Podcast
Questions and Answers
EASY What should plant operators be well versed in during an electrical power failure?
EASY What should plant operators be well versed in during an electrical power failure?
- Firefighting procedures
- First aid techniques
- Electrical wiring practices
- Plant blackout procedures (correct)
What happens to electrically powered equipment during a power failure?
What happens to electrically powered equipment during a power failure?
- It stops, unless connected to an uninterruptable power source (UPS) (correct)
- It automatically restarts when power is restored
- It continues to operate on backup power
- It slows down to conserve energy
Which equipment will restart automatically when power is restored?
Which equipment will restart automatically when power is restored?
- Main boiler pumps
- Centrifugal pumps
- Large air compressors
- Lighting and power receptacles (correct)
What should operators know about control valves during an electrical power failure?
What should operators know about control valves during an electrical power failure?
What is a critical aspect of restarting equipment after a power failure?
What is a critical aspect of restarting equipment after a power failure?
What should operators know about electrical equipment during an electrical power failure?
What should operators know about electrical equipment during an electrical power failure?
What can be used to manually operate an automatic transfer switch during an electrical power failure?
What can be used to manually operate an automatic transfer switch during an electrical power failure?
What is an important consideration during an electrical power failure?
What is an important consideration during an electrical power failure?
What is the purpose of a UPS system in a power plant?
What is the purpose of a UPS system in a power plant?
What happens to valves during a power failure?
What happens to valves during a power failure?
What is the purpose of a seal oil pump?
What is the purpose of a seal oil pump?
What can cause a loss of boiler feedwater?
What can cause a loss of boiler feedwater?
What is the purpose of a low water alarm?
What is the purpose of a low water alarm?
What is a possible cause of feedwater pump failure?
What is a possible cause of feedwater pump failure?
What should be done if the boiler feedwater pump trips?
What should be done if the boiler feedwater pump trips?
What is the purpose of circulating hot feedwater through the standby pump?
What is the purpose of circulating hot feedwater through the standby pump?
What is a possible cause of a low water condition?
What is a possible cause of a low water condition?
What is the purpose of a UPS system's automatic transfer switch?
What is the purpose of a UPS system's automatic transfer switch?
What could be a reason for the failure of the feedwater control valve?
What could be a reason for the failure of the feedwater control valve?
What should you do if the boiler feedwater pumps are supplying feedwater at the correct pressure?
What should you do if the boiler feedwater pumps are supplying feedwater at the correct pressure?
What could happen if a condensate transfer pump fails?
What could happen if a condensate transfer pump fails?
What is a sign of an open or defective blowdown valve?
What is a sign of an open or defective blowdown valve?
What should you do if a boiler trips on low water?
What should you do if a boiler trips on low water?
Why must a boiler be inspected after a low water condition?
Why must a boiler be inspected after a low water condition?
What is a consequence of an improperly functioning low water cut-off device?
What is a consequence of an improperly functioning low water cut-off device?
What should you do if the feedwater control valve is suspected of being damaged?
What should you do if the feedwater control valve is suspected of being damaged?
Why must the boiler be cooled before inspection?
Why must the boiler be cooled before inspection?
What could cause the deaerator water level to drop?
What could cause the deaerator water level to drop?
What can cause excessive fuel pressure in a main flame?
What can cause excessive fuel pressure in a main flame?
What can cause inadequate fuel pressure in a main flame?
What can cause inadequate fuel pressure in a main flame?
What is the purpose of the high fuel pressure cut-off switch?
What is the purpose of the high fuel pressure cut-off switch?
What can cause inadequate atomizing medium pressure?
What can cause inadequate atomizing medium pressure?
What should be done to the fuel strainer if the fuel oil supply pressure is low?
What should be done to the fuel strainer if the fuel oil supply pressure is low?
Why may UV scanners need to be replaced?
Why may UV scanners need to be replaced?
What can happen to flame rods over time?
What can happen to flame rods over time?
What should be ensured during annual burner maintenance?
What should be ensured during annual burner maintenance?
What can cause flame instability in a main flame?
What can cause flame instability in a main flame?
Who should be contacted to adjust the fuel pressure and the high fuel pressure cut-off?
Who should be contacted to adjust the fuel pressure and the high fuel pressure cut-off?
What type of equipment is typically used in power plants?
What type of equipment is typically used in power plants?
When a power failure occurs, what happens to valves that fail open?
When a power failure occurs, what happens to valves that fail open?
What should the operator do immediately after a power failure?
What should the operator do immediately after a power failure?
What happens to the boiler feedwater regulating valves during a power failure?
What happens to the boiler feedwater regulating valves during a power failure?
What is the purpose of banking the fire in a solid fuel boiler?
What is the purpose of banking the fire in a solid fuel boiler?
What should the operator do with the boiler steam outlet valves during a power failure?
What should the operator do with the boiler steam outlet valves during a power failure?
