Hvax Flashcards
Supercritical Boiler operates at 3206.2 psig or 705.4 degrees in a Supercritical Boiler water and steam have the same?
Density
Spreader and chain grate stokers are type of ______ stokers?
Overfeed
What is the temperature leaving from the DA Tank?
212F 230F (110)
What is the name of the pump that pumps water back to the condenser?
Condensate feed pump
What color is the tank 404A of refrigerant?
Orange
What color is the tank 407C of refrigerant?
Medium brown
In a Y configuration, you read 208 volt across the phases, what is the reading from phase to ground?
120 volt
What is the drop in refrigerant for R-22?
R-417 A
What by product has the largest of heating value?
Butane
What is the accumulation test?
To test for relieving the capacity of the boiler of safety valve, that doesn’t exceed 6 percent of M.A.W.P.
.What type of oil is used in HFC refrigerant?
Ester Oils
What is a counter flow turbine?
To balance the blades
What does an orifice plate do in the operation of a boiler?
Balance heat transfer
Why do you extract steam from turbine?
Used for heating domestic water or warming cool area
What does a three elements feed water regulate sense?
Liquid level in the boiler drum, Flow of feed
water to the boiler drum, and Flow of steam leaving the boiler drum
What are the 4 steps for a Zeolite rejuvenation water softener process?
Backwash, Brine Flush,
Rinse and Service.
What controls water temperature by throttling on the Leslie feed water pressure?
Aqua Stat
. How do you increase the feed water pressures on a stream turbine pump? regulator.
Increase the feed water
pressure by throttling on the Leslies feed water pressure
Turbines turn kinetic energy into what kind of energy?
Mechanical
When boilers are in operation, super heater drains are ———
and when boilers
Are on warm up super heater drains are —–
Closed
open
What types of blades are on the turbine?
Stationary and Rotating
A water seal is used to stop what on a turbine?
Leakage Air
A turbine that make use of high velocity steam?
Impulse turbine
At what temperature you should not use copper or brass for the gauges?
406 F Page 353 BOG
What does a 3 element feed water regulator is sense?
Liquid Level in the boiler, Flow of water to
the drum, Flow of Steam leaving the boiler drum. Drum Level
- What is the % or low Nox is permitted in a building?
1000 ppm or less 90%
What is AHU system has a constant airflow?
CAV
The removal of moisture from air using a cooling coil is called
Passive dehumidification.
Why should steam leaks in a boiler system be repaired as soon as possible?
All leaks should be
immediately repaired to avoid further damage and also to prevent personal injury and loss of steam
from leaks also energy waste and increase fuel cost to plant
When is the best to open water wall header drain valves?
Under no circumstance, should water wall
headers be blown down while the boiler is operating, if they are, the boiler normal circulation will
upset and overheat. Tubes will bulge or rupture.
. A boiler has 2800 furnace temperature and 600 stack temperature reading. What is the boiler
efficiency?
Boiler Efficiency = (Input – Loss Stack x 100) = 2800 – 600 = 2200 x 100 = 78.57
2800 2800
TE = 2800 – 600 = 2200
TE = 2200 / 2800 = .785
TE = .785 x 100 = 78.57
TE = 100 – 78.57 = 21%
TE = 100 – 21 = 79%
What scale can be removed by boiling or raising water temperature?
Temporary
The Chief heat producing elements in fuel controls are?
Carbon and Hydrogen
A dry pipe located in the steam space of a fire tube and water tube boilers used is?
To remove moisture from the steam
What is the year of Clean Air Act?
1963
Switch boards are rated as to the maximum voltage they are can handle what?
Amp
What is a 4 WYE or (Delta) system phase to neutral is?
277 Volt
How do we remove condensable in the condensate tank?
Vacuum pump
- A vacuum condensate tank is a condensate return tank equipped with a vacuum pump that creates a vacuum on the return line.
Page 103 brown book
An internal feed water line in a water tube boiler is placed below water level and extended in the
drum?
For better distribution and less thermal shock
what is the purpose of using a wet scrubber?
To remove Sulfur Dioxide
Why is air bypassed around the air heater?
To ensure that the flue gas temperature does not fall below a minimum temperatures at low loads.
Name two widely used secondary elements which convert differential pressure to a usable output
signals?
Transmitter and Receiver, (Transduce pressure)
Controls the rate of combustion, which determines the amount of fuel that can burned?
