Black Smoke from the Funnel: What to do? PART24

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Black Smoke from the Funnel: What to do?

Black Smoke from the funnel is a sign of poor maintenance and malfunction of the machinery. It is a serious issue as it violates Marpol 73/78 Annex VI and can lead to inspections and detention of the ship. In a ship with multiple machines the identification of the faulty unit is a difficult task.

The reasons black smoke is wrong are:                                   

1.     It indicates that shipkeeping and maintenance is not proper and up to the mark.

2.     It indicates the lack of competency of the engineers.

3.     It is polluting.

4.     It increases the risk of an uptake fire.

Marpol Annex VI has set standards for air pollution and the sulphur content of the exhaust gases. Back smoke indicates that the combustion is incorrect. It suggests a bad fuel efficiency and an increase in the fuel consumption.

Causes of Black Smoke

The dark color of the smoke is caused by suspended fine carbon particles due to incomplete combustion taking place. However the offending machine has to be identified before any corrective action can be made. In marine diesel engines the poor combustion is basically due to two main reasons; the first one is insufficient air supply and the second one is incorrect fuel injection.

The air-related problems in marine diesel engines may be due to the following reasons:

5.     The turbocharger air filter is choked.

6.     The turbocharger turbine blades are fouled and damaged; therefore it is giving insufficient air to the engine.

7.     The turbocharger inlet grid in the exhaust manifold is choked, and therefore the turbocharger is running at low speed.

8.     The compressor blades are dirty or damaged.

9.     The scavenge ports of the engine may be dirty and choked.

10.   The scavenge valves may be faulty or damaged.

11.   The nozzle ring of the turbocharger is soiled.

12.   The engine room blowers are not supplying sufficient air as the filters are choked.

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