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boiler plant operation > 3E Common Exam Questions > Flashcards

3E Common Exam Questions Flashcards

1
Q

What is a blowdown tank and what are the piping connection requirements

A 
A blowdown tank is used to collect blowdown water and temper it before going out the drain. 1” MINIMUM 21/2” MAXIMUM
BLOWDOWN TANK VENT SHOULD BE OF
SUFFICIENT SIZE TO RELEASE FLASHING 
STEAM.
MAWP BLOWDOWN TANK: 50 PSI
BLOWDOWN TANK DISCHARGE LINE:NPS 2” MINIMUM SIZE
GAUGE GLASS
PRESSURE GAUGE
THERMOMETER
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2
Q

What is specific heat

A

Specific heat is the heat required to raise one pound of any substance 1℉

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3
Q

What is a pressure vessel

A

A PRESSURE VESSEL IS A CLOSED VESSEL IN WHICH THE SOURCE OF PRESSURE IS EXTERNAL TO ITSELF. ANY PRESSURE VESSEL NOT IDENTIFIED AS A BOILER

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4
Q

How do you plug a firetube/watertube

A

UP TO 10% OF THE TUBES CAN BE PLUGGED BEFORE REPLACEMENT IS REQUIRED.
IDENTIFY LEAKING TUBE(S) AT BOTH ENDS AND MARK.
(THIS STEP MAY REQUIRE A SQUEEZE/HYDRO)
DRAIN BOILER BELOW LEAKS. LOCK OUT/TAG OUT BOILER.
HAVE CORRECT WEDGE SHAPED TUBE PLUGS ON HAND.
APPLY LOCTITE OR PIPE DOPE TO TUBE PLUG.
USING SMALL SLEDGE HAMMER DRIVE PLUG INTO TUBE.
SOLID TUBE PLUGS WILL BE DIFFICULT TO REMOVE LATER ON.
PERFORM SQUEEZE TO ASSURE TIGHTNESS.

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5
Q

How do you replace a boiler tube

A

REPLACEMENT OF BOILER TUBES IS BEST LEFT TO PROFESSIONALS!
REMOVE DAMAGED/LEAKING TUBE.
CLEAN UP TUBE HOLES WHICH MAY BE DAMAGED IN THE REMOVAL PROCESS.
INSERT NEW TUBE.
EXPAND TUBE INTO TUBE HOLE (ROLLING) USING TUBE EXPANDER.
(IT IS POSSIBLE TO OVEREXPAND TUBES - USE CAUTION)
BEAD OVER TUBE ENDS (FIRETUBE)
FLARE TUBE ENDS (WATERTUBE)
CONDUCT SQUEEZE TO DETERMINE TIGHTNESS.

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6
Q

Hydrostatic pressure test

A

A FULL HYDROSTATIC PRESSURE TEST MUST ONLY BE PERFORMED UNDER THE DIRECTION OF THE AUTHORIZED INSPECTOR.
(A BOILER SQUEEZE AT/BELOW NORMAL OPERATING PRESSURE CAN BE PERFORMED ANYTIME BY PLANT OPERATORS)
REMOVE/GAG SAFETY VALVES
REMOVE/ISOLATE APPURTENANCES UNABLE TO WITHSTAND TEST PRESSURE
FILL BOILER UNTIL WATER COMES OUT BOILER VENT
(WATER TEMP. 70℉ MINIMUM 120℉ MAXIMUM)
RAISE PRESSURE WITH FEEDPUMP. USE HAND PUMP FOR CLOSE CONTROL OF PRESSURE
HOLD TEST PRESSURE PER INSTRUCTIONS OF AUTHORIZED INSPECTOR
USUALLY THE PRESSURE IS REDUCED TO MAWP FOR CLOSE VISUAL INSPECTION

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7
Q

ACCUMULATION TEST

A

AN ACCUMULATION TEST IS NOT NORMALLY PERFORMED BY PLANT OPERATORS (NOT DONE 600 PSI AND ABOVE)
AN ACCUMULATION TEST IS NOT PERFORMED ON BOILERS EQUIPPED WITH SUPERHEATERS, REHEATERS OR HIGH TEMP. HW BOILERS
ISOLATE BOILER AT MAIN STEAM STOP VALVE(S)
FIRE BOILER (INCREASE FIRING RATE TO MAXIMUM AS PRESSURE INCREASES)
CONTINUE TO FIRE UNTIL SAFETY VALVE(S) LIFT
OBSERVE HIGHEST PRESSURE OBTAINED
BOILER PRESSURE SHOULD NOT EXCEED MAWP + 6%

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8
Q

What are the benefits of water walls

A

WATERWALL HEATING SURFACE IS TAKEN AS “EXTENDED SURFACE”
THE PORTION EXPOSED TO THE PRODUCTS OF COMBUSTION

BENEFITS
INCREASE IN BOILER HEATING SURFACE
REDUCED REFRACTORY AREA
LESS AIR INFILTRATION
IMPROVED CIRCULATION
INCREASE IN BOILER EFFICIENCY
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9
Q

