Tank Cleaning Practice

Date: 2015-10-07; view: 580.

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11Describe the pictures. What method and equipment for tank cleaning up do you see in pictures.

12Watch the video and say if the statements are true or false. Correct the false once.

1. When tanks are to be inspected or maintenance must be performed within a tank, it must be not only cleaned, but made "gas-free."

2. The COW system is used to remove asphaltic deposits and wax.

3. Water washing systems uses rotating high-pressure water jets to spray cold water inside the tank.

4. After a tank is cleaned, the liquid is left in the tank and used as ballast water.

5. To free tank from hydrocarbons fresh air is blown into the tank.

6. After a tank is gas-free, "mucking" is generally done by able seamen and deck officers using tools such as mops, buckets, rags and sponges.

13 Read the text.

a) Think of the title and subtitles of the text.

b) Replace the images ( / / ) with word or word combinations from the box.

__________________________________

1.________________________

washing (COW) is washing out the residue from the tanks of an oil tanker using the cargo itself, after the cargo tanks have been emptied. is pumped back and preheated in the slop tanks, then sprayed back via high pressure nozzles in the cargo tanks on to the walls of the tank. Due to the sticky nature of the , the oil clings to the tank walls, and such oil adds to the cargo 'remaining on board' (the ROB). By COWing the tanks, the amount of ROB is significantly reduced, and with the current high cost of oil, the financial savings are significant. MARPOL 73/78 made this mandatory equipment for oil tankers of 20,000 tons or greater deadweight.

2._____________________

Originally oil tankers used one set of tanks for cargo and about one third of the same tanks were for water ballast on their empty trips. High pressure, hot, jets were used to clean the tanks and the mixture of and residue called slops discharged into the sea, as was the oil-contaminated ballast water. The 1954 OILPOL Convention attempted to reduce the harm by prohibiting such discharges within 50 miles (80 km) of most land and 100 miles (160 km) of certain particularly sensitive areas.

3______________________

The discharges from washing were still considered a problem and during the 1960s the approach began to be adopted. The mixture of cleaning water and residue was pumped into a slop tank and allowed to separate into oil and water during the journey. The water portion was then discharged, leaving only in the slop tank. This was pumped into the main tanks and the new cargo of it.

14Watch the video again and answer the questions.

1 What types of tank cleaning operations do you know? What are their advantages/disadvantages?

2 What factors influence the necessary degree of cleanliness?

3 Why is it important to drain the tanks after cleaning?

4 In what cases do we need heat the cargo?

5 Why do we need to monitor tank's atmosphere?

15Solve the quiz

1 What International Code Flag is hoisted to denote loading of flammable liquid is going on?

a) Bravo c) Golf

b) Hotel d) Zebra

2 What is the first safety precaution observed in tankers before loading?

a) connect bonding cable

b) secure mooring lines

c) connect cargo hose

d) connect vapour line

3 Smoking is NOT permitted on the weather decks of tank vessels

a) when loading cargo through open hatches

b) except when water is being used to- control the decks

c) except when sand pails are provided and are filled

d) under any circumstances unless the vessel is gas free and is not alongside

4 To which place do tanker crew and visitors go to smoke cigarettes?

a) head c) cabin

b) mess hall d) authorized smoking area

5 When is cleaning by crude oil wash in the tankers done?

a) while discharging cargo

b) before drydocking

c) while at anchor

d) while at sea

6Which one of the following is one major advantage of the load-on-top system?

a) cargo tanks corrosion is reduced

b) oil that was previously lost is recovered

c) discharge time is significantly reduced

d) no danger of contamination

7 What should be done with the oil residues left in the tank when the vessel is within a special area?

a) retain on board

b) discharge when 30 miles offshore

c) wait till darkness then discharge overboard

d) may be discharged anytime

8 What instrument is used to determine the depth of oil over the water in the slop tank?

a) interface detector c) cross bar

b) ullage tape d) sounding tape

9 What is the state of the tank or compartment that has been tested and found to be without toxic and explosive gases?

a) gas-tested c) aerated

b) gas-free d) fresh tank

10 What shall be continuously provided in an enclosed space with working crew?

a) water c) ventilation

b) watches d) equipment

11What equipment is used when entering a compartment that is NOT gas-free?

a) life line

b) breathing apparatus

c) face mask

d) asbestos suit

12 What is the instrument that is used to measure concentrations of combustible gas and air mixture?

a) psychrometer c) explosimeter

b) gas meter d) oxymeter

13 What size of oil tankers is required to be built with double hulls as approved by IMO for oil pollution prevention?

a) over 30,000 DWT

b) over 5,000 DWT

c) over 20,000 DWT

d) over 10,000 DWT

14If it becomes necessary to pump bilges while a vessel is in port, which of the following procedures should be followed?

a) Pump only if discharged is led to a shore tank or barge

b) Pump only during the houses of darkness

c) Pump only on the outgoing tide

d) Pump only as much as is necessary

15When oil is accidentally discharged into the water, what should you do after reporting the discharge?

a) Prevent spreading and removes as much oil as possible from the water

b) Throw chemicals on the water to disperse the oil

c) Throw sand on the water to sink the oil

d) Request the coast guard to take care of cleaning up the oil

16The oil record book is required to be carried aboard:

a) tanker

b) passenger vessels

c) cargo vessels

d) all of the above

17 Bilge soundings indicate

a) the amount of condensation in the hold

b) whether the cargo is leaking or not

c) whether the ship is taking on water

d) all of the above

18When removing the cap from a sounding tube, the sound of air is escaping indicates that the tank

a. is full

b. may be partially flooded

c. level has dropped

d. is completely flooded

16 Tick the type of accident occurred on board.