Hydrates, Emulsion & Compressors

Question 1

As the pressure of the system increases, the hydrate formation temperature:

a) Remains constant.
b) Increases.
c) Decreases.
d) Is dependent solely on the freezing point of water.

Answer 1

b) Increases.

Question 2

It is possible to predict the formation of hydrates in a gas line when the operator knows the gas lines:

a) Pressure and metal composition.
b) Pressure and temperature.
c) Temperature and metal composition.
d) Temperature and diameter.

Answer 2

b) Pressure and temperature.

Question 3

Freshly retrieved hydrates are:

a) Completely unaffected when exposed to atmospheric conditions.
b) Never ignitable.
c) Denser than water ice.
d) Very much like dirty ice or packed snow in appearance.

Answer 3

d) Very much like dirty ice or packed snow in appearance.

Question 4

Hydrates occur in two forms, referred to as Structure I and Structure II. Structure I hydrate formations consist of a smaller, cubic structure that can only accommodate:

a) Methane.
b) Ethane.
c) Hydrogen sulphide.
d) All of the above.

Answer 4

d) All of the above.

Question 5

Bottomhole chokes are a way of reducing hydrate problems downhole. A bottomhole choke is run on, or landed in, a landing nipple, near the:

a) Surface choke.
b) End of the producing tubing.
c) Heat string run alongside the production tubing.
d) Top of the producing tubing.

Answer 5

b) End of the producing tubing.

Question 6

Glycols are generally not used to dehydrate sour gas because:

a) They are ineffective in removing water vapour from sour gas.
b) They cause turbulence in the gas stream.
c) There are serious environmental concerns about their use.
d) They are non-corrosive.

Answer 6

c) There are serious environmental concerns about their use.

Question 7

Methanol is a desirable hydrate inhibitor because it:

a) Is non-toxic.
b) Is soluble in all proportions in water.
c) Requires no special care in handling or storage.
d) Has a vapour pressure less than water.

Answer 7

b) Is soluble in all proportions in water.

Question 8

In a conventional completion, a spring-loaded, side door choke assembly, and a glycol injection nozzle must be installed in the bottom of the tubing string above the packer:

a) After the tubing is run.
b) When the casing-tubing annulus is completely full.
c) Before the tubing is run.
d) Before the casing is placed in position.

Answer 8

c) Before the tubing is run.

Question 9

Ammonium carbonate will form when ammonia is added to gas streams containing more than 0.1 mole percent:

a) Carbon dioxide.
b) Hydrogen sulphide.
c) Butane.
d) Water.

Answer 9

a) Carbon dioxide.

Question 10

Hydrates can be formed from ___________ at elevated pressures and often at temperatures above 0°C (32°F ).

a) Gases.
b) Solids.
c) Liquids.
d) All of the above

Answer 10

a) Gases.

Question 11

Gas hydrates are complex compounds that contain:

Answer 11

Water, hydrocarbons and others substances such as hydrogen sulphide

Question 12

What problems do hydrate cause?

Answer 12

1. Plug pipes and instruments
2. Corrosion of equipment
3. Damage to pipelines
4. Accumulation of water which reduces the effective diameter of the pipe and lowers its capacity

Question 13

Freshly retrieved hydrates

Answer 13

Resemble dirty ice, are less dense than water ice, crackle when exposed to atm conditions, may be ignitable

Question 14

Prevention of hydrates

Answer 14

Rate of flow, proper P & T, gas dehydrator, control of turbulence

Question 15

Hydrate control

Answer 15

1. Hydrate Inhibitors: Methanol and Glycol
2. Ammonia
3. Application of heat

Question 16

Engines for gas compression services are usually equipped with which of the following engines protection shutdowns:

a) High lube oil pressure
b) Overspeed
c) Low jacket water temperature
d) Fuel Pressure

Answer 16

b) Over-speed

Question 17

In a natural gas powered engine used to run a compressor, the oil temperature is usually controlled by a ……………. that has the engine ………….. circulating through it.

a) shell and tube HE, crankcase oil
b) shell and tube HE, jacket water
c) Pipe coil HE, jacket water
d) Pipe coil HE, crankcase oil