ECONOMIZER/AIR-PREHEATER EFFICIENCY GAIN

A

ECONOMIZER
A 1% GAIN IN EFFICIENCY
FOR EACH 10℉ RISE IN
FEEDWATER TEMPERATURE

GAIN CAN BE 1 – 15%
GAIN IN EFFICIENCY DECREASES
AS TEMPERATURE INCREASES

AIR-PREHEATER
A 1% GAIN IN EFFICIENCY FOR EACH 40℉ RISE IN
COMBUSTION AIR TEMPERATURE

GAIN CAN BE 1 – 10%
GAIN IN EFFICIENCY DECREASES
AS TEMPERATURE INCREASES

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10
Q

What can you do with your 3rd’s

A

Third class, to have charge of and operate a boiler or boilers not exceeding, in the aggregate, 150 horsepower when solid fuel is burned or not exceeding, in the aggregate, 500 horsepower when steam is generated by the use of liquid or gaseous fuel, electric or atomic energy or any other source of heat and an engine or engines not exceeding 50 horsepower each or to operate a second class plant under the engineer in direct charge thereof.

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11
Q

Define potential and kinetic energy

A

Potential is energy pocessed by reason of position or deformation, kinetic is energy pocessed by motion

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12
Q

What are the 3 types of heat transfer

A

Radiation - heat transfer by light waves without a material carrier
convection - heat transferred by currents in a fluid
convection - heat transferred molecule to molecule

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13
Q

How to determine engine hp

A 
P.L.A.N.  
33,000
P = MEAN EFFECTIVE PRESSURE
L = LENGTH OF STROKE
A = AREA OF HP PISTON
N = NUMBER OF STROKES/MIN.
SIMPLE ENGINE = 40 PSI, CONDENSING ENGINE = 50 PSI
COMPOUND ENGINE = 70 PSI VARIABLE SPEED USE AVERAGE SPEED
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14
Q

How do we determine turbine hp

A 
BASED ON EXTERNAL DIAMETER OF STEAM SUPPLY PIPE
LESS THAN 1 ¾ INCHES = < 9 HP
> 1 ¾ - 3 ½ INCHES = 50 HP
> 3 ½ - 5 INCHES = 150 HP
 > 5 INCHES = UNLIMITED HP
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15
Q

How many btu’s in a mechanical hp hour

A

1,980,000 / 778 = 2,545

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16
Q

How many btu’s in a kilowatt hour

A

2545 /.746 = 3,413

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17
Q

BTU’ Input

A

33,475 /.80 = 41,840

ASSUMES 80% BOILER EFFICIENCY

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18
Q

One kilowatt

A

1.34 HP (1000/746)

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19
Q

ONE BTU

A

778 FT/LBS. OF WORK

JOULE’S EQUIVALENT

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20
Q

Define boiler heating surface

A

The parts of the boiler with water on one side (wet steam) and products of combustion on the other. measured on the hot gas side always expressed as square feet

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21
Q

What are the safety valve requirements as to the number and capacity of a boiler that contains 625 sq ft of heating surface and is operating at 125 lbs pressure

A

2 safety valves required over 500sq ft of heating surface or for an electric boiler 1,100 kw. One or more pressure relief valves on the boiler proper shall be set at or below the maximum allowable working pressure (except as noted in PG-67.4).If additional valves are used the highest pressure setting shall not exceed the maximum allowable working pres- sure by more than 3%. The complete range of pressure settings of all the saturated‐steam pressure relief valves
on a boiler shall not exceed 10% of the highest pressure to which any valve is set.

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22
Q

How is the heating value of fuel determined

A

Ultimate analysis, (lab + dulongs formula)

Bomb calorimeter

Proximate analysis + graph

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23
Q

When are 2 or more safety valves required on a boiler

A

Over 500sq ft of heating surface or for an electric boiler 1,100 kw. One or more pressure relief valves on the boiler proper shall be set at or below the maximum allowable working pressure (except as noted in PG-67.4).If additional valves are used the highest pressure setting shall not exceed the maximum allowable working pres- sure by more than 3%. The complete range of pressure settings of all the saturated‐steam pressure relief valves
on a boiler shall not exceed 10% of the highest pressure to which any valve is set.

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24
Q

When using 2 safety valves how are the safety valves mounted and how are they set

A

When two or more pressure relief valves are used on a boiler, they may be mounted either separately or as twin valves made by placing individual valves on Y‐bases, or duplex valves having two valves in the same body casing. Twin valves made by placing individual valves on Y‐bases, or duplex valves having two valves in the same body, shall be of approximately equal capacity.
When not more than two valves of different sizes are mounted singly the relieving capacity of the smaller valve shall be not less than 50% of that of the larger valve.

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25
Q

What is a safety valve

A

An automatic pressure relieving device actuated by the static pressure upstream of the valve and characterized by a full opening pop action. Used for Gas or Vapor Service.

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26
Q

What is a safety relief valve

A

Used where a gas/vapor or liquid service. (Example: Economizers)

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27
Q

How do we determine minimum safety valve relieving capacity requirements

A

4 ways
Table pg-70, often referred as appendix table a-44
Accumulation test
Maximum fuel burned formula (code formula)
Maximum evaporative capacity by measuring the feedwater

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28
Q

How would you order a new safety valve

A

Take the information off of the old one

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29
Q

How would you start a boiler using #6 fuel oil

A

IT MAY NESSECARY TO RECIRCULATE OIL TO GET PROPER TEMP.
(OIL SHOULD BE 180-200℉)
CHECK LINE UP OF GAS (PILOT) VALVES.
LINE UP ATOMIZING STEAM/AIR. (DRAIN CONDENSATE FROM LINES)
ESTABLISH DRUM LEVEL. ALLOW FOR SWELL.
PURGE FURNACE BEFORE LIGHT-OFF ATTEMPT.
WITH OIL AT PROPER TEMP. AND PRESSURE ATTEMPT LIGHT-OFF
IF BURNER DOES NOT LIGHT, ISOLATE MAIN FUEL, PURGE AND TRY AGAIN.
ONCE BURNER IGNITES, ADJUST AIR DAMPERS.

