Dioxide and Marine Microorganisms

Certain shipping lanes pass through industrially dense coastal areas where the air contains acidic gases such as sulfur dioxide, which combine with water vapor to form corrosive acidic media. Additionally, bilge water and container interiors may harbor microorganisms whose metabolic by-products are also corrosive.

2. Core Anti-Corrosion Measures

2.1 Surface Treatment and Coating Protection

1. Substrate preparation: Steel structural components, base frames, and fuel tanks must undergo sandblasting or shot blasting before painting, achieving Sa2.5 cleanliness to ensure coating adhesion.

2. Primer selection: Apply epoxy zinc-rich primer or epoxy zinc phosphate primer. The cathodic protection effect of zinc inhibits steel rusting at the source, with a dry film thickness of no less than 60 µm.

3. Intermediate and top coats: Use epoxy micaceous iron oxide intermediate coat for enhanced barrier protection, and polyurethane or fluorocarbon top coat for excellent weatherability and salt-spray resistance. The total dry film thickness of the coating system should reach at least 200 µm.

4. Weld seams and edge reinforcement: Pre-coat coating-vulnerable areas such as welds, bolted connections, and cut edges to prevent film thinning caused by the edge effect.

2.2 Integrated Packaging Protection

1. Vacuum aluminum foil packaging: Seal the entire generator set (or core components) in aluminum-plastic composite film under vacuum to isolate external humid air and salt spray. The aluminum foil layer must provide excellent oxygen and moisture barrier properties, and heat-sealed joints must pass leak testing.

2. Desiccant placement: Place sufficient silica gel or montmorillonite desiccant inside the packaging based on internal volume, generally no less than 500 g/m³. Include humidity indicator cards to monitor internal humidity in real time.

3. VCI auxiliary protection: For motor windings, control cabinet interiors, and precision instruments, place volatile corrosion inhibitor (VCI) paper or VCI emitters. These slowly release corrosion-inhibiting gas molecules within the sealed space, forming a molecular-level protective film on metal surfaces.

4. Wooden crates and fumigation: Use non-fumigated plywood crates or solid wood crates treated with IPPC-certified fumigation. Ensure adequate skid height at the crate base to prevent direct contact with bilge water.

2.3 Component-Specific Protection

Component	Key Anti-Corrosion Measures
Engine	Drain coolant and engine oil; seal all openings with plastic plugs; apply anti-corrosion grease to fuel injectors and intake/exhaust manifold flange faces.
Generator	Windings must undergo insulation impregnation at the factory; place desiccant inside; seal the junction box and apply conductive grease to terminals to prevent oxidation.
Control System	Place desiccant and a temperature/humidity data logger inside the control cabinet; verify door gasket integrity; retain original anti-static packaging for PLC modules.
Fuel Tank	Fill the interior with dry nitrogen to slight positive pressure, or fill with anti-corrosion oil to prevent internal rust; reinforce the external coating.
Radiator	Apply salt-spray-resistant clear coat to copper/aluminum fins; wrap the core with moisture-proof film to prevent fin oxidation and discoloration.
Battery	Remove and ship separately before sea transport; drain electrolyte; apply petroleum jelly or anti-corrosion grease to terminals.

2.4 In-Container Environmental Control

1. Container selection: Prefer general-purpose (GP) dry cargo containers. Inspect container sealing integrity before loading and replace damaged gaskets to prevent seawater ingress.

2. Desiccant arrangement: Hang container-specific desiccant poles (calcium chloride type) on the container interior walls—no fewer than 4 per 20-foot container—to effectively absorb moisture.

3. Ventilation and moisture isolation: Maintain a ventilation gap of no less than 5 cm between equipment and container walls; lay moisture-proof pallets or plastic sheeting at the bottom to avoid direct contact with the container floor.

4. Securing and isolation: Fasten the generator set securely with steel wire ropes or lashing straps to prevent coating abrasion from movement during transit; isolate from other metal cargo with wooden boards or foam to avoid galvanic contact corrosion.

3. Pre-Shipment Inspection Checklist

☐ Overall exterior coating free from scratches or peeling; touch-up areas fully cured and dry.

☐ All openings, flanges, and interfaces sealed and plugged.

☐ Vacuum packaging passes airtightness test; humidity indicator card shows normal reading.

☐ Desiccant quantity sufficient and not yet saturated.

☐ Crate markings clear: center of gravity, lifting points, moisture protection, this side up, fragile labels all present.

☐ Accompanying documents (certificate of conformity, manual, packing list) sealed in waterproof bags.

☐ Container interior clean and dry; gaskets intact.

☐ Equipment securely fastened; skid height meets requirements.

4. Post-Arrival Inspection and Maintenance Recommendations

1. Prompt unpacking and inspection: Unpack and inspect equipment as soon as possible after arrival. If the humidity indicator card has changed color or the desiccant is saturated, immediately perform drying procedures on the equipment.

2. Insulation testing: Before commissioning, perform insulation resistance tests on generator windings and control circuits. If resistance values are low, subject the equipment to drying treatment before energizing.

3. Surface re-inspection: Check whether the coating sustained damage during transit; promptly touch up scratched areas to prevent rust from spreading from the damaged points.

4. Lubrication and maintenance: Refill with specification-compliant engine oil and coolant; apply grease to all moving parts; confirm no seizing before starting a trial run.

Conclusion

Anti-corrosion protection for diesel generator sets during sea transportation is a systematic engineering endeavor requiring a complete closed-loop approach—from coating protection and packaging sealing to component-specific treatment and in-container environmental control. A lapse at any stage can result in irreversible corrosion damage during the long voyage. Enterprises should establish standardized sea-transport anti-corrosion operating procedures and tailor them to destination port climate conditions, shipping route duration, and equipment configuration, ensuring that every generator set is delivered to the customer in pristine condition.

This article is for technical reference only. Specific anti-corrosion plans should be developed in consideration of the generator model, shipping route, and destination environmental conditions. Consultation with professional packaging and logistics teams is recommended.

Post time: Sep-16-2026