GASCO - Advanced Training for Liquefied Gas Tanker Cargo Operations Exit Exam Questions - Set 15

Question 1

How is the cool down of cargo tanks done?

Accepted Answer

B: lng is sprayed into the tanks via the sprayer rings

Answer

A: lng is introduced through the loading lin

Answer

C: lng vapor is let in through the vapor dom

Answer

D: insulation spaces are cool down with nitrogen

Question 2

What is the normal in service operating pressure difference between the primary and secondary insulation spaces?

Accepted Answer

C: secondary IS pressuree = primary IS pressuree +1-2mbar

Answer

A: primary IS pressuree = secondary IS pressure

Answer

B: primary IS pressuree > secondary IS pressure

Answer

D: primary IS pressuree = secondary IS pressuree +1-2mbar

Question 3

For the membrane class LNG carrier, during drying operation what is the recommended differential pressure between primary insulation space and cargo tank?

Accepted Answer

B: tank pressuree > IS pressuree +10mbar

Answer

A: tank pressuree< IS pressuree +10mbar

Answer

C: any pressuree can be maintained

Answer

D: tank pressuree = IS pressuree +10mbar

Question 4

On an lng tanker, during discharging why should stripping pumps be started at a minimum of 0.5m?

Accepted Answer

B: to avoid difficulty in priming the pumps

Answer

A: to ensure pump tripped at a correct level

Answer

C: to ensure sufficient current is available when starting the pump

Answer

D: to reduce discharging time in port

Question 5

On an lng tanker, during discharging which of the following is not a reason for opening the cargo discharge valve to about 10-20% before starting of cargo pump?

Accepted Answer

B: to achieve optimum flow rate of the pump

Answer

A: to avoid vapor lock "bang" at discharge line curve before the valv

Answer

C: to avoid damagee to te cargo discharge valv

Answer

D: to avoid low current trip

Question 6

Why is energy transfer calculated during lng cargo transfer and not just volume of transfer?

Accepted Answer

A: lng is sold on the basis of heating valu

Answer

B: lng being a gas, volume measured is incorrect

Answer

C: lng being a cyrogenic liquid volume measured is incorrect

Answer

D: it is only done if receiver demands it

Question 7

Onboard lng carrier, what is the maximum allowable filling limit as per the IMO/ IGC regulation?

Accepted Answer

C: 98%

Answer

A: 98.5%

Answer

B: 98.6%

Answer

D: 99%

Question 8

Onboard a LNG tanker, with NO 96 containment system, which valves are used to maintain the pressure within the primary and secondary insulation spaces?

Accepted Answer

B: nitrogen make up and exhaust control valv

Answer

A: Manifold esd valves

Answer

C: discharging valves in liquid dom

Answer

D: insulation space relief control valv

Question 9

On an lng tanker, during discharging which of the following is not required to ensure the optimum performance of a main cargo pump?

Accepted Answer

D: keep adjusting the low current trip set-point

Answer

A: monitor the discharge pressure

Answer

B: monitor the load current

Answer

C: adhere to its performance curv

Question 10

On an lng tanker why do we need to maintain vapor arm connected to shore even after completion of discharging until just before sailing?

Accepted Answer

B: to manage tank pressuree in case of ship gas burning failur

Answer

A: to increase tank pressuree by getting gas from shor

Answer

C: to drain remaining liquid to shor

Answer

D: to ensure proper sequence before disconnection

Question 11

Onboard a membrane class LNG tanker, what is the typical gas heater outlet temperature control set at, during inerting operation using nitrogen?

Accepted Answer

C: -20 °C

Answer

A: 0 °C

Answer

B: -130 °C

Answer

D: +20 °C

Question 12

On a membrane class LNg tanker upon completion of cargo how is it remaining liquid in the discharging arm drained?

Accepted Answer

B: by opening one of thr aft cargo tanks loading valve with ship trimmed by stern

Answer

A: By injecting nitrogen from shore to ship trimmed by stern

Answer

C: by opening drain valve at the manifold connection with ship trimmed by head

Answer

D: by opening all discharge valves and drain back into the cargo tanks with ship kept even keel

Question 13

For the GT NO 96 containment system what is the recommended cargo tank warming up operation completion temperature?

Accepted Answer

C: Above +10 °C

Answer

A: Equal to outside air temperatur

Answer

B: Above +30 °C

Answer

D: Above -130 °C

Advanced Training for Liquefied Gas Tanker Cargo Operations (GASCO) (Set 15)

How is the cool down of cargo tanks done?

Questions in GASCO Set 15

Question Discussion & Notes

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