This Article You will know about , What is Economizer fire ? How it is Occur ? How to Prevent ? Action taken |
So, Let us start every point related to it.
Read about :- Air starting line explosion and safety device
What is Economizer Fire ?
A fire occur in the coil of economizer when main engine running in the sea for for generating the steam. In simple language, a fire takes place in the economizer.
what is Economizer ?
A Economizer is a device which is used for generating steam by using using waste heat of Exhaust gas of Main Engine. Or, It is a saving energy device which reduce the cost of steam production by saving the fuel.
Actually, in the economizer, main engine exhaust gas used for heating the water. Heat from Main exhaust gas used as heat source to heat the water. The efficiency of main engine power plant increase by using waste heat gas from exhaust gas.
How Economizer Fire Occur
The main reason for Fire occur in Economizer is catching Fire in the Carbon deposits.
Dry Carbon :- On the tube of economizer, Carbon Deposits or soot is stick to the Tube because of passing of main engine exhaust gas. The ignition temperature of dry carbon is 1000 degree celcius. So, it is not harmful because exhaust gas temperature available at tube of economizer is around 400 degree celcius.
But, the ignition temperature of carbon in the wet conditions is less around 200 degree celcius. In economizer dry carbon becomes wet when unburnt fuel oil or lube comes in contact and temperature drop to 200 degree celcius. When exhaust gas of main engine paases through tube and suddenly catches fire. Thus, fire in economizer takes place.
Fire Triangle complete in the economizer, and the fire takes place.
1.Combustible Materials :- A Combustible materials are wet carbon deposits on the tube.
Dry carbons on tubes of economizer is available in bulk but their ignition temperature is 1000 degree celcius. when dry carbon get wet when dry carbon come in contact unburnt lube oil or fuel oil.
2.Heat source :- Heat source is waste heat from exhaust coming from main engine.
3.Oxygen :-Oxygen is available at economizer. The excess carbon deposits and proper heat transfer not take place causing tube get red hot . It would act as a source pf ignition.
What are the reasons for Carbon deposits ?
These are the following reasons for the carbon deposits in the tubes :-
- Due to improper combustion of fuel in the Main Engine.
- If maneouvring time is long.
- Lube oil feed for cylinder liner lubrications is incorrect.
- Fuel injectors Maintenance or overhauling is not done for a long time, Injector dripping.
- Exhaust valve of M/E leaking.
Types of fire occur in EGB
there are two types of fire occur in EGB. These are :-
- Minor Fire
- Major fire :- A.) Hydrogen Fire And B. ) Metal Fire
1. Minor Fire
Minor fire in EGB is only due to burning of wet carbon on the tubes. How will you know that EGB fire ? You Know when – the outlet temperature of exhaust coming out through funnel is more than the inlet temperature of the exhaust gas.
2. Major Fire
If Minor fire occur and preventive action not taken by Engineers and finally major fire takes place.
During EGB fire, we should never perform extinguishing of fire by direct water. If extinguishing done by water then it cause hydrogen fire.
Reaction of hydrogen fire are :-
2H2O———–>2H2 + O2
From above chemical reaction , we can conclude that formation of H2 takes place. And this hydrogen starts burning cause hydrogen fire. Again this fire again converted inro metal fire. Metal fire occur because oxygen is available and it started oxidising the metal of tubes.
We have seen that how economizer fire occur.
Preventive action perform in case of Economizer Fire
- During EGB fire never ever carry out the soot blowing.
- Inform the bridge
- Call the engineers.
- As soon as possible stop the main engine.
- Now, Stop the A/E ( Auxiliar Blower ) , Close the Drain of turbocharger , Put canvas on the blower side of turbocharger so that air not go to scavenge manifold ,Also shut off aa the drains of scavenge.
- If You are on port, Boiler Is running then stop the boiler. Or In the case Both boiler or EGB is in use then stop both.
- For fire fighting of EGB fire, there are some permanent arrangements.
- In older ship , there is no fire fighting system for EGB. In that conditions , we do only water cooling. Never Do direct extinguishing of fire with water because it leads to major fire. A. Hydrogen and B. metal fire.
- We never stop the boiler circulation pump. But in the conditions, if water level of hot well/ Cascade tan decreasing. It means water tube get burst. So, in this conditions stop the boiler circulation pump otherwise leads to hydrogen fire.
Must read :- Soot blowing procedure
What are indications of EGB fire ?
- The exhaust coming from funnel is higher than inlet temperature.
- Sparks coming from funnel.
- Economizer body get overheated.
- From smoke smell at economizer platform.
How to prevent EGB fire ?
As we studied above , we understand we need to maintain engine properly that proper combustion of fuel and soot blowing done regularly.
- Maintain the lube oil feed setting,
- Fuel use for combustion is well treated.
- Soot blowing done properly.
- Never run engine at low load for longer time
- Maintain and overhaul of fuel injector and pumps regularly
- Also Maintain Exhaust valve, because leaking of exhaust valve exhaust temperature high.
What is uptake fire ?
Uptake fire is fire in the Economizer. uptake fire is called exhaust has boiler due to ignition of wet carbon deposits on the tubes.
Note :- Uptake fire is also known as Economizer Fire.
What is EGB Fire ?
EGB means Exhaust Gas Boiler. EGB fire is same as Uptake fire or fire in economizer fire.
What is EGB ?
An Exhaust Gas Boiler is a type of heat recovery system on ships that uses the exhaust heat of the main engine to generate steam while it is being released into the atmosphere.
Which gas is used to EGB ?
Carbon Dioxide – CO2