112 Questions
What is the primary purpose of routine fireside cleaning in modern steam generators?
To maintain boiler efficiency and steaming capacity
What is the effect of soot and ash deposits on heat transfer surfaces in boilers?
They reduce the heat transfer rate
What can be an indication of poor heat transfer performance in boilers?
High flue gas temperatures and a reduction in steam production
What can be used to maintain flue fireside cleanliness in boilers?
Soot blowers, periodic water washing, or mechanical cleaning
What can be a consequence of ash accumulation in boilers?
Restricted flow and impeded heat transfer
What is the primary maintenance aspect of heat transfer surfaces in boilers?
Surface cleanliness and good flue gas flow
What is the primary purpose of soot blowers in fireside cleaning?
To permit in-service fireside cleaning
What is the effect of increased fireside deposits on boiler operation?
Lower boiler efficiency and higher flue gas temperatures
When is it necessary to perform out-of-service cleaning?
During the annual or semiannual scheduled outages
What is the purpose of a chemical treatment in fireside cleaning?
To remove corrosive compounds from the boiler
What is the effect of fireside deposits on pressure differential across heat transfer surfaces?
It increases the pressure differential
What is the primary concern when introducing water during cleaning?
Ensuring the water is introduced with great care
What is the advantage of in-service fireside cleaning?
It reduces the need for out-of-service cleaning
What is the purpose of visual examination of deposit patterns during an outage?
All of the above
What is the result of heavy fireside deposits on draft loss?
It increases draft loss
What is the effect of fireside deposits on steam production?
It decreases steam production
What is the primary purpose of continuous in-service cleaning in boilers?
To optimize the boiler's heat transfer efficiency and availability
What is the most common method of in-service fireside cleaning in boilers?
Soot blowers
What is the purpose of the poppet valve in soot blowers?
To introduce dry, high-pressure steam into the lance
What is the advantage of using air as a soot blowing medium?
It is compact, simple in construction, and relatively inexpensive
What is the purpose of acoustic cleaning systems in boilers?
To knock ash off boiler tubes with acoustic energy
What is the characteristic of acoustic cleaning systems?
They operate continuously in successive short cycles
What is the purpose of rapping systems in boilers?
To remove deposits from the heating surfaces without additional cleaning medium
What is the effect of the rapping system on the heating tube bundles?
It shakes off the material buildup
Why is it important to drain the condensate from the soot blower lance?
To prevent erosion from moisture or condensate
What is the advantage of using steam as a soot blowing medium in larger boilers?
It is available whenever the boiler is in service
What is the primary advantage of pneumatic rapping systems over other methods?
They enable higher impact energies
What is the purpose of the falling shot system in boilers?
To remove ash deposits from the tube surfaces
Why are explosives sometimes used in in-service cleaning?
To remove large deposits that cannot be dislodged by conventional methods
What is the purpose of retractable soot blowers in the radiant zone of the boiler?
To clean heat transfer surfaces
Why do retractable soot blowers retract when not in use?
To prevent overheating and damage
What is the primary cause of slag buildup in the radiant zone of the furnace?
Molten ash coming into contact with cool furnace walls
How do short retractable wall blowers remove ash deposits?
By using a jet of superheated steam or air
What is the purpose of the long retractable soot blower?
To clean the radiant and convection heating surfaces
Why do long retractable soot blowers hang from a carriage outside the boiler furnace?
To prevent overheating and damage
What is the purpose of the inner tube in the long retractable soot blower?
To convey steam to the nozzle
What is the primary function of the chains and reduction gear mechanism in a stationary soot blower?
To rotate the lance and clean more area
Where are air heater soot blowers typically located?
Over the top of the heat exchange surface
What is the minimum boiler load required for stable combustion during soot blowing, according to ASME BPVC Section VII?
50 percent
What is the purpose of the hopper in a falling shot cleaning system?
To collect the ash particles and shot
What is the advantage of not requiring a supply of air or steam for the operation of falling shot cleaning?
It reduces the steam consumption of the soot blowers
What is the primary function of the distributing chamber in a falling shot cleaning system?
To recycle the iron shot
What is the purpose of the pneumatic conveying system in a falling shot cleaning system?
To return the shot to the top distributing chamber
What happens to the ash particles that are removed by the shot in a falling shot cleaning system?
They are recycled with the shot
What is the advantage of using falling shot cleaning in small plants?
It does not affect the turbine steam supply
What is the purpose of the control screen for soot blower sequencing and operation?
To sequence the soot blowers and alert the operator of stuck blowers
What is the purpose of the sealing arrangement in the soot blower system?
To prevent steam from escaping
What is the function of the drive motor in the soot blower system?
To push the soot blower lance into the furnace
How does the linkage connected to the carriage function in the soot blower system?
It opens the soot blower poppet valve
What is the purpose of the rollers on the inner support in the soot blower system?
To support the lance
Why is it important to maintain steam flow to the soot blower until it is fully retracted?
To prevent the lance from overheating
What is the purpose of the two opposed nozzles at the tip of the retractable soot blower lance?
To emit a jet of superheated steam or compressed air
Why is it important to adjust the soot blower so that it does not impinge directly upon tubes?
To prevent the tubes from eroding
In which zones of the boiler are stationary non-retractable soot blowers typically used?
Convection zones, such as the economizer, generating bank, and air heater
How are the lance tubes held in place in stationary soot blowers?
With bearings
What is the purpose of sequencing the use of multiple soot blower units in a boiler?
To move the ash and soot to a specific point in the boiler for removal
What is the primary consequence of soot and ash deposits on heat transfer surfaces in boilers?
Reduced heat transfer rate
Why is routine fireside cleaning essential in modern steam generators?
To maintain boiler steaming capacity and efficiency
What is the effect of ash accumulation on gas flow in boilers?
