Boiler Operation Flashcards
the number of pounds of steam generated per hour at the pressure and temperature required for all purposes to develop contract shaft horsepower of the ship divided by the number of boilers installed is defined as
boiler full power capacity
boiler overload capacity is normally what percentage of boiler full power capacity?
120%
a pressure specified by the boiler manufacturer as a criterion for the boiler design is termed as?
design pressure
what is the minimum steam drum pressure on an operating boiler?
85% of boiler operating pressure
what type of circulation would installing the generating tubes at an increased inclination be?
accelerated natural
what type of boiler conceits of one or more water drums?
drum type
do header type boilers have a water drum?
no
the term high pressure boiler refers to a boiler operating at what pressure?
751 psi or above
what two sheets of steel make up the construction of the steam drum?
wrappers sheet and tube sheet
what purpose do the generating tubes serve?
provide the area in which most of the saturated steam is generated
what is the function of the waterfall tubes?
to protect furnace refractories, and allow a higher heat release
water screen tubes protect the superheater from what?
direct radiant heat
what is installed between the inner and outer casings of the boiler to carry the downward flow of relatively cool water and thus maintain the boiler circulation?
downcomers
what portion of the steam drum contains a manhole to the drum for cleaning, inspecting and repair?
drumhead
which tubes of high firing rates do not generate steam?
downcomers
what boiler component preheats the feed water priors to its entering the steam drum?
economizer
what function do the metal projections on the economizer tubes serve?
to extend the heat transfer surface of the tubes
what is the heating source of the economizer?
combustion gases
what is the standard size of the firebrick?
2 1/2” x 4 1/2” x9”
insulating block is capable of withstanding surface temperature of?
1500 degrees F
what joins the boiler to the smoke pipe?
uptakes
refractory expansion joints are normally what size?
1/4”
what is the preferred material for expansion joints construction?
styrofoam
a boiler punge will have how many volumetric air changes?
five
a boiler must always be purged in accordance with what?
purge table
during a furnace inspection prior to light off the boiler inspection device (bid) fogs up, what is the probable cause?
presence of fuel oil in the furnace
can raw fuel be removed from the furnace by purging the boiler?
No, the fuel must be wiped up
once a boiler purge is complete, fires must be lighted within what time frame?
5 minutes
if ignition fails to occur within 2 to 3 seconds what action must be taken?
shut the burner fuel oil manifold valve, safety shutoff device and investigate the cause.
during a heaving black smoke condition the burner flame will be what color?
dark orange
an incandescent dazzling white burner flame is an indication of what?
excessive air
fuel oil temperature at the burner front shall not exceed what temperature?
125 degrees F
what is the function of the boiler sliding feet?
to allow for expansion and contraction of the boiler during light off and cool down
the steam generators separate the steam and water mixture by what action?
centrifugal action
the majority of the steam that leaves the superheater goes where?
main engines
a short term decrease in drum water level which results from a change in firing rate or steam flow without any corresponding change in the feeding rate is termed what?
shrink
the amount of heat is applied to steam to raise its temperature above the saturation temperature, while maintaining constant pressure is defined as?
superheat
what is the basic cause of all boiler explosions?
the accumulation of unburned fuel or combustion vapors at some point in the system
Steam soot blower elements add rotated at a rate of?
10 to 15 seconds per 90 degrees rotation
The minimum steam atomization temperature at the burner front is?
370 degrees F
The desired range of steam atomization temperature is?
400 degrees F plus or minus 10 degrees F
What prevents windmilling of an idle force draft blower, while the other force draft blower is online?
Automatic shutters
The chick facing of the sliding feet is constructed of what material?
Phosphorus bronze
What term is usually attributable to deficiency of air and excessive vibration of the boiler?
Panting
Heavy and prolonged seawater contamination of the fuel oil will from what type of corrosive products on the brick work?
Slag formation
What function does nichrome wire serve in the refractory?
As an anchoring device
A boiler that provides some means of controlling the degree of super heat independently of the rate of steAm generation is said to have?
Controlled superheat
Most modern naval boilers are designed for what type of circulation?
Accelerated natural circulation
What is the function of refractory materials?
To confine the heat to the firebox and protect the casing and structural members from overheating
What are the three end points a steaming boiler has?
End point of circulation
End point of modifier carryover
End point of combustion
How are individuals economizer tubes connected?
By U-bends at the tube ends
What tier of refractory is preferred for small repairs or where standard size brick or tile cannot be used?
Castable fireclay
Castable refractory must be air cures for how long prior to baking out?
Two days
What type of tile is made of silicon carbide?
Baffle tile
Who determines the combination of boilers and burners to be used, that gives the greatest plant efficiency with due regard to providing for safety and military requisites?
Engineering officer
When warming up steam assisted atomizers, how long do you allow for warmup with steam prior to light-off?
3 to 5 minutes
When using compressed air for light off, hat is the required pressure of the compressed air?
85 to 150 psig
Where can guidance and general information of saturated steam in the 150 psig steam system?
In line desuperheater
Is it allowable to use shore steam for steam atomization?
No, due to its poor quality
The torch man shall wear what protective gear, during boiler light off?
Fire retardant coveralls, eye shield, and burner man gloves
During boiler light off what tile must always be followed?
Two man rule
On a D type boiler with an integral superheater, what protects the superheater from overheating during the initial steam formation?
Superheater protection steam (SHPS)
Superheater protection steam is taken from what system?
150 psig auxiliary steam system
Water gage glasses are checked for satisfactory operation after light off by blowing down when the D type boiler reaches what pressure?
100 to 200 psig
Sputtering burner flames are an indication of what?
Water in the fuel oil
White smoke is caused by what?