Answer 17

b) shell and tube HE, jacket water

Question 18

When starting a gas compressor after the engine have been started, and the lubrication system has been checked, the next step in the sequence is to:

a) Increase the engine speed slightly when loading
b) Run the engine at slow speed
c) Shut the starting air supply valve
d) Reset the panel timer and turn the magneto switch to ON

Answer 18

a) Increase the engine speed slightly when loading

Question 19

One advantage of turbo charging an engine used to drive a compressor is that:

a) The thermal efficiency is improved but fuel consumption is increased
b) The total heat rejection to the jacket water is reduced approximately 30% less than a naturally aspirated engine
c) The thermal efficiency is improved and fuel consumption is reduced
d) The total heat rejection to the jacket water is increased approximately to 30% more than natural aspirated engine

Answer 19

a) The thermal efficiency is improved and fuel consumption is reduced

Question 20

Engines for gas compression services are usually equipped with which of the following engines protection shutdowns:

a) High lube oil pressure
b) High jacket water temperature
c) Low jacket water temperature
d) Variable speed

Answer 20

a) High lube oil pressure

Question 21

In an axial compressor, each pair of moving and fixed blades rows constitute:

a) A seal
b) An impeller shaft
c) A Stage
d) Pressure reduction

Answer 21

c) A Stage

Question 22

In an axial compressor, when the gas passes through the fixed blades, its pressure is further increased by conversion of:

a) Discharge rate
b) Velocity
c) Volume

Answer 22

b) Velocity

Question 23

One of the function of lubricant additives is to:

a) decrease effect of gas dilution
b) Promotes oxidation
c) Increase effect of gas dilution
d) Decrease wettability

Answer 23

a) decrease effect of gas dilution

Question 24

By definition, internal lubrication is not required by:

a) Rotary compressor vanes
b) Connecting rod bearings
c) Cylinder walls
d) Centrifugal compressors impellers

Answer 24

d) Centrifugal compressors impellers

Question 25

For external lubrication of reciprocating compressor using a pressure type of lubrication system, oil is:

a) Pumped from the crankcase to the bearings
b) Splash to the bearing using the movement of the crankshaft
c) Supplied directly to the feed stock within the compressor lines
d) Pumped from the bearings to the crankcase

Answer 25

a) Pumped from the crankcase to the bearings

Question 26

In large reciprocating compressors a mechanical lubricator that feeds oil directly to the cylinder is driven by the :

a) Compressor cylinder rods
b) Rings or a drive chain
c) Crankshaft
d) Crankcase bearings

Answer 26

c) Crankshaft

Question 27

Rod run-out is a term that describes the normal lineal motion of the piston rod within the compressor cylinder

a) True
b) False

Answer 27

b) False

Question 28

In the channel type compressor valve, the gas enters to the ——– plate, pushes the channel up off the seat plate against the springs and then passes through the openings in the ———– plate

a) Stop, Port
b) Upper, valve
c) Port, stop
d) Lower, valve

Answer 28

c) Port, stop

Question 29

Liquid carryover from a compressor can be minimized by:

a) An adequate knock out drum or separator located as close to the cylinder as possible
b) A change in springs, plate thickness, material or valve lift
c) Steam trace in the compressor discharge line
d) Removing the insulation from the lines between compressor cylinders

Answer 29

a) An adequate knock out drum or separator located as close to the cylinder as possible

Question 30

Compressor suction valves failures or gaskets leakages:

a) It is difficult to determine because of the normally high temperatures involved
b) Can be determined by feeling the suction valve cover
c) Should be corrected at the next regular service interval
d) It is difficult to determine because of the line pressure pulsations

Answer 30

b) Can be determined by feeling the suction valve cover

Question 31

The major cause of packing failure is

a) The amount of plastic used in packing
b) Freedom of packing movement in the cylinder
c) Incorrect fitting of the packing
d) Pressure breakers rings

