MDE 9 Q2

1. Which of the following products obtained from the distillation of crude oil is commonly used as fuel for marine diesel engines?

B) Heavy Fuel Oil (HFO)

Explanation: Heavy Fuel Oil (HFO) is a product of crude oil distillation that is commonly used as a fuel for marine diesel engines due to its high energy content and relatively low cost. It is especially used in large marine engines and boilers.

The correct answer is:

B) From the use of additives or contaminants introduced during refining

Explanation:

According to ISO 8217, aluminium and silicon oxides in marine fuel oil typically come from contaminants introduced during the refining process or from additives used in the fuel. These oxides can originate from:

• Additives: Some fuel additives may contain aluminium or silicon compounds. When these additives are used, they can contribute to the presence of these oxides in the fuel.
• Contamination: During the refining process or handling of the fuel, contaminants can introduce these oxides. For example, the use of certain equipment or the presence of particulate matter during the fuel processing or transfer stages can lead to the inclusion of these oxides.

The other options are less relevant because:

• A) Through contamination from metal components in the fuel system: While metal components can introduce contaminants into the fuel, aluminium and silicon oxides are more commonly associated with additives or process contaminants.
• C) From corrosion of the engine parts and fuel tanks: Corrosion generally produces metal oxides like iron oxides, not aluminium or silicon oxides.
• D) Through the absorption of atmospheric dust and debris: Atmospheric dust and debris could introduce various particles but are not typically significant sources of aluminium and silicon oxides in marine fuels.

2. Which product derived from crude oil distillation is typically used for heating and cooling systems on a vessel?

C) Gas Oil

Explanation: Gas Oil, also known as Marine Gas Oil (MGO) or Intermediate Fuel Oil (IFO), is often used for heating and cooling systems on vessels. It has a lower viscosity compared to HFO and is suitable for use in auxiliary engines and heating systems.

3. What is a typical use of the product "Marine Diesel Oil" (MDO) on board a vessel?

B) As a fuel for auxiliary engines and generators

Explanation: Marine Diesel Oil (MDO) is typically used as a fuel for auxiliary engines and generators on board vessels. It is a middle distillate that is more refined than HFO and suitable for use in smaller engines and machinery.

B) They cause abrasive wear and damage to engine components

Explanation:

Aluminium and silicon oxides in marine fuel oil can have a detrimental effect on engine performance primarily due to their abrasive nature. These oxides can cause wear and damage to various engine components, such as:

• Fuel Injectors: Abrasive particles can erode the nozzle tips and reduce their efficiency.
• Pumps: The particles can cause excessive wear on fuel pumps and other moving parts.
• Cylinder Liners and Pistons: Prolonged exposure to these abrasives can lead to scoring and reduced engine life.

The other options are incorrect because:

• A) They enhance fuel combustion efficiency and increase engine power: Aluminium and silicon oxides do not enhance combustion efficiency. Instead, they cause mechanical issues that can reduce engine performance.
• C) They improve the lubrication properties of the fuel: Oxides do not improve lubrication properties; in fact, they can contribute to abrasive wear, which is contrary to improved lubrication.
• D) They increase the fuel's cetane number and reduce ignition delay: Aluminium and silicon oxides do not affect the cetane number of the fuel. Cetane number is influenced by the chemical composition of the fuel, not by particulate contaminants.

The correct answer is:

A) By using a centrifuge to separate solid particles from the fuel

Explanation:

A centrifuge is commonly used to remove solid particles, including aluminium and silicon oxides, from marine fuel oil. The centrifuge operates by spinning the fuel at high speeds, which forces the denser solid particles to the outer edges of the centrifuge bowl. This process effectively separates the solid contaminants from the cleaner fuel.

The other options are less effective or not typically used for this purpose:

• B) By adding chemical additives to dissolve the oxides: Chemical additives can help with certain types of contaminants but are not specifically designed to dissolve or remove solid particles like aluminium and silicon oxides.
• C) By filtering the fuel through a high-pressure filtration system: While filtration is used to remove particulates, high-pressure filtration systems are more suited for removing smaller particles and may not be as effective as a centrifuge for removing larger or more abrasive particles.
• D) By blending the fuel with a different grade of oil: Blending with another grade of oil does not remove the contaminants; it only dilutes them. This method does not address the issue of solid particles in the fuel.

Using a centrifuge is a widely accepted and effective method for managing particulate contamination in marine fuels, ensuring cleaner fuel and reducing potential damage to engine components.

4. Which distillation product is commonly used for cleaning and degreasing mechanical parts on a vessel?

B) Solvent

Explanation: Solvents, which can be derived from various distillation products, are commonly used for cleaning and degreasing mechanical parts on a vessel. They help to dissolve and remove grease, oil, and other contaminants from machinery and equipment.

5. Which product from the distillation of crude oil is used for lubrication of machinery and engines on board a vessel?

C) Lubricating Oil

Explanation: Lubricating Oil is specifically refined for use in lubricating machinery and engines. It reduces friction and wear between moving parts, ensuring smooth operation and prolonging the life of engine components and machinery.