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Home Online tests Test about Handling Nitrogen onboard Chemical Tankers
Online testing: Test about Handling Nitrogen onboard Chemical Tankers
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The test consists of 80 random questions.
Total questions on this topic: 93
Total questions on this topic: 93
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Click on the boxes next to the two main reasons behind the use of nitrogen on chemical tankers:
Answer
You have just completed loading 450 tonnes of Caustic Soda to two tanks on your vessel and will be trading to NW Europe with an ETA Rotterdam of December 6th. What would be a prudent operational measure to carry out?
Additional line blowing.
Additional sampling.
Additional venting.
Additional ballasting.
What is “dew point”?
The temperature at which a gas is saturated with respect to a condensable component.
The temperature at which a condensable component is saturated with respect to a gas.
The temperature at which a saturated gas becomes in ambient.
The temperature at which dry-ice melts in acetone.
What size of cargo tank would cause special inerting requirements (as listed under the 2 000 Amendments to the SOLAS 1974 Protocol) to be implemented on a chemical tanker carrying low-flash products?
5 000 cubic meters.
3 000 cubic meters.
2 000 cubic meters.
1 000 cubic meters.
If a cargo additive is oxygen dependent and prolonged blowing of a cargo hose with nitrogen takes place, what may happen?
The efficiency of the additive will be increased.
The efficiency of the additive may be significantly reduced.
Immediate polymerization will occur around the cargo pump.
The colour of the cargo will be affected.
Click on the boxes next the correct reasons for cleaning a hose prior to disconnection:
Answer
Under normal circumstances, gas moves through a pipeline more easily than liquid. True or False?
True.
False.
Which regulations detail the requirements for the control of tank atmospheres in compartments containing chemicals?
The ICS Tanker Safety Guide (Chemicals).
SOLAS 1974.
The IBC Code.
ISGOTT.
Purging is defined by which of the following statements?
The filling of a cargo tank and associated piping systems, or the spaces surrounding a cargo tank, with a saturated gas or vapour which will not support condensation and which will not react specifically with the cargo, and maintaining that condition.
The filling of a cargo tank and associated piping systems, or the spaces surrounding a cargo tank, with a gas or vapour, which will not support combustion and which will not react with the cargo and maintaining that condition.
If a ship enters a channel, where the water is relatively cold and still, what may occur in the cargo tanks?
Desorption in the upper area of the wing tanks.
Steam emission.
Evaporation on the bulkheads.
Sweating of the bulkheads.
The term “Asphyxiates” is applied to:
All oxygen dependent inhibitors.
Inerting techniques on chemical tankers.
All inert gases.
All cargoes with a high evaporation rate.
Click on the boxes to indicate the main types of nitrogen system, which may be encountered aboard a chemical tanker:
Answer
When purging a cargo tank with nitrogen, the critical relationship is:
Tank capacity measured against nitrogen supply rate.
Liquid flow in versus liquid flow out.
Rate of nitrogen supply measured against cargo pump capacity.
Rate of nitrogen flow in versus capacity of venting system out.
The MARPOL 73/78 regulations require chemical tankers of 30 000 dwt and over to inert all cargo tanks containing petroleum products with a flash point of 60 °C and less. True or False?
True.
False.
When maintaining a nitrogen pad on passage, a daily application will involve:
Low pressure and high volume.
High pressure and high volume.
Low pressure and low volume.
High pressure and high volume.
Inert gas drawn from an in-line unit in the main or auxiliary boiler exhaust, cannot normally be used in chemical tanker operations, because:
The gas will be above the LEL.
SOLAS requires this type of generator to be fitted only on oil tankers.
It will be laden with hydrocarbons and soot particles, that would have a significant negative impact on the cargo quality.
MARPOL Annex II prohibits tank washing direct to sea after inerting with such gases.
What additional precautions may have to be taken when discharging vegetable oils to rail cars on shore?
A fresh water supply adjacent to the shore gantry.
Extra personnel should be positioned on the ship’s manifold to ensure continuous communication.
An air or nitrogen supply to hand at the ship’s manifold, for use in line clearing in the event of protracted delays due to shifting and repositioning of rail cars.
Written procedures to cover the discharge should be drawn up by the vessel and signed by a shore representative prior to commencement of discharge.
You are the officer on watch and are about to undertake a line clearing operation from shore. What must you ensure is available in the required tank?
