Some of the remotest corners of the earth are home to massive deposits of natural gas. But building modern and environmentally sound gas processing plants in the desert or the Arctic presents massive challenges – even for experienced engineers. To overcome the practical and cost efficiency hurdles presented by these hostile environments, Linde decided to build a team with the necessary expertise at its Competence Centre Modularisation (CCM). The modularisation concept involves the pre-fabrication of plant modules at Linde’s designated yards and subsequent shipping to the assembly site.
Typical design of a modular air separation plant
Linde has been successfully taking the modularisation route for many years. By setting up the CCM, the company is now bundling the experience it has gained in the construction of complex plants for inaccessible places. Melkøya is an example of one such ambitious project realised by Linde engineers. The island, whose name literally means “Milk Island”, is a small uninhabited speck of land to the far north of Norway. From here, the cities of St. Petersburg and Helsinki are nearer than the national capital Oslo. In fact, most travellers would never even have heard of it – unless they happened to pass it by on their way to the nearby port town of Hammerfest. For well over a decade, however, the names Hammerfest and Melkøya have been synonymous with impressive feats of engineering. This is where the Norwegian company Statoil operates the world’s most northerly natural gas liquefaction plant. The planning, construction and start-up were all managed by Linde.
Hammerfest is Europe´s northern-most city.
Moving on to the southerly tip of Europe
The LNG plant in the Norwegian Sea was an impressive and pioneering project which pushed the engineers into new terrain – and not just geographically! The coldbox, which is where the natural gas is liquefied by cooling it to minus 163 degrees Celsius, is as large as a 20-storey building. 62 metres high and 3,500 tonnes in weight, the entire box was shipped to the island after being assembled in Antwerp, Belgium. Other components, such as the floating process plant – a 35,000-tonne concrete giant equipped with high-tech process modules – travelled around the entire continent by ship from the southern Spanish city of Cadiz.
The difficult conditions at the shipping destination explain these elaborate transport arrangements. If nothing exists at your destination, you have no choice but to bring everything there. “There are no people, there is no infrastructure and no proper energy supply – so you basically have to start from scratch,” says Christian Proske, Head of CCM. Then there is the high cost of labour in countries like Norway and Australia. If the number of on-site workers that need board, lodging and wages can be kept to a minimum, the overall costs of the plant can be reduced.
Proven, secure fabrication hubs
In the case of the LNG plant in Kwinana, Australia, several factors added to the appeal of modularisation. Apart from the high labour costs and lack of infrastructure, the intense heat of Western Australia makes it very difficult to realise complex construction projects. The solution for Linde was to have the plant pre-fabricated in Thailand and transported to Kwinana by ship. “My yard is a proven and secure environment,” explains Proske. “I have a team that knows what it’s doing and cranes in situ, so I need less scaffolding and face less risk due to adverse weather conditions.”
Linde has now established a global network of yards to assemble complete modules or even entire plants, including sites in Thailand, Portugal and Mexico. Further cooperation agreements are in the pipeline. The benefits of modularisation for customers include customised designs, shorter transport routes and lower costs.
In previous projects, modularisation only came into play at the planning stage. In future, Linde wants to pull the modular versus on-site stick-build decision forward to the very start of preparations.
“We cannot say that one method is generally better than the other,” says Proske, who recommends deciding on a case-by-case basis. “We will not necessarily opt for modularisation every time. Our job is to establish the best concept for each project and then follow that path.”
Floating LNG plants
The advantages of modularisation are particularly evident in the case of floating LNG plants. Here, Linde is part of a consortium seeking to unlock natural gas reserves located far offshore and liquefy the gas on the spot. Floating LNG platforms could be used in the Arctic or for gas fields stranded in the middle of the ocean.
“This is an interesting opportunity for us,” reckons Proske. “The outer shell of the ship looks like an oil tanker, and then you have all the process modules on deck – an entire plant producing liquefied natural gas on the open sea.” Based on the experience gained in recent years, Proske now sees the company in “a much strong position”. It looks like it’s full steam ahead for Linde in the area of modularisation!
Engineer at work. Kwinana plant, Australia.