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30
Q

Describe cold end corrosion

A

Corrosion that occurs in the low temperature components of a boiler such as economizers and air pre heaters, induced draft fans, and flues

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31
Q

What causes cold end corrosion

A

Caused when the temperature of the metal drops below the sulfuric acid dewpoint of the flue gas

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32
Q

How would you conduct a Bacharach fyrite test

A

THE BACHARACH FYRITE TEST KIT INCLUDES A CLOSED CYLINDER CONTAINING REAGENT AND TUBING TO TRANSFER FLUE GAS SAMPLE FROM BREECHING/STACK TO CLOSED CYLINDER.
ZERO OUT GRADUATED SCALE ON CYLINDER.
CONNECT TUBING FROM BREECHING/STACK TO CYLINDER.
PUMP BULB TO TRANSFER FLUE GAS TO CYLINDER.
(FOLLOW GUIDELINES – THE BULB MAY HAVE TO BE SQUEEZED 15-20 TIMES)
4) REAGENT IN CYLINDER ABSORBS SPECIFIC GAS (O2/CO2). SHAKE WELL.
5) USING SLIDE RULE, ENTER FLUE GAS TEMP. AND PUT POINTER AT SPECIFIC READING.
6) READ COMBUSTION EFFICIENCY IN WINDOW

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33
Q

How do we determine combustion efficiency

A

Boiler heat balance,

Portable analyzers, ORSAT AND BACHARACH FYRITE, Electronic analyzers such as a continuous emissions monitoring (CEM)

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34
Q

What are the losses in a boiler

A 
Heat loss out the stack , 10%
Water vapor (from burning hydrogen)
Unburned fuel in the ash
Incomplete combustion
Moisture in the fuel
Moisture in the combustion air
Radiation
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35
Q

What is electrolosis

A

A PROCESS BY WHICH ELECTRIC CURRENT IS PASSED THRU A SUBSTANCE TO EFFECT A CHEMICAL CHANGE. ELECTROLYSIS OF AN AQUEOUS SOLUTION OF SODIUM CHLORIDE YIELDS SODIUM HYDROXIDE AND CHLORINE GAS. HYDROGEN CAN BE SEPARATED FROM OXYGEN BY THE ELECTROLYSIS OF WATER

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36
Q

What are some common tests on feedwater in power plants

A 
P or m alkalinity
Conductivity
PO4 residual
O2 residual
PH
Hardness
For high purity plants
ph
Phosphate
Silica
Coinductivity
Cation/Specific conductivity
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37
Q

Why do we treat feedwater

A

Prevent sludge from depositing on boiler
surfaces

Prevent scale from forming on boiler surfaces

Prevent corrosion of boiler metal

Prevent carry over with the steam leaving the boiler

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38
Q

What are Chlorides

A

CHLORIDE IONS (CHLORIDES) ARE MINERAL SALTS THAT CAN CAUSE SCALE ON BOILER SURFACES AND ARE USED TO MONITOR CYCLES OF CONCENTRATION AND CONTROL BLOWDOWN RATES.
THE CHLORIDE TEST IS MOST CONVENIENTLY DONE ON THE SAME SAMPLE AS THE P-ALKALINITY TEST DONE ON BOILER WATER.
(THE CHLORIDE TEST WILL NOT WORK ON HIGH pH BOILER WATER)

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39
Q

What is a volute pump

A

A CENTRIFUGAL PUMP THAT HAS AN INCREASED AREA OF THE PUMP CASING THAT CONVERTS HIGH VELOCITY TO PRESSURE.

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40
Q

What is required NPSH and Available NPSH

A 
REQUIRED NPSH (NPSHR) IS SET BY THE PUMP MANUFACTURER AND IS THE DISTANCE (HEAD) REQUIRED TO PREVENT CAVITATION.
AVAILABLE NPSH (NPSH3) TAKES INTO ACCOUNT VALVES, FITTINGS, STRAINERS, ETC. (FRICTION) THAT WILL REDUCE NPSH.
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41
Q

What are wearing rings

A

Usually sit on both sides of the impeller, prevents leakage around it and protects the pump from damage by targeting the wearing rings

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42
Q

Lantern rings

A

Water is directed over the lantern rings and it is directed to the packing to keep the packing cool

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43
Q

How many BTU’s are in a boiler horsepower? A kilowatt hour?

