GASCO exit exam questions and answer quiz contain questions Answer
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When the nitrogen generator remains in the
"purge mode" it means that the nitrogen produced is
Supplied continuously to cargo area
Vented continuously
to atmosphere.
Continuously supplied to gas burning system
Re-circulated continuously within the nitrogen generator
Onboard an LNG Tanker, while vaporizing during
cargo discharge using the main vaporizer, what is the approximate desired
outlet temperature of LNG vapour?
-140°C
-130°C
-150°C •
-120°C
When the nitrogen generator remains in the
"purge mode" it means that the nitrogen produced is Supplied continuously to cargo area
Supplied continuously to cargo area
Vented continuously
to atmosphere.
Continuously supplied to gas burning system
Re-circulated continuously within the nitrogen generator
Advantages of
reliquefaction planton LNG tankships will not include,
Total quantity of LNG loaded can be delivered to the customer
Reduction in heel required on ballast voyage
Lower SOx and NOx
emissions
Proven technology and easy availability of crew
What should the
ship be provided with to enable an LNG Tanker to change LNG liquid to LNG
vapour?
Heater
Vaporizer
Low duty (LD) compressor
High duty (HD) compressor
What happens when,
in an air dryer plant, the seawater flow into refrigerant condenser is
insufficient?
Air over cooled at refrigerant condenser output
Air not cooled enough
at refrigerant condenser output •
Moisture in air frozen at refrigerant condenser output
Refrigerant condenser output not affected at all
In an Air Dryer
plant, which of the following is not one of its uses?
Supply air to pressurize water ballast tanks to empty flooded ballast tanks after grounding
Maintain a non-corrosive atmosphere in the tanks when they are open for long periods
Supply air to
ventilate the accommodation
Aerate the cargo tanks, which naturally must be done prior to inspection or maintenance
Your vessel has completed loading and is
ready for gauging. Which of the following should you ensure?
All personnel should be onboard and ready in their departure stations
Custody transfer system should be closed and isolated In the presence of shore representatives
All cargo systems on
the ship should be closed and the shore connections isolated or disconnected
Cargo system valves should be lined - up to fill the largest tank in the ship to allow topping – up
What is the least a person should do before
entering machinery spaces?
Wear appropriate
personal protective equipment
Inform the bridge
Inform his superiors
Gas pressurizes the liquid out of the soda
acid type- water extinguisher through the dip tube.
hydrogen
oxygen
nitrogen
carbon-dioxide
Smoke detectors
are activated when,
the density of smoke
or tiny particles created by the fire are high <
the density of smoke creates an obstruction
the smoke particles come in the way of light
What is the typical dew point of dry air used
for aerating?
+ 55°C to +65°C
-55°C to -65°C
-140°C to -165°C
Same as atmospheric air
What is the main reason for a membrane class
LNG tanker to retain a small quantity of cargo ("heel") during
ballast passage?
To ensure easy starting of cargo pump at loading port
To reduce the consumption of heavy fuel oil on passage
To avoid bottom of the cargo tank coming into contact with oxygen
For cold maintenance
of the cargo
If an LNG sale
document was marked as Cost, Insurance, Freight (CIF), after discharge who
would be the owner of the 'heel' retained onboard?
The buyer owns all
the cargo including heel less normal boil - off
The heel belongs to the seller
The seller has owns the heel less normal boil-off
The buyer owns only the cargo less normal boil-off
What is the main danger
when discharging a damaged cargo tank in a normal manner?
Discharging pump will trip due to debris in the tank
Discharging time will be shorter due to less cargo in the tank
Collapse of secondary membrane due to high differential head
Collapse of the
primary membrane due to high differential head
Which of the
following is not a sign of an LNG gas (vapor) leak into insulation spaces?
Comparing to normal trends - high temperature variations on barrier spaces
Increase of pressure in insulation spaces
Icing of sea water
outside hull when ship at anchor
Sudden rise in percentage of methane vapour in insulation spaces
How can we deal with a minor cargo spill
(leak) from valve flanges or glands?
By bandaging the leak area with cotton rags and spraying it with freshwater
By using bonding tape and seal
By using cryogenic foam
By using bonding cream and seal
What is the
definition for the term "minor failure of membrane?
Activation of gas detection equipment for insulation despite of purging with nitrogen
Fatigue cracks develop with obvious signs of pressure rise and the presence of methane vapor
Porosity of membrane which allows limited liquid into insulation spaces
Minor fatigue cracks,
passing liquid into the insulation space and becomes gaseous
During a cargo handling operation which of
the following precautions need not be observed to deal with spillage?
Fire fighting equipment on standby mode
Manifold shipside water spray curtain used
Ship cordoned off
with LNG containment boom
Deck fire main on standby mode
If insulation damage occurs, how does filling
the ballast tanks with sea water help in maintaining the hull steel
temperature?
Through slow heat transfer, as sea water conducts heat better than air
Through better heat
transfer, as sea water conducts heat better than air
Due to the improved that transfer to outside sea at ambient temperature
As sea water temperature is much lower than LNG temperature, thus helping the heat transfer
Onboard an LNG
carrier, with NO 96 containment system, what will happen when pressure inside
primary space is equal to cargo tank pressure?
Primary barrier strips will be shifted from its original position
Primary barrier will be pressed hard onto primary insulation box
Primary barrier will collapse inward
Nothing will happen -
no damage to primary barrier
What is the
protection available for the auxiliary cargo pump against frequent start and
stop action?
High discharge pressure alarm
No number of starts
No limits of start and stop
Only certain number
of starts allowed
Onboard a
membrane class LNG tanker, during purging cargo tanks with LNG, what is the
target value for completion of purging or gassing up operation?
Methane content >5% by volume
Methane content >21% by volume
Methane content >
80% by volume
Methane content > 10% by volume
Which insulation
space should be evacuated first to prevent possibility of membrane failure?
Primary space first; thereafter secondary spaces
Secondary spaces
first; thereafter primary spaces
Both insulation spaces at the same times
Evacuate cargo tank space first then secondary spaces
What is the
typical dew point of dry air used for aerating?
+ 55°C to +65°C
-55°C to -65°C
-140°C to -165°C
Same as atmospheric air
Which equipment
is used for evacuating the insulation spaces?
Vacuum pumps
HD blowers
LD blowers
Water ballast ejector
Onboard an LNG
tanker, during gas burning, what is an option available if LD compressor is out
- of - service during gas burning?
Gas burning shall be stopped
Tank pressure shall be dropped via venting each cargo tank
Gas burning can be
continued via "free - flow"
Steam dump shall be manually controlled throughout the operation
Onboard an LNG
carrier, what is the objective of purging or gassing - up with LNG vapor prior
to cool down?
To initiate cool down cargo tanks prior loading
To clear dust and foreign particles in the tank
To remove any gases
such as CO2 that may freeze
To rest cargo tanks' cryogenic properties
Onboard an LNG
tanker, during gas burning, what is the typical temperature range at the heater
outlet to the boilers?
4-20° C to 4-30° C
-20° C to -30° C
-20° C to o°C
+5°C to —5°C
A soda acid type-
water extinguisher containssolution in the container.
sodium-carbonate
sodium-sulphate
sodium-nitrate
sodium-bicarbonate