What is the purpose of an Emergency Power Supply System (EPSS)?
What is the purpose of an Emergency Power Supply System (EPSS)?
What should the operator do with the breakers in an electrical distribution room during a power failure?
What should the operator do with the breakers in an electrical distribution room during a power failure?
What happens to the fuel line safety shut-off valves during a power failure?
What happens to the fuel line safety shut-off valves during a power failure?
What is the purpose of automatic load-shedding equipment in an EPSS?
What is the purpose of automatic load-shedding equipment in an EPSS?
What is the consequence of an FD fan failure if the combustion air proving switch does not shut down the burner?
What is the consequence of an FD fan failure if the combustion air proving switch does not shut down the burner?
What should be done immediately if the combustion air proving switch fails to operate?
What should be done immediately if the combustion air proving switch fails to operate?
Why is it important to allow air to enter the furnace after shutting down the boiler?
Why is it important to allow air to enter the furnace after shutting down the boiler?
Who should be contacted to replace and adjust the combustion air proving switch?
Who should be contacted to replace and adjust the combustion air proving switch?
What should be done after repairing the FD fan failure?
What should be done after repairing the FD fan failure?
What is the consequence of a failure of the electric motor, fan bearing, coupling, or fan belt?
What is the consequence of a failure of the electric motor, fan bearing, coupling, or fan belt?
What should you do if the water level is outside of the visible portion of the gauge glass?
What should you do if the water level is outside of the visible portion of the gauge glass?
What should you do if the boiler water level is below the lowest visible part of the gauge glass?
What should you do if the boiler water level is below the lowest visible part of the gauge glass?
What is a potential consequence of a high boiler water level?
What is a potential consequence of a high boiler water level?
What should you do when a flame failure occurs?
What should you do when a flame failure occurs?
What may cause a flame failure during the pilot trial for ignition period?
What may cause a flame failure during the pilot trial for ignition period?
What is recommended by ASME CSD-1 for automatically fired boilers?
What is recommended by ASME CSD-1 for automatically fired boilers?
What should you do if the pilot flame fails during pilot ignition?
What should you do if the pilot flame fails during pilot ignition?
What is a possible cause of flame failure during the run period?
What is a possible cause of flame failure during the run period?
What should you do after correcting the cause of a flame failure?
What should you do after correcting the cause of a flame failure?
What may occur if excessive combustion air is provided during the pilot trial for ignition period?
What may occur if excessive combustion air is provided during the pilot trial for ignition period?
MEDIUM What is the primary purpose of a UPS system in a power plant?
MEDIUM What is the primary purpose of a UPS system in a power plant?
What happens to valves during a power failure?
What happens to valves during a power failure?
What is the purpose of a low water alarm?
What is the purpose of a low water alarm?
What is a common cause of feedwater pump failure?
What is a common cause of feedwater pump failure?
What is the purpose of circulating hot feedwater through the standby pump?
What is the purpose of circulating hot feedwater through the standby pump?
What is a critical aspect of restarting equipment after a power failure?
What is a critical aspect of restarting equipment after a power failure?
What is the purpose of a seal oil pump?
What is the purpose of a seal oil pump?
What can cause a loss of boiler feedwater?
What can cause a loss of boiler feedwater?
What happens when a power failure occurs?
What happens when a power failure occurs?
What is the purpose of an Emergency Power Supply System (EPSS)?
What is the purpose of an Emergency Power Supply System (EPSS)?
What is the primary concern for an operator during a power failure?
What is the primary concern for an operator during a power failure?
What happens to heating system control valves during a power failure?
What happens to heating system control valves during a power failure?
What is the purpose of closing the main and pilot test firing valves during a power failure?
What is the purpose of closing the main and pilot test firing valves during a power failure?
What is the function of an Emergency Power Supply System (EPSS)?
What is the function of an Emergency Power Supply System (EPSS)?
Why is it important to open all breakers in an electrical distribution room during a power failure?
Why is it important to open all breakers in an electrical distribution room during a power failure?
What happens to boiler feedwater regulating valves during a power failure?
What happens to boiler feedwater regulating valves during a power failure?
What is the purpose of banking the fire in a solid fuel boiler during a power failure?
What is the purpose of banking the fire in a solid fuel boiler during a power failure?
What should the operator do with the boiler steam outlet valves during a power failure?
What should the operator do with the boiler steam outlet valves during a power failure?
What happens to fuel line safety shut-off valves during a power failure?
What happens to fuel line safety shut-off valves during a power failure?
What is the purpose of automatic load-shedding equipment in an EPSS?
What is the purpose of automatic load-shedding equipment in an EPSS?
During a power failure, which of the following types of equipment typically restarts automatically when normal power is restored?
During a power failure, which of the following types of equipment typically restarts automatically when normal power is restored?
What is a critical consideration for plant operators during an electrical power failure?
What is a critical consideration for plant operators during an electrical power failure?
