Quiz 8
Foaming in the boiler water is a result of
excessive suspended solids
Inside a tube with streamline fluid flow, temperatures are relatively constant.
false
The Cooling Water Temperature leaving a tower increases as the Wet Bulb Temperature
increases
when lighting a furnace, the first thing that should be done is
purge the firebox with steam
Which of the following parts is not a furnace part
riser tube
define "boiler load"
the plates demand for steam
A superheater adds btu to the steam and gives it the capacity to do more work
true
What are five operating problems associated with boiler operations.
tube rupture, soot buildup, loss of water flow, flame impingement, scale and water purity
Fouling resistance is determined by all of the following except the
tube-and-shell pressure rating
the coolest tube in the boiler system is the
water make-up
The lowest temperature at which fuel oil gives off sufficient vapors to burn continuously ignited defined as the
flash point
The lowest temperature at which fuel oil gives off sufficient vapors to burn continuously when ignited is defined as the
flash point
The term applied to gas vapors when they ignite and return back to the source is
flashback
A process technician can reduce fouling in a heat exchanger by
increasing fluid velocity, lowering the temperature, adding inhibitors
Steam line water hammer can best be prevented by
keep line drained and insulated
Steam line water hammer can be best prevented by ____.
keeping line drained and insulated
The amount of combustibles in the flu gas is
percent combustibles
draft gauges on a furnace measure
pressure difference between the inside of the furnace and the outside air pressure
In a fire tube boiler, what type of plug is fitted to put the fires out when the vital part is exposed?
a fusible plug
the air registers are locates on the
burner
Range of the Cooling tower is
Difference between hot water inlet temperature and cold water outlet temperature
which statement listed best describes the term draft?
the flow of air and combustion gasses through a furnace
Dissolved oxygen can be removed from the boiler by....
treating the water with chemical scavengers
One way to check boiler draft balance is to look at
inspect the firebox through view ports
Fin fans and cooling towers do the same thing.
true
What is the shockbank
tubes located directly above the firebox. They receive radiant and convective heat.
What is a spud?
A group of gas filled tubes in a natural gas burner.
What is a hot spot?
A hotspot occurs in a fired heater when a furnace tube, refractory or are of the furnace gets too hot.
What are the four fired heater "furnace" designs.
A-frame, box, cabin, cylindrical
what are the four fired heater "furnace" designs
A-frame, box, cabin, cylindrical
The most corrosive substances in the boiler water are oxygen and_____.
Carbon dioxide
_____ results when water is heated to the boiling point(sensible heating) and then vaporized with additional heat(latent heat).
Saturated steam
What five features are furnaces classified by?
Shape, type of draft, number of fireboxes, number of passes, volume occupied by combustion gasses
What is "Flash Steam"
Steam formed from hot condensate when the pressure is reduced.
What is a hot spot
a hotspot occurs in a fired heater when a furnace tube, refractory or area of the furnace gets too hot
the four draft types are
balanced draft, forced draft, induced draft, natural draft
Difference between the cold water temperature at tower outlet and the entering air with wet bulb temperature is defined as
approach
The process of breaking up the fuel into fine particles is to ensure good combustion is called
atomization
Which of these methods can be used to reduce the amount of solids in cooling water?
blow down catch basin
The air registers are located on the
burner
What is used to evenly distribute air and fuel vapors over an ignition source and into a boiler firebox.
burner
Oil accumulation in boiler water would
cause foaming and carryover from the boiler.
A device mounted on the inlet side of a shell and tube heat exchanger that is used to channel flow in a multipass heat exchanger.
channel head
Excluding "Hybrid Flows" there are three basic flow configurations which are
cocurrent flow, counter flow, crossflow
There are four basic flow configurations which are(alphabetical order)
cocurrent flow, counter flow, crossflow, hybrids such as cross, counterflow and multi pass flow
What are carbon deposits in the tubes of a furnace called?
coke deposits
Fans are used in a water tube boiler system to
control oxygen flow rate
In the Process Industry__________ in the most common type of equipment that employs direct contact heat transfer.
cooling tower
Dissolved gases are removed from the boiler feedwater because they may cause
corrosive condition in the boiler
____ is the term generally used to describe the flow of air and combustion gasses through a furnace.
cross draft
The two design of induced draft cooling towers are
cross draft, counter flow
Primarily the three types of "Baffle Designs in shell and tube heat exchangers are
cut-segmental baffles disc and doughnut baffles orifice baffles
The ratio of dissolved solids in circulating water to dissolved solids in makeup is called as
cycle of concentration
The water make-up system takes its level measurement from the
deaerator and steam-generating drum
The water make-up system takes its level measurement from the______
deareator and steam-generating drum.
