Welcome to the website where you can find answers for the Computer Based Test (CBT) also known as Crew Evaluation System (CES) on the subject «Volatile Organic Compounds». This site will help you as a marine specialist improve your knowledge with the help of open information, where you can find questions as well as answers for them. CES/CBT based on practical information and marine specialists experience.
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The current test contains Seagull CES questions on Volatile Organic Compounds. These questions can be used to test the competence of a specialist. Volatile organic compounds (VOCs) are generated in tanker tanks during the transport of crude oil. They are a mixture of heavy hydrocarbons, not suitable for use as a fuel for piston units. The issue of recycling is one of the most important, since emissions into the oceans harm the environment.
The topic “VOC Compounds” includes theoretical and practical information on safety when working with tanks containing oil, gas. Knowledge of this information directly indicates the competence of the employee holding the relevant position on the ship. The employee must be aware of the release of volatile compounds, their disposal.
This page contains answers to Seagull CES CBT (Crew Evaluation System/Computer Based Test) test about Volatile Compounds, and serve as a database of questions and answers, using which seafarer can prepare to exams for getting certificate of competence, or just to challenge yourself with knowledge in this theme.
CBT CD 0196 – VOC.pdf
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Amount of questions: 55.
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An unsaturated vapour may be defined as not being in contact with its liquid phase. Which of the given options is the main source of unsaturated vapour in a cargo tank of a crude oil tanker?
Air and Inert Gas.
Sediments.
H2S.
Tank anodes.
As a crude oil tanker cargo tank fills with liquid cargo what will occur in the ullage space of the cargo tank:
Saturated and unsaturated vapour mix together and become the Total Vapour Pressure.
Saturated vapour from the cargo pushes the inert gas out through the vent system.
The space above the liquid becomes saturated.
The vapour above the liquid becomes neutral when mixed with the inert gas.
As part of the VOC control measures certain operational records must be maintained. Select, from the given options, all of those that should be recorded when any VOC is released from a crude oil tanker:
Target operating pressure for the voyage.
Time and pressure within the system before releasing the VOC.
Time and pressure within the system after the releasing the VOC.
Person in charge of the VOC release.
Location of vessel at the time of release.
As a part of recommended VOC emission control measures, which of the given options is the condition when COW operations are allowed to be carried out at sea?
Between multiple discharge ports.
Only on ballast voyages.
Only if heavy weather ballast is required for the safety of the ship.
Only for sludge control.
Best practice for VOC control, as detailed in this module, recommends that the ship should define a cargo tank target operating pressure which should be as high as safety possible. What should the target pressure be relative to the P/V valve setting pressure?
About 70 % of P/V valve setting pressure of 1 400 mmWG.
About 70 % of P/V valve setting pressure of 1 500 mmWG.
About 80 % of P/V valve setting pressure of 1 500 mmWG.
About 80 % of P/V valve setting pressure of 1 200 mmWG.
Controlling emissions of volatile organic compound (VOC) from ships is expected to have a significant beneficial impact. Which of the given options is expected to be the most beneficial result of these control measures?
Reduced atmospheric pollution and reduced human health risk.
Total prevention of memory impairment.
Total exacerbation of asthma.
Reduced marine and atmospheric pollution.
During loading of a crude oil cargo, the vapour displaced by the cargo is released to the atmosphere via the mast riser. Which of the given options best describes the most likely composition of the released vapour?
All compounds in VOC including inert gas.
Only NMVOC and inert gas.
Only the inert gas and Methane.
Only Methane, Ethane and inert gas.
During the loaded voyage, the temperature of the gases or vapours in the ullage space of the cargo tanks and the liquid cargo varies. Which of the given options is the main reason that the liquid phase temperature varies less than the gas or vapour phase temperature?
Hull design and sea water temperature.
The outdoor temperature.
The composition of cargo.
The cloud point of the cargo.
In a CVA type adsorption process used for VOC emission control the crude oil vapours are filtered through active carbon beds. What means is normally used to lower the pressure in the carbon bed for the purpose of desorbing the gases?
A vacuum pump.
An eductor.
Liquid gravity.
Temperature drop.
In a condensation type VOC control system, the vapours are liquefied and drained to the NMVOC storage tank. Which of the given options is the maximum pressure in the tank at ambient temperature, as stated in this module?
14 bar.
12 bar.
9 bar.
15 bar.