What should you do if the boiler water level is below the lowest visible part of the gauge glass?
What should you do if the boiler water level is below the lowest visible part of the gauge glass?
What is the purpose of load shedding strategies in a power plant?
What is the purpose of load shedding strategies in a power plant?
What should plant operators know about control valves during an electrical power failure?
What should plant operators know about control valves during an electrical power failure?
What could cause severe and destructive water hammer?
What could cause severe and destructive water hammer?
What should you do if the flame fails during pilot ignition?
What should you do if the flame fails during pilot ignition?
What is the purpose of a standby generator in a power plant?
What is the purpose of a standby generator in a power plant?
What is a possible cause of flame failure?
What is a possible cause of flame failure?
What is a potential consequence of not restarting equipment in the correct sequence after a power failure?
What is a potential consequence of not restarting equipment in the correct sequence after a power failure?
What should you do if the boiler operates with its water level below the lowest visible part of the gauge glass?
What should you do if the boiler operates with its water level below the lowest visible part of the gauge glass?
What should plant operators do if a standby generator fails to start automatically during a power failure?
What should plant operators do if a standby generator fails to start automatically during a power failure?
What is the purpose of the pilot turndown test?
What is the purpose of the pilot turndown test?
What is a key consideration for plant operators when responding to an electrical power failure?
What is a key consideration for plant operators when responding to an electrical power failure?
What should you do if the boiler water level is above the highest visible part of the gauge glass?
What should you do if the boiler water level is above the highest visible part of the gauge glass?
What can cause an influx of feedwater to rapidly evaporate?
What can cause an influx of feedwater to rapidly evaporate?
What should you do if the safety valve try lever is operated?
What should you do if the safety valve try lever is operated?
What should you do if damage is suspected or there are signs of overheated surfaces?
What should you do if damage is suspected or there are signs of overheated surfaces?
What should be done if a draft fan fails and the combustion air proving switch fails to shut down the burner?
What should be done if a draft fan fails and the combustion air proving switch fails to shut down the burner?
Why is it important to close the FD fan damper after an FD fan failure?
Why is it important to close the FD fan damper after an FD fan failure?
What should be done to the furnace after shutting down the boiler due to an FD fan failure?
What should be done to the furnace after shutting down the boiler due to an FD fan failure?
What is the consequence of an FD fan failure if the combustion air proving switch does not shut down the burner?
What is the consequence of an FD fan failure if the combustion air proving switch does not shut down the burner?
Who should replace and adjust the combustion air proving switch?
Who should replace and adjust the combustion air proving switch?
What is the final step in rebooting the boiler after an FD fan failure?
What is the final step in rebooting the boiler after an FD fan failure?
What can cause a main flame to be unstable?
What can cause a main flame to be unstable?
What should trip the boiler if the fuel pressure is too high?
What should trip the boiler if the fuel pressure is too high?
What can cause inadequate fuel pressure in an oil burner?
What can cause inadequate fuel pressure in an oil burner?
What should be done to the fuel strainer if the fuel oil supply pressure is low?
What should be done to the fuel strainer if the fuel oil supply pressure is low?
Why may UV scanners need to be replaced?
Why may UV scanners need to be replaced?
What should be ensured during annual burner maintenance?
What should be ensured during annual burner maintenance?
What can happen to flame rods over time?
What can happen to flame rods over time?
What should be contacted to adjust the fuel pressure and the high fuel pressure cut-off?
What should be contacted to adjust the fuel pressure and the high fuel pressure cut-off?
What can cause flame instability in a main flame?
What can cause flame instability in a main flame?
What can happen if the combustion air proving switch fails to operate?
What can happen if the combustion air proving switch fails to operate?
What should be suspected if the feedwater control valve stem is fully open, but the boiler water level is still low?
What should be suspected if the feedwater control valve stem is fully open, but the boiler water level is still low?
What can happen if a condensate transfer pump fails?
What can happen if a condensate transfer pump fails?
What should be checked first if the boiler water level is low and the feedwater control valve is fully open?
What should be checked first if the boiler water level is low and the feedwater control valve is fully open?
What is a possible cause of a low boiler water level?
What is a possible cause of a low boiler water level?
What should be done if the boiler trips on low water?
What should be done if the boiler trips on low water?
What can cause damage to boiler tubes?
What can cause damage to boiler tubes?
What should be done if the feedwater control valve is suspected of being damaged?
What should be done if the feedwater control valve is suspected of being damaged?
What can cause a low water condition in the boiler?
What can cause a low water condition in the boiler?
What should be done if the boiler feedwater pumps are supplying feedwater at the correct pressure, but the boiler water level is still low?
What should be done if the boiler feedwater pumps are supplying feedwater at the correct pressure, but the boiler water level is still low?
What is a consequence of an improperly functioning low water cut-off device?
What is a consequence of an improperly functioning low water cut-off device?
During a power failure, which valve fails open?