Independent portable ullaging equipment.
An inert atmosphere.
Adequate pressure to ensure good flow in the vapour return system.
Adequate space to accommodate the remaining product without exceeding maximum filling limits.
Any operation involving nitrogen must be governed by an appreciation of:
Tank capacity measured against nitrogen supply rate.
Liquid flow in versus liquid flow out.
Rate of nitrogen supply measured against cargo pump capacity.
Rate of nitrogen flow in versus capacity of venting system out.
Symptoms of skin damage resulting from contact with liquid nitrogen may resemble which of the following conditions?
Melanoma.
Dengue fever.
Frostbite.
Alaplecia.
Which of the following is a true statement?
Extended blowing of a cargo hose will lead to the destabilisation of an additive.
Polymerization will result from prolonged blowing of a cargo hose with air.
The specification of a colour sensitive cargo will be adversely affected if the cargo hose is blown with nitrogen after discharge.
Prolonged blowing of the cargo hose used for loading a cargo containing an oxygen-dependant additive with nitrogen may lead to a significant drop in the efficiency of that additive.
Dew point is defined by which of the following statements?
The temperature at which a gas is saturated with respect to a condensable component.
The temperature at which a condensable component is saturated with respect to a gas.
The temperature at which a saturated gas becomes in ambient.
The temperature at which dry-ice begins to melt in acetone.
Click on the boxes next to the two accepted methods of replacing the atmosphere in cargo tanks:
Answer
Which of the following items must a vessel legally have on board prior to loading a cargo of Styrene Monomer?
A Certificate of Purify.
A Certificate of Analysis.
A Certificate of Test.
A Certificate of Inhibitor.
What precautions should be taken after loading an inhibited cargo, where the shore then cleared the line to the ship using nitrogen?
Ensure maintenance of the nitrogen blanket throughout the voyage.
If not already known, request confirmation of the purity level of nitrogen required for maintaining the nitrogen blanket during the voyage from the Ship Operator.
To prevent the possibility of condensation forming in the line system, ensure that the pump stack and manifold valves are immediately closed and kept closed during the entire voyage.
Ensure sufficient oxygen is introduced into the cargo line and pump stack as soon as practicable after completion of loading, in order to avoid subsequent valve seizure as a result of polymerized product.
What should be reached before commencing any operation involving nitrogen?
Agreement on completion time.
Agreement on who will operate the shore valves.
Joint calculation of the minimum nitrogen quantity required.
The full agreement on and understanding of all aspects of the operation by all parties involved.
If during loading of liquid nitrogen, drops of the liquid are allowed to contact the steel deck, which of the following risks is created?
A toxic atmosphere will develop.
Localised steel fracture.
Localised steel delamination.
Extensive steel distortion.
You have just loaded a cargo of Toluene. What particular hazard must you be aware of in terms of line clearing?
Toluene has a high melting point.
Toluene is a static accumulator.
Toluene needs to be blanketed.
Toluene is a high viscosity cargo.
Regular nitrogen cylinders are:
50-60 litres capacity at 90-100 bar pressure.
100-120 litres capacity at 200-220 bar pressure.
40-50 litres capacity at 180-200 bar pressure.
180-200 litres capacity at 45-50 bar pressure.
Inert gases are all:
Aspirates.
Asynchronites.
Propyloxyphenes.
Asphyxiates.
The term applied to the decomposition of vegetable oils is:
Putrefaction.
Distillation.
Pyrolyzation.
Reactivation.
Which of the following cargoes is an example of one loaded in a tank, where the surrounding empty voids and ballast tanks will also be inerted?
Propylene Glycol.
Propylene Oxide.
Propyl Ether.
Propylamine.
The safest time to add nitrogen to a cargo tank is:
Immediately after loading.
Prior to loading.
As the cargo is being loaded.
As the vessel approaches the discharge port.
You are to receive cargo from rail cars. Which of the following risks should you be specifically aware of?
Once the maximum operating pressure is achieved in the rail car, its safety valves will lift.
As a tank car finishes, nitrogen may pass into the ship’s tanks, resulting in an overflow or structural damage if not controlled.
As a tank car commences, the ship’s tank will be over-pressured and structural damage will result.
The pressure build-up in the ship’s tank may result in a reduced discharge rate from the rail cars.
Assuming the vessel is fitted with the appropriate equipment, which of the following mediums is employed in drying cargo tanks, as an alternative to nitrogen?