Answer 31

c) Incorrect fitting of the packing

Question 32

When a hydrate plug is suddenly released, the result can be _________and subsequent accidents and equipment damage

a) Freezing of lines
b) Line failure
c) Void space in the host molecules
d) Evaporation

Answer 32

b) Line failure

Question 33

When bleeding pressure off a line block by a hydrate plug:

a) Reduce the pressure, equally, on both sides of the line
b) Ensure that any bends in the bleed lines are unrestrained and free to move at all points where the line change directions
c) Move the hydrate plug by increasing or decreasing the pressure on one side of the plug
d) All short nipples should be removed upstream from the bleed valve before relieve the pressure through the lines

Answer 33

a) Reduce the pressure, equally, on both sides of the line

Question 34

When obtaining a representative sample of liquid for determining BS&W, the sample should:

a) Be allowed to age and settle down
b) Be taken as far as possible from the test water
c) Be taken as close to the test meter as possible
d) Not to be heated to treater operating temperature before spinning

Answer 34

a) Be allowed to age and settle down

Question 35

In a single acting reciprocating gas compressor, compression takes place:

a) At both end of the cylinder at the same time
b) At one end of the cylinder only
c) Before the gas enters the cylinder intake valve
d) Alternately at both ends of the cylinder

Answer 35

b) At one end of the cylinder only

Question 36

The classification of gas compressor best suited for high flow applications is the:

a) Reciprocating
b) Rotary displacement
c) Centrifugal
d) Plunger

Answer 36

c) Centrifugal

Question 37

With the dynamic class of gas compressor:

a) A definite amount of gas is compressed for every stroke or revolution
b) The velocity of the gas is converted to pressure in a diffusing section
c) There are two general types: reciprocating and rotary
d) The gas is compressed by the pushing action of pistons, vanes or lobes

Answer 37

b) The velocity of the gas is converted to pressure in a diffusing section

Question 38

The primary purpose of the internal intake and discharge valves on a reciprocating compressor is to:

a) Control the flow of cooling water around the cylinder
b) Isolate the compressor during maintenance
c) Control the flow of gas entering and leaving the cylinder
d) Control the temperature of the gas inside the cylinder

Answer 38

c) Control the flow of gas entering and leaving the cylinder

Question 39

There is only one compression stroke for every crankshaft or flywheel in a/an:

a) Single acting compressor
b) Double-acting compressor
c) Angle type multi crank configuration
d) Dynamic compressor

Answer 39

a) Single acting compressor

Question 40

In a compressor that uses the balanced/opposed cylinder configuration, the cranks are arranged so that:

a) All pistons are always moving in the direction
b) No piston movement is required
c) Opposite piston are always moving in the same direction
d) Opposite pistons are always moving in opposite direction

Answer 40

d) Opposite pistons are always moving in opposite direction

Question 41

The surge limit of a centrifugal compressor is the:

a) maximum capacity that the compressor will deliver at any given pressure
b) Point at which the suction pressure is greater than the discharge pressure
c) Point on the pressure-volume curve where the compressor will no longer deliver discharge
d) Absolute maximum pressure that can be developed by the compressor

Answer 41

***c) Point on the pressure-volume curve where the compressor will no longer deliver discharge

Question 42

You are working in a gas plant when an alarm indicates that the capacity of the #3 compressor is about to fall below surge point. The compressor is an axial flow type. To correct this before surging begins, you:

a) Close the discharge line blow-off valve to the suction side
b) Open the discharge line blow-off valve to the suction side
c) Open a suction line blow-off valve to the discharge side
d) Close a suction line blow-off valve to the discharge side

Answer 42

b) Open the discharge line blow-off valve to the suction side

Question 43

The type of control used in centrifugal type compressors to ensure that the compressor is always loaded to above the flow rate at which surging starts is called a:

a) Variable speed control
b) Valve unloader
c) Bypass control
d) Clearance pocket

Answer 43

c) Bypass control

Question 44

VFD units are utilized with:

a) Internal combustion engines
b) Electric motors
c) Gas turbines
d) Steam turbines

Answer 44

***b) Electric motors

Question 45

Side steam compressors are popular in process gas streams on flows from economizers in refrigeration compression. The compressors are ________ centrifugal compressors.