During a power failure, which valve fails open?
What is the purpose of opening drum vents after a power failure?
What is the purpose of opening drum vents after a power failure?
What is the purpose of an Emergency Power Supply System (EPSS)?
What is the purpose of an Emergency Power Supply System (EPSS)?
What should the operator do immediately after a power failure?
What should the operator do immediately after a power failure?
What happens to fuel line safety shut-off valves during a power failure?
What happens to fuel line safety shut-off valves during a power failure?
What is the purpose of banking the fire in a solid fuel boiler?
What is the purpose of banking the fire in a solid fuel boiler?
HARD What should the operator do with the boiler steam outlet valves during a power failure?
HARD What should the operator do with the boiler steam outlet valves during a power failure?
What is the purpose of automatic load-shedding equipment in an EPSS?
What is the purpose of automatic load-shedding equipment in an EPSS?
What happens to boiler feedwater regulating valves during a power failure?
What happens to boiler feedwater regulating valves during a power failure?
What should the operator do with the breakers in an electrical distribution room during a power failure?
What should the operator do with the breakers in an electrical distribution room during a power failure?
What could cause a boiler to trip on low water?
What could cause a boiler to trip on low water?
What should be checked first if a feedwater control valve fails?
What should be checked first if a feedwater control valve fails?
What may indicate a problem with the boiler blowdown or blowoff valves?
What may indicate a problem with the boiler blowdown or blowoff valves?
What should be done if the boiler feedwater pumps are supplying feedwater at the correct pressure?
What should be done if the boiler feedwater pumps are supplying feedwater at the correct pressure?
What could happen if the condensate transfer pump fails?
What could happen if the condensate transfer pump fails?
What should be done if the deaerator water level cannot be restored?
What should be done if the deaerator water level cannot be restored?
What should be done if the boiler trips on low water?
What should be done if the boiler trips on low water?
What is a possible cause of a low water condition in the boiler?
What is a possible cause of a low water condition in the boiler?
What should be done if the feedwater control valve is suspected of being damaged?
What should be done if the feedwater control valve is suspected of being damaged?
Why must the boiler be cooled before inspection?
Why must the boiler be cooled before inspection?
What is a critical consideration for plant operators when restarting equipment after a power failure?
What is a critical consideration for plant operators when restarting equipment after a power failure?
What is the primary purpose of a UPS system in a power plant?
What is the primary purpose of a UPS system in a power plant?
What is a common strategy for dealing with electrical power failures in a power plant?
What is a common strategy for dealing with electrical power failures in a power plant?
What is a key consideration for plant operators when dealing with control valves during an electrical power failure?
What is a key consideration for plant operators when dealing with control valves during an electrical power failure?
What is the purpose of a standby generator in a power plant?
What is the purpose of a standby generator in a power plant?
What is a common issue with electrical equipment during an electrical power failure?
What is a common issue with electrical equipment during an electrical power failure?
What is a key consideration for plant operators when responding to an electrical power failure?
What is a key consideration for plant operators when responding to an electrical power failure?
What is the purpose of an automatic transfer switch in a power plant?
What is the purpose of an automatic transfer switch in a power plant?
What is the primary purpose of a Uninterruptible Power Supply (UPS) system in a power plant?
What is the primary purpose of a Uninterruptible Power Supply (UPS) system in a power plant?
What is the typical duration of power supply from a UPS system's battery?
What is the typical duration of power supply from a UPS system's battery?
What is the primary function of a seal oil pump?
What is the primary function of a seal oil pump?
What is the consequence of a failed feedwater control valve?
What is the consequence of a failed feedwater control valve?
What is the purpose of a low water alarm in a power plant?
What is the purpose of a low water alarm in a power plant?
What is the recommended action if the standby feedwater pump is not automatic?
What is the recommended action if the standby feedwater pump is not automatic?
What is the purpose of circulating hot feedwater through the standby pump?
What is the purpose of circulating hot feedwater through the standby pump?
What is a possible cause of feedwater pump failure?
What is a possible cause of feedwater pump failure?
What should be done if the boiler feedwater pump trips?
What should be done if the boiler feedwater pump trips?
What is the consequence of a loss of boiler feedwater?
What is the consequence of a loss of boiler feedwater?
What should be done if the boiler water level is below the lowest visible part of the gauge glass?
What should be done if the boiler water level is below the lowest visible part of the gauge glass?
What could be the cause of flame failure during the pilot trial for ignition period?
What could be the cause of flame failure during the pilot trial for ignition period?
What should be done to the pilot flame if it fails during pilot ignition?
What should be done to the pilot flame if it fails during pilot ignition?
What is the purpose of blowoff valves in high boiler water level situations?
What is the purpose of blowoff valves in high boiler water level situations?
What should be done if the boiler operated with its water level below the lowest visible part of the gauge glass?
What should be done if the boiler operated with its water level below the lowest visible part of the gauge glass?
