TEST 3

Question 1

Which boiler type contains the boiling water inside the boiler tubes and the hotcombustion gases on the outside of the tubes?

Answer 1

Watertube boiler.

Question 2

Which boiler type contains the boiling water outside the boiler tubes and the hotcombustion gases on the inside of the tubes?

Answer 2

Firetube boiler

Question 3

What is a steam drum?

Answer 3

Cylindrical vessel located at the top of the boiler. Provides a space for thesaturated steam generated in the tubes and for the separation of Moisturefrom the steam.

Question 4

What is a superheater?

Answer 4

A heat exchanger bundle that raises the steam temperature above saturatedtemperature to ensure dry steam is in the steam header.

Question 5

What is an economizer?

Answer 5

A heat exchanger which preheats the boiler feedwater before it enters theboiler. Combustion gases are used to preheat the feedwater.

Question 6

What is an desuperheater?

Answer 6

A device to cool down superheated steam by injected boiler feedwater.

Question 7

What are the steam generating tubes called in a watertube boiler?

Answer 7

Risers.

Question 8

What is the approximate water level in a steam drum?

Answer 8

Half full.

Question 9

What is the water circulation pattern in a water tube boiler?

Answer 9

From steam drum, to downcomer, to mud drum, to riser, to steam drum, outsteam nozzle.

Question 10

Why is it important to maintain good water quality in a boiler? Select all reasons thatapply.

Answer 10

1. Maintain clean heat transfer surfaces to allow rapid and efficient heattransfer
2. Must be relatively free of deposit forming solids.
3. Reduce rate of metal corrosion.

Question 11

What device is used to remove CO2 and O2 gases from boiler feedwater?

Answer 11

Dearator.

Question 12

At what pH should boiler water feedwater be maintained?

Answer 12

Alkaline.

Question 13

What chemical can be added to the boiler feedwater to remove O2 in the water?

Answer 13

Sodium sulfite.

Question 14

Select the variables used in 2-element steam drum level control?

Answer 14

1. Steam drum level.
2. Steam flow.

Question 15

Sort the order of events to describe boiler swell?

Answer 15

1.Demand for steam increases.
2. Steam header pressure decreases.
3. Boiler master increases firing rate.
4.More water vapour is present in the steam drum
5.In the steam drum, the water/vapour mixture density decreases.
6.The drum level increases.

Question 16

The primary function of combustion control is to deliver air and fuel to the burner ata rate that satisfies the firing rate demand and at a mixture (air/fuel ratio) thatprovides safe and efficient combustion.

Answer 16

True

Question 17

What is the controlled variable to the boiler master?

Answer 17

Steam header pressure.

Question 18

What term describes the additional temperature and energy added to the saturatedsteam by the boiler?

Answer 18

Superheat.

Question 19

Refer to the following SAMA drawing. What happens when the plant master sendsan increasing firing rate demand signal to the combustion control?

Answer 19

High selector chooses firing rate as RSP to air flow controller.

Question 20

Superheaters are designed to provide more superheat than required. How is thefinal superheat controlled?

Answer 20

Vary the boiler feedwater rate in the desuperheater.

Question 21

Why is excess air required during combustion? Select all that apply.

Answer 21

B) Ensure fuel doesn’t accumulate in the windbox.
C) Ensure unburned fuel doesn’t go up the stack.
D) Achieve complete combustion.

Question 22

A high pressure boiler has which boiler drain valve arrangement?

Answer 22

A fast opening guard valve and a slow opening valve on the line from the lowestpart of the boiler.

Question 23

Internal water treatment has what affect on the solids concentration in the boiler?

Answer 23

Increases the speed of solids concentration buildup.

Question 24

What is the primary effect of blowdown within the boiler?

Answer 24

Lower solids concentration.

Question 25

Why is too much air added to the fuel not desirable?

Answer 25

Wastes fuel by carrying excess heat up the stack.

Question 26

Answer 26

Clamp the O2 trim controller output to prevent driving air/fuel ratio beyondsafe limits.