a) Single stage
b) Two-stage
c) Reciprocating
d) Four-stage

Answer 45

***b) Two-stage

Question 46

Because their configuration provides a _________ the use of horizontal allows for optimal release of trapped gas

a) Superior control of process temperatures
b) Greater surface area
c) Reduced surface area
d) Greater degree of level control

Answer 46

***b) Greater surface area

Question 47

The large surface area provided within a horizontal separator allows for:

a) Optimum released of trapped gas
b) Optimum retention of trapped gas
c) Ease of liquids level control
d) Lower equipment cost when compared to vertical separators

Answer 47

***a) Optimum released of trapped gas

Question 48

Inter-coolers are never equipped with safety valves, pressure gauges and thermometers or compressed gas and cooling water piping

a) True
b) False

Answer 48

b) False

Question 49

The inlet nozzle in the primary section of separator vessels is designed to take advantage of the effects of the:

a) Centrifugal force of the inlet stream
b) Centripetal force of the inlet stream
c) gravitational forces within the compartment
d) Centrifugal force of the discharge stream

Answer 49

***a) Centrifugal force of the inlet stream

Question 50

A header is installed in the gas outlet downstream of a scrubber to;

a) Provide a final collection spot for any liquids carried over from the scrubber
b) Keep the pressure entering the compressor as low as possible
c) Allow equal distribution of the gas to more than one compressor
d) Reduce the velocity of the gas between the scrubber and the compressor

Answer 50

*** a) Provide a final collection spot for any liquids carried over from the scrubber

Question 51

One theory regarding the effect that chemical reagents have on emulsions assumes that the chemical makes the film of emulsifying agent elastic, around the water droplet, and causes the film to have a very high coefficient of expansion.

a) True.
b) False.

Answer 51

b) False.

Question 52

When electricity is used to treat emulsions, the electric field created causes the emulsion particles to:

a) Lose their charge.
b) Be mutually attractive.
c) Dispersed in tiny droplets.
d) Be mutually repulsive.

Answer 52

b) Be mutually attractive.

Question 53

After the bottle test has been made, the chemical pump is adjusted until it adds chemical in the ratio indicated by the bottle test. If the bottle test indicated one chemical to be added at the rate of 0.6 mL of 2% solution per 100 mL of emulsion, that has to be expressed in terms of litres of chemical and cubic meters of emulsion. In operating conditions at the lease, that ratio would equal:

a) 12 L of chemical per 100 m3 of emulsion.
b) 6 L of chemical per 100 m3 of emulsion.
c) 1.2 L of chemical per 100 m3 of emulsion.
d) 60 L of chemical per 100 m3 of emulsion.

Answer 53

a) 12 L of chemical per 100 m3 of emulsion.

Question 54

When performing a bottle test, the sample should be:

a) Agitated and heated to 100ºC regardless of lease conditions.
b) Allowed to age and settle out.
c) Accumulated from sampling points downstream of the point of chemical injection.
d) As fresh as possible.

Answer 54

b) Allowed to age and settle out.

d) As fresh as possible.

Question 55

In addition to the equipment used in the bottom sediment and water test, all of the following pieces of equipment are required to perform a bottle test except:

a) Demulsifying compounds.
b) A hydrometer.
c) One graduated 2 mL syringe.
d) A water bath, with thermostatic control.

Answer 55

b) A hydrometer.

Question 56

When preparing a 2% solution of treating compound, a choice of solvent must be made. Although it has been used, kerosene is not recommended because:

a) A large number of demulsifying agents are insoluble in it.
b) In warm weather, it is too volatile.
c) It must be cut with up to 25% methanol.
d) In cold weather, the solution may crystallize.

Answer 56

a) A large number of demulsifying agents are insoluble in it.

Question 57

7. To break down a petroleum emulsion, the properties of the emulsifying agent must be: (choose all that apply)

a) Negated.
b) Destroyed.
c) Neutralized.
d) Both b and c.