Ash accumulation restricts gas flow
What is the primary indication of poor heat transfer performance in boilers?
High flue gas temperatures and a reduction in steam production at a given firing rate
What is the result of a gradual buildup of fireside or waterside deposits in boilers?
Reduced heat transfer performance
What is the primary purpose of maintaining flue fireside cleanliness in boilers?
To maintain boiler efficiency and steaming capacity
What is the primary effect of fireside deposits on boiler operation?
Lower boiler efficiency due to reduced heat transfer
During a major outage, what is typically done to the furnace water walls?
They are washed with high-pressure water
What is the primary consideration when deciding between in-service and out-of-service cleaning?
The amount of out-of-service time required
What is the result of increased draft loss through the boiler, economizer, superheater banks, or air heaters?
Heavy fireside deposits
What is the purpose of soot blowers in solid fuel-fired units?
To remove ash and soot from heat transfer surfaces
What is the effect of fireside deposits on fireside temperatures?
They increase fireside temperatures
What is the primary benefit of in-service cleaning?
Reduced downtime
What is the purpose of a chemical treatment during a major outage?
To reduce corrosion
What is the effect of fireside deposits on steam production?
They decrease steam production
What is the primary consideration when introducing water during cleaning?
The potential for corrosive compounds to form
What is the primary reason for using steam as a soot blowing medium in larger boilers?
It is available whenever the boiler is in service
What is the purpose of the poppet valve in soot blowers?
To introduce dry, high-pressure steam into the lance
Why is it important to drain the condensate from the soot blower lance?
To prevent erosion from moisture or condensate
What is the advantage of acoustic cleaning systems?
They require less energy than other soot blowing operations
What is the purpose of rapping systems in boilers?
To remove deposits from the heat transfer surfaces
Why are soot blowers in radiant zones designed to withstand more heat than those in convection zones?
Because they are subjected to higher temperatures
What is the effect of increased fireside deposits on boiler operation?
Decreased pressure differential across heat transfer surfaces
What is the primary advantage of using air as a soot blowing medium?
It is compact and simple in construction
What is the purpose of the wave generator in acoustic cleaning systems?
To produce a series of sound-induced pressure fluctuations
What is the characteristic of acoustic cleaning systems that allows them to operate continuously?
They operate in successive short cycles
What is the primary advantage of using explosives for in-service cleaning in boilers?
It can dislodge larger deposits that cannot be removed with conventional methods
What is the purpose of the jet at the end of the lance in a short retractable wall blower?
To blast superheated steam or air against the slag deposits
What is the characteristic of falling shot systems?
They use small steel balls to remove deposits
What is the purpose of the carriage in a long retractable soot blower?
To hang the soot blower outside the boiler furnace
What is the primary cause of slag buildup in the radiant zone of the furnace?
Ash contained in the fuel may melt in the high temperature
Why are pneumatic rapping systems recommended for heavy deposits?
They enable higher impact energies and have a better cleaning effect
What is the purpose of the internal feed tube in the long retractable soot blower?
To convey steam from the poppet valve to the outer tube
What is the result of the falling shot on the ash deposits in the boiler?
The ash deposits are removed from the tube surfaces
What is the purpose of the retractable blower in the radiant zone of the boiler?
To remove slag deposits from the heat transfer surfaces
What is the primary concern when using explosives for in-service cleaning in boilers?
The proper training and certification of operators involved in explosive procedures
What is the primary reason for rotating the lance in a stationary soot blower?
To clean substantially more area than a non-rotating lance
Where are the nozzles situated in an air heater soot blower?
Over the top of the heat exchange surface
What is the minimum boiler load required for stable combustion during soot blowing, according to ASME BPVC Section VII?
50% of the boiler capacity
How are the iron shot or pellets recycled in a falling shot cleaning system?
They are pneumatically conveyed back to the distributing chamber
What is the purpose of the control screen for soot blower sequencing and operation?
To sequence the operation of the soot blowers
Why is it necessary to ensure furnace pressure is below atmospheric during soot blowing?
To prevent blowback through inspection doors and other openings
What happens to the large ash particles that are removed by the shot in a falling shot cleaning system?
They are broken up into fine particles and carried away by the flue gas
What is the primary advantage of falling shot cleaning over other methods of cleaning?
It does not require a supply of air or steam for operation
What is the purpose of the distributing chamber in a falling shot cleaning system?
To distribute the iron shot or pellets to the tubes
What is the primary purpose of the hopper in a falling shot cleaning system?
To collect the ash particles that are removed
What is the primary function of the pinion gear in the soot blower drive system?
To push the lance into the furnace
What is the purpose of the forward position limit stop in the soot blower system?
To prevent the lance from moving too far into the boiler
Why is it necessary to maintain steam flow to the soot blower until it is fully retracted?
To prevent the lance from overheating
What is the purpose of the chain and sprocket arrangement in the soot blower system?
To rotate the lance during the cleaning cycle
What is the effect of impinging directly upon tubes with the soot blower?
The tubes will be rapidly eroded
What is the purpose of the bearings in stationary soot blowers?
To hold the lance tube in place
What is the purpose of sequencing the use of multiple soot blower units in a boiler?
To allow the ash and soot to be moved to a specific point in the boiler for removal
What is the purpose of the rollers on the inner support in the soot blower system?
To assist in supporting the lance
What is the effect of moisture in the blowing medium on the erosion of tubes?
It increases the rate of erosion
What is the purpose of the limit switch in the soot blower system?
To shut down the drive motor
Test your knowledge on the importance of routine fireside cleaning in steam generators that use solid or heavy fuel oils. Learn how it affects boiler efficiency, availability, and steaming capacity. Understand the impact of soot and ash deposits on steam temperature control.
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