1. Inert Gas Generators (IGG)
How this works: Inert Gas Generators (IGG) produce inert gases that are delivered to a ship’s cargo tanks, to prevent the combustion of fuel oil and air (i.e. explosions), by maintaining a low level of oxygen (less than 5%). The IGGs consist of two main units – the burner and the scrubber. The former burns fuel to produce gas with an oxygen level of about 2-4%, before passing through the scrubber unit, where it is cooled and cleaned by seawater before being distributed into cargo tanks.
Inert gas generator produce inert gas by combustion of fuel oil and air to low flammable level <5% and it can be delivered to cargo tanks as inert gas.
How this system compares: IGGs are a lot more complicated than other types of inert gas systems. They contain many different components such as the scrubber pump, fuel oil pump, blowers and ignition burners, relying on all these to run. Each of these components should adhere to a maintenance schedule. For example, if not maintained regularly the control air system is prone to break down, as oil and water can be found in the control air, affecting the operation of the system.
Where this is used: IGGs are used on board oil and product tankers.
2. Flue Gas Systems
How this works: Flue gas systems are another common type of IGS. Flue gas produced by a ship’s boilers are used to produce inert gas by drawing it through the scrubber with a fan, washing and cooling it before being directed to the vessel’s cargo tanks as inert gas. No further treatment other than washing and cooling is needed as flue gas is already inflammable, containing less than 5% of oxygen.
It utilize the flue gas from the boilers and drawn through the scrubber by fan and when the oxygen content below low flammable level it can be delivered to cargo tanks as inert gas.
How this system compares: Flue gas systems are more straightforward than Inert Gas Generators, as the inert gas’ oxygen level can be controlled by the combustion in the boiler. (How else is this system different from others)
Where this is used: Flue gas systems are used on crude oil tankers and product tankers.