A

There are 33475 BTU’S in a horsepower and 3413 BTU’S in a kilowatt hour

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44
Q

What is cold end corrosion

A

The corrosion that develops in the low temperature components of a boiler such as economizers, air preheaters, induced draft fans, scrubbers and flues. Cold end corrosion occurs when the temperature of the metal drops below the sulfuric acid dew point. The temperature at which sulfuric acid will first condense varies from between 240 and 330 degrees F. Cold end corrosion is prevented by monitoring the temperature of the flue gas to ensure that exiting flue gas temp is above 330 degrees F

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45
Q

Explain why it is necessary to treat boiler feedwater

A

Prevent sludge, prevent scale, prevent corrosion, and prevent carryover

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46
Q

Name four (4) things you would find on a boiler stamp.

A

Serial Number
BTU Input
Tube Size
Heating Surface

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47
Q

Explain the five (5) headings on the steam tables

A
  • Absolute Pressure
  • Temperature
  • Specific Volume, The amount of space the material will occupy in cubic feet per pound
  • Enthalpy, Total heat available for work measured in BTU’S /LB
  • Entropy, Total heat unavailable for work
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48
Q

A boiler has 3 inch diameter tube holes pitched 5.25 inches apart. What is the ligament efficiency

A

Ligament efficiency = P-D/P

5.25-3/5.25 = .428

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49
Q

Explain what happens to steam pressure, volume and velocity thru a steam turbine Curtis Stage

A

As steam passes through the first stage nozzle there is a large pressure drop increasing the volume and velocity of the steam. The high velocity steam is directed to the first row of moving blades giving up some of that velocity to rotate the rotor. The steam then travels through a redirecting blade which sends the steam into a second set of moving blades

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50
Q

What is the purpose of a thrust bearing? Name two types of thrust bearings

A

Used to absorb axial movement of the rotor, Two types of thrust bearings are the Kingsbury and the Tapered Land bearing

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51
Q

What is the definition of latent heat

A

Latent heat is heat added to a substance that causes a change of state without a corresponding change in temperature

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52
Q

What is erosion? What is corrosion?

A

Erosion is the wearing away of metal due to mechanical forces and corrosion is the wasting away of metal from chemical forces

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53
Q

Explain the steps necessary to start a non-condensing steam turbine.

A
  • Make ready driven piece of equipment (feed pump, fan, compressor, etc)
  • Check lubrication on turbine, check open turbine casing drains, open turbine exhaust valve fully wide
  • Crack open throttle valve and roll the turbine to 200 – 300 RPM and trip turbine
  • Relatch turbine and roll up to 500RPM and sound out.
  • Continue roll up until governor takes over, you are now at full speed/no load
  • Put driven piece of equipment in service
  • Close turbine casing drains
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54
Q

Find the heating surface of a water tube 4” (inches) in diameter and 16’ (feet) long

A

Outside diameter in feet (always measured on the hot gas side) X 3.14 X length of tube X number of tubes
4’’/12 X 3.14 X 16’X1 = 16.74 cu ft

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55
Q

Convert the following fractions to decimal: 1/4 23/28 7/16

A

¼ = .250
23/28 = .821
7/16 = .437

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56
Q

Explain the operation of a volute centrifugal pump

A

As the impeller of a centrifugal pump rotates water enters the center of the impeller and is thrown outward by centrifugal force. The water leaves the impeller at high velocity and is converted to pressure in the volute section of the pump

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57
Q

How do you conduct a hydrostatic test on a boiler

A

Note: A full hydrostatic pressure test must only be
performed under the direction of the authorized inspector
- Remove or gag safety valves if removed install blank or blind flange
- Remove or isolate appurtenances unable to withstand test pressure such as gage glass
- Shut main steam stop and blowdown valves and loto boiler
- Fill boiler until water comes out the boiler vent. Min temp 70F, Maximum temp 120F in no case can the temperature be lower than atmospheric
- Raise pressure with hand pump for close control of pressure. Test pressure should be at 1.5 times the MAWP
- Hold pressure per instructions of authorized inspector
- Usually the pressure is reduced to MAWP for close visual inspection
Reference ASME Code section #7 for guidance

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58
Q

A boiler has two (2) individually mounted safety valves. What are the sizing requirements

A

The relieving capacity of the smaller valve shall not be less than 50% of that of the larger valve

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59
Q

What is CO2, SO2, N2, O2, and NH3

A 
CO2, Carbon Dioxide
 SO2, Sulphur Dioxide
N2, Nitrogen
 O2, Oxygen
NH3, Ammonia
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60
Q

What is meant by “critical speed” in a steam turbine

A

Certain speeds that cause excessive vibration due to harmonic imbalance. Pass through critical speeds quickly by increasing the ramp rate on the turbine

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61
Q

Name three (3) ways to determine boiler efficiency

A
  • Boiler heat balance
  • Portable analyzers, ORSAT and BACHARACH FYRITE
  • Electronic Analyzers, CEM’S (Continuous Emissions Monitoring)
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62
Q

Explain the operation of a centrifugal mechanical governor

A

With the turbine at rest the flyballs will be at the inner most position causing the valve to be wide open. As the turbine comes up to speed centrifugal force will cause the flyballs to move towards the outer position, compressing the spring and causing the valve to move towards the closed position.

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63
Q
  • What is deaeration?
A

The removal of oxygen in feedwater by mechanical seperation / chemical addition using sodium sulfite

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64
Q

*Start a small non condensing turbine.