In an Absorption System being used for VOC emission control the NMVOCs are absorbed into the oil. Which gases are normally routed to the riser?
Methane, ethane and inert gas.
Only the unsaturated gases.
Only the saturated gases.
Propane and butane.
In which IMO regulations are the detailed requirements regarding VOC Management Plans to be found?
In MARPOL Annex VI.
In MARPOL Annex I.
In SOLAS.
In ISGOTT.
In which publication would you find the safety device requirements for the vapour control system on tankers?
In SOLAS.
In MARPOL.
In the Safety Manual.
In ISGOTT.
One of the VOC emission control systems found on board crude oil tankers is known as the KVOC system. What is the significant feature of a KVOC type emission control system?
It uses a large diameter drom column.
It uses a small diameter drom column.
It uses an eductor to evacuate vapour.
It uses a vacuum pump to create an under pressure in the pipelines.
One of the requirements within a VOC Management Plan is that an estimate of the quantity of VOC released during a voyage is recorded. How can this requirement be met?
By recording the pressure at the start and end of release and the length of time of the release.
By recording how long the inert gas plant is in use.
By using an automatically controlled venting system.
By increasing the liquid height in the P/V breaker.
Record keeping is necessary in order to document compliance with the requirements of VOC emission control. Is this statement True or False?
True.
False.
Select from the given options all of those, that are considered to be “best practices” to be adopted to reduce VOC emissions during a loaded voyage on a crude oil tanker?
Set the target operating pressure for the cargo tanks as high as safety possible.
When venting to reduce excessive tank pressure, vent as little as possible.
If filling inert gas to prevent under pressure, use as little inert gas as possible.
If crude oil washing reduce the cycle time as much as possible.
Select from the given options all of those that are considered to be “best practices” to be adopted to reduce VOC emissions during cargo loading on a crude oil tanker:
Reduce the loading rate.
Plan the loading procedure to reduce cargo agitation in the oil tanks.
Keep the cargo tank pressure as high as safely possible.
Use the vapour returns lines when shore facilities are available.
Communicate with the terminal before loading starts.
Select, from the given options, all of those that are considered to be “best practices to be adopted to reduce VOC emission during cargo discharge and COW operations on a crude oil tanker”:
Continuously monitor the pressure of the cargo tanks during discharge to avoid excessive supply of inert gas.
As far as possible a closed cycle method should be used for COW operations.
Use a defined volume of crude oil for the COW from a specified cargo tank instead of fresh crude oil.
All COW operations should comply with the requirements and procedures set out in the class approved COW manual.
Excessively gassy cargoes should not be used for crude oil washing.
Select, from the given options, the one which most accurately completes the following statement: “The temperature of the gas phase in a crude oil cargo tank will change more rapidly…”
During day and night cycle.
During loading of the cargo tank.
During discharging of the cargo tank.
During transportation.
Select from the options given all of those, which are criteria that influence the VOC release from the cargo of a crude oil tanker:
The volatility or vapour pressure of the crude oil.
The temperature of the liquid and gas phases of the crude oil tank.
The pressure setting or control of the vapour phase within the cargo tank.
The size or volume of the vapour phase within the cargo tank.
The Gothenburg Protocol has set emission limits for which of the pollutants?
Sulphur, NOx, VOCs and ammonia.
Carbon dioxide and carbon monoxide released from ships.
Inert gas.
Nitrogen and carbon dioxide released from ships.
The temperature of the liquid phase in a crude oil cargo tank does not vary much, except:
When heating or cooling of the cargo is being carried out.
When proceeding from a cold region to a warm region.
When proceeding from a warmer region to a colder region.
When the ship is stationary in warm climate.
There are various methods used to control VOC emissions from crude oil tankers including cargo tank pressure variations. Will increasing the pressure in the cargo tanks by adding inert gas prevent VOC release?
No.
It depends on the temperature of the cargo.
Yes.
Yes, but only if the inert gas has a very low O2 content.
There are various methods used to control VOC emissions from crude oil tankers including the so called Venturi system. Which of the given options may be considered as the main feature of the Venturi system?
The VOC is re-absorbed back into the cargo.
The VOC is directed back into the cargo via a side stream.
The VOC is injected at the top of the tank.
The Venturi draws VOC from the inert gas vent line.
Under new IMO requirements all crude oil tankers must carry a VOC Management Plan on board. Which authoritative body is required to approve the VOC Management Plan?
The Administration.