What is a consequence of an improperly functioning low water cut-off device?
What is a consequence of an improperly functioning low water cut-off device?
Why must the boiler be cooled before inspection?
Why must the boiler be cooled before inspection?
What is the purpose of the annual pilot turndown test?
What is the purpose of the annual pilot turndown test?
What should be done if the boiler water level is above the highest visible part of the gauge glass?
What should be done if the boiler water level is above the highest visible part of the gauge glass?
Who should be contacted to adjust the pilot flame?
Who should be contacted to adjust the pilot flame?
What may arise in the furnace due to the presence of unburned fuel if an FD fan fails and the combustion air proving switch does not shut down the burner?
What may arise in the furnace due to the presence of unburned fuel if an FD fan fails and the combustion air proving switch does not shut down the burner?
What should be done if the combustion air proving switch fails to operate?
What should be done if the combustion air proving switch fails to operate?
Who should replace and adjust the combustion air proving switch?
Who should replace and adjust the combustion air proving switch?
What should be done to the furnace when it has cooled down after an FD fan failure?
What should be done to the furnace when it has cooled down after an FD fan failure?
What should be done after repairs have been completed and the cause of the FD fan failure has been determined?
What should be done after repairs have been completed and the cause of the FD fan failure has been determined?
What is the purpose of closing the FD fan damper after an FD fan failure?
What is the purpose of closing the FD fan damper after an FD fan failure?
What is a common cause of flame instability in a main flame?
What is a common cause of flame instability in a main flame?
What is the primary function of the high fuel pressure cut-off switch?
What is the primary function of the high fuel pressure cut-off switch?
What can cause inadequate atomizing medium pressure in a main flame?
What can cause inadequate atomizing medium pressure in a main flame?
What is the recommended action if the fuel oil supply pressure is low?
What is the recommended action if the fuel oil supply pressure is low?
What is the purpose of the flame safeguard control system?
What is the purpose of the flame safeguard control system?
What is a common cause of flame failure in a main flame?
What is a common cause of flame failure in a main flame?
What is the recommended action if the fuel oil strainer is blocked?
What is the recommended action if the fuel oil strainer is blocked?
What is the purpose of the low fuel pressure cut-off switch?
What is the purpose of the low fuel pressure cut-off switch?
What can cause excessive fuel pressure in a main flame?
What can cause excessive fuel pressure in a main flame?
What is the recommended action if the flame safeguard control system fails to operate?
What is the recommended action if the flame safeguard control system fails to operate?
Study Notes
Power Plant Operations and Equipment Failures
- Power plant equipment failures can occur despite best efforts, and operators must know how to respond to adverse conditions.
- Operators must be well-versed in plant blackout procedures and follow them closely to ensure safe operations.
Electrical Power Failures
- Electrical power failures require immediate and effective operator response.
- Key considerations for operators include:
- Positions of control valves in case of failure (open, shut, or last position)
- Equipment fed by standby power and uninterruptible power sources
- Manual startup of standby generators and automatic transfer switches
- Plant load shedding strategies
- Restarting equipment after power restoration
Equipment Restart After Power Failure
- Some equipment will restart automatically when power is restored, including:
- Lighting and power receptacles
- Pumps and fans that cycle on or off regularly
- Smaller air compressors and refrigeration compressors
- Equipment that requires manual restart includes:
- Fuel oil pumps
- Boiler feedwater pumps
- Chilled water pumps
- Condenser water pumps
- Boiler draft fans
- Condensate transfer pumps
- Large air compressors
Valve Failure
- Valves go to a fail-safe position during power failure, with some failing open and others failing shut or closed.
- Self-powered regulating and control valves continue to operate in response to their set point and process variable.
- Specific valve failures to be aware of:
- Heating system control valves typically fail open
- Fuel line safety shut-off valves fail closed
- Fuel line bleed valves fail open
- Boiler feedwater regulating valves fail closed (unless self-powered)
Boiler Operations and Safety
- On power failure, the operator must ensure the boiler fire is extinguished and the boiler feedwater is stopped.
- The main and pilot test firing valves must be closed to prevent unattended light-off when power is restored.
- For boilers firing solid fuel, the operator must "bank" the fire by shutting down draft fans, closing combustion air dampers, and closing flue or stack dampers.
- Banking may also involve covering the fire with green coal or ashes, or excluding oxygen by adding steam or other extinguishing medium.
Plants with No Backup Power
- Plants without backup power remain "dead" until normal utility power is restored.
- The operator's job is to put the plant in a safe state until power returns, involving tasks such as:
- Monitoring the boiler as it cools down
- Isolating the boiler feed pumps
- Closing the feedwater control valves
- Closing the fuel line test firing valves
- Opening the boiler non-return valve drain
Plants with Emergency Power Supply Systems (EPSS)
- Plants with EPSS have backup diesel engines, natural gas engines, or gas turbines operating standby generators.