Answer 57

d) Both b and c. (Destroyed and Neutralized)

Question 58

8. When conducting a bottle test, you need to ensure that the sample used be:

a) As fresh as possible.
b) At least 12 hours old.
c) Representative of the past 48-hours of flow.
d) Aged 24 hours before testing

Answer 58

a) As fresh as possible.

Question 59

Why is kerosene not recommended as a solvent in preparing a 2% solution of treating compound?

a) Because some solutions deteriorate to one-half the treating efficiency within thirty days.
b) Because in cold weather the solutions may crystallize.
c) Because in warm weather, it is too volatile.
d) Because it contains a large number of demulsifying agents that are insoluble.

Answer 59

d) Because it contains a large number of demulsifying agents that are insoluble.

Question 60

When taking 0 to 10% BS and W samples with 100 ml centrifuge tubes, the water-cut is determined by:

a) Recording the difference in readings between the two tubes.
b) Adding the readings of both tubes together.
c) Recording the reading from the tube with the highest reading.
d) Recording the reading from the tube with the lowest reading.

Answer 60

b) Adding the readings of both tubes together.

Question 61

A gas compressor that gives two compression strokes for every crank shaft revolution is the:

a) Multicrank two cylinder configuration.
b) Dynamic compressor.
c) Single cylinder, double-acting compressor.
d) Single acting compressor

Answer 61

c) Single cylinder, double-acting compressor.

Question 62

The classification of gas compressor best suited for high flow, low pressure applications is the:

a) Reciprocating.
b) Rotary displacement.
c) Centrifugal.
d) Axial.

Answer 62

b) Rotary displacement.

Question 63

The classification of gas compressor best suited for high flow, low pressure differential applications is the:

a) Reciprocating.
b) Rotary displacement.
c) Centrifugal.
d) Axial.

Answer 63

d) Axial.

Question 64

The classification of gas compressor best suited for all flows and pressures is the:

a) Reciprocating.
b) Rotary displacement.
c) Centrifugal.
d) Axial.

Answer 64

a) Reciprocating.

Question 65

The two general types or designs of dynamic class gas compressors include:

a) Rotary and axial flow.
b) Centrifugal and reciprocating.
c) Axial and rotary.
d) Axial and centrifugal.

Answer 65

d) Axial and centrifugal.

Question 66

The type of gas compressor commonly used as a booster in the gas processing industry is the:

a) Rotary displacement.
b) Reciprocating.
c) Axial.
d) Centrifugal.

Answer 66

b) Reciprocating.

Question 67

An axial flow compressor is more unstable than the centrifugal type, as its:

a) Recycle valve is equipped with a positioner to minimize stroking time
b) Surge limit occurs at lower flows
c) Output is controlled by flow transmitters
d) Surge limit occurs at higher flows

Answer 67

d) Surge limit occurs at higher flows

Question 68

A pressure switch in the discharge side of a compressor is used to activate the:

a) Surge control
b) Stop/start control
c) Bypass control
d) Variable speed control

Answer 68

b) Stop/start control

Question 69

A variable speed control is used to:

a) Maintain the discharge pressure at a constant value
b) Shut down the compressor when little or no air is required by the system
c) Sense the pressure in the discharge side of the compressor
d) Run the compressor driver at constant speed at all times

Answer 69

a) Maintain the discharge pressure at a constant value

Question 70

One method of unloading a compressor is to:

a) Use a suction control valve in the suction line to restrict the flow of gas to the compressor
b) Use a regulator in the steam supply to the steam turbine
c) Use a control valve in the discharge line to restrict the flow of gas to the compressor
d) Hold the compressor suction valves in the closed position

Answer 70

a) Use a suction control valve in the suction line to restrict the flow of gas to the compressor

Question 71

The bypass control ensures that the compressor is always loaded to:

a) Below the flow rate at which surging starts
b) Maximum capacity
c) Above the flow rate at which surging starts
d) Minimum capacity

Answer 71

c) Above the flow rate at which surging starts

Question 72

The surge limit of a centrifugal compressor is the:

a) Maximum capacity that the compressor will deliver at any given pressure
b) Point at which the suction pressure is greater than the discharge pressure
c) Point on the pressure-volume curve where the compressor will no longer deliver to the discharge
d) Absolute maximum pressure that can be developed by the compressor

