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WorksheetsRe-assessment
Total questions: 40
Worksheet time: 15mins
During routine boiler water testing, the pH is recorded at 9.0. What is the likely risk in this situation?
Scale formation increases significantly
Risk of acidic corrosion and pitting
Embrittlement of boiler steel
Excessive foaming
You find dissolved oxygen levels above recommended limits in boiler water. The immediate treatment required is (a) .
A junior engineer records boiler water hardness at 70 PPM. What is the operational implication?
High corrosion risk due to acidity
Scale and sludge formation
Increase in foaming tendency
Reduced conductivity readings
Why is oil contamination in boiler water considered critical during operation?
It causes pH to become highly alkaline
It promotes foaming and overheating
It increases dissolved oxygen concentration
It increases hardness level
Match the following property parameters with their corresponding checks for a high-pressure boiler experiencing constant scaling despite treatment.
Oil content
Check for impurities in the fuel
Conductivity
Measure the ability of water to conduct electricity
pH level
Assess the acidity or basicity of the water
Alkalinity
Determine the concentration of hydroxide ions
If the total solids/conductivity reading exceeds the recommended limit, (a) occurs.
If phosphate concentration falls below 30 PPM in boiler water, what problem might arise?
Corrosion from chloride ions
Hardness salts remain unreacted causing scale
Excess foaming due to oil contamination
Alkalinity increases beyond safe limits
While bunkering fuel, the chief engineer decides to mix two different fuel oils in the same tank. What is the primary risk?
Increased catalytic fines concentration
Sulphur content infringement or compatibility issues
Flash point increases above safe limit
Pour point drops below usability temperature
The environmental impact of using heavy fuel oil with high sulphur content is that it (a) .
If flashpoint of fuel oil supplied is recorded at 55°C, what is the action required onboard before usage?
Heat the fuel to raise its flashpoint
Reject the fuel as it does not meet SOLAS minimum flashpoint
Mix with higher flashpoint fuel
Increase purifiers’ throughput
A fuel sample shows catalytic fines content at 80 mg/kg. The potential machinery implication is (a) .
During cold weather, fuel fails to flow smoothly from storage tanks due to (a) .
Match the following reasons for the criticality of water content in heavy fuel oil with their corresponding effects.
It increases density causing flow issues
Increased viscosity leading to pump issues
Causes corrosion and energy loss on combustion
Metal degradation and reduced efficiency
Raises flashpoint beyond limits
Higher ignition risk
Improves atomisation characteristics
Better fuel spray for combustion
Among fossil fuels, (a) has the lowest CO₂ emission.
You find the lube oil viscosity index is very low. This indicates that (a) .
Match the following actions to the appropriate responses when the water content in trunk type engine lube oil exceeds 0.5%.
Continue operation; within limit
Operation can proceed without concern
Increase purification throughput
Enhance the purification process
Immediate action is required to reduce water
Take urgent measures to lower water content
Add dispersant additives
Incorporate additives to disperse water
What is the function of dispersancy additives in lube oil?
Neutralises acidity in oil
Removes catalytic fines
Keeps carbon and sludge suspended for removal
Increases flash point of oil
During inspection, lube oil pour point is found to be -10°C. What does this imply?
Oil is unsuitable for cold operations
Oil has high water content
Oil is highly viscous
Oil is suitable for cold weather operations down to -10°C
If flashpoint of lube oil reduces significantly, what is the operational risk?
Increased risk of crankcase explosion
Reduced detergency property
High viscosity variation with temperature
Low carbon residue formation
What is the significance of TAN and TBN in lube oil monitoring?
TAN indicates alkalinity, TBN indicates acidity
TAN indicates acidity, TBN indicates alkalinity
Both indicate viscosity changes
Both measure flashpoint variations
Match the following dangers with their corresponding causes related to alkalinity in boiler water.
Pitting corrosion of shell plates
High alkalinity leading to localized corrosion
Embrittlement of steel parts
High pH causing steel to become brittle
Insufficient protection from acidic corrosion
Inadequate buffering capacity against acids
Reduced phosphate reaction efficiency
Impaired chemical treatment processes
Match the following operational measures with their corresponding actions based on a conductivity reading of 6500 µS/cm.
Increase phosphate dosing
To manage scaling and corrosion in the boiler
Increase boiler blowdown to reduce solids
To lower the concentration of dissolved solids in the water
Reduce feedwater temperature
To improve the efficiency of heat transfer
Add sodium sulfite
To prevent oxygen corrosion in the system
If dissolved oxygen remains high despite chemical dosing, the system component that might be malfunctioning is (a) .
A sudden drop in pH to 6.0 in cooling water indicates (a) risk.
Why is phosphate treatment preferred in boiler water systems?
To increase alkalinity directly
To react with hardness salts preventing scale
To reduce oil contamination risk
To improve dissolved oxygen removal
Which parameter ensures prevention of acidic corrosion in boiler water?
Maintaining pH above 10.5
Maintaining chloride ions below 200 PPM
Increasing phosphate concentration above 100 PPM
Keeping conductivity below 2000 µS/cm
Why is chloride ion monitoring important in boiler feedwater?
Indicates presence of oxygen
Indicates possible seawater contamination
Indicates oil contamination
Indicates hardness content
A fuel oil sample has high CCAI value (>870). What is its implication during combustion?
Better ignition quality
Increased flashpoint
Inferior ignition quality with ignition delay
Reduced catalytic fines content
Why is kinematic viscosity critical for fuel injection systems?
Controls ignition quality directly
Affects ease of atomisation and pumpability
Determines sulphur content
Reduces water contamination risk
Match the following operational steps with the correct actions to take when receiving bunkered fuel with high water content.
Heat the fuel
First step to ensure fuel quality
Purify through separators
Essential for removing impurities
Mix with another fuel batch
Not recommended for high water content
Transfer to day tank directly
Direct transfer may cause issues
What are the implifications of out of parameters of yor boiler water?
What is the primary consequence of using fuel oil with a high viscosity in a marine engine?
Increased fuel consumption
Higher risk of engine overheating
Lower combustion efficiency
Difficulty in fuel atomisation
How does maintaining a proper pH level in boiler water affect overall system performance?
Prevents scale formation and corrosion
Increases fuel efficiency
Reduces water treatment costs
Enhances heat transfer efficiency
What is the impact of high total dissolved solids (TDS) in boiler water?
Lower energy consumption
Increased risk of scaling and carryover
Enhanced water clarity
Improved heat transfer
What is the primary role of oxygen scavengers in boiler water treatment?
To prevent foaming
To increase pH levels
To reduce dissolved oxygen content
To enhance conductivity
How does high alkalinity in boiler water affect the system?
Increases risk of corrosion
Promotes scale formation
Improves heat transfer efficiency
Reduces foaming tendency
Match the following consequences of using low-quality fuel oil in a marine engine with their descriptions.
Increased emissions and deposits
Higher pollution levels and engine wear
Improved combustion efficiency
More efficient fuel usage
Lower operational costs
Reduced expenses on fuel
Enhanced lubrication properties
Better engine performance
What is the consequence of low alkalinity in boiler water?
Increased risk of corrosion
Higher foaming tendency
Improved heat transfer
Reduced scaling potential
How does the presence of dissolved oxygen in boiler water affect system integrity?
It promotes scale formation
It reduces water treatment costs
It increases corrosion rates
It enhances heat transfer efficiency
What is the impact of using low-quality fuel oil in a marine engine?
Increased emissions and pollution
Improved engine performance
Lower fuel consumption
Reduced maintenance requirements
