Тест о Flue Gas Plant (CES v5.0)

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Right answers:
1

According to the Fire Safety Systems Code what is the maximum oxygen content permitted in the cargo tanks of an oil tanker?

Your answer is correct:

8 % by volume.
2

According to the Fire Safety Systems Code which one of the following would be considered a safe amount of oxygen in the output from an inert gas plant?

Your answer is correct:

Less than 5 % oxygen.
3

According to the instructions in this module, which of these options would be carried out first when starting up a flue gas plant?

Your answer is correct:

Open the boiler uptake valve.
4

How often must the scrubber be flushed with water?

Your answer is correct:

Every time it is used.
5

If the inert gas at the blower outlet gets too hot a high temperature alarm is given. What will happen if the temperature of the gas continues to rise?

Your answer is correct:

The inert gas blowers will stop and the gas regulating valve closes.
6

In an oil cargo tank in which there is a mixture of hydrocarbon gas and air, which of the following is the best definition of the “Lower flammable limit” (LFL)?

Your answer is correct:

It is the concentration of hydrocarbon vapor below which there is insufficient gas in the mixture to support combustion.
7

In an oil cargo tank in which there is a mixture of hydrocarbon gas and air, which of the following is the best definition of the “Upper flammable limit” (UFL)?

Your answer is correct:

It is the concentration of hydrocarbon gas above which there is insufficient oxygen to support and propagate combustion.
8

In relation to oil tanker cargo spaces which one of the following is the best definition of the expression “gas freeing”?

Your answer is correct:

To introduce fresh air into a tank.
9

In relation to oil tanker cargo spaces which one of the following is the best definition of the expression “purging”?

Your answer is correct:

To blow inert gas into a tank to reduce the oxygen or hydrocarbon gas level.
10

In some types of inert gas plants using flue gas, air is supplied to the boiler uptake valves. What is the reason for this?

Your answer is correct:

To ensure no flue gas leaks pass the uptake valves when the plant is shut down.
11

In which one of the following IMO publications would you find the requirements for the design of a new inert gas system?

Your answer is correct:

International Code for Fire Safety Systems (FSS Code).
12

Many oil tankers are fitted with an inert gas system supplying their cargo tanks. What is the main purpose of introducing inert gas into a cargo tank?

Your answer is correct:

To create a non-explosive atmosphere in the tank.
13

On an oil tanker how long must the deck water seal supply be left on after the inert gas system is shut down?

Your answer is correct:

It must be left running continuously to maintain an adequate seal.
14

On inert gas plants when the scrubber water flow drops below a certain rate an alarm is given. What will happen if the flow rate drops further?

Your answer is correct:

The inert gas blowers will stop and the gas regulating valve closes.
15

In some inert gas plants using flue gas the speed of the blowers is variable. Which of the following is the best explanation for fitting variable speed blowers?

Your answer is correct:

The pressure of the gas delivered to the deck can be controlled.
16

Select the best option from those given to complete the following statement in relation to protection against excessive vacuum as fitted to the inert gas deck main. The correct operation of the pressure/vacuum breaker is dependent on:

Your answer is correct:

The correct specific gravity of the liquid and the liquid column height.
17

Some oil tankers are fitted with one large inert gas blower and one smaller blower. Which of the following is the best explanation for fitting a small blower?

Your answer is correct:

It can be used when topping up the gas pressure at sea.
18

The power supply to a flue gas type inert gas plant is normally left on, even when the plant is shutdown. Which of the following best describes the reason for this?

Your answer is correct:

Some alarm functions must be operational even when the plant is not.
19

These diagrams below represent different types of deck seals. Which one is the wet type deck seal?

Your answer is correct:

A.
20

What is the Fire Safety Systems Code requirement regarding non return devices in the inert gas main for inert gas systems on oil tankers?

Your answer is correct:

There must be, at least, two devices one of which should be a water seal type.
21

What is the main risk associated with dilution of a normally inerted cargo oil tank atmosphere with fresh air?

Your answer is correct:

During the process the atmosphere may be within the flammable range for some of the time.
22

What is the purpose of the deck water seal fitted to an oil tanker’s inert gas system?

Your answer is correct:

To prevent backflow of hazardous vapors into the gas safe areas.
23

What is the purpose of the pressure/vacuum breaker fitted to an oil tanker’s inert gas system?

Your answer is correct:

To relieve excess pressure or vacuum in the inert gas main.
24

What is the recommended period for opening up the non-return valve on deck for internal inspection?

Your answer is correct:

Once a year.
25

When an oil tanker has a flue gas type inert gas plant which is also used for gas freeing of cargo tanks, where is the air normally drawn from?

Your answer is correct:

The blower fresh air inlet.
26

When entering any part of the inert gas system to carry out maintenance or inspections, which of the following is the main danger to personnel?

Your answer is correct:

Oxygen deficiency.
27

When opened up the scrubber unit of a flue gas type, inert gas plant is found to contain a mattress of polypropylene mesh. Which of the following is the best explanation for this mesh being there?

Your answer is correct:

It is fitted to the scrubber to dry the gas.
28

When the inert gas plant on an oil tanker suffers an automatic shutdown, which one of the options below is true of the seawater pumps and blowers?

