Marine Fuel Oil Systems Overview

Marine Fuel Oil Systems

• Consist of three subsystems: fuel transfer, fuel oil treatment, and fuel oil supply
• Fuel Transfer System: receives and stores fuel, delivers to settling tanks
  • Fuel loaded through deck fill connections with sample connections for testing
  • HFO loaded in storage tanks with heating coils
  • HFO transferred to settling tanks via FO transfer pumps with suction strainers
  • Pumps can transfer fuel between storage tanks and to deck connections for offloading
  • Settling tanks allow gross water and solids to settle on the bottom
• Fuel Oil Treatment System: transfers fuel from settling tanks to service tanks
  • Cleaning heavy fuel oils (HFO) commonly uses a two-stage process
  • Fuel is heated in a settling tank to 50-60°C, then drawn out by the purifier inlet pump
  • The inlet pump delivers fuel to a heater, raising temperature to 80°C, then to the centrifugal purifier
  • Purified fuel is transferred to a centrifugal clarifier by the purifier discharge pump
• Fuel Oil Supply System: supplies clean fuel to the main engine and auxiliary engines

Marine Fuel Oil Production Process

• Describes the refining process of crude oil to produce different fuel oil types.
• Distillation: Process used to separate liquids from nonvolatiles based on boiling points.
• Heavy Fuel Oil (HFO): Tar-like consistency, also known as bunker fuel or residual fuel oil.
  • Result of distillation and cracking of petroleum
  • Contaminated with aromatics, sulfur, and nitrogen, making emissions more polluting.

Marine Fuel Oil Use Onboard Ship

• Explores the different types of marine fuels used onboard ships
• Very Low Sulfur Fuel Oil (VLSFO): Sulfur content 0.5% or less by weight.
  • Mandated by IMO 2020 regulation, requiring reduction in sulfur content from 3.5% to 0.5% since January 1, 2020.
  • VLSFO has become a preferred choice due to lower cost and simpler implementation compared to MGO and scrubbers.
• Marine Gas Oil (MGO): Consists exclusively of distillates.
  • Distillates are components of crude oil that evaporate and condense into liquid fractions during fractional distillation.
• Cellulosic Ethanol: Second-generation biofuel derived from low-value biomass with high cellulose content.
  • Examples include wood chips, crop residues, municipal waste, sugarcane bagasse, and various grasses.
  • Used primarily as a gasoline additive due to lower conversion rate compared to first-generation biofuels.

Effects and Carbon Emissions of Conventional Fuels Onboard Vessels

• Conventional fuels like HSFO, LSFO, and MGO are carbon-rich substances, contributing significantly to carbon emissions.
• Greenhouse Gas Emissions: Contribute to climate change by trapping heat in the atmosphere.
• Fossil Fuel Dependence: Drives the reliance on fossil fuels, contributing to environmental concerns.

Role of Non-Fossil Fuels in Carbon Emission Reduction

• Non-fossil fuel sources play a crucial role in reducing carbon emissions and mitigating climate change.
• Renewable Energy Sources
  • Solar Energy: Converts sunlight directly to electricity using photovoltaic cells.
  • Wind Energy: Uses wind turbines to generate electricity.
  • Hydro Energy: Generates power through water flow, typically via dams.
  • Geothermal Energy: Utilizes heat from Earth's interior to generate power.
• Nuclear Power: Not renewable, but generates electricity with minimal CO₂ emissions using nuclear reactions.
  • Presents challenges related to waste management and safety concerns.
• Bioenergy: Derived from organic materials like plant and animal waste, including biofuels and biogas.
  • Considered carbon-neutral as plants absorb CO₂ during growth, offsetting emissions during combustion.

Effects of Impurities in Fuel Oil

• Metals (Abrasive Wear): Cause abrasive wear on engine components, leading to deposit formation in the combustion chamber and on valves.
• Ash Content (Deposits): Can form deposits on engine components, reducing efficiency and increasing maintenance needs.
• Microbial Contamination (Bacteria and Fungi): Presence of water and organic matter can produce sludge and acids, leading to clogged filters, corrosion, and fuel quality issues.

Effects on Main and Auxiliary Engines

• Main Engines:
  • Performance Degradation: Impurities reduce combustion efficiency, lowering power output and increasing fuel consumption.
  • Increased Wear and Tear: Contaminants cause abrasive damage, reducing engine life and increasing maintenance.
  • Corrosion: Water and sulfur compounds accelerate corrosion in engine parts.
  • Operational Issues: Fuel filter clogging, injector fouling, and engine knocking cause breakdowns and downtime.
• Auxiliary Engines:
  • Fuel System Problems: Similar to main engines, impurities cause clogged filters and fuel system components.
  • Efficiency Loss: Reduced combustion efficiency leads to higher operational costs.
  • Increased Maintenance: Frequent maintenance needed to address contaminant-related issues.
  • Reliability Issues: Operational problems affect engine reliability and availability.

Mitigation Strategies for Impurities

• Proper Storage: Store fuel in clean, dry, and sealed containers to prevent contamination.
• Regular Filtration: Use high-quality fuel filters and change them frequently to remove particulates and water.
• Water Separation: Implement water separators to remove water from fuel.
• Chemical Additives: Use additives to neutralize sulfuric acid and inhibit microbial growth.
• Regular Monitoring: Conduct fuel quality tests and engine inspections to detect and address contamination early.

Properties of Fuel Oil to be Checked During Mixing

• Density/Specific Gravity: The mass of a liquid per unit volume at a specified temperature (15°C).
  • Used to calculate fuel weight and oil-water interface position in high-speed separators.
  • Essential for calculating fuel calorific value.
• Kinematic Viscosity: Measures a fluid's internal resistance to flow under gravity.
• Calculated Carbon Aromaticity Index (CCAI): Indicates the fuel's burning tendency (ease or difficulty).
• Pour Point: Lowest temperature at which oil flows under gravity.
• Viscosity: Decreases when fuel is heated, important for pumping and atomizing fuel for combustion.
• Flash Point: Lowest temperature at which fuel releases vapor at atmospheric pressure.
• Catalytic Fines (Aluminum + Silicon): Small amounts from refining processes can cause catastrophic wear on pumps, nozzles, cylinder liners, and piston rings.
  • Effective separation through purifiers is crucial to remove cat fines.