单选题Biodegradation of the oil slick in sea water is assisted by all the following marine micro-organisms which are capable of metabolising oil compounds except（）.A bacteriaB mouldsC yeastsD seals

What is the most usual reason for the fresh water-sea water heat exchanger fouling in the sea side?

A.lube oil sludge accumulating in it

B.dirt and scale etc , formed on the surfaces

C.deformation of the tubes and the shell or the plates

D.lube oil leakage into sea-water side

Oil slick caused by spillage of oil from tanker ship is ______.

A.a drop of oil

B.the emulsion of oil at sea surface

C.the weathered oil

D.the oil floating on the surface of the sea water

A.Low level is monitored on the drain tank and header tank.

B.If there is high differential the filters pressure across the circulating

pumps is alarmed

C.The lubricating oil purifier cannot take oil from the drain tank

D.If the sea water pressure falls, this also operates an alarm

______is not a process of weathering of the oil spilled in the sea water.

A.Biodegradation

B.Dissolution

C.Cleaning up by crew with skimmers

D.Oxidation including photooxidation

Biodegradation of the oil slick in sea water is assisted by all the following marine micro-organisms which are capable of metabolising oil compounds except ______

A.bacteria

B.moulds

C.yeasts

D.seals

OIL-IN-WATER are ______．

A.sediment of oil in water

B.oil dissolvents in water

C.solid oil aggregates

D.droplets of oil suspended in water

第二组

The only attention that heat exchanger should require is to ensure that the heat transfer surfaces remain substantially clean and the flow passages generally clear of obstruction. Indication that undue fouling is occurring is given by a progressive increase in the temperature difference between the two fluids, over a period of time, usually accompanied by a noticeable rise in pressure loss at a given flow.

Fouling on the sea-water side is the most usual cause of deterioration in performance. The method of cleaning the sea water-side surfaces depends on the type of heat exchanger. With shell-and-tube heat exchangers, the removal of the header covers or, m the case of the smaller heat exchangers, the headers themselves, will provide access to the tubes. Obstructions, dirt, scale etc., can then be removed, using the tools provided by the heat exchanger manufacturer. Flushing through with fresh water is recommended before a heat exchanger is returned to service. In some applications, such as piston oil cooling, progressive fouling may take place on the outside of the tubes. Most manufactures recommend a chemical flushing pr6cess to remove this in situ~ without dismantling the heat exchanger.

Plate heat exchangers may be cleaned by unclamping the stack of plates and mechanically cleaning the surface of each plate as recommended by the manufacturers. The plate seals may require replacement from time to time and here the manufacturers&39; instructions should be closely followed

By which of the following indication, can we conclude that the lube oil-sea water heat exchanger is unduly fouled?

A.the heat exchanger lube oil inlet temperature lowering

B.the heat exchanger sea-water outlet pressure rise

C.the heat exchanger temperature difference between lube oil and sea water increasing

D.the heat exchanger pressure difference between sea water inlet and outlet decreasing

______is not a process of weathering of the oil spilled in the sea water.

A.Emulsification

B.Sedimentation / Sinking

C.Oxidation including photooxidation

D.Burning organized by RCC