Compressed air.
Condensed air.
De-humidified air.
De-natured air.
During line clearing operations, which particular area is it critical, that ship’s personnel man throughout?
Adjacent to the VHF radio.
The gangway.
Fore and aft.
The manifold.
If a chemical tanker has tank-cleaning machines with a nozzle throughput of more than 17,5 cubic meters per hour, is it subject to inerting requirements in cargo tanks containing low-flash products?
Yes.
No.
You are discharging vegetable oils to rail cars on shore. What additional precautions is it prudent to adopt?
Keeping a fresh water supply adjacent to the shore gantry to wash down any spillage.
Positioning extra personnel on the ship’s manifold to ensure continuous communication.
Blowing down of ship’s lines in the event of a protracted delay between groups of rail cars.
Drawing up written procedures to cover the discharge and have them signed by a shore representative prior to commencement of discharge.
Approximately how long will it take to deliver 5 000 cubic meters of nitrogen gas through a 100 mm (4″) pipeline at 5,2 bar (75 psi)?
30 minutes.
45 minutes.
15 minutes.
60 minutes.
By injecting nitrogen into the shore pipeline during the loading process, which of the following advantages may be obtained?
The requirement to pre-inert is much reduced.
The need to pre-inert is avoided entirely.
The need to monitor nitrogen levels after loading is eliminated.
Loading can take place at a higher rate.
To obtain around 2 % oxygen content in a cargo tank by the dilution method, approximately how many volume changes of pure nitrogen will need to be injected:
1,3.
2,1.
3,5.
4,5.
Which method of atmosphere replacement is generally practised on chemical tankers?
Dislocation.
Dilution.
Dissolution.
Displacement.
Which of the following items are required to be indicated on a Certificate of Inhibitor?
Answer
What term is applied to the discharge of rail cars by the application nitrogen?
Pushing off.
Pressing off.
Pulling off.
Putting off.
The maintenance of a nitrogen pad is also sometimes referred to as:
Purging.
Blowing.
Blanketing.
Blending.
Inert gases create which of the following:
An oxygen deficient atmosphere.
An oxygen enhanced atmosphere.
An oxygen rich atmosphere.
An oxygen compliant atmosphere.
What possible source of contamination might be encountered if steam is used during tank cleaning?
Residual chemicals.
Boiler treatment chemicals.
Organic chemicals.
Compressed chemicals.
Which International Chamber of Shipping publication contains specific details on the use of nitrogen on chemical tankers?
Inert Gas System.
SOLAS 1974.
The Nitrogen Handling Manual.
The Tanker Safety Guide – Chemicals.
Identify the correct relationship for rail car safety and operating settings on US tanks cars from the list below:
Safety valve: 12 bar, maximum operating pressure: 8 bar.
Safety valve: 5,2 bar, maximum operating pressure: 4,1 bar.
Safety valve: 4,1 bar, maximum operating pressure: 5,2 bar.
Safety valve: 8 bar, maximum operating pressure: 5 bar.
Which of the following items have to be entered on an enclosed space entry permit? Select all applicable answers:
Answer
Which of the following statements is an accepted definition of purging?
Pre-drying.
The filling of a cargo tank and associated piping systems, or the spaces surrounding a cargo tank, with a saturated gas or latent vapour, which will not induce hydrolysis, and maintaining that condition.
The filling of a cargo tank and associated piping systems, or the spaces surrounding a cargo tank, with a gas or vapour, which will not support combustion and which will not react with the cargo, and maintaining that condition.
The gas-freeing of a cargo tank, to a level at which the hydrogen sulphide content, as measured, is less than 35 ppm.
Nitrogen from cylinders will need to pass through which of the following for safe use on deck?
A reactivation valve.
A cooler.
A de-humidified unit.
A reduction valve.
The illustration shows a compressed air supply rigged to blow a pipeline. Click on the correct sequence to ensure no back-flow of product occurs when commencing blowing the line:
Supply valve / drain-cock / manifold valve.
Supply valve / manifold valve / drain-cock.
Drain-cock / manifold valve / supply valve.
Manifold valve / drain-cock / supply valve.
Unconsciousness resulting from entering into an inerted space without breathing apparatus can occur earliest in which of the following times?
2 minutes.
1 minute.
45 seconds.
20 seconds.
Which of the following risks may be deemed to exist with a direct transfer from rail cars to a ship?