Question 27

Which statement is false when an induced draft fan is used?

Answer 27

A high stack is required.

Question 28

A boiler has a balanced draft system. There is a strong burning smell and smokey airleaking out of the boiler. What is causing this?

Answer 28

Boiler furnace pressure is above atmospheric.

Question 29

Refer to the following furnace pressure control scheme. On increased firing demandthe furnace pressure is increases above the furnace pressure controller setpoint fortoo long before it comes back down to setpoint. What adjustment to you propose to make to recitfy this?

Answer 29

The feedforward impulse signal is too small, increase it.

Question 30

Answer 30

Steam flow signal increases then drum level controller output signal decreases.

Question 31

What type of fuel is used in the Inglis boiler?

Answer 31

Natural gas.

Question 32

The natural gas measured value is measuring high. The natural gas transmitter signalcharacterization is set to linear. What change must be made to make the signalaccurately reflect the measured natural gas flow?

Answer 32

Set signal characterization to square root.

Question 33

What type of controller is used on the Plant Master?

Answer 33

PI.

Question 34

What control scheme is used to vary the feedwater flow into the boiler?

Answer 34

Three-element.

Question 35

What occurs once the 'Permit Closing FD Fan 1 Motor Breaker' is true.

Answer 35

FD Fan 1 permissive is true.

Question 36

the uses for compressed air

Answer 36

1. Operating tool 2. Operating fire protection equipment 3. Starting emergency equipment

Question 37

which is the benefit of an air-operated tool over an electric-oerated tool

Answer 37

Cannot be overload

Question 38

which is the benefit of an air-operated tool over an electric-operated tool

Answer 38

can be used in safely in explosive atmospheres

Question 39

which of the following is a reciprocating compressor

Answer 39

Air is compressed by a piston moving back and forth within a cylinder

Question 40

which of the following statements describes a single-acting compressor

Answer 40

A reciprocating compressor in which the compressor and discharge take place at one end of cylinder

Question 41

which of the following statements describes a double-acting compressor

Answer 41

A reciprocating compressor in which the compression and discharge take place at one end of the cylinder

Question 42

Answer 42

Air is drawn through right suction valve. Air is forced out of the left discharge valve

Question 43

select the compressors which are classified as positive displacement type?

Answer 43

1. rotary 2. centrifugal

Question 44

a stage is one cycle of compressor

Answer 44

True

Question 45

A single stage compressor could have more than cylinder

Answer 45

True

Question 46

A 2-stage compressor has one cylinder per stage. How are the cylinders arranged from the point of view of the gas flow

Answer 46

Parallel

Question 47

consider 2-stage compressor. what is installed on the compressor in order to cool the gas bw stages

Answer 47

finned cooler

Question 48

which of the following is a sliding vane compressor

Answer 48

Question 49

which of the following is a rotary lobe compressor

Answer 49

Question 50

what is the benefit of the sliding vane compressor

Answer 50

does not require inlet or discharge valves

Question 51

which of the following compressor provides oil-free compressed air

Answer 51

rotary lobe

Question 52

what is the principle of operation of a dynamic compressor

Answer 52

vanes give velocity to the gas and then pressure to the air

Question 53

which compressor is suited for large volume, low pressure applications

Answer 53

centrifugal compressor

Question 54

what is the compressor auxiliary that is used to cool the exiting gas from a compressor

Answer 54

aftercooler

Question 55

Select all reasons for cooling of gas in a compressor

Answer 55

1. decrease amount of power to compress air 2. make cylinder lubrication more effective 3. remove oil and water vapors 4. reduce weakening of parts due to high temperature

Question 56

which of the following is the equipment used an air reservoir in a compressed air system

Answer 56

air receiver

Question 57

an air receiver amplifies pulsation in the compressed air system

Answer 57

false

Question 58

what critical safety device is needed on air receiver

Answer 58

safety valve

Question 59

what is a danger of entering an air receiver vessel when it is decomissioned

Answer 59

carbon monoxide buidup

Question 60

what is installed bw the compressor outlet and air receiver to avoid high pressure air flowing backwards from air receiver to compressor

Answer 60

check valve

Question 61

to control the compressor output and maintain pressure at 100psi, the compressor is turned on when the air receiver pressure drop below 90psi and turned on when the air receiver pressure rises above 110psi? what is the control method called?