Primary Air page 141 SE-Book
Name a technique to reduce the sulfur dioxide emissions from a coal plant?
Bag filter house
How do you ensure that complete combustion will take place?
Secondary Air page 141 SE-Book
An automatic control valve commonly used to maintained feed water levels in a boiler whose internal design is constructed with two valves and discs is referred to as?
A balance valve 401 bog
What are the following techniques to control nitrous oxides emissions?
Inject ammonia into the furnace of a boiler
What is the purpose of the Steam Packing on the low side?
(water seal) To prevent leak on Condenser
Why are sealing glands needed in a turbine?
Sealing in a turbine do one of 2 jobs!
1. They are preventing steam from leaking out of the casing along the shaft at the steam
end.
- They are stop air from leaking into the casing at the vacuum end.
When did it become unlawful to vent CFC and HCFC to the atmosphere?
7-1-92
When did it become unlawful to vent HFC to atmosphere?
11-15-92
On the low side of the system, what is the relief pressure limit of a rupture disc?
15psi
What is the device that secures the blades to the fly wheel?
Tenon
Erosion on blades?
Corrosion
———— valves are set lower than the drum safety valve
Super heater safety
- How much condenser of cooling water is needed to condense of 1lb of steam?
50 lbs
How the voltage is wired on a collector AC/DC High/Low for collector Plates fly ash?
High DC to the probes and grounded collector plates
What is the name for water treatment test chemicals?
Reagents
The exhaust from steam or turbine is used to do what?
Preheat feed water
How do you know when your DA Tank is not working properly?
Excess used of oxygen scavenger of chemicals (Sulfite).
How do you treat temporary of Hardness?
Boiling the water
How do you treat for Permanent of Hardness?
Use Chemical
What Coal has a high fixed carbon?
Anthracite
What is the power rate on a motor control of the contactor/contactor increase NEMA?
Increase
What is used to remove Fly Ash?
Mechanical Collector page 720 red book
Under what condition do you blowdown the water wall when it is in service?
Never/Under no condition
What does the whistle on the top of the water column indicate?
High and low water condition
What boiler used an on/off button?
HWHT boiler
- What pump is used to move condensate steam?
Condensate pump
Where a mercury switch on-off control is installing in the boiler?
. Vertical position / Low water Cutoff
When warm up the boiler to cut in line, all suddenly the boiler went to full load and the water level
in the drum slowly went down. What would be the operator do?
Immediately secure the fire page 39 # BOG Book
What is the condenser sub-cooling range?
10-20
What is used to stiffen the outer rim of the blade or the nozzle against the vibration and confines the steam to the blades path?
Shroud ring page 566
A switchboard is rated for?
Current or Amp
What is the copper test is used to detect?
Heat exchanger and pumping equipment with copper parts
Particulate are remove from the combustion service by?
Bag filter house
All of the following are the synthetic refrigerant oils, except?
Polyol Esters (POA)
What is the function of the diffuser ring on a turbine type of centrifugal pump?
To Converting velocity to pressure.
To ensure that the feed water entering to the boiler is equally distribute therefore by?
Reducing the thermal shock to the boiler
3.What type of boilers can rate over 350 F?
Package / Fire tube boiler
One pound of water expands 1602 times when in changes to steam. By taking into account that at
14.7 psia, and 212 degrees Fahrenheit, the volume of the saturated vapor of water is 26.28 per cubic
foot, divided by the volume of the saturated liquid of water at 0.01672 per cubic foot, we arrive at an
expansion rate of 1602.87
26.80 / 0.01672 = 1602.87
—————- is a method of starting a turbine in which steam is distributed equally
Through the control valves to each section of the nozzle block so that the turbine is heated
Evenly.
Full Arc admission
.What are the causes for boiler to be explosion?
In-proper fuel and air mixer
What happen to the De-aerator tank when it is mal-function?
Oxygen Scavenger
What is needed for the burner complete the cycle of combustion
Secondary air
9.On/off Switches are operating for what type of boiler?
Fire tube boiler
————- is the most effective method of reducing the NOx emission, especially
Where high removal efficiencies are required. This process removes NOx from the flue gas
By a reaction with ammonia in the presence of a catalyst. Reaction takes place in the
Temperature range of 500 to 800 F, and therefore, an SCR is located typically downstream of
The economizer on a boiler and prior to the air heater.