Once the maximum operating pressure is achieved in the rail car, its safety valves will lift.
As a tank car finishes, nitrogen may pass into the ship’s tanks, resulting in an overflow or structural damage if not controlled.
As a tank car commences, the ship’s tank will be over-pressured and structural damage will result.
The pressure build-up in the ship’s tank may result in a reduced discharge rate from the rail cars.
Why is a hose cleared prior to disconnection? Click on the boxes next to the relevant reasons:
Answer
Chemicals tankers operating predominantly in which of the following trades routinely use oil-fired inert gas (assuming they are fitted with the appropriate generating equipment)?
Acids.
Heavy Oils.
Propylene Oxide.
Gasolines and Light Gas Oils.
A supply through a 100 mm (4″) line, delivered at 5,2 bar (75 psi), can introduce which of the following volumes of nitrogen?
27 cubic meters/min.
47 cubic meters/min.
343 cubic meters/min.
87 cubic meters/min.
Which of the following chemicals has an inhibitor added for marine transportation?
Iso-propyl alcohol.
Ethyl acrylate.
Caustic soda solution.
Sulphuric acid.
Humid atmospheric conditions may cause a cargo tank to:
Tolerate.
Steam.
Evaporate.
Sweat.
Click on the boxes to indicate items of information that must appear on a Certificate of Inhibitor:
Answer
If an amount of nitrogen equivalent to 3,5 times the volume of a cargo tank was injected into that space (by dilution), what level of oxygen might it be reasonable to expect at that time?
5 %.
1 %.
8 %.
2 %.
Click on the boxes next to the terms, which describe the two methods of line clearing of a pipeline to a ship:
Answer
Should unbroken blisters resulting from a steam burn be left intact?
Yes.
No.
The two parts of the rotating bed in a de-humidifier unit are referred to as:
Answer
What must the responsible officer ensure is available in a tank prior to a line clearing operation?
An inert atmosphere.
Adequate pressure to ensure good flow in the vapour return system.
Adequate space to accommodate the remaining product without exceeding maximum filling limits.
Independent portable ullaging equipment.
Putrefaction is a term applied to which of the following terms?
The dissolution of Caustic Soda.
The blanketing of low-flash cargoes.
The decomposition of vegetable oils.
The pyrolyzation of light refraction oils.
Gas bubbling through a cargo, as happens during hose blowing, is particularly hazardous with which category of cargoes?
Acids.
Inorganic chlorides.
Water-sensitive products.
Static accumulator cargoes.
If a vessel has just loaded a solidifying or high-viscosity cargo, what procedure may routinely need to be implented?
Additional sampling.
Additional line blowing.
Additional venting.
Additional ballasting.
Which of the following items must a vessel legally have on board prior to loading a cargo of Methyl Acrylate?
A Certificate of Purify.
A Certificate of Analysis.
A Certificate of Test.
A Certificate of Inhibitor.
What colour identification strip is commonly used to mark nitrogen lines?
Signal Red.
International orange.
Signal Yellow.
Powder blue with a 10 cm (4″) green stripe.
The traditional manual dew point meter employs which of the following substances?
Answer
De-humidified air can be made more efficient for drying tanks by:
Cooling.
Heating.
Filtering.
Pressurizing.
Allowing for regional variations regular nitrogen cylinders are commonly:
70-75 litres capacity at 125-130 bar pressure.
200 litres at 50 bar pressure.
100 litres capacity at 175-200 bar pressure.
40-50 litres capacity at 180-200 bar pressure.
Oil tankers use an inert atmosphere specifically to prevent:
Corrosion of the tank surfaces.
Fire or explosion in a tank containing a hydrocarbon gas/air mixture.
Loss of cargo quantity during a loaded passage.
Reduction of cargo quality during a loaded passage.
Click in the boxes next to mediums commonly used in drying cargo tanks:
Answer
Click on the boxes to indicate the two types of shipboard nitrogen generator:
Answer
Under normal circumstances, which moves through a pipeline more easily?
Liquid.
Gas.
What is the term applied to the technique of recycling the exhaust atmosphere during a purging operation, using it to commence purging down in a second compartment?
Consolidation inerting.
Cascade purging.
Collection inerting.
Exhaust recycling.
What additional process can be applied to de-humidified air to make it more efficient in drying tanks?
Cooling.
Heating.
Filtering.
Depressurizing.
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