English Maritime Terminology on Ship and Cargo Handling

7.3 Liquid Cargo Handling

Liquid cargo, encompassing a wide range of substances from crude oil to refined petroleum products, chemicals, and liquefied gases, presents unique challenges in its handling and transportation.

Types of Liquid Cargo

• Crude Oil: Unrefined petroleum extracted from the earth, typically transported in bulk carriers.
• Refined Petroleum Products: Processed crude oil, including gasoline, diesel, fuel oil, and jet fuel.
• Chemicals: A diverse range of liquid chemicals, such as acids, alkalis, and solvents.
• Liquefied Gases: Gases cooled to extremely low temperatures to liquefy them for transportation, such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG).

Ship Types for Liquid Cargo

• Crude Oil Tankers: Designed to transport large volumes of crude oil in bulk.
• Product Tankers: Equipped with multiple cargo tanks to carry various refined petroleum products.
• Chemical Tankers: Specialized vessels designed to transport hazardous and non-hazardous chemicals.
• Gas Carriers: Specifically designed to transport liquefied gases at cryogenic temperatures.

Liquid Cargo Handling Equipment

• Cargo Pumps: Used to transfer liquid cargo between the ship's tanks and shore pipelines.
• Cargo Piping System: A network of pipes and valves that connects the cargo tanks to the cargo pumps and shore pipelines.
• Cargo Heating System: Used to heat viscous cargoes, such as heavy fuel oil, to improve flow properties.
• Inert Gas System: Used to purge cargo tanks with inert gas to prevent explosions.
• Stripping System: Used to remove residual cargo from tanks after discharge.

Loading Operations

1. Pre-Loading Inspection:
• Inspect cargo tanks for cleanliness and integrity.
• Check cargo piping system for leaks and obstructions.
• Verify cargo temperature and pressure.
• Cargo Hose Connection:
• Connect cargo hoses between the ship and shore pipeline.
• Ensure proper sealing to prevent leaks.
2. Cargo Pump Start-up:
• Start cargo pumps and adjust flow rate as required.
3. Cargo Loading:
• Monitor cargo loading rate and tank levels.
• Ensure proper temperature and pressure control.
4. Inert Gas System Operation:
• Maintain inert gas blanketing in cargo tanks to prevent oxygen ingress.
5. Cargo Tank Ullage Measurement:
• Measure the ullage (empty space) in cargo tanks to determine cargo quantity.

Discharging Operations

1. Pre-Discharge Inspection:
• Inspect cargo tanks and piping system for readiness.
• Check cargo hoses for leaks and damage.
2. Cargo Pump Start-up:
• Start cargo pumps and adjust flow rate as required.
3. Cargo Discharging:
• Monitor cargo discharge rate and tank levels.
• Ensure proper temperature and pressure control.
4. Stripping System Operation:
• Use stripping system to remove residual cargo from tanks.
5. Inert Gas System Operation:
• Maintain inert gas blanketing in cargo tanks during and after discharge.

Safety Considerations

• Fire Safety: Implement strict fire prevention and firefighting measures.
• Explosion Safety: Maintain inert gas blanketing in cargo tanks to prevent explosions.
• Toxic Gas Hazards: Ensure proper ventilation and personal protective equipment for handling toxic chemicals.
• Spill Prevention and Response: Have contingency plans in place for accidental spills.
• Crew Training: Provide comprehensive training to crew members on liquid cargo handling procedures and emergency response.