Common failures and maintenance of marine boiler combustion

1. Sudden flameout during operation (the boiler steam pressure has not reached the upper limit)

The possible reasons are:

(1) The daily fuel tank runs out of fuel

(2) The oil circuit is cut off, such as the fuel solenoid valve is closed due to damage to the coil

(3) There is water in the fuel (the residual water is not released in time).

(4) The air supply is interrupted or the air volume is seriously insufficient.

(5) Automatic protection function (such as dangerous water level, low oil pressure, low wind pressure or flame sensor failure, etc.).

2. Doesn't catch fire

In addition to the above reasons, it may also be

(1) Excessive air volume

(2) The injector is blocked

(3) The electric igniter is malfunctioning (such as poor electrical igniter circuit contact, dirty carbon on the electrode surface, improper electrode spacing, damage to the transformer, etc.).

3. Gas explosion in the furnace (cold explosion)

Gas explosion in the furnace is a dangerous accident of oil-fired boilers, which usually occurs after ignition or flameout of hot furnace. The reason is that a large amount of fuel oil accumulates at the bottom of the furnace, which evaporates into combustible gas and accumulates in the furnace. Once it is ignited, a large amount of smoke is suddenly produced, causing the pressure in the furnace to increase sharply and explode.

The main reasons for the gas explosion in the furnace are:

(1) Pre-sweeping before ignition and insufficient sweeping after flame-out; or insufficient pre-sweeping before re-ignition after ignition failure.

(2) After the furnace is shut down, the fuel system leaks due to valve parts, and the fuel leaks into the furnace and is ignited by the residual heat.

In order to prevent boiler gas explosion accidents, the following measures should be taken for the burners and fuel oil systems of marine boilers

(1) The pre-sweep air should be sufficient, and the pre-swept air should be re-ignited after the ignition fails.

(2) In case of emergency shutdown, the quick-closing valve should be closed first, and then post-sweeping should be performed.

(3) Strengthen the inspection of the fuel system and the automatic combustion control device. If oil leakage or other problems are found, they should be repaired in time.

4. Boiler surge (roar)

This is mainly due to unstable combustion, which leads to pressure fluctuations in the furnace. The main reasons are:

(1) The fuel supply pressure fluctuates, or the fuel atomization is poor, and the large oil droplets are flame retarded.

(2) The air volume is insufficient or the wind pressure fluctuates.