SCR Technology
————or air cocks are installed on top of the steam drum to expel air from inside the
Steam drum during cold boiler light-off or when filling the boiler. The air vents or air cocks are shut
when the boiler starts generating steam
Air vents
What is the minimum clearance that an open type of expansion tank from the highest heating
element?
Minimum of 4 feet above the highest heating element
How many gallons of water will a pump, size 6x4x6 inch, double acting duplex, pump at 80 strokes
per minute if overall water pump efficiency is 85 percent?
Gallons = 20,508 / 231 = 89 gpm
What should the temperature be when the water leaves the DE aerator?
The water temperature should be within 3 F to 5 F of the temperature of the steam entering the de-aerator
What % of oxygen is in the air?
21 %
A hot water system that uses the same pipe for supply and return is called?
One pipe system
A condensate pump is located 75” below the feed water heater and its discharge gauge reads 75 psi.
The pressure at the inlet to the heater is ___ psi?
75 – .433 = 32.475
75 psi –32.475 = 42.525
A boiler generates 50,000 lbs of steam/hr at a pressure of 350 psi. The steam contains 1200 Btu/lb.
The feed water temperature is at 120 F. The boiler consumed 450 gallons (gal) of the oil containing
142,000 Btu/gal. What is the thermal efficiency
TE = Ws ( Hs – ( T wf – 32 )
Wf x C
TE = 50,000 (1200 – (120 -32)
450 X 142,000
TE = 50,000 x 1,112
450 x 142,000
TE = 55,600,000
63,900,000
TE = 0.8701095462 or 87.01%
How many gallons of water will a pump, size 6 x 4 x 6 in Double Acting Duplex at 80 strobes per
Minute if water pump efficiency is 85%?
88 gpm
231
1.Pump HP
HP = GPM x 8.33 x Head x SP GR
33,000 x Efficiency of pump %
Centrifugal
What HP is required to drive a pump that is running at 68% efficiency and delivery 450 GPM
Against a head of 822”feet?
= 137 hp
A 3 phase of 460 volts motor draws a current of 52 amps. The motor has an efficiency rating
Of 94% and a power factor of 80%. Determine the HP?
41.7 HP
A single phase 115 volt AC motor has an efficiency rating of 92% and a power factor of 80%.
Determine the HP if the amp load is 4.4 amps?
HP = 115 x 4.4 x .92 x .80
746
HP = 372.4 = .4991 = ½ HP
746
½ HP
A boiler is rated at (86,250 lbs, 88,250 lbs, 96,250 lbs) of steam per hour. What is the
equivalent Boiler horsepower?
2500 lbs
Where is the condenser pump pumping water from?
Hot well
What types of blades are on the turbine?
Stainless steel blades
Identify of D-4 Boiler?
Economic-type fire tube boiler consisting of three passes with arched crown sheet and stayed
surface.
Three phase 480 volt in a circuit and draw current at 84 amperes. What is the load in
Kilovolt and amperes?
HP = 69.7536 or 70
—————is the condition that results when air is blown through a grid at a rate
Sufficient to overcome the static weight of the solids atop the grid to a point where the
Mass of these solids, referred to as a bed, behaves like a boiling liquid.
Fluidization
What happens to the water in a boiler that is at 80% load of a suddenly, the flame goes
off?
Water will shrink and cause a low water condition.
A chief engineer preparing for mud drum inspection, which of the following will you not
do?
Set up a 110 volt lighting for inspection
Where is the pressure control located in the boiler?
It is locate on the main steam header
Which of the following statement is true concerning fire tube and water tube boilers?
Water tube boiler’s biggest advantage over a fire tube boiler___? ____flexibility to
increase Capacities and pressure
The wasting away of metals by chemical action is called
corrosion
A circuit that offers no resistance to the flow of electron is
. Short Circuit
.What other parts of the steam turbine blades suffer from damage?
. Blade roots and shroud
0.If a throttle valve is close at 80 %, what will happen to the throttle valve later on in a long period of
the operation?
. cutting Action
The perforated baffle plate at the steam outlet in a boiler steam is installed to?
Provided directly below the steam inlet to protect the tube bundle against moisture
impingement
.How would you know if super-heater safety valve set corrected?
A. it will pop open before the drum safety valve
The type of mercury tube pressure control must mount in what position?