Answer 72

***d) Absolute maximum pressure that can be developed by the compressor

Question 73

A typical two-stage compressor is not normally equipped with a:

a) High lube oil temperature shutdown
b) High lube oil pressure shutdown
c) High intercooler temperature alarm
d) High discharge gas pressure alarm

Answer 73

b) High lube oil pressure shutdown

Question 74

A typical two-stage compressor would have an automated shutdown device that would be activated under the following condition:

a) Low lubricating oil temperature
b) High lube oil pressure
c) Low lubricating oil pressure
d) High lubricating oil level

Answer 74

c) Low lubricating oil pressure

Question 75

To prevent surging, the capacity of the compressor must:

a) Be below the surge limit
b) Not be allowed to fall below the surge limit
c) Not produce a pressure equal to that in the system
d) Be shut down immediately

Answer 75

b) Not be allowed to fall below the surge limit

Question 76

One method of preventing a compressor from going into surge is to:

a) Recycle some of the discharge gas back to the suction when the flow becomes low
b) Throttle in the discharge valve and create a higher backpressure on the compressor
c) Throttle in the suction to the compressor to prevent the pressure from becoming too high
d) Open a vent to atmosphere when the compressor gets close to maximum capacity.

Answer 76

a) Recycle some of the discharge gas back to the suction when the flow becomes low

Question 77

The connecting rods of a reciprocating compressor are constructed of:

a) Stainless steel.
b) Cast iron.
c) Forged steel.
d) Aluminum.

Answer 77

c) Forged steel.

Question 78

In the disc type compressor valve the gas enters through:

a) The ribbed upper body.
b) The port plate.
c) The ribbed lower body.
d) The stop plate.

Answer 78

a) The ribbed upper body.

Question 79

The reciprocating compressor running gear component that transmits the rotational motion of the crankshaft into linear motion is called the:

a) Piston rod.
b) Crosshead.
c) Connecting rod.
d) Piston.

Answer 79

c) Connecting rod.

Question 80

The reciprocating compressor running gear component that has a threaded hole in one end into which the piston rod fits is called the:

a) Crosshead.
b) Crank shaft.
c) Connection rod.
d) Cylinder.

Answer 80

a) Crosshead.

Question 81

The reciprocating compressor running gear component that is supported by the main bearings is called the:

a) Frame.
b) Crank shaft.
c) Crosshead.
d) Cylinder

Answer 81

b) Crank shaft.

Question 82

The reciprocating compressor running gear component that attaches the piston to the crosshead is called the:

a) Crank shaft.
b) Connecting rod.
c) Piston rod.
d) Frame.

Answer 82

c) Piston rod.

Question 83

In high-pressure ratio and high differential pressure applications which valve type is most commonly used?

a) Plate or disc type.
b) Strip type.
c) Poppet type.
d) None of the above.

Answer 83

a) Plate or disc type.

Question 84

In sliding vane rotary compressors, a pressure lubricator supplies the oil and may discharge the oil:

a) Along the cylinder walls.
b) Into the gas discharge.
c) To the rings or a drive chain.
d) Into the gas intake.

Answer 84

d) Into the gas intake.

Question 85

The lubrication supply for crankshaft bearings, connecting rod bearings and crosshead on reciprocating compressors, as well as rotor shaft bearings on rotary and dynamic compressors is an ____________ type.

a) Internal.
b) External.
c) None of these.
d) Either of these

Answer 85

b) External.

Question 86

In reciprocating compressors where a pressurized lubrication delivery system is used, a pump driven by the ________________ delivers oil to the crankshaft and connecting rod bearings.

a) External driver.
b) Compressor shaft.
c) Valve unloader.
d) Casing.

Answer 86

b) Compressor shaft.

Question 87

In a sliding vane compressor where the oil supplied by a pressure lubricator discharges into the gas intake, the oil:

a) Is carried by the gas to the rotating vanes.
b) Is splashed onto the cylinder walls.
c) Is spread by the cylinder head.
d) Is discharged to the crankcase.

