Marine inerting
Nitrogen Generators for Marine and Chemical Tankers
A nitrogen generator for chemical tankers makes inert gas on board from compressed air, so a vessel can blanket and purge its cargo tanks without carrying bottled nitrogen or relying on flue gas. Membrane systems are compact, continuous, and tolerant of ship motion, which makes them the standard way to inert cargo on tankers and offshore.
Membrane
Proven at sea
95-99%
Typical inerting purity
Continuous
On-demand on board
No flue gas
Clean, dry nitrogen
Why tankers run on nitrogen
A chemical or product tanker carries cargoes that can react with oxygen or form a flammable atmosphere in the space above the liquid. Inerting that space with nitrogen removes the oxygen, so there is nothing left to support combustion and nothing to oxidize a sensitive cargo. Marine inerting typically keeps cargo-tank oxygen below about 8% by volume, the threshold widely used to prevent combustion on tankers.
A nitrogen generator for chemical tankers makes that inert gas on board, on demand, from the vessel's compressed air. That matters because many chemical cargoes cannot tolerate the soot, sulfur, and moisture in boiler flue gas, the older inerting medium. Clean, dry nitrogen blankets and purges them safely, and a marine nitrogen generator produces it continuously without the logistics of bottled gas.
The same logic applies across the fleet. A nitrogen generator for ships supports inerting, purging, and cargo-line drying on product tankers, offshore units, and other vessels that handle reactive or flammable cargo. The sections below cover the main marine applications and why membrane separation suits life at sea.
Marine nitrogen applications
Where on-board nitrogen does the work on chemical tankers, product tankers, and offshore units.
Cargo tank inerting
Nitrogen displaces the oxygen in the space above the cargo so the atmosphere cannot support combustion. This is the core safety function on a flammable-cargo tanker, held throughout loading, voyage, and discharge.
Chemical cargo blanketing
Sensitive chemical and product cargoes are padded with nitrogen to keep oxygen and moisture away from the surface, preventing oxidation, polymerization, and off-spec product on the voyage.
Purging & gas-freeing
Before tank entry, cleaning, or a cargo change, nitrogen purges flammable vapor and residual cargo out of the tank, bringing the atmosphere to a safe condition for the next operation.
Void & cofferdam inerting
Cofferdams, void spaces, and other enclosed areas around the cargo block can be inerted with nitrogen to control the atmosphere and reduce corrosion and fire risk.
Line & pump drying
Dry nitrogen clears and dries cargo lines, manifolds, and pumps between cargoes, removing moisture and residual product so the next cargo is not contaminated.
Offshore & FPSO
Offshore production and storage units use nitrogen for tank and vessel inerting, purging, and seal gas, where a continuous on-board supply is far more practical than delivered gas.
Why membrane separation suits life at sea
Marine inerting favors membrane nitrogen because it is rugged, continuous, and easy to scale to a vessel.
Built for motion
The membrane itself has no moving parts and no adsorbent beds to cycle, so it tolerates vibration and ship motion well. There is little to wear out in the separation stage, which is what a vessel needs on a long voyage.
Continuous and compact
A membrane nitrogen generator makes inert gas on demand from the ship's compressed air, in a compact skid that is light relative to stored gas. Output follows demand, so the vessel is never waiting on a delivery.
Purity to match the cargo
Inerting typically runs 95% to 99%. Where a sensitive chemical cargo needs higher purity, a PSA system can be specified instead, so the supply matches what the cargo actually requires.
For the technology behind it, see how membrane nitrogen generation works. Onshore, the same inerting and purging logic drives our oil and gas nitrogen systems.
Frequently asked questions
Why do chemical tankers use nitrogen?
Chemical and product tankers use nitrogen to inert the space above the cargo. Removing the oxygen means the atmosphere cannot support combustion, and it keeps oxygen and moisture away from cargoes that would otherwise oxidize or react. Marine inerting typically holds cargo-tank oxygen below about 8% by volume, the threshold widely used to prevent combustion on tankers.
What is a nitrogen generator for chemical tankers?
It is an on-board system that makes inert nitrogen from the vessel's compressed air, usually by membrane separation. Instead of carrying bottled nitrogen or relying on boiler flue gas, the ship produces clean, dry nitrogen on demand for blanketing, purging, and line drying. A nitrogen generator for chemical tankers gives the crew inert gas whenever the cargo operation needs it.
What oxygen level does marine inerting require?
For tanker cargo tanks, the atmosphere is generally held below about 8% oxygen by volume, the level widely used as the safe ceiling to prevent combustion. The exact target depends on the cargo and the vessel's procedures. The nitrogen supply is sized so the tank can be brought to and held at that condition through loading, voyage, and discharge.
Should a marine inert gas system use membrane or PSA?
Membrane is the usual choice for a marine inert gas system because it is rugged, continuous, and tolerant of ship motion, with no adsorbent beds to cycle. Where a sensitive chemical cargo needs higher purity than membrane delivers efficiently, a PSA system can be specified instead. The right choice comes down to the purity the cargo requires.
What nitrogen purity does marine inerting need?
Inerting typically runs 95% to 99% nitrogen, which is enough to bring cargo-tank oxygen down to a safe level. Some sensitive chemical cargoes call for higher purity to prevent any reaction at the surface, and those can be supplied with a higher-purity system. We size purity to the cargo rather than over-specifying it.
Why use nitrogen instead of flue gas?
Boiler flue gas was the older inerting medium, but it carries soot, sulfur, and moisture that many chemical cargoes cannot tolerate. A nitrogen generator produces clean, dry nitrogen that will not contaminate or react with the cargo, which is why product and chemical tankers favor on-board nitrogen for blanketing and purging.
Can a nitrogen generator be used on other ships and offshore?
Yes. A nitrogen generator for ships supports inerting, purging, and line drying across product tankers, offshore production and storage units, and other vessels that handle reactive or flammable cargo. Anywhere a vessel needs a steady inert-gas supply, on-board generation is more practical than carrying delivered gas.
How is a marine nitrogen generator supplied?
Gas Generation Solutions designs and supplies the nitrogen system, sized to the vessel's flow, purity, and pressure, and provides the system drawings and compressed-air requirements. Integration into the ship is handled by the vessel's yard and engineers. Tell us the cargo and the duty and we will size the right system for it.