Vertical position
————— is a series of tubes taken from the main steam drum and located in the
Direct path of the flue gases or located close to the combustion chamber to receive heat
Directly from the flame of combustion. It is designed to raise the temperature of steam
Without raising the corresponding pressure.
A super heater
What type of combustion is designed?
Post combustion
What is the flareback?
Flame discharge from the boiler through access the door or port, caused by delayed
Ignition or furnace pressures build up.
What is the steam packing?
The shaft at high pressure end of turbine must be packed to prevent leakage steam
From turbine.
What type of superheat is direct for the heat chamber?
Convection
What type of heat is steam turbine from the centrifugal?
Increase from pressure to velocity
What is the source of air to remove none condensable gas in a condenser?
Ejectors
What do you used to extract steam turbine?
Heat Feed water
A Coal stoker that uses a feed RAM is a?
Underfeed stoker
What is the permissible OSHA exposure level for asbestos for an 8 hour time weighted average?
0.1 fiber/cc
Why must soot blowers be provided of coal burning boilers?
a.
For cleaning ash from the furnace walls and from the convection heating surface
On a boiler equipped with a superheated, which safety valve should be lift first, and why?
- a. Combustible
b.Total dissolved solids
c.
d.CO2 only - s
- 159.
160
161.
162.
163.Air heaters?
a.
164.DE aerators?
a. Are used to reduce oxygen and other dissolved gases in a steam plant.
The superheated safety valves should lift before any of the drum safety valves. Superheated depend on Steam flowing through them to avoid overheating. Steam is diverted from the superheated when a Drum safety opens.
A DE aerator in a boiler feed water system removes _____?
Dissolved gases
How are none condensate gases and air removed from condensers?
Ejector
What is the purpose of the Wet Scrubbers?
Is used to clean air pollution control devices that are liquid to remove temperature monitors
at the point where the gas streams the spray.
—————, part of the ash is removed from the combustion zone by directing the burner
flame downward over pool of molten slag. The slag pool is kept hot enough to remain molten so
that the slag flows continuously over a water-cool weir, or ring, into a quenching pit where it is
broken up by water.
slag-tap furnace
. Emission standards have risen on fossil-fuel-fired utility power plants so that particulate
collection equipment has reached 99 percent efficiency.
Fabric filters
Soot blower?
Steam or air is used to blow soot from heating surface.
Is a major problem in burning coal and other solid fuels?
Particulate discharge?
————– are applied to boilers firing solid fuels, seldom on boilers firing gas or oil.
Air heaters
Are used to reduce oxygen and other dissolved gases in a steam plant.
.DE aerators
On a boiler equipped with a superheated, which safety valve should be lift first, and why?
The superheated safety valves should lift before any of the drum safety valves. Superheated depend on Steam flowing through them to avoid overheating. Steam is diverted from the superheated when a Drum safety opens.
A 7ft boiler drum is 5/8 thick, and its metal has a tensile strength of 1,200 psi. These joints are
80% efficient and the factor of safety is 5. What are the MAWP?
MAWP = 34.28 psi
5.A 72” boiler drum is ½” thick, and its metal has a tensile strength of 65,000 psi. These joints are 82%
efficient and the factor of safety is 5. What are the MAWP and bursting pressure? Note: the factor of
safety is the ratio of bursting pressure to MAWP.
BP = 740 PSI
In a steam turbine trap drains are used in which______ are when it is being startup ______ and
are used when in operation?
. Open/Bypass
What is the winding of the coil on the contactor which output is the main load?
Secondary
Fuses are connected in _____ with a circuit to protect it from over currents?
Series
It takes exactly one pound of water to make ——pound of steam.
one
ASME Boiler and Pressure Vessel Code, Section I, defines a High Temperature Hot Water Boilers
system as one using water at temperature at? Page 129 BOG and page 23
Operating at temperatures of over 250F and pressures of over 160psi
What is the Chief chemical compound in temporary hard water?
a.
Calcium Bicarbonate
What is the cause of the fire tube boiler tubes failure?
Poor Circulation due to the design is difficulty to detect.
Also known as alkaline hardness because the salts dissolve to form an alkaline solution.
Temporary Hardness
a type of hardness that can be reduced only by the use of chemicals or
distillation.
Permanent Hardness?
Under what condition is air by-passed around the air heater?
When steaming at low of minimum load or steam at low rate
A turbine speed can be fine-tuned while operating with a device which is known as a?
Over speed governor
What is the purpose of the nozzle in a turbine?
