Prelude FNLG - the longest ship in the world

This giant can be called anything you like: a ship, a ship, a superbarge with engines, a floating factory platform or a plant. But a fact is a fact: the Prelude FNLG object is almost half a kilometer long - 488 m. At the sight of this monster, next to which the Titanic seems like a toy, there is an assumption that it was built to set a new record. But this is absolutely not the case: huge and expensive ships have a purely practical purpose.

Why build big ships

Until 2013, the Japanese supertanker Seawise Giant, launched in 1979, was considered the largest floating object. The ship was produced in a single copy. Its dimensions were so huge that it could not pass through the Panama or Suez canals, even the way to the English Channel was ordered for it.



As a result of limited use, the giant has turned into a static facility, "engaged" in the production and storage of petroleum products. It seemed that the era of giants was over and it was unprofitable to build such superships - no one would do it. But no! Prelude FNLG was finally born. Who needs it and why?

Purpose

Such ships form a whole class of ships. Their designation is "driven" into the name - Floating Liquefied Natural Gas Platform (abbreviated as FLNG) - a floating platform for the production of natural gas. These are factories that convert fossil fuel into a compressed state. Today, "blue fuel" is mainly produced on land through classical wells. Another technology that has recently created a boom in the US is shale gas. But, as it turned out, the extraction procedure is expensive and harmful to the environment.

There is a third way - the use of the continental shelf. This technique is carried out in Russia on Sakhalin. The technology is very complex: 3 onshore platforms and 1 offshore platform are involved, located 16 km from the coast. Of the four facilities, one produces gas from a depth of 48 m, which then goes to the shore through pipes laid at the bottom. Further, through the highways, "blue fuel" enters a special factory complex, where it undergoes initial processing. And only then the gas reaches the enterprise engaged in its liquefaction.

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Based on the above, it is clear how important floating processing plants are. We received gas and immediately turned it into a liquefied state. At the same time, there is no need for long-term transportation associated with passing service.

How the floating plant was created

The first known attempt to design such a plant was made back in 1979 in Monaco, where the Norwegians proposed an original project at a conference on gas processing technologies. It was supposed to use the Kengan fossil fuel deposit in the Persian Gulf. But the Islamic Revolution in Iran crossed out the plans. Other projects were later proposed, but they were all considered very expensive. The development of Shell, which ordered the construction of a floating LNG plant from the Koreans in the Samsung Heavy Industries concern, turned out to be more or less justified.

Where Prelude is used

The ship was built "for" a specific field "Brows", located 100 km from the coast of Australia, well known for its high environmental standards. Because of them, amazing inconsistencies began.



The deposit was forbidden to be developed with the help of a coastal plant for environmental reasons. At a distance of 50 km from the proposed construction was a tourist center. And while Shell already had permission to develop the field. A paradoxical situation developed: it was possible to produce gas, but not to liquefy it. The way out is the construction of a floating plant. This would fit into the environmental standards of Australia, and it would also be cheaper than transporting gas for tens of kilometers, and then also processing it at an enterprise that needs to be built.



Therefore, they did not spare money on the ship: every day of “idle” turned into huge losses. The manufacturing technology of the barge consisted in welding individual sections.



While the ship was being built, the gas was transported to land in the usual way. Launching took place in 2013. It took 2 years to build, but in fact the floating enterprise was already being finalized “on the go” - equipped with additional equipment. Some options:

• ? length, width and height - 488, 74, 195 m, respectively
  
• ? displacement - 600 thousand tons
  
• ? storage capacity - 229 thousand cubic meters. m LNG
  
• ? annual production volume - 3,6 million tons
  
• ? used water (taken from a depth of 150 m already cooled) - 50 thousand cubic meters / h
  

To understand the “capabilities” of the platform, it is enough to say that the volumes it produces are much less than the annual gas demand of such a “state within a state” as Hong Kong (for 2021, the population is 7,6 million people).



The object does not have propulsion engines that would allow it to travel long distances. This can only be done with the help of tugs.



However, the floating plant is equipped with three Rolls-Royce electric propulsion units for orientation purposes. The power of each is 6700 liters. With. They help the ship to change position during a storm, strong wind (the maximum value is up to 70 m/s, which corresponds to powerful type 5 cyclones). As the largest floating object in the world, Prelude FLNG has been listed in the Guinness Book of Records.

How does a floating platform work?

Prelude Flng is operated 475 km from the mainland. The estimated service life is at least 25 years. The body of the platform in terms of strength and geometry is adapted to any onslaught of the elements. An interesting mooring system (developed in Saudi Arabia). This is a tower with a height of 93 m. In its lower part there are 4 “sets” of anchors. They hold the platform in place, but, on the other hand, allow it, if necessary, to turn with the help of water jet engines relative to the storm front.



Electricity is generated by steam turbines and seven Kawasaki boilers. They produce steam that turns three generators: 40 megawatts each. The entire technological system is divided into several modules, which were assembled on land and then lifted onto the ship.

Prospects

This object is one of a kind, but it is unlikely to be the last. The effectiveness of the platform will be clear after the end of its service life, but experts are already confident that this design will justify itself economically. The benefits are obvious:

• ? the possibility of developing fossil fuels in hard-to-reach areas
  
• ? savings on logistics
  
• ? compliance with environmental requirements
  
• ? in case of depletion of the deposit, the plant can be moved to a new location
  

"Oils on the fire" was added by the customer of the project, the Shell concern. Judging by the management's statements, Prelude is not the end goal. A more extensive “territory” object is already planned. There are no restrictions on dimensions - the platform does not need to "care" about the dimensions in order to pass through narrow straits. Therefore, the length of 488 m cannot be called the limit: the figure can be both 600 and 700 meters.