The Classification Society.
The Port State Control.
The USCG.
VOC emissions will occur during COW operations on board crude oil tankers. Which of the given options is used to reduce VOC emission when COW operations are carried out during a laden voyage?
Reduce the duration of the closed cycle washing program.
Reduce the pressure on the COW machines.
Perform an open cycle washing program.
Use of multistage COW programmes.
VOCs are classed as organic chemicals. What is the definition of the term organic chemicals as used in this module?
Organic chemicals are substances that contain of hydrocarbons.
Organic chemicals are substances that contain hydrogen.
Organic chemicals are substances that contain nitrogen.
Organic chemicals are substances that contain oxygen.
Vapours that are released directly into the air during cargo operations on board crude oil tankers are considered hazardous. Which of the given options is the most likely to be adversely affected by the release of these vapours?
Human health and the atmosphere.
Marine environment.
The ships paintwork.
Coastal Plants and land animals.
What is the definition of true vapour pressure (TVP)?
The true vapour pressure (TVP) is the combined result of the saturated and unsaturated vapour pressures present in a defined closed system.
True vapour pressure is an expression for a substance’s internal energy.
It is the vapour pressure due to hydrocarbons with up to 4 carbon atoms, which are at room temperature and atmospheric pressure.
The true vapour pressure is the pressure at which vapour of the substance can be liquefied.
What is the main benefit of using closed cycle crude oil washing (COW) on board crude oil tankers?
VOC emissions are reduced as only a defined amount of crude oil is used.
VOC emissions are totally avoided since all the gases and vapours are condensed.
VOC emissions are reduced because all tanks are closed.
No slop tank is required for closed cycle operations.
What is the main purpose of P/V breaker fitted to the cargo system of a crude oil tanker?
It provides secondary protection to the tank structure from over and under pressure.
It provides primary protection to the tank structure from over pressure.
It provides a means of venting the gases and vapours from the tank as cargo is loaded.
It provides oxygen content readings of the cargo tanks.
What is the main purpose of P/V valve fitted to a cargo tank of a crude oil tanker?
It provides secondary protection to the tank structure from over and under pressure.
It provides primary protection to the tank structure from over pressure.
It provides a means of venting the gases and vapours from the tank as cargo is loaded.
It provides an indication of the pressure in the cargo tank.
What is the main purpose of the VOC management plan?
To ensure that the operation of a tanker, to which regulation 15.6 of the revised Annex VI applies, prevents or minimizes VOC emission to the extent possible.
It totally prevents VOC emission into the atmosphere.
It is requirement of the Kyoto protocol.
It is a requirement of port State control.
What is the main purpose of the vapour emission control pipe line fitted on board a crude oil tanker?
Direct the vapours from the cargo tanks to the shore system.
Direct the cargo vapours from cargo tank to the engine room.
Direct the cargo vapours from cargo tank to burn in the boilers.
Direct the cargo vapours from cargo tank to vapour absorption system.
What is the major source of volatile organic compound from ships?
The majority of VOC comes from cargo tanks of oil tankers.
The majority of VOC comes from incomplete combustion in ship’s engines.
The majority of VOC is released from ship’s air conditioning compressors.
The majority of VOC is released from ship’s boilers.
What is the procedure for the maintenance of the P/V valves fitted to the cargo system of crude oil tankers?
The maintenance should be carried out in accordance with the directions in the vessel’s planned maintenance system and the maker’s manual.
The maintenance should not be carried out until the valves start leaking.
The maintenance should be carried out during each loaded passage.
The maintenance should be carried out during cargo discharge.
What is the purpose of VOC emission control from ships?
To prevent or minimize the release of VOC as much as possible during loading, discharging and transit.
Only to prevent or minimize the release of VOC as much as possible during loading at offshore terminals.
Only to prevent or minimize release of VOC as much as possible during production.
Only to prevent or minimize release of VOC as much as possible during cargo transfer.
What is the purpose of the vapour recovery systems installed on-board crude oil tankers?
To control the VOC emissions to the atmosphere, when the plant is in operation.
To extract the hydrocarbon gases from the cargo to be used to run the ship’s engines.
To liquefy the hydrocarbon gases emitted from the cargo and then use the liquid to run the ships compressors.
To maintain the cargo specifications of the loaded cargo.
What is the requirement, if any, with regard to the experience of the person intended to act as a designated person in relation to VOC control?