- The generators are connected to automatic load transfer switches that supply power to essential loads.
- EPSS are designed to supply long-term power to essential loads, such as:
- Control room panels and instrumentation
- Emergency lighting
- Feedwater control valves
- Fuel control valves
- Boiler feedwater pumps
- Condensate pumps
- Turbine seal oil pumps
- Turbine lubricating oil pumps
- Fire water pumps
Uninterruptible Power Supply (UPS)
- A UPS maintains power to critical equipment through a system of batteries, rectifiers, power inverters, and automatic transfer switches.
- UPS systems are designed for short-term power supply, typically up to 6 hours.
- Examples of UPS-powered equipment include:
- Instrumentation and controls
- Computers
- Lighting
Feedwater System
- A loss of boiler feedwater can result in a low water condition and a boiler trip.
- Causes of feedwater loss include:
- Pump failure
- Control valve failure
- Failure to return condensate to the plant
- The operator must take steps to restore feedwater flow, including:
- Starting the standby feedwater pump
- Checking the feedwater control valve position
- Modulating the bypass valve manually
- Repairing the feedwater control valve
Boiler Trips and Low Water Conditions
-
If the cause of low water cannot be determined quickly, the boiler must trip on low water.
-
After tripping, the pilot and main test firing valves must be shut, and the boiler must be isolated, cooled, and inspected.
-
If the boiler sustains a low water condition, the fires will continue to operate, and metal surfaces can overheat and weaken.
-
The operator must trip the boiler manually, shut the test firing valves, and isolate, cool, drain, and open up the boiler for internal inspection.### Flame Failure and Safeguard Controls
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Low atomizing medium cut-off switch should extinguish the burner before flame failure occurs to prevent poor quality oil flame.
-
Defective or improperly adjusted switch can cause the flame safeguard control to trip the burner off.
Failure of Flame Detection and Flame Safeguard Controls
- Flame scanners can fail and need replacement after 40,000 hours of operation or sooner if exposed to high temperature.
- Ensure flame scanners have adequate cooling air while in service to prolong their lifespan.
- Flame rods can warp and come out of alignment over time, leading to failure to detect the pilot or main flame.
- Ceramic insulators can fail and short out the flame rod.
- Annual maintenance is necessary to ensure flame rods are clean, ceramic insulators are intact, and they are properly aligned.
Flame Safeguard Control System Failure
- Flame safeguard controls (programmed combustion controllers and primary controls) can also fail.
- Defective programmed combustion control or flame amplifier may cause the boiler to fail to light off or experience repeated flame failures.
- Contact a certified technician to inspect the operation of the flame safeguard control system and replace defective components.
Forced Draft Fan Failure
- Forced draft fans can fail due to failure of the electric motor, fan bearing, coupling, or fan belt.
- If the draft fan fails, the combustion air proving switch should open and extinguish the burner to prevent explosive conditions.
- If the switch fails to operate, the flame will become excessively smoky.
- In case of FD fan failure, shut down the main and pilot test firing valves, close the FD fan damper, and follow the normal boiler shutdown procedure.
- Replace the combustion air proving switch, adjust according to the burner manufacturer specifications, and test prior to placing the boiler in service.
- Purge the furnace prior to beginning a normal restart after repairs.
Power Plant Operations and Equipment Failures
- Power plant equipment failures can occur despite best efforts, and operators must know how to respond to adverse conditions.
- Operators must be well-versed in plant blackout procedures and follow them closely to ensure safe operations.
Electrical Power Failures
- Electrical power failures require immediate and effective operator response.
- Key considerations for operators include:
- Positions of control valves in case of failure (open, shut, or last position)
- Equipment fed by standby power and uninterruptible power sources
- Manual startup of standby generators and automatic transfer switches
- Plant load shedding strategies
- Restarting equipment after power restoration
Equipment Restart After Power Failure
- Some equipment will restart automatically when power is restored, including:
- Lighting and power receptacles
- Pumps and fans that cycle on or off regularly
- Smaller air compressors and refrigeration compressors
- Equipment that requires manual restart includes:
- Fuel oil pumps
- Boiler feedwater pumps
- Chilled water pumps
- Condenser water pumps
- Boiler draft fans
- Condensate transfer pumps
- Large air compressors
Valve Failure
- Valves go to a fail-safe position during power failure, with some failing open and others failing shut or closed.
- Self-powered regulating and control valves continue to operate in response to their set point and process variable.
- Specific valve failures to be aware of:
- Heating system control valves typically fail open
- Fuel line safety shut-off valves fail closed
- Fuel line bleed valves fail open
- Boiler feedwater regulating valves fail closed (unless self-powered)
Boiler Operations and Safety
- On power failure, the operator must ensure the boiler fire is extinguished and the boiler feedwater is stopped.
- The main and pilot test firing valves must be closed to prevent unattended light-off when power is restored.