A
  • Make ready driven piece of equipment (feed pump, fan, compressor, etc)
  • Check lubrication on turbine, check open turbine casing drains, open turbine exhaust valve fully wide
  • Crack open throttle valve and roll the turbine to 200 – 300 RPM and trip turbine
  • Relatch turbine and roll up to 500RPM and sound out.
  • Continue roll up until governor takes over, you are now at full speed/no load
  • Put driven piece of equipment in service
  • Close turbine casing drains
65
Q

What is the board of boiler rules

A

A group within the DFS that deals with the construction, installation and inspection of boilers. Meet infrequently every year

66
Q

Who is on the Board of boiler rules

A

Ed Kawa, Chief of boiler inspections, and representatives of operating engineers, boiler manufacturers, insurers, and users of boilers

67
Q

A water tube boiler with 66 tubes 3” O.D. and 18’ long. Find the heating surface.

A

3/12x3.14x18x66=

68
Q

Why is there a pressure drop in a Curtis stage turbine?

A

As steam passes through the nozzles there is a pressure drop increasing the velocity of the steam, the steam is directed through the moving blades to turn the rotor.

69
Q

How is oxygen removed mechanically

A

Oxygen is removed mechanically by a deaerator. As condensate and make up water enters the top of deaerator its directed over a series of trays, steam makes direct contact with the water which liberates greater than 99% of the oxygen non condensable gases which exits out the vent
Removes o2 and non-condensable gases
Stores feedwater
Heats feedwater
Low pressure area for chemical addition
Provides proper NPSH to boiler feed pumps to prevent cavitation

70
Q

What is pitting? How can you tell if the pitting is active or inactive?

A

Pitting is the formation of small holes in the surface of the boiler plates, caused by oxygen and poor circulation or an acidic condition with the boiler water.
Shiny metal surface indicates active pitting, Inactive pitting has a layer of magnetite (orange brownish color)

71
Q

What is cavitation? -or- What is net positive suction head available and required

A

Cavitation is defined as the sudden formation and collapse of low pressure bubbles in the pump due to mechanical forces, NPSH is the minimum NPSH required to prevent cavitation set by the manufacturer, Available NPSH is actual NPSH taking losses due to piping

72
Q

Name 7 things you will find on a Mollier Chart

A 
Lines of constant Enthalpy
Lines of constant Entropy
Lines of constant pressure
Lines of constant quality
Lines of constant temperature
Saturation line
Degree of superheat
Standard atmosphere
73
Q

What is the coefficient of expansion for carbon steel

A

.00000734 in/ft for 1 deg F

74
Q

What is kinetic energy? Potential energy

A

Kinetic energy is the energy that a body has due to its motion, potential energy is energy posessed by reason of position or deformation

75
Q

Perform an accumulation test in detail

A

Test should not be performed without notice given to the inspector.
Shut all steam discharge outlets from the boiler and force the fires to the maximum.
The safety valves shall pop and relieve all steam generated without the steam pressure rising 6% above the highest set valve pressure but in no case more than 6% above the MAWP.
This test is not to be done on a boiler with a superheater or reheater

76
Q

Regarding superheaters, what is radiant pass and convection pass. What loads do they operate best at

A

Radiant superheaters absorb heat from the direct radiant heat from the flames, Convection superheaters absorb heat from the products of combustion passing over it, located somewhere in the gas passage before the stack. Radiant superheaters work best at low loads, convection superheaters work best at higher loads

77
Q

How many btu’s in a horsepower hour? Kilowatt Hr

A

2545 btu’s in hp hr and 3413 in KW hr

78
Q

What can you do with a third class engineers license

A

Have charge of and operate a boiler or boilers not exceeding in the aggregate 150 hp when solid fuel is burned or not exceeding in the aggregate 500 hp when steam is generated by the use of liquid or gaseous fuel, electric or atomic energy or any other source of heat and an engine or engines not exceeding 50 hp each or to operate a 2nd class plant under the engineer in direct charge thereof

79
Q

License requirements

A

Operators are responsible for the boilers during their shift under the engineer in charge.
Completes and signs the operators log book on a daily basis, records made available to the district inspector upon request

80
Q

Requirements for reportable accidents

A

Owner / user or engineer in charge of steam boilers or engines shall notify the Mass emergency management agency within 24 hours of the event

81
Q

Requirements for accepting / leaving a position

A

All engineers or fireman in charge of steam boilers or engines shall notify the dfs within 7 days of the location of the boilers and / or engines of which he is in charge. When accepting a position as engineer or fireman in charge the dfs need to be notified withinRequirements for an engineer in charege 7 days

82
Q

Requirements for engineer in charge

A

Make daily visits to the plant and leave daily written instructions to the operating personnel made available upon request to the district inspector
Review the operators log book daily and perform his duties at the facilities five working days per week

83
Q

Welded repair info / requirements

A

All welded repairs require documentation. An R1 form must be completed by contractor and the engineer in charge has to make sure everyone that is supposed to get a copy gets one, (dfs).
An R1 Form is for a welded repair
An R2 Form is for an alteration

84
Q

Mechanical repair to boiler external piping systems. What are requirements

A

Completed under the supervision of the engineer in charge, engineer in charge needs to fill out a form obtained from the dfs recording all work performed. records are kept on file at the location of the boiler and be accessible to the division and authorized inspectors. Repairs need to meet original code of construction. Completed forms and attachments submitted to dfs within 7 days of completion of repairs