Your answer is correct:

Only the seawater pumps are left running.
29

When working inside parts of the inert gas system, such as the scrubber or deck water seal, which procedure must be followed?

Your answer is correct:

Enclosed space entry.
30

Which of the following are hazards that may exist within a tanker’s inert gas plant if vapors are allowed back from the oil cargo tanks? Select all that apply:

Correct answer:

Flammable.

Your Answer:

Oxygen deficiency.
31

Which of the following best describes the action to be taken by the watchkeeper as soon as the blower in a flue gas type inert gas plant is stopped during shutdown of the plant?

Correct answer:

The blower washing water should be turned on.

Your Answer:

The scrubber water should be turned off.
32

Which of the following best describes the most likely cause of low deck main pressure while a flue gas type inert gas plant is running?

Your answer is correct:

Cargo discharge rate in excess of the blower output.
33

Which of the following best describes the most likely cause of the boiler soot blowers failing to work while a flue gas type inert gas plant is running?

Your answer is correct:

The interlock is operating to prevent excessive soot entering the inert gas.
34

Which of the following best describes the most likely initial consequence of low boiler load when a flue gas type inert gas plant is running?

Correct answer:

A high oxygen level.

Your Answer:

A low deck main pressure.
35

Which of the following best describes the reason for the fixed oxygen meter being fitted close to its sampling point?

Your answer is correct:

To reduce the time between the sample being taken and analyzed.
36

Which of the following is the best definition for “inert gas”, as used to protect the cargo spaces of oil tankers?

Your answer is correct:

It is a gas containing insufficient oxygen to support the combustion of hydrocarbons.
37

Which of the following is the best explanation of the purpose of the scrubber unit in a flue gas type inert gas plant?

Your answer is correct:

To cool the gas while removing soot particles and sulphur dioxide.
38

Which of the following is the location that the gas regulating valve is required to be fitted to in inert gas systems on oil tankers?

Your answer is correct:

The bulkhead, where the inert gas main passes from the gas safe area into the cargo area.
39

Which of the following is the main purpose of filling the free space above the oil cargo onboard a tanker with inert gas?

Your answer is correct:

To keep the tank atmosphere outside the flammable range.
40

Which of the following is the typical oxygen level in the exhaust gas that can be achieved from good combustion in a ship’s boiler?

Your answer is correct:

4 to 5 %.
41

Which of the following operations is carried out last when shutting down a typical flue gas plant?

Correct answer:

Shutdown the scrubber water pump.

Your Answer:

Close the gas regulation valve.
42

Which one of the following automatically prevents excessive overpressure or vacuum in the inert gas main?

Your answer is correct:

P/V Breaker.
43

Which one of the following is a check that should be carried out on a P/V valve fitted to an inert gas deck main?

Your answer is correct:

Check the liquid level when the system is at atmospheric pressure.
44

Which one of the following is a maintenance problem that can be seen during an external examination of the blower of an inert gas plant?

Your answer is correct:

Cracking.
45

Which one of the following is likely to happen if the oxygen content of the inert gas being supplied to the cargo spaces of an oil tanker rises above 8 % and the “high-high” oxygen alarm sounds?

Your answer is correct:

The gas regulating valve will automatically close, and the vent or recirculation valve will open.
46

Which one of the following is likely to occur if the flue gas temperature is too high at the blower outlet?

Your answer is correct:

The coating in the blower may be damaged.
47

Which one of the following is the generally agreed reason for the rise in explosions experienced in the 1960s and 1970s, as oil tankers became larger?

Your answer is correct:

Static electricity.
48

Which one of the following is the minimum required capacity of the blowers fitted to an oil tanker’s inert gas plant, as a proportion of the ship’s maximum cargo discharge rate?

Your answer is correct:

125 % in total.
49

Which one of the following should be done before starting up the flue gas plant?

Your answer is correct:

Calibrate the fixed oxygen analyser.
50

Which one of the following would be the best gas to use to zero the fixed oxygen analyser monitoring an inert gas plant?

Your answer is correct:

Nitrogen.
51

Which one of the following would expect to happen if the blower on a flue gas plant tripped out overload?

Your answer is correct:

The inert gas system will shutdown.
52

Which one of the following would you expect to happen on an oil tanker if the pressure in the inert gas main falls to about 50 mm Water Gauge during cargo discharge operations?

Your answer is correct:

The cargo pumps shutdown automatically.
53

Which one of the oxygen levels given in the options is the minimum level for the oxygen content in the output from a flue gas plant that you should take action to investigate why the oxygen content is not lower?

Your answer is correct:

5 %.
54

Which term is used to identify the operation whereby inert gas is introduced into a cargo tank in order to reduce the oxygen content throughout the atmosphere of the tank to 8 % or less by volume?

Correct answer:

Inerting.

Your Answer:

Purging.
55

Which three of the given options are likely causes of high oxygen content indication on the oxygen analyser fitted to a flue gas plant?

Your answer is correct:

Incorrect calibration of the oxygen analyser.
56

Which two of the following are alarms that are normally found on a flue gas scrubber?

Your answer is correct:

Low water flow.
57

Which two of the following are alarms that are normally found on an inert gas deck main?

Your answer is correct:

Low pressure.
58

Which two of the following are items that should be checked during the internal inspection of a flue gas scrubber?

Your answer is correct:

Corrosion of sensors.
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