- For boilers firing solid fuel, the operator must "bank" the fire by shutting down draft fans, closing combustion air dampers, and closing flue or stack dampers.
- Banking may also involve covering the fire with green coal or ashes, or excluding oxygen by adding steam or other extinguishing medium.
Plants with No Backup Power
- Plants without backup power remain "dead" until normal utility power is restored.
- The operator's job is to put the plant in a safe state until power returns, involving tasks such as:
- Monitoring the boiler as it cools down
- Isolating the boiler feed pumps
- Closing the feedwater control valves
- Closing the fuel line test firing valves
- Opening the boiler non-return valve drain
Plants with Emergency Power Supply Systems (EPSS)
- Plants with EPSS have backup diesel engines, natural gas engines, or gas turbines operating standby generators.
- The generators are connected to automatic load transfer switches that supply power to essential loads.
- EPSS are designed to supply long-term power to essential loads, such as:
- Control room panels and instrumentation
- Emergency lighting
- Feedwater control valves
- Fuel control valves
- Boiler feedwater pumps
- Condensate pumps
- Turbine seal oil pumps
- Turbine lubricating oil pumps
- Fire water pumps
Uninterruptible Power Supply (UPS)
- A UPS maintains power to critical equipment through a system of batteries, rectifiers, power inverters, and automatic transfer switches.
- UPS systems are designed for short-term power supply, typically up to 6 hours.
- Examples of UPS-powered equipment include:
- Instrumentation and controls
- Computers
- Lighting
Feedwater System
- A loss of boiler feedwater can result in a low water condition and a boiler trip.
- Causes of feedwater loss include:
- Pump failure
- Control valve failure
- Failure to return condensate to the plant
- The operator must take steps to restore feedwater flow, including:
- Starting the standby feedwater pump
- Checking the feedwater control valve position
- Modulating the bypass valve manually
- Repairing the feedwater control valve
Boiler Trips and Low Water Conditions
-
If the cause of low water cannot be determined quickly, the boiler must trip on low water.
-
After tripping, the pilot and main test firing valves must be shut, and the boiler must be isolated, cooled, and inspected.
-
If the boiler sustains a low water condition, the fires will continue to operate, and metal surfaces can overheat and weaken.
-
The operator must trip the boiler manually, shut the test firing valves, and isolate, cool, drain, and open up the boiler for internal inspection.### Flame Failure and Safeguard Controls
-
Low atomizing medium cut-off switch should extinguish the burner before flame failure occurs to prevent poor quality oil flame.
-
Defective or improperly adjusted switch can cause the flame safeguard control to trip the burner off.
Failure of Flame Detection and Flame Safeguard Controls
- Flame scanners can fail and need replacement after 40,000 hours of operation or sooner if exposed to high temperature.
- Ensure flame scanners have adequate cooling air while in service to prolong their lifespan.
- Flame rods can warp and come out of alignment over time, leading to failure to detect the pilot or main flame.
- Ceramic insulators can fail and short out the flame rod.
- Annual maintenance is necessary to ensure flame rods are clean, ceramic insulators are intact, and they are properly aligned.
Flame Safeguard Control System Failure
- Flame safeguard controls (programmed combustion controllers and primary controls) can also fail.
- Defective programmed combustion control or flame amplifier may cause the boiler to fail to light off or experience repeated flame failures.
- Contact a certified technician to inspect the operation of the flame safeguard control system and replace defective components.
Forced Draft Fan Failure
- Forced draft fans can fail due to failure of the electric motor, fan bearing, coupling, or fan belt.
- If the draft fan fails, the combustion air proving switch should open and extinguish the burner to prevent explosive conditions.
- If the switch fails to operate, the flame will become excessively smoky.
- In case of FD fan failure, shut down the main and pilot test firing valves, close the FD fan damper, and follow the normal boiler shutdown procedure.
- Replace the combustion air proving switch, adjust according to the burner manufacturer specifications, and test prior to placing the boiler in service.
- Purge the furnace prior to beginning a normal restart after repairs.
Power Plant Operations and Equipment Failures
- Power plant equipment failures can occur despite best efforts, and operators must know how to respond to adverse conditions.
- Operators must be well-versed in plant blackout procedures and follow them closely to ensure safe operations.
Electrical Power Failures
- Electrical power failures require immediate and effective operator response.
- Key considerations for operators include:
- Positions of control valves in case of failure (open, shut, or last position)
- Equipment fed by standby power and uninterruptible power sources
- Manual startup of standby generators and automatic transfer switches
- Plant load shedding strategies
- Restarting equipment after power restoration
Equipment Restart After Power Failure
- Some equipment will restart automatically when power is restored, including:
- Lighting and power receptacles
- Pumps and fans that cycle on or off regularly
- Smaller air compressors and refrigeration compressors
- Equipment that requires manual restart includes:
- Fuel oil pumps
- Boiler feedwater pumps
- Chilled water pumps
- Condenser water pumps
- Boiler draft fans
- Condensate transfer pumps
- Large air compressors
Valve Failure
- Valves go to a fail-safe position during power failure, with some failing open and others failing shut or closed.