Answer 87

a) Is carried by the gas to the rotating vanes.

Question 88

The “wetability” of a lubricant refers to:

a) The lubricants ability to resist the thinning effect caused by increasing oil temperature.
b) The lubricants ability to adhere to metal surfaces.
c) The lubricants ability to decrease friction.
d) The lubricants ability to inhibit oxidation.

Answer 88

b) The lubricants ability to adhere to metal surfaces.

Question 89

Lubrication is a vital part of compressor operation aimed at:

a) Sealing and corrosion reduction.
b) Reducing wear caused by friction.
c) Eliminating friction and wear.
d) Shock absorption and wear reduction.

Answer 89

b) Reducing wear caused by friction.

c) Eliminating friction and wear.

Question 90

Internal lubrication of a reciprocating compressor refers to:

a) Lubrication of the cylinder valves.
b) Lubrication of the stuffing box.
c) Lubrication of the cylinder walls and pistons.
d) Lubrication of the vanes and casing walls.

Answer 90

c) Lubrication of the cylinder walls and pistons.

Question 91

One of the functions of lubricant additives is to:

a) Increase effects of gas dilution.
b) Increase the lubricant pour point.
c) Decrease detergency.
d) Depress the lubricant pour point.

Answer 91

d) Depress the lubricant pour point.

Question 92

In a force-feed lubrication system, the system must be designed to provide _________________ to force feed the lubricator or pump.

a) A gravity feed.
b) Negative pressure.
c) Positive pressure.
d) Mechanical energy.

Answer 92

d) Mechanical energy.

Question 93

The “lubricity” of a lubricant refers to:

a) The lubricants ability to reduce gas dilution.
b) The lubricants ability to resist the thinning effect caused by increasing oil temperature.
c) The lubricants ability to adhere to metal surfaces.
d) The lubricants ability to decrease friction.

Answer 93

d) The lubricants ability to decrease friction.

Question 94

In the plate disc type valve, the gas enters through the ribbed upper valve body and forces the valve discs:

a) Up against the cushioning action of the spring.
b) Up off the seat plate.
c) Down against the cushioning action of the spring.
d) Through the port plate.

Answer 94

c) Down against the cushioning action of the spring.

Question 95

In the channel type valve, strips of self-lubricating material are placed within the channels to:

a) Allow metal-to-metal contact between the channels and the valve springs.
b) Prevent metal-to-metal contact between the channels and the valve springs.
c) Force the valve discs down against the cushioning action of the spring.
d) Force the valve discs up away from the cushioning action of the spring.

Answer 95

b) Prevent metal-to-metal contact between the channels and the valve springs.

Question 96

To prevent condensation in the cylinder suction port or cylinder bore, cooling jacket water should be maintained above gas suction temperature at a minimum of:

a) The same temperature as the incoming gas temperature.
b) 10ºC below the incoming gas temperature.
c) 100ºC above the incoming gas temperature.
d) 10ºC above the incoming gas temperature.

Answer 96

d) 10ºC above the incoming gas temperature.

Question 97

On multistage compressors, a rise in interstage pressures indicates that:

a) There is a problem in the lower (upstream) stage.
b) There is a problem in the next higher (downstream) stage.
c) The discharge temperature from the upstream cylinder is too high.
d) The discharge temperature from the upstream cylinder is too low.

Answer 97

a) There is a problem in the lower (upstream) stage.

Question 98

On multistage compressors, a drop in interstage pressures indicates that:

a) There is a problem in the lower stage cylinder.
b) There is a problem in the next higher (downstream) stage.
c) The discharge temperature from the downstream cylinder is too high.
d) The discharge temperature from the upstream cylinder is too low.

Answer 98

a) There is a problem in the lower stage cylinder.

Question 99

To aid in determining the required frequency of strainer cleaning, pipeline filters should be equipped with a:

a) Knockout storage drum.
b) Gas line heater.
c) Differential pressure gauge.
d) Decompression cylinder.

Answer 99

c) Differential pressure gauge.