85
Q

Nox limits

A

20 ppm at alnylam, state limit is 30 ppm for nrwer boilers ( constructed after 2000) 70 ppm for older boilers. Mass law supersedes federal law in environmental matters

86
Q

Opacity limits

A

In no case shall exceed 20% opacity for a period or aggregate period of time in excess of 2 minutes during any 1 hour period provided that at no time during said 2 minutes shall the opacity exceed 40%

87
Q

Visible emissions (old standard), CMR-310 SEC 7

A

1 on chart for a period or aggregate period of time in excess of 6 minutes during any 1 hour period provided that at no time during said 6 minutes shall the shade density or appearance be =/> no 2 on chart (ringleman scale)

88
Q

What is a third class plant

A

Up to 150 bhp when solid fuel is burned, up to 500hp when liquid or gaseous fuel is burned, operate engines none of which=h exceed 50 hp

89
Q

What is a 2nd class plant

A

Unlimited bhp and engine none of which shall exceed 150 hp

90
Q

What is the largest engine a third engineer can operate

A

Up to 150 hp under the engineer in charge, can be in charge of a 5o hp engine or turbine

91
Q

What are the three types of boiler inspectors

A

Ins company inspectors
Shop inspectors (work for manufacturer)
DFS inspectors

92
Q

If in charge of a plant can you stand watch 5 miles away

A

Yes, you can only be in charge of 1 plant but can stand watch for as many as you can get to, no set limit to being an operator

93
Q

What is the board of boiler rules

A

A group within the dfs that deals with the construction, installation and inspection of boilers, they meet infrequently every year

94
Q

Who is on the board of boiler rules

A

Ed Kawa, chief of boiler inspectors
Representatives of operating engineers
Boiler manufacturers and insurers
users of boilers

95
Q

Periodic attendance, non continuous attendance , continuous attendance

A

Periodic boilers operating at 9 - 250 hp in the aggregate
non continuous attendance, boilers operating at 251 - 500 hp in the aggregate
continuous attendance, boiler operating over 501 hp

96
Q

Main difference between non continuous and periodic

A

Non continuous requires remote monitoring equipment to alert the operator

97
Q

Can a first fireman operate a steam turbine

A

Yes up to a 50 hp turbine

98
Q

HP of turbine in a first class plant

A

Unlimited hp

99
Q

4 reasons why you would use condensers

A

reduce back pressure on the steam turbine which increases the heat (enthalpy) drop through the turbine (more btu’s available to do work)

reclaim high quality condensate

condensate is dearated in the condenser

All steam drains are routed to the condenser

100
Q

Describe a surface condenser

A

Use water from oceans, rivers, streams as the cooling medium. they are shell and tube heat exchangers with the water going thru the tubes and the condensing steam surrounds the tubes, condensate collects in a hot well and is picked up by condensate pumps. Circulating water pumps pump water from the condenser to cooling towers where heat is rejected to atmosphere. Inlet and outlet temperature is important on single pass surface condensers due to discharge temperature limits. In mass the limit is 98 deg F

101
Q

What is ph, if ph goes from 10 to 11 what does this mean?

A

PH is the logarithm of the reciprocal of the hydrogen ion concentration. If ph goes from 10 to 11 it becomes 10 times more basic

102
Q

What are some of the problems with surface condensers

A

Tubes plugging with material

103
Q

Name 3 types of surface condensers

A

Single pass
Two pass, can have higher discharge temperatures using cooling towers to discharge to atmosphere, (rejects heat to atmosphere) (does not use seawater)
Split/divided condenser, allows for cleaning one side while keeping unit on line. allows for cleaning while keeping the turbine online

104
Q

What is laning in regards to surface condensers

A

The omission of whole sections of condenser tubes force steam deeper into the shell so the tubes do more work

105
Q

Name components of a surface condenser

A 
Shell
Exhaust nozzle (hood)
Expansion joint
Impingement plate (reduce erosion)
Water boxes (lined to reduce erosion)
Tubes
Tube sheets
Steady Plates
Hotwell
106
Q

What material are condenser tubes made of

A

For freshwater the tubes are constructed of alloys of copper, aluminum, admiralty metals, and/or stainless steel
For seawater, titanium or stainless steel

107
Q

Name some reasons why condenser tubes are bowed

A

Allow for drainage
Reduce vibration
reduce tube erosion from rubbing on steady plates

108
Q

How are condenser tubes installed

A

They are installed using a combination of packing and ferrules and are usually flared at the inlet. Floating tube sheets are also used to allow for expansion and contraction of the tubes

109
Q

How are condensers supported

A

Condensers and turbine are rigidly supported with expansion joint between them
Hung from the turbine (smaller units), expansion is downward. all connections have expansion joints
Rigid connection with condenser supported by springs. All connections have expansion joints

110
Q

What typical auxiliary equipment would you find on a condenser

A

Travelling screen
Circulating water pump (use cutlass bearings)
Water box priming system, used on ocean systems, pulls air and non condensable gasses out of the condenser using a vacuum pump

111
Q

What happens when you have a sudden reduction in steam in a condenser

A

Causes a vacuum

112
Q

What prevents a vacuum from forming in a condenser

A

Air removal equipment
- Vacuum pump and steam jet air ejectors are used to maintain vacuum. advantages of steam jet air ejectors over vacuum pumps are they are cheaper to operate (not electrically driven and nothing is wasted, virtually all steam returned to process