- Self-powered regulating and control valves continue to operate in response to their set point and process variable.
- Specific valve failures to be aware of:
- Heating system control valves typically fail open
- Fuel line safety shut-off valves fail closed
- Fuel line bleed valves fail open
- Boiler feedwater regulating valves fail closed (unless self-powered)
Boiler Operations and Safety
- On power failure, the operator must ensure the boiler fire is extinguished and the boiler feedwater is stopped.
- The main and pilot test firing valves must be closed to prevent unattended light-off when power is restored.
- For boilers firing solid fuel, the operator must "bank" the fire by shutting down draft fans, closing combustion air dampers, and closing flue or stack dampers.
- Banking may also involve covering the fire with green coal or ashes, or excluding oxygen by adding steam or other extinguishing medium.
Plants with No Backup Power
- Plants without backup power remain "dead" until normal utility power is restored.
- The operator's job is to put the plant in a safe state until power returns, involving tasks such as:
- Monitoring the boiler as it cools down
- Isolating the boiler feed pumps
- Closing the feedwater control valves
- Closing the fuel line test firing valves
- Opening the boiler non-return valve drain
Plants with Emergency Power Supply Systems (EPSS)
- Plants with EPSS have backup diesel engines, natural gas engines, or gas turbines operating standby generators.
- The generators are connected to automatic load transfer switches that supply power to essential loads.
- EPSS are designed to supply long-term power to essential loads, such as:
- Control room panels and instrumentation
- Emergency lighting
- Feedwater control valves
- Fuel control valves
- Boiler feedwater pumps
- Condensate pumps
- Turbine seal oil pumps
- Turbine lubricating oil pumps
- Fire water pumps
Uninterruptible Power Supply (UPS)
- A UPS maintains power to critical equipment through a system of batteries, rectifiers, power inverters, and automatic transfer switches.
- UPS systems are designed for short-term power supply, typically up to 6 hours.
- Examples of UPS-powered equipment include:
- Instrumentation and controls
- Computers
- Lighting
Feedwater System
- A loss of boiler feedwater can result in a low water condition and a boiler trip.
- Causes of feedwater loss include:
- Pump failure
- Control valve failure
- Failure to return condensate to the plant
- The operator must take steps to restore feedwater flow, including:
- Starting the standby feedwater pump
- Checking the feedwater control valve position
- Modulating the bypass valve manually
- Repairing the feedwater control valve
Boiler Trips and Low Water Conditions
-
If the cause of low water cannot be determined quickly, the boiler must trip on low water.
-
After tripping, the pilot and main test firing valves must be shut, and the boiler must be isolated, cooled, and inspected.
-
If the boiler sustains a low water condition, the fires will continue to operate, and metal surfaces can overheat and weaken.
-
The operator must trip the boiler manually, shut the test firing valves, and isolate, cool, drain, and open up the boiler for internal inspection.### Flame Failure and Safeguard Controls
-
Low atomizing medium cut-off switch should extinguish the burner before flame failure occurs to prevent poor quality oil flame.
-
Defective or improperly adjusted switch can cause the flame safeguard control to trip the burner off.
Failure of Flame Detection and Flame Safeguard Controls
- Flame scanners can fail and need replacement after 40,000 hours of operation or sooner if exposed to high temperature.
- Ensure flame scanners have adequate cooling air while in service to prolong their lifespan.
- Flame rods can warp and come out of alignment over time, leading to failure to detect the pilot or main flame.
- Ceramic insulators can fail and short out the flame rod.
- Annual maintenance is necessary to ensure flame rods are clean, ceramic insulators are intact, and they are properly aligned.
Flame Safeguard Control System Failure
- Flame safeguard controls (programmed combustion controllers and primary controls) can also fail.
- Defective programmed combustion control or flame amplifier may cause the boiler to fail to light off or experience repeated flame failures.
- Contact a certified technician to inspect the operation of the flame safeguard control system and replace defective components.
Forced Draft Fan Failure
- Forced draft fans can fail due to failure of the electric motor, fan bearing, coupling, or fan belt.
- If the draft fan fails, the combustion air proving switch should open and extinguish the burner to prevent explosive conditions.
- If the switch fails to operate, the flame will become excessively smoky.
- In case of FD fan failure, shut down the main and pilot test firing valves, close the FD fan damper, and follow the normal boiler shutdown procedure.
- Replace the combustion air proving switch, adjust according to the burner manufacturer specifications, and test prior to placing the boiler in service.
- Purge the furnace prior to beginning a normal restart after repairs.
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Description
This quiz covers common equipment failures in power plants and the general principles for responding to adverse conditions. It's essential for Power Engineers to know and practice these procedures to respond correctly in emergency situations.
