CLICK HERE TO DOWNLOAD PPT ON Inert Gas System
Inert Gas System Presentation Transcript
1.Inert Gas System
2.A Brief history
In the 1960s, three tanker’s in three different parts of the world exploded causing a major disaster and loss of life.
The common link was that all the three ships were performing tank cleaning operations.
Tanks were being washed down with jets of water on an oily surface in an Hydrocarbon and Oxygen rich atmosphere.
In short.. the atmosphere was
NOT INERT, BUT EXPLOSIVE.
In the 1960s, three tanker’s in three different parts of the world exploded causing a major disaster and loss of life.
The common link was that all the three ships were performing tank cleaning operations.
Tanks were being washed down with jets of water on an oily surface in an Hydrocarbon and Oxygen rich atmosphere.
In short.. the atmosphere was
NOT INERT, BUT EXPLOSIVE.
3.To protect the Oil Tankers form such disasters in the future
A Inert Gas System was developed
A Inert Gas System was developed
4.What is Inert Gas ?
It is a gas which contains insufficient Oxygen to support combustion.
Keeping tanks inerted means cutting one side of the fire triangle and hence avoiding any chances or Fire or Explosion.Why do we need Inert Gas ?
For the Safety of Oil Tank vessels against
fire and explosion risks
It is a gas which contains insufficient Oxygen to support combustion.
Keeping tanks inerted means cutting one side of the fire triangle and hence avoiding any chances or Fire or Explosion.Why do we need Inert Gas ?
For the Safety of Oil Tank vessels against
fire and explosion risks
5.A Tanker with gas and oxygen inside the cargo tank is like a Floating Bomb which can explode with the slightest spark
6.What happens if the Tanker Explodes ?
7.What is a Fire Triangle
It describes the three different factors required for ignition of a fire.
Air (Oxygen)
Heat (External Spark)
Fuel (Cargo)
8.The Oxygen Depleted Condition
It describes the three different factors required for ignition of a fire.
Air (Oxygen)
Heat (External Spark)
Fuel (Cargo)
8.The Oxygen Depleted Condition
9.The Flammability diagram
10.What is the percentage of oxygen required to sustain combustion ?
What percentage of oxygen are we required to maintain
in the cargo tanks ?
By law less than 8 %.
Some ports require a vessel to maintain less than 5 %.
A Cargo tank is considered “Inerted” when the oxygen content in the tank is less than 8 % by volume
What percentage of oxygen are we required to maintain
in the cargo tanks ?
By law less than 8 %.
Some ports require a vessel to maintain less than 5 %.
A Cargo tank is considered “Inerted” when the oxygen content in the tank is less than 8 % by volume
11.How can we produce such Inert Gas
(oxygen depleted gas) on board a ship ?
From the Exhaust Gases (Flue gas) of a boiler. The combustion of the Boiler can be controlled to reduce the oxygen to less than 5 % in its exhaust.
Why can’t we use the Exhaust from the
Ships Main Engine or Auxiliary Engine?
Engines are designed to work with higher percentage of oxygen for better combustion and efficiency. These exhaust gases are rich in oxygen and much above 11 %. Hence not suitable for use as Inert Gas.
(oxygen depleted gas) on board a ship ?
From the Exhaust Gases (Flue gas) of a boiler. The combustion of the Boiler can be controlled to reduce the oxygen to less than 5 % in its exhaust.
Why can’t we use the Exhaust from the
Ships Main Engine or Auxiliary Engine?
Engines are designed to work with higher percentage of oxygen for better combustion and efficiency. These exhaust gases are rich in oxygen and much above 11 %. Hence not suitable for use as Inert Gas.
12.How much does it cost us to make Inert Gas on board ?
It is almost free of charge because
Inert gas is mainly used during the discharge of the vessel.
The Boiler is anyway running during the discharge of cargo to power the turbines of the cargo oil pumps.
13.When Is Inert Gas Plant Used
During Discharging to replace the volume of the Liquid in the tank.
For Purging, so as to replace the atmosphere in the tank.
To Top up cargo tanks in loaded voyages.
It is almost free of charge because
Inert gas is mainly used during the discharge of the vessel.
The Boiler is anyway running during the discharge of cargo to power the turbines of the cargo oil pumps.
13.When Is Inert Gas Plant Used
During Discharging to replace the volume of the Liquid in the tank.
For Purging, so as to replace the atmosphere in the tank.
To Top up cargo tanks in loaded voyages.
14.Can the Exhaust gases of the boiler sent straight to the cargo tanks ?
Due to the following reasons
The Exhaust gases of the boiler are very hot and dirty and requires treatment prior they are sent to the cargo tanks.
Any connection between the Non hazardous area (Engine room) and the Hazardous area(Cargo Tanks) calls for safety barriers between the two areas so as to prevent back flow of flammable gases to the boiler from the cargo tanks.
15.A Typical Block Diagram of Inert Gas System
Due to the following reasons
The Exhaust gases of the boiler are very hot and dirty and requires treatment prior they are sent to the cargo tanks.
Any connection between the Non hazardous area (Engine room) and the Hazardous area(Cargo Tanks) calls for safety barriers between the two areas so as to prevent back flow of flammable gases to the boiler from the cargo tanks.
15.A Typical Block Diagram of Inert Gas System
16.A Marine Boiler
17.Scrubber
18.Inert Gas Blower
19.The Deck Seal
20.Deck Seal
21.Deck Seal Viewed from the Bridge of one of our Tanker
22.Pressure Vaccum Breaker
23.Pressure Vaccum Breaker
24.Pressure Vaccum Breaker
25.The Mast Riser
26.Black Sea Loading at a SBM
27.What are Vapor Connections ?
28.High Velocity Pressure and Vaccum Valve
29.What is a Tank branch Valve ?
As seen in the Photo the valve is shut and if the vessel continuous to load / discharge in this condition. It will cause the cargo tank to damage due to under / over pressurization
The PV valve will come in operation much earlier and avoid the damage
As seen in the Photo the valve is shut and if the vessel continuous to load / discharge in this condition. It will cause the cargo tank to damage due to under / over pressurization
The PV valve will come in operation much earlier and avoid the damage
30.High Velocity Pressure and Vaccum Valve
The Shape and Pressure setting of the valve is such that it allows the vapor to vent more than 30 m / sec
This allows it to rise high enough for dispersing safely
Also avoids traveling of any spark back to the tank.
The Shape and Pressure setting of the valve is such that it allows the vapor to vent more than 30 m / sec
This allows it to rise high enough for dispersing safely
Also avoids traveling of any spark back to the tank.
31.A Typical High Velocity valve Of another Vessel in the fleet
32.Inert Gas Generator
This equipment is fitted on some of our vessels in the fleet and is used to fill up small quantities of Inert gas to TOP Up the tanks during the loaded passage, when the ullage spaces of the cargo tanks are small .
This equipment is fitted on some of our vessels in the fleet and is used to fill up small quantities of Inert gas to TOP Up the tanks during the loaded passage, when the ullage spaces of the cargo tanks are small .
Posts
0 comments