113
Q

Explain how a steam jet air ejector works

A

Steam jet air ejectors work on the principle that steam passing through a restricted area (nozzle) will experience a velocity increase (pressure drop) that will create a low pressure area across the suction tube drawing non condensable gasses into the diffuser section which converts velocity to pressure

114
Q

why do we use a loop seal

A

A loop seal is required to return recovered condensate from the inter/after condensers to the hotwell which is at a higher pressure. A leg (drip leg) is provided to prevent the condensate from the hotwell to be drawn into the inter/after condenser. You need a loop seal to create a higher pressure to return the condensate from the inter / after condenser to the hotwell. The height of the loop seal will provide sufficient pressure (usually between 6 - 9 feet) to prevent flow from the hotwell to the inter/after condenser. *** not all plants direct condensate from the after condenser to the hotwell

115
Q

Why use vacuum pump in condensers and what are the downsides vs steam jet air ejectors

A

Vacuum pumps are used to pull air and non condensable gasses from the condenser, the downside of using vacuum pumps are that they require electricity ( costly to operate)

116
Q

What are some water side (tubes) problems with condensers..

A

Issues with condensers causes an increase in back presssure in the turbine
Water side leaks contaminate condensate
Tube leaks (difficult to locate)
-temporarily plug tubes with sawdust
- condenser hydro is often used with dye to pinpoint leaking tubes
- Gas (freon) is used by pulling vacuum and checking sections of tubes and placing a gas analyzer at air injector outlet
Dirty tubes
travelling screen dirty
circulating water flow issues
high water level in hotwell
problems with water box priming system

117
Q

Name some problems with condensers on the shell side

A 
Vacuum breaker leaks
Expansion joint leaks
loop seal lost
problems with air removal equipment
valve packing leaks
pump seral leaks
118
Q

How would you respond to rising back pressure in a condenser

A

Reduce load on the machine
put extra air removal equipment into service
check seal system (proper pressure)
check circulating pumps
check temperature rise across the condenser
Check water level (water box priming )

119
Q

What do they mean by condensate depression

A

Under cooling / sub cooling

120
Q

What is macro fouling in a condenser

A

Debris on tube sheet causing a decrease of water flow and temperature rise in the condenser

121
Q

What is micro fouling

A

Debris in condenser tubes resulting in a decreased temperature rise across the condenser

122
Q

What is hogging

A

Allowing steam and non condensable gasses to vent to atmosphere to reduce the time required to pull vacuum on condenser

123
Q

What is the purpose of an impingement plate on a condenser.

A

As steam reaches the end of the turbine water droplets form, to remove them impingement plates are used to protect the tubes from high velocity water droplets hitting the tubes, impingement plate need to be replaced often

124
Q

Where would you use an air cooled condenser

A

Air cooled condensers are used primarily where water availability is a problem, an air cooled condenser can be used anywhere and are frequently used to satisfy 0 discharge requirements

125
Q

How does a direct acting air cooled condenser work

A

Functions the same way as a radiator, steam exhausted from a turbine is directed into the tube banks with fans directing cool air over the tubes, the condensed steam is collected in a tank and condensate pumps return the condensate to the system

126
Q

What are some disadvantages of using an air cooled condenser

A

Major disadvantage is the loss in turbine efficiency due to higher backpressures which is dependent on ambient air temperatures

Air cooled condensers use a lot of electricity

127
Q

What type of tubes are used in an air cooled condenser

A

Finned tubes to optimize cooling ability to condense steam

128
Q

What is a direct acting air cooled system

A

It is when exhaust from the turbine goes directly to the acc, the steam gets condensed and is returned to the system

129
Q

What is a indirect dry cooling system (cooling towers)

A

Classified as Natural draft (hyperbolic), forced draft, and induced draft

  • Natural draft uses a hyperbolic tower that creates air flow due to the venturi effect of the design with the height of the tower determining the amount of air flow. The advantage of this system is no fans are used
  • Forced draft towers use a fan located at the base of the tower forcing air up through the tower
  • induced draft towers use a fan on top of the tower that pulls air into and through the tower
130
Q

What are some problems associated with cooling towers

A
  • evaporation
  • Drift, (water falls outside the basin)
  • blowdown (cooling towers require a lot of blowdown)

Losses can be substantial with 5 - 15% make up for each loss, while it is rare to see 45% loss, make up in cooling towers between 25 - 30% is quite common

131
Q

Formula for calculating cooling tower requirement

A 
Large volumes of water are required to condense steam, the formula is Q= H-(Tc-32)/T2 - T1
Q= quantity of water
H= Enthalpy of exhaust steam
Tc= Temperature of the condensate
T2=Temperature of the leaving water
T1= Temperature of the entering water
132
Q

Steam exhausts to a condenser @ 1100 btus/lb, the hotwell temperature is 100deg F and the entering cooling water is 80 deg F with a 10 deg rise across the condenser. How much cooling water is required