Approach of a cooling tower is
difference between cold water outlet temperature and wet bulb temperature
what are the designs of shell & tube heat exchangers
fixed tubesheet, floating head, removable bundle, u-tube
What are the designs of Shell & Tube Heat exchangers
fixed tubesheet, floating tubes, removable bundle, u-tube
the term applied to gas vapors when they ignite and return back to the source is
flashback
Tube____ is caused by improper fuel to air ratio and can damage firebox tubes if not corrected
impingement
What is flame impingement in a furnace/fired heater?
impingement occurs when the flames touch the refractory or tubes.
Where are the radiant tubes located in a furnace
in or near the firebox
Where are the radiant tubes located in a furnace?
in or near the firebox
What is the purpose of a gauge glass on a steam boiler?
indicating the correct water level in the boiler
What are three operational hazards associated with the operation of a boiler systems.
instrument failures exceeding boiler temperatures or pressures hazards associated with leaks
what are three operational hazards associated with the operation of a boiler system?
instrument failures exceeding boiler temperatures or pressures hazards associated with leaks
What are three personal hazards associated with the operation of a boiler system
isolation of hazardous energy permit labeled"lock-out, tag-out" opening and blinding hazards associated with using natural gas
what are three personnel hazards are associated with the operation of a boiler systems
isolation of hazards energy permit labeled "lock-out tag-out" opening and blinding hazards associated with using natural gas
The flow of air through a furnace is referred to as
oxygen percentage
A____ is given to each continuous uninterrupted path that the process fluid takes in a furnace
pass
The amount of comubstibles in the flue gas is
percent combustibles
The maximum capacity of a boiler is the
pounds of steam it will produce in 1 hour at a given pressure and temperature
the maximum capacity of a boiler is the
pounds of steam it will produce in 1 hr at a given pressure and temperature
Carbon deposits are most likely to be found in the
radiant tube
Carbon deposits are most likely to be found in the
radiant tubes
________and_______are the two primary classifications of Heat Exchangers.
recuperative, regenerative
The three major factors that attribute to Heat Exchanger fouling are
type of fluid being handled, velocity, amount of solids in fluid stream
The heat exchanger that is designed to take the highest flow rates and largest temperature differences is
u-tube
In a water-tube boiler, the____ passes through the tubes and the____ passes across the outside surface of the tubes.
water, hot gasses of combustion
the three main purposes for chemically treating boiler water are
reduce foaming and moisture carryover to reduce the formation of scale on the waterside of the boiler to reduce to a minimum corrosion of the boiler metal
The three main purposes for chemically treating boiler water are
reduce foaming and moisture carryover to reduce the formation of scale on the waterside of the boiler to reduce to a minimum corrosive of the boiler metal
A boiler safety valve must be capable of
remaining open until excess pressure in the steam drum is relieved
the primary purpose of a condensate recovery system is
remove oxygen remove slugs of water from steam save money
As boiler feed water temperature increases, impurities precipitate and adhere to the hot metal surfaces of the boiler, forming
scale
Per the textbook, furnaces may be classified by what five features?
shape, type of draft, number of fireboxes, number of passes, volume occupied by combustion gases
In the Processing Industry_______ in the most common type of Recuperative Heat Exchanger employed.
shell & tube
On a simple shell and tube heat exchanger, a process technician would close which of the following valves first?
shell inlet valve #3 steam
A stationary or movable device used to remove unburned hydrocarbons from the upper section of the furnace is a
soot blower
What is the "charge" of a furnace
the initial flow into the furnace
Define Condesate
the liquid formed when steam passes from the vapor to the liquid state
Define Condensate
the liquid formed when steam passes from the vapor to the liquid state.
