Super Tanker-Engineering Connections

LNG carrier. Liquefied Natural Gas. At room temperature, it turns into highly flammable gas.


Liquid Nitrogen: Avoid leaking liquid gas to catch fire.
Chromium: Reduce the brittle of steel in super-cold temperatures.
Spherical tankers: Reduce the Free Surface Effect for transporting liquid gas.
Baffles: Ballast compartment needed water to be stable as the liquid gas tanker are empty.

She is larger than Titanic. Let's see how these ships shift huge quantities of gas around the world.

Inside the gas tanker



Turn the gas into the liquid that can't catch fire.



If any  of the liquid leaked out from this tanker and turned back into vapor that would be catastrophic. But it doesn't thanks to a prewar mail plane.

They couldn't cross the Atlantic until they are able to take on fuel on flight.



We take Aerial Refueling for granted, but aviation fuel is like natural gas, highly flammable.
A quick squirt of nitrogen don refueling pipes removes any risk of explosion.

This thin layer of aluminium is the outermost skin. On the other side, there is a layer of insulation.
It's porous and steeped in  nitrogen. In case of a leak, nitrogen stops a volatile cargo reacting with oxygen and the insulation keeps it in liquid form.

But these super-cold temperatures involves the engineering challenges. Steels pipe is not suitable material for transport the liquid gas.

After the steel soaked in the liquid nitrogen, it would be extremely brittle. Easy to broken. Instead, the tankers engineers needed a material that can withstand super-cool temperatures, which brings us back cutlery of stainless steel variety. In 1913, British chemist Harry Brearley was looking for tough metal for gun barrels. He mixed chromium and steel, but it was too soft. However, it reveals two benefits. It didn't rust and is better for the liquid gas tanker putting this stainless steel in deep freeze sea doesn't make it brittle. Because the alloy elements in the stainless steel, it's changed its crystal structure. The way the atoms are arranged in the metal.

Simply adding chromium can make ordinary brittle steel withstand cryogenic  temperatures.

Transporting mass liquid gas across the sea faced the challenge is similar with the Fire Trucker.
The engineers needed to avoid sloshing. And engineers have two different liquids to worry about on these tankers. On the way out, they have cargo of liquid gas and on the return journey, as it's empty. The supertanker carries water as ballast to stabilize the ship.

Free Surface Effect

The car rolled over on the road.

As in the corner, the momentum of the slosh capsized this little van.

MS Herald of Free Enterprise, the Free Surface Effect capsized this ship, as water gushed into the doors had accidentally remained open.

To reduce the free surface area, the gas tankers are spherical. Less rooms for sloshing.
So the tankers in normal circumstances is either almost entirely full or or empty.

Empty cargo would ride high in the sea. To lower it, the water is pumped into the ballast compartments in the hull beneath the gas tankers. But space doesn't allow these compartments to be spherical, so preventing sloshing here is the different solution.

Baffling System. Prevent the tanker from capsizing.

Empty of full this ship is stable. Dividers in the ballast compartment under the gas tanker stops water sloshing around. Surprisingly, the baffles didn't used on the liquid gas tankers, due to the friction could heat up the cargo that  would turn liquid back gas.

Proplelling would be the problem. Due to the inertial force is extremely large.

Aeolipile. Third Law.
The mutual forces of action and reaction between two bodies are equal, opposite and collinear.

The turbine was driven by the steam which is similar with the nuclear plant.





Darwin noticed the boiling point varies at different altitudes. The higher altitude, the lower boiling point of water.

Suck air out of the canopy, that's lowering the air pressure. Water will boil at lower temperature.

No heat here, room temperature. As you can see the marshmallow expanded due the low pressure.

Look at that water is boiling at room temperature.

On the ship, just like the vacuum flask, they boiled water at a low temperature by reducing the pressure.





Cold water will flash condense the steam, reducing the pressure. The steam will condense back to water.

Lower pressure inside the tank. Liquid gas carrier instantly turned team back to water using
flash condensation. That creates low pressure area like the vacuum flask.

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