Excessive air
If you are unable to correct the white smoke condition within one minute, what action must be taken?
Secure the boiler
Adjusting the fuel oil header pressure during a white smoke condition can lead to what?
A boiler explosion
Water contamination tests for fuel oil storage and service tanks and procedures for cleaning such contaminated tanks can be found were?
NSTM 541, petroleum and fuel oil testing
The term residual fires means what?
The presence of fire at the burner tips or on the firebox deck after the boiler has been secured
What is the total heating surface of a naval boiler defined as?
That portion of the heat transfer tubes which is exposed on one side to the gases of combustion and on the other side to the water or steam being heated
The term steaming hours indicates what?
The time during which the boiler has fires lighted for raising steam and the time during which it is generating steam
Unevaporated boiler water carried out of the steam drum with the steam cause but the malfunctioning steam drum internals is termed?
Priming
Two or more boilers operating simultaneously and connected so their output forms a common supply, are said to be operating?
In parallel
All boiler tubes are identified in what manner?
Tube rows are identified by lettering and individual tubes in each rows by numbering
What function does the steam smithing system serve?
To extinguish boiler air casing fires
Insulating block is capable of withstanding what maximum temperature?
1500 degrees F
What refractory is used for the innermost layer of the firebox furnace?
Firebrick
What type of burner front cracking, is caused by stresses resulting from the normal expansion and contraction?
Radical cracking
What is used to keep a record of defective boiler tubes and renewed tubes?
Boiler tube renewal sheet
What actions shall be taken if you discover lumps in a newly opened bag of castable?
Lumps indicate moisture contamination therefore the castable must be discarded
Excerpt during emergencies, what boiler firing date shall never be exceeded?
Five percent
Prior to entering the boiler drums or firebox the boiler must be certified to be?
Gas free
Why are all naval boilers lates up when idle for more than 24 hours?
To prevent oxygen corrosion of the boiler watersides
What are the five wet lay up methods?
Steam blanket Nitrogen Hot deaerated full Sodium nitrite Hydrazine/ morpholine
What are the two dry lay up methods?
Heated air lay up
Desiccant
a steam lay up shall be monitored at what frequency by the responsible watch stander?
hourly
when is a steam blanket lay up considered lost?
when the boiler steam pressure falls to atmopheric pressure and cannot be re-established
what is the maximum time limit for a steam blanket lay up?
30 consecutive days from securing
what is the minimum pressure required for a nitrogen blanket lay up?
5 psig
the oil king shall check lay up status at what interval?
daily
the deaerated feedwater used in the hot deaerated backfill lay up shall meet what dissolved oxygen limit?
15 PPB (parts per billion)
what is the maximum time limit for a hot deaerated fill lay up?
14 consecutive days from securing
how long is it permissible to interrupt a steam or nitrogen blanket lay up to perform emergency repairs?
only once during the lay up period for a maximum of 8 hours
who administers the hydrazine/morpholine lay up?
industrial activity
ship’s force when chelant is installed
what is the maximim time limit for a nitrogen blanket lay up?
30 consecutive days from securing
when is the industrial hydrazine/ morpholine lay up considered lost?
if the hydrazine concentration falls below 10 ppm the lay up is lost
how long is the hydrazine/morpholine lay up good for?
indefinitely as long as the required hydrazine concentration is maintained
what is the required amount of sodium nitrite, that is used for a sodium nitrite wet lay up?
10 pounds per 1,000 galloons of feedwater
what is the time limit on a sodium nitrite wet lay up?
no time limit
disposal of sodium nitrite shall be in accordance with NSTM chapter?
593, pollution control
hot air lay up installation shall be inspected at what interval to ensure proper operation?
each watch
how much desiccant is used for a proper dry lay up?
16 pounds for every 1,000 galloons of cold water capacity
how many pounds of sodium nitrite are added to the boiler, prior to placing the boiler on a dry lay up?
10 pounds per 1,000 galloons
how is desiccant lay up monitored after the lay up is established?
hourly by the responsible watch stander and daily by the oil king
what is used to indicate that a desiccant lay up is within requirements?
humidity indicator cards
when the humidity indicator cards indicate that the humidity is over 50 percent what action must be taken?
desiccant must be replaced with fresh material
what are the 3 authorized cleaning methods for removing soft deposits?
high pressure water jet
EDTA
power driven wire brush
what is the purpose of the apron plates?
they from an annular passageway for the steam and water mixture from the generating tubes to the separators
what type of hazard does soot create?
fire hazard
how are handhole seats properly cleaned?
with a power driven cup brush
what is installed to keep moisture out of the uptakes and boiler firesides?
stack covers
stack rain gutters serve what purpose?
to allow proper draining of the stack
what is the periodicity of lubricating sliding feet?
monthly in accordance with PMS
what are the three times that sliding feet are checked to verify movement?
before light off
during boiler warmup
after the boileris placed online
what boiler hydrostatic test is required for checking valve and fitting tightness?
100 percent hydro
what hydrostatic test methods use design pressure?
135 percent and 150 percent
what is the minimum water temperature used for hydrostatic testing?
70 degrees F
what is the maximum water temperature used for hydrostatic testing?
120 degrees F
what hydrostatic test methods use boiler steady state operating pressure?
100 percent and 125 percent
how long must hydrostatic pressure be maintained prior to conducting the inspection of pressure parts?
15 minutes
what holds firebrick and burner tile in place?
anchor bolts
what function do the steam drum swash plates have?
they are used to reduce the surging or swashing of water from one end of the drum to the other as the ship moves
what are the four main kinds of generating and circulating tubes?
generating tubes in the main bank
waterwall tubes
water screen tubes
downcomers