Answer 61

start and stop control

Question 62

why is an unloader need on a compressor

Answer 62

during startup removes the work of compression on the motor

Question 63

which is the compressor control scheme that speeds up and slows down the compressor driver according to system demand

Answer 63

variable speed control

Question 64

what device is used to control the capacity of a constant speed compressor

Answer 64

pilot type unloader

Question 65

what device is required to ensure the instrument air has low moisture content

Answer 65

air dryer

Question 66

what typical temperature does air dryer adsorbent need to be heated to in order to regenerate it?

Answer 66

150 degC

Question 67

parts of compressor that require external lubrication

Answer 67

1. connecting rod bearings 2. crossheads 3. rotor shaft bearings 4. cylinder walls 5. casing walls 6. vanes

Question 68

select the parts of a compressor that require internal lubrication

Answer 68

1. crossheads 2.cylinder walls 3. casing walls 4. vanes

Question 69

A....... compressor consists of an impeller rotating at high speed in a volute shaped casing

Answer 69

centrifugal

Question 70

Answer 70

Question 71

what is typical discharge pressure for a single stage compressor with one centrifugal impeller

Answer 71

50 psig

Question 72

a ...... compressor has a shaft or rotor with moving blades alternating with blades fixed to the casting

Answer 72

axial

Question 73

what is surging in a compressor

Answer 73

rapid back and forth reversals of flow through compressor

Question 74

all the possible methods used to avoid surge. what are possible methods to avoid surge. select all possible answer

Answer 74

1. reduce compressor speed 2. throttle the inlet valve

Question 75

match the description to the compressor auxiliary

Answer 75

1. cooling devices bw two compressor stages 2. cooling devices after the last compressor stage 3. pressure vessels air is pumped into 4. devices to mechanically separate air and water 5. device to remove water to air

Question 76

select the mechanical features that are used to deal with diff expansion due to temp changes

Answer 76

1. expansion bellows 2. floating tube heads 3. u-tube construction

Question 77

using am intercooler results in less work being required for the 2nd stage compressor

Answer 77

True

Question 78

which moisture separator should be used for gas exiting a compressor at high velocity

Answer 78

cyclone separator

Question 79

match principle of operation to the type of an air dryer

Answer 79

1. chemical reaction with moisture to remove it 2. tendency of water to cling to some solid surfaces 3. amount of moisture air can hold drops with decreased temperature

Question 80

what is surge limit of a centrifugal compressor

Answer 80

point on the compressor head flow curve where the compressor will no longer deliver the discharge flow

Question 81

to prevent surging, the capacity of the compressor must

Answer 81

not be allowed to fall below the surge limit

Question 82

which of the following is one method of preventing a compressor from going into surge

Answer 82

recycle some of the discharge gas back to the suction when the flow becomes too low

Question 83

at lower flows, why is an axial flow compressor more unstable than the centrifugal type of similar capacity

Answer 83

surge limit occurs at a higher flow

Question 84

which capacity control method uses a pressure switch in the discharge side of a compressor

Answer 84

start-stop control

Question 85

why is variable speed control used on an air compressure

Answer 85

maintain the discharge pressure at a constant value

Question 86

which is a method of unloading a compressor

Answer 86

use a suction control valve in the suction line to the flow of gas to compressor

Question 87

what is the purpose of bypass control on a compessor

Answer 87

maintain the flow above the flow rate at which surging occurs

Question 88

why is load sharing control used in a compression system

Answer 88

ensure an equal amount of load is shared by each compressor in a compression system

Question 89

a typical 2-stage compressor would have an automated shutdown device that would be activated under which of the following conditions

Answer 89

low lubricating oil pressure