To increase steam velocities
What is the purpose of a turbine thrust bearing?
To oppose the turbine shaft thrust
Shaft sealing in high output is done with?
Labyrinth seals
What do the stationary nozzles of an impulse turbine convert the thermal energy of the steam into?
Kinetic energy
What do you call a reading from the center point of an impeller across to the gauge?
Static pressure
To test the low fuel cut out of the boiler, how is the operate test. The boiler operate must do what?
Turn off the option high fire
What are the 3 things that control the boiler?
On/Off, position, metering
If start of the motor increases, what happened to your NEMA number?
Will Increase
- A cubic foot of # 4 is 7 gallons. How many gallons of a tank with 10 feet of diameter and 30 feet
high?
16,485
To reduce pressure from the city water to the boiler, what type of valve is used?
Pressure reduce valve
What is the safety of factor of 1200 psi and the maximum of pressure is 200 psi?
1200 psi / 200 psi = 6
.In a 4 Y circuit phase to ground is 120 volts, how many volts on the phase to phase.
208v
Which of the following is not the purpose of an air cock vent?
a.
When raising steam in a boiler
.In a thermocouple “cold” junction is in which point?
Reference point
- A boiler 7 feet in diameter, with 5/8” thick plate and 12000 pounds of tensile strength, efficiency of
the joint is 85%, the factor safety is 5. What is the maximum allowable working pressure?
. 30
197.134a and R 410 use what type of oil?
Poe ( polyester oil
The heat in the exhaust steam is 1125 BTU/LB. The temperature of the water entering the heater is 110F and
the temperature leaving the heater is 195F. What is the fuel saving?
= 0.81 x 100 = 8.1 %
- If 108 volt/208 volt what is a 4 WYE or (Delta) system phase to neutral is?
202.
a.
203.
a. 208 Volt
To prevent caking and drying coal entering the pulverize____??????
Warm air is used
Why should air be admitted over the fire?
It creates turbulence in the flues gases above the top of the fuel bed to help complete
combustion.
What is a force applied on to the unit area?
Pressure
204.Which of the following is not the purpose of an air cock vent?
Raising the steam
205.Viscosity of oil is measured in which of the following units?
Standard Say bolt Universal
Residual Sodium sulfite in the boiler for corrosion oxygen should be
20/3 ppm and 40/6 ppm.
.What type of stay is used to support the combustion chamber of the scotch marine boiler?
Diagonal Horizon Stay
Accelerated circulation water tube in one characterize by?
Heated down comers
At 5 PSIG, how many cubic feet does 1 pound of saturated steam occupy?
At 5 PSIG, one pound of saturated steam occupies 20 cubic feet.
At 100 PSIG, how many cubic feet does one pound of saturated steam occupy?
At 100 PSIG, one pound of saturated steam occupies 3.9 cubic feet.
Superheated steam is steam that exists at a temperature higher than the saturation
temperature. Superheated steam is produced mainly in plants that operate steam turbines for
electrical or mechanical power
How high is a column of water that exerts 1 psi at the bottom?
= 2.309 ft
.How much pressure is found at the bottom of a column of water 125” high?
P = water column x 0.433
P = 125’ ft x 0.433
P = 54.125 psi
Why should air be admitted over the fire?
It creates turbulence in the flue gases above the top of the fuel bed to help completed combustion.
Why is coal ground too fine power?
So that it can be burned in suspension using pulverized coal burner.
What is fluidized bed boiler?
Is a boiler in which fuel are burned in a bed of inert material such as limestone and ash.
.Why is coal ground to fine power?
So that it can be burned in suspension using pulverized coal burner.
What are combustible reuse?
Are unburned or partly burned places of coal in the ash coming off the grates
What name of device between the rotatory cup blades?
Nozzle or fix blade
What type of boiler used on/off button?
a. Package boiler
Discharge diameter pipe of a safety valve?
At least 6 ft high discharge pipe diameter should be equal to the discharge of the safety valve and ½ in larger.
What is a clinker?
Is a mass of coal and ash that are fused together during of burning
How is viscosity of fuel oil measured?
Viscosity is the resistance to floor of liquid. And thick liquid has high viscosity while thin liquid
has low viscosity
Which pump is operated with the valve is close?
Jet pump
What happen when the boiler is overheating?
. Failed to clean the deposit on the tube
How is superheat safety valve set?
Lower than the drum safety valve