Before a burner is lit in a boiler, the operator must make sure that
the pilot is lit fuel gas is open to the burner valve proper operating level has been established
Before an explosion can occur in the boiler furnace, source of ignition for the explosive mixture , sufficient air to form an explosive mixture, and
there must be an accumulation of unburned fuel
Before an explosion can occur in the boiler furnace, source of ignition for the explosive mixture, sufficient air to form an explosive mixture, and.....
there must be and accumulation of unburned fuel.
Purpose of Louver is
to change the direction of air inlet flow in the uniform manner, to prevent the water droplets splashing out of the tower
Why should condensate be removed from steam lines?
to prevent water hammer
Purpose of Draft Eliminator is
to reduce the entrainment of water droplets in air
What is the purpose of an induced-draft fan on a balanced draft furnace?
to remove combustion gasses
Dissolved oxygen can be removed from the boiler water by
treating the water with chemical scavengers
A safety valve pops open fully and immediately because the valve disc that closes against the seat of the safety valve is made in a two-stage pattern.
true
A safety valve pups open fully and immediately because the valve disc that closes against the seat of the safety valve is made in a two-stage pattern.
true
Hairpin heat exchangers are relatively easy to clean and install.
true
On a simple shell and tube heat exchanger, a process technician would turn the device into a bomb if he closed which of the following valve first.
tube outlet valve #2 process fluid 325 F
what are five operating problems associated with boiler operations
tube rupture soot buildup loss of water flow flame impingement scale and water purity
If the water level drops below the tubes in a fired tube boiler, damage may occur to
tubes
Heat exchanger may have____or____ phase flow on each side.
two, multi
The downcomer is connected to the
steam-generating drum and mud drum
The burners in a water tube boiler are surrounded by which tubes?
steam-generating tubes
The four draft types utilized on a furnace designs are
Balanced Draft, Forced Draft, Induced Draft, Natural Draft
A fin fan is and example of a________heat exchanger.
air-cooled
what are the best conditions for efficient heat transfer to occur.
when a large temperature differences exist between the products being heated and cooled, when the heating or coolant flow rates are higher, when the exchangers cross sectional area is the largest
Double pipe heat exchangers are used
when heat transfer area required in very high (less than 100 sq. ft)
In Evaporative cooling tower system the make-up water source is used to replenish around____of water lost to evaporation and draft.
2%
A better Performance indicator of the Cooling tower is its....
Approach
The process of breaking up the fuel into fine particles is to ensure good combustion is called_____
Atomization
Define boiler load.
Boiler load is defined as the plants demand for steam.
______ is the process by which superheated steam is restored to its saturated state, or the superheat temperature is reduced.
Desuperheating
What is flame impingement in a furnace/fire heater?
Impingement occurs when the flame touch the refractory or tubes.
How does a feed water economizer work?
It allows heat transfer to occur from the flue gasses to the feed water.
What is the shockbank?
Tubes located directly above the firebox. They receive radiant and convective heat.
Per the course textbook, list the six ways air can enter a furnace
air shutters located on the burner, air registers located on the burner, idle burners, open peepholes, leaks in the furnace casing, damage heater box gaskets
What are six ways air can enter a furnace
air shutters located on the burner, air registers located on the burner, idle burners, open peepholes, leaks in the furnace casing, damaged header box gaskets
what are the categoreis of Recuperative Heat Exchangers
direct indirect specials
Shell and tube nomenclature includes all of the following except
divided
A hairpin heat exchanger is an example of
double pipe
what are the designs or Tubular Heat Exchangers
double pipe Shell & Tube Spiral Tube
what are the designs of tubular heat exchangers
double pipe, shell & tube, spiral tube
Plate and frame heat exchangers tend to foul easily because they have close clearances and low pressure drops across the plates.
false
Turbulent flow allows molecules of fluid to mix and absorb heat energy better that laminar, but it enhances the stationary film along the shall and tube walls.
false
From the choices provided, select ONLY,ALL, the factors affects the cooling tower performance
head load, the range, wet bulb temperature, the approach
The safety valve keeps a boiler from exceeding its
maximum allowable working pressure(MAWP)
A type of heat exchanger that channels the tube-side flow across the tube bundle more than once is
multi-pass, u-tube, floating head
Most fired furnaces use
natural gas
what must be done to prevent damage from vacuum when draining a boiler?
open the vent valve