Inert Gas System Explained: Enhancing Safety on Oil Tankers

Posted on Jun 12, 2024 at 11:06 PM

Operating an oil tank is not a piece of cake. The transportation of large quantities of flammable cargo makes ships vulnerable to a mixture of risks like fire and explosion. 

The maritime industry always looks for the perfect solution to improve safety measures. One of the most important innovations is the Inert Gas System. This system has a central role to play in preventing combustion and in making the handling of cargo safe.

In this article, we will discuss the Inert Gas System, what it is, and how it increases the levels of safety on a cargo ship.

What is an inert gas system?

An inert Gas System also known as an IG System is a safety feature implemented in oil tankers designed to prevent and reduce fire or explosion. It works by lowering the oxygen content in the cargo tanks to a level that cannot burn, effectively making the environment non-flammable. 

Conventionally, the inert gas (Like nitrogen, hydrocarbon, argon, or helium) is generated by passing the flue gases from the ship’s boilers or main engine through a scrubbing process to cool, purify, and then transport to the fuel cargo tanks.

Inert Gas System: How it works

The operation of Inert Gas Systems involves several key components and stages:

• Gas Source: The raw source of inert gas is the flue gas of the ship’s boilers or the exhaust gas of the main generator.

• Scrubber Unit: The flue gas is then transferred to a scrubber where it is cooled and washed to remove materials, such as soot and sulfur, that may be present in the gas.

• Gas Blower & Cooling: Once washing or scrubbing is done, the gas is passed through blowers to cool it further to manage its temperature.

• Inert Gas Distribution: It is then conducted to the cargo tanks where it pushes out the oxygen-enriched air within the tanks.

The Inert Gas System regulates the oxygen concentration to below 8% to make the atmosphere in the cargo tanks nonflammable, thus minimizing fire or explosion hazards.

Why are inert gas systems important?

As previously discussed, the IG system acts as a protective measure between the vessel’s structure and the corrosive environment to prevent corrosion, here’s why it’s so important:

Enhancing Safety

The main purpose of the IGS is to improve the safety of oil tankers. Namely, by keeping oxygen concentration levels low within the cargo tanks, it actually precludes the conditions necessary for combustion to take place. 

This is particularly important during loading and unloading processes when the chances of vapour spreading (like carbon dioxide) are at their most elevated.

These systems, although fairly simple, contribute to the overall safety of the maritime world and prevent the need to use techniques like bioremediation to couteract oil spills, because with inert gas systems, they’re less likely to happen.

Regulatory Compliance

Supervisory authorities including the International Maritime Organization (IMO) guidelines require the usage of Inert Gas Systems on oil tankers of a particular size. These requirements are important for the safety of the vessel and its crew as well as for the protection of the environment to avoid the occurrence of oil spills or fires.

Economic Benefits

Although an inert gas system requires investment in installation and maintenance, the long-term economic benefits are great. Preventing burning fires and explosions not only protects people and machinery equipment but also lowers insurance costs and decreases time and money for recovery.

Subsystems of the Inert Gas System

An efficient Inert Gas System typically includes several critical components:

• Inert Gas Generator: This creates inert gas through the suppression and purging of the vapours and gases from the ship’s generators.

• Scrubber Unit: This unit cools and scrubs the inert gas before it is admitted into the cargo tanks.

• Blowers: These blowers are used to force the inert gas into the cargo tanks.

• Inert Gas Distribution Network: This network of pipes and valves distributes the inert gas evenly across all the tanks that have been used to carry the cargo.

• Deck Seal: This avoids back flow of gases to the engine room from the tanks thus creating safe and clean spaces.

• Pressure and Oxygen Monitoring Systems: These control the pressure and the amount of oxygen in the system and make sure that the levels do not go beyond the tolerable limit.

Implementation and Operation

Now that we’ve gone through the what and why, it’s time to get to the how, how can you use this system in your work?

Installation

The process of installing an Inert Gas System on board an oil tanker is a delicate process that requires a number of tools and a lot of planning. The system has to blend well with the rest of the infrastructure associated with the vessel so that it functions well.

Maintenance

It is equally important to ensure that the Inerting Gas System is always in good working condition, and this can only be achieved through regular maintenance. This is done through regular checks and servicing of the scrubber unit, the blowers, and the overall network of gaseous distribution. Any detected anomalies or malfunctions should be handled to avoid system failure since they are vital in the system.

Crew Training

It is important to train the crew adequately on the proper usage and maintenance of the Inert Gas System through an Oil spill management courses online. Crew members are required to learn about the system's capabilities, the actions they have to undertake when an alarm is triggered, and the initial steps they should take if malfunctions occur, fire extinguishing, or making sure it's controlled and doesn't put anyone at risk.

An inert gas system is one of the most important safety solutions when it comes to marine supply chains. Safety is a product of safe procedures, start incorporating inert gas systems and keep your ship a safe space today!