A

Q= H-(Tc-32)/T2 - T1
1100-(100-32)/90-80
1032/10 = 103.2 LBS OF WATER PER LB OF STEAM

133
Q

How do you start a surface condenser

A

Open suction valve(s) and start circulating pump
Open discharge valve(s)
Close all condensate drains/vents
Start water box priming system
Place air removal equipment in operation, put seals on turbine, pull vacuum
Operate condensate pump as needed during startup, roll turbine
As load increases remove extra air removal equipment

134
Q

Heating systems

A

1 pipe system are when the steam supply and condensate return all happens in 1 pipe, more economical to build than 2 pipe systems. downside is water hammer

2 pipe systems are when the steam supply and condensate returns are in 2 separate pipes, most plants today use 2 pipe systems

2 types of return systems
dry return system condensate and airin condensate return line
wet return system condensate lines below the normal water level, they stay flooded and corrosion is reduced

Hartford loop (loop seal) minimizes low water level conditions in home heating boilers. it allows for the return of low pressure condensate to a boiler at a higher pressure without the use of a pump

Loop seals today are seen in steam jet air ejectors which pull air and non condensable gasses out of the condensers. Pressure at the steam jet air ejector is lower than pressure in the hotwell of the condenser so a loop seal is required to deliver low pressure condensate from the steam jet air ejector back to the hotwell

135
Q

How is a vacuum prevented in a deaerator

A

By using a vacuum breaker

136
Q

Explain how a deaerator works

A

Condensate returns to the top of DA and pass through nozzles which break up condensate to a fine spray which cascades over baffles. Steam entering from the bottom scrub the O2 and non condensable gasses before going out the vent. The condensate then drops into the storage area of the DA providing positive suction head to the boiler feed pumps

137
Q

Why is there a pressure regulator on the steam supply to the DA

A

To maintain the pressure in the DA, typically 5 - 10 psi and heat the feedwater.

138
Q

What information is found on the boiler stamp and where is it located

A
  • Manufacturers serial number
  • Certified by _______Name of manufacturer
  • MAWP
  • Heating surface
  • Year built
  • Fire tube the stamping is located on either side of the the shell near the NOWL and as near as practical to the front tube sheet
  • On water tube boilers the stamping is on a head of the steam drum near and above the manhole.
  • Superheaters, Economizers, and waterwalls have their own boiler stampings
139
Q

How is moisture separated in a fire tube boiler? In a water tube boiler?

A

Moisture is separated by a dry pipe in fire tube boilers and cyclone separators, baffle plates , and scrubbers in water tube boilers

140
Q

Where in the boiler are radiant and convection type superheaters located

A

Radiant superheaters are located in the furnace section of the boiler in direct line of sight with the boiler, convection type super heaters are located in the back gas passages that doesn’t see the fire

141
Q

At what loads do radiant and convection type superheaters perform best

A

Radiant super heaters perform best at low loads while convection superheaters perform best at high loads, these two types of superheaters are frequently used together to get a more uniform temperature profile

142
Q

Relieving capacity of safety valves on superheaters

A

Super heater safety valves can account for up to 25% of the boiler and is always set at the lowest pressure to assure steam flow through it

143
Q

How do you prevent overheating of super heater during start up

A

Start up super heater at low fire, when you get steam out the vent or super heater drains you can increase load

144
Q

What are the benefits of superheated steam

A

No moisture
More BTU’S per lb of steam
Travels longer distances without condensation

145
Q

How do we control super heat temperature

A
  • Attemperators (desuperheaters) spray water into the steam, water evaporates and lowers steam temp
  • Tilting burners
  • Bypass dampers
  • Using a combination of both radiant and convection type superheaters
  • Flue gas recirculation
146
Q

What is the overall gain in using super heaters

A

2 - 5 %

147
Q

What are the benefits to the turbine when using superheated steam

A

Less erosion on turbine blades and less steam flow due to higher enthalpy

148
Q

What does high and low CO2 indicate

A

High CO2 indicates high combustion efficiency and low CO2 indicates low combustion efficiency

149
Q

At which temperature will sulfuric acid first condense (acid dewpoint)

A

240 - 330 deg F

150
Q

Explain cold end corrosion

A

Temperature of the metal in economizers , air preheaters induced draft fans, may drop below the sulfuric acid dewpoint. It is important to keep these surfaces at temps than the acid dewpoint of the flue gas, especially during start up when these components are cold

151
Q

What does cold end corrosion look like

A

Rust colored corrosion that occurs on economizers and air preheaters

152
Q

Is cold end corrosion an issue when burning natural gas

A

No, natural gas has no Sulphur in it

153
Q

Explain block and bleed in regards to gas piping

A

Block and bleed is an NFP requirement. there are 2 maxon valves with a vent valve between them to atmosphere. When valves are closed the vent valve will be open, when valves are open vent valve will be closed

154
Q

List the piping components of a typical arrangement for burning #6 oil

A 
Oil Tank
suction strainers
pressure gage
pumps
heaters (Steam and Electric)
pressure gage
discharge strainers
low oil temp switch
high oil temp switch
low pressure switch
pressure regulating valve
SSOV
burner
155
Q

What is draft

A

Difference in pressure between 2 points that causes gas or air to flow

156
Q

How is draft measured

A

By a manometer

157
Q

What are 2 types of manometers

A

U-tube

inclined tube

158
Q

2 types of draft

A

Mechanical draft, powered driven fans

Natural draft, height of the stack and dampers

boiler plant operation (12 decks)

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