WorksheetsBoiler/ Cooling Sys. (week 12)
Total questions: 30
Worksheet time: 1hrs 17mins
A cooling water system on a ship is essential for regulating the heat generated by the engine and other machinery.
True
False
VFD on pump for cooling water system stands for?
Vibration Fault Detector
Vortex Flow Detector
Variable Frequency Drive
Variable Fuel Density
Valve Function Driver
Importance of using a VFD (Variable Frequency Drive) on a cooling water pump? (choose all the correct answers)
If temp is low (e.g., low engine load), pump slows down to save energy and prevent overcooling.
If cooling water temp rises (e.g., due to increased engine load), the controller increases VFD output frequency → pump spins faster → more cooling water flow.
The VFD continuously adjusts the pump speed based on real-time temperature feedback, maintaining optimal cooling and minimizing energy use.
It's a type of motor controller that varies the frequency and voltage supplied to an electric motor, allowing precise control over its speed and torque.
VFD allows precise control of motor speed, which is crucial for matching pump output to system demand (e.g., flow or pressure).
Boiler water system is a system that generates and utilizes steam through evaporation and condensation, used for heating, fuel oil treatment, and other processes. It does not require high-quality treated water to avoid scaling and corrosion.
True
False
The primary purpose of a heat exchanger is to efficiently transfer heat between two fluids without mixing them. It allows the transfer of heat from a hot fluid to a cooler one, which helps maintain proper operating temperatures for various systems and equipment.
True
False
A 3-way regulating valve works by controlling the flow of fluid between three ports (inlet and two outlets). The main purpose of this valve is to regulate the temperature or flow of fluids by diverting the flow between two separate paths, depending on the system’s requirements.
True
False
Preheats feedwater using exhaust gases to improve efficiency.
Boiler Drum
Economizer
Feedwater Pumps
Deaerator
Removes dissolved gases (like oxygen and CO₂) to prevent corrosion.
Boiler Drum
Economizer
Feedwater Pumps
Deaerator
Main vessel where water is stored, heated, and partially converted to steam.
Boiler Drum
Economizer
Feedwater Pumps
Deaerator
Deliver water into the boiler drum under pressure.
Boiler Drum
Economizer
Feedwater Pumps
Deaerator
______________ is steam that exists at the boiling point of water for a given pressure — meaning it’s in equilibrium with water (i.e., both water and steam coexist at the same temperature and pressure).
Saturated steam
Superheated steam
________ is steam that has been heated beyond its boiling temperature.
Saturated steam
Superheated steam
Tubes that carry hot water and steam up to the steam drum after heating.
Downcomer
Riser Tubes
Superheater
Heats saturated steam to make it hotter and dry.
Downcomer
Riser Tubes
Superheater
Pipes that carry cool water down from the steam drum to the boiler’s bottom.
Downcomer
Riser Tubes
Superheater
Location of superheater in boiler water system onboard?
Outside furnace, away from heat
Inside furnace, exposed to flame
After steam drum, in the hot flue gas path
Boiler Water System onboard.......
Closed-Loop
Open-Loop
Closed-Loop and Open-Loop
Cooling Water System onboard.......
Open-Loop
Closed-Loop
Open-Loop and Open-Loop
Purpose of expansion tank on a cooling water system: (choose all the correct answers)
As water heats up in the cooling system, it expands. It provides a space for this increased volume, allowing the system to handle the additional water without causing an increase in pressure that could damage pipes, valves, or other components.
Ensures that the cooling system remains at a constant pressure, despite changes in water temperature. This helps to keep the cooling system running smoothly and prevents overpressure situations that could lead to equipment failures.
Preventing Overpressure: The expansion tank ensures that pressure stays within safe operating levels by absorbing the excess volume of heated water.
If there’s a leak in the system, the volume of water in the system will decrease. The expansion tank helps maintain stable pressure by compensating for the lost water.
Purpose of redunduncy:
Preheats feedwater using exhaust gases to improve efficiency.
Deliver water into the boiler drum under pressure.
Backup systems (like dual feed pumps) ensure uninterrupted operation.
To ensure that there is always a backup cooling system available, even if the primary system fails.
Ensures that if one component fails (e.g., a pump), another can step in to maintain cooling and prevent overheating or system damage.
Distinguishing Features and Components: Cooling Water System (choose all the correct answers)
Heat exchangers, pumps, expansion tank
Temperature regulation valves
Freshwater and seawater loops
Steam drum, economizer, superheater
Evaporation-condensation cycle
Distinguishing Features and Components: Boiler Water System (choose all the correct answers)
Steam drum, economizer, superheater
Freshwater and seawater loops
Water treatment units (dosing system, blowdown)
Evaporation-condensation cycle
Feedwater pump, condensate system, deaerator
Function of blowdown system?
Shows the water level inside the boiler drum. Critical for safe operation.
Relieve excess pressure to prevent explosions.
Removes sludge, impurities, and dissolved solids from the boiler.
Regulates the release of steam from the boiler to various systems.
Function of Safety Valves?
Injects treatment chemicals to maintain water quality.
Regulates the release of steam from the boiler to various systems.
Removes sludge, impurities, and dissolved solids from the boiler.
Relieve excess pressure to prevent explosions.
Shows the water level inside the boiler drum. Critical for safe operation.
Injects treatment chemicals to maintain water quality.
Safety Valves
Water Level Gauge
Blowdown System
Chemical Dosing Unit
Pressure & Temperature Sensors
Implication of Out-of-Range Parameters Effect: Cooling Water System: Biological fouling
Corrosion of engine components
Scaling in jacket coolers, reduced heat transfer efficiency
Localized pitting corrosion, especially in aluminum parts
Blockages, poor circulation, higher temperature
Implication of Out-of-Range Parameters Effect: Boiler Water System: TDS (Total Dissolved Solids)
Too low → scale; Too high → foaming, deposits in drum
Acidic water → corrosion of steam drum, tubes, and piping
Promotes pitting and oxygen corrosion
Foaming, carryover of water into steam system
What will happen if blowdown rate is too frequent than the required rate.
Wastes treated water and chemicals
Accumulation of sludge and solids
Effects of Deterioration (choose all the correct answers)
Reduced efficiency
Component failure
Unsafe operation
Low maintenance costs
Manufacturers provide specific operating ranges and treatment procedures for each water system, including: (choose all the correct answers)
Blowdown schedule and volume
Maximum and minimum allowable levels of parameters
Recommended chemicals
Steps for corrective actions in case of parameter excursions
Water sampling and testing frequency