Question 100

The main purpose of mechanical packing in a reciprocating compressor is to seal the rod to:

a) Prevent the high-pressure gas in the cylinder from escaping.
b) Allow the high-pressure gas in the cylinder to escape to prevent cylinder wear.
c) Prevent lube oil from the piston rod from entering the cylinder.
d) Prevent cooling jacket water from mixing with the cylinder lube oil at the piston rod.

Answer 100

a) Prevent the high-pressure gas in the cylinder from escaping.

Question 101

In selecting mechanical packing material, condition of the rod and the surface finish on the rod are minor considerations.

a) True.
b) False.

Answer 101

b) False.

Question 102

Provided there is no shut-off valve between an aftercooler and an air receiver, a safety valve on the aftercooler is unnecessary.

a) True
b) False

Answer 102

b) False

Question 103

Gas compressor intercoolers should be equipped with:

a) A safety valve
b) Mist extractors
c) Vents
d) A coalescing section

Answer 103

a) A safety valve

Question 104

To reduce the gas temperature between states of a gas compressor ___________ is utilized.

a) A mist extractor
b) An intercooler
c) A separator
d) An aftercooler

Answer 104

b) An intercooler

Question 105

Intercooling involves:

a) Cooling the gas by water injection.
b) Cooling the gas following the completion of compression.
c) Cooling the gas between stages of compression.
d) Cooling the gas before compression.

Answer 105

c) Cooling the gas between stages of compression.

Question 106

Which of the following is not a result of cooling the gas with an intercooler and/or aftercooler:

a) More effective cylinder lubrication
b) Reduces weakening of parts due to high temperatures
c) Removal of water and oil vapours from the gas stream
d) Increased the amount of power required to compress the gas

Answer 106

d) Increased the amount of power required to compress the gas

Question 107

Large, multi-stage gas compressors are usually configured in a _______________ arrangement to aid in balancing residual axial thrust forces.

a) Double-flow
b) Side-by-side
c) Front-to-back
d) Back-to-back

Answer 107

d) Back-to-back

Question 108

An engine exhaust temperature controller is affected by:

a) Fuel gas consumption.
b) Crankcase pressure.
c) Air-to-fuel ratio.
d) Lube oil pressure.

Answer 108

c) Air-to-fuel ratio

Question 109

A naturally aspirated integral engine has which of the following components in its fuel system?

a) A carburetor.
b) An atomizer.
c) A vaporizer.
d) A fuel-mixing valve.

Answer 109

a) A carburetor.

Question 110

The most widely used compressor driver in the low power range is the:

a) Squirrel cage induction motor.
b) Steam turbine.
c) Gas turbine.
d) Synchronous motor.

Answer 110

a) Squirrel cage induction motor.

Question 111

A turbocharger may increase the output of a given engine by as much as:

a) 15%.
b) 50%.
c) 30%.
d) 90%.

Answer 111

b) 50%.

Question 112

A turbocharger is driven by:

a) A separate motor.
b) Engine lubricating oil pressure.
c) The exhaust gas of the engine.
d) Belts connected to the engine crankshaft.

Answer 112

c) The exhaust gas of the engine.

Question 113

Idling an engine for a few minutes prior to total shutdown avoids:

a) Warping engine crankshafts.
b) Warping engine intake valves.
c) Warping engine camshafts.
d) Warping engine exhaust valves

Answer 113

d) Warping engine exhaust valves

Question 114

Compressor cylinders operating on bypass may:

a) Heat up.
b) Cause hydrates to form.
c) Damage the governor.
d) Result in warping cylinder parts.

Answer 114

a) Heat up.

Question 115

A compressor log book should include:

a) Readings such as temperatures and pressures.
b) Details of maintenance work.
c) Any unusual conditions experiences.
d) All of the above.

Answer 115

d) All of the above.

Question 116

In plants where steam is readily available for plant use, a ______________ that uses ________________ rate is used.

a) Single stage turbine, low steam.
b) Single stage turbine, high steam.
c) Multistage turbine, low steam.
d) Multistage turbine, high steam.

Answer 116

c) Multistage turbine, low steam.