They should have at least one-year experience on crude oil tankers where their duties included all cargo handling operations relevant to VOC management and COW operations.
They should have at least 9 month’s experience on oil tankers with some involvement in COW operations.
There is no such requirement for the designated person to have any experience of crude oil tankers.
They should have at least 6 month’s experience on oil tankers with some involvement in COW operations.
What target pressure, according to this training module, should be maintained in the ullage spaces of tanks during loading to minimise VOC release to the atmosphere?
As high as safely possible, at about 70 % of the pressure release setting on the P/V valves.
90 % of the P/V valve setting pressure.
100 % of the P/V valve setting pressure.
As low as possible and no more than 50 % of the pressure release setting of the P/V valves.
What was the main goal of the Kyoto Protocol?
To lower overall emissions from six greenhouse gases – carbon dioxide, methane, nitrous oxide, sulphur hexafluoride, HFCs and PFCs.
To arrange the developed nations to pay for the maintenance of climate change.
To arrange the developed nations to pay underdeveloped nations to control emissions.
Arrange to keep a record of each nations greenhouse gas emissions.
What will be the probable result when VOCs react chemically with NOx in the atmosphere in the presence of sun-light?
Ozone and smog will be produced.
Sulphur will be produced.
Toluene will be produced.
Hydrogen Sulphide will be produced.
When considering crude oil tanker operations what is meant by the term volatile organic compounds?
They are organic chemicals that easily vaporize at normal conditions and enter in to the atmosphere.
They are organic chemicals that vaporize and enter in to the atmosphere only when heated.
They are organic chemicals that vaporize and enter in to the atmosphere only when agitated.
They are organic chemicals that vaporize and enter in to the atmosphere only after a chemical reaction.
Which of the factors given in the options will determine whether a crude oil is suitable for use in COW operations?
How potentially gassy the crude is.
How viscous the crude oil is.
What the cloud point of the crude oil is.
What the density of the crude oil is.
Which of the given options best describes the main factors that will influence the effect on health of human of exposure to VOC emissions on board a crude oil tanker?
The concentration of the VOCs and the level and length of time of exposure.
Only the level and length of time of exposure.
Only the weight of the person and the length of time of exposure.
Only the concentration of NMVOCs in the VOCs.
Which of the given options is a common, alternative name for methane?
Natural gas.
Hydrogen sulphide.
Liquid petroleum gas.
Propane.
Which of the given options is considered as the main cause of the evolution of NMVOC in the cargo pipeline system during loading?
Pressure drops in the loading pipeline (drop lines).
High temperature on the cargo during loading.
High inert gas pressure in the tank.
The composition of the crude oil.
Which of the given options is generally regarded as the primary safety mechanism for the protection of cargo tanks from over or under pressure?
The P/V valve.
The non-return valve.
The water seal.
The P/V breaker.
Which of the given options is generally taken as the maximum design pressure of a cargo tank of a crude oil tanker?
At least 2 500 mmWG.
At least 2 000 mmWG.
At least 1 500 mmWG.
At least 3 500 mmWG.
Which of the given options is one of the preferred requirements described in this module for the person appointed as the VOC designated person on board a crude oil tanker?
They should have at least one year’s experience on crude oil tankers.
They should be a serving Chief Officer.
They must be aware of the location of the VOC manual.
They must have carried out crude oil operations on at least 6 occasions.
Which types of ship are required to carry and follow an approved VOC management plan on board?
Every oil tanker carrying crude oil regardless of whether existing or new.
Every new oil tanker built after 10 October 2010.
Every Cargo ship 500 GT or more.
Every Chemical tanker regardless of existing or new.
Why are the emission control requirements for crude oil tankers limited to non-methane volatile organic compounds, NMVOCs, and do not include methane?
As it is not deemed cost-efficient to recover methane.
As methane constitutes such a small part of the VOC.
As methane will be removed during the production process.
As methane will be transported by dedicated ships.
Why is methane treated differently from other VOC’s?
Because methane boils at -162 °C and its emissions are deemed to be too costly to control.
Because methane is not a threat to the environment.
Because methane is an unsaturated hydrocarbon.
Because methane is inorganic.
With regard to VOC emissions, what effect, if any, will increasing the cargo tank pressure have during cargo loading operations?
It will result in a reduction in emissions.
It will have no effect on the emissions.
It will result in an increase in emissions.
It will result in increased emissions of non-methane VOC’s.
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