It all started with an idea in 2014. AF Gruppen wanted to see if it was possible to reduce the number of bottles of oxygen by dismantling modules on platforms out in the North Sea. Purchasing manager in AF Offshore Decom, Jan-Frode Pedersen, says it has been a long process. 

- It has been a long canvas to bleach. Such operations require large amounts of oxygen, and it is demanding to get enough out to the platforms. We had to convince the customer that it is a good idea to use liquid oxygen on the platform instead of traditional offshore gas racks. With good documentation and risk assessments, we received, with the support of Linde, acceptance of this concept. The customer was of course concerned about safety, since there is a lot of work with open flames on a platform that can be risky.

When the customer, after extensive risk assessments and a detailed review of the proposed solution, agreed to the project, the idea was to use liquid oxygen (LOX) rather than compressed. Together with Linde, AF Offshore Decom has developed a solution that can handle such large assignments.

Linde went from delivering several bottles and packages of compressed gas, to the delivery of tanks with liquid oxygen (LOX) of approx. 7,500 liters pr. tank. This reduced the need for transport from six to one truck on the specific delivery. At the same time, this solution was less space-consuming on ships and on board the rig - and not least, this reduced the need to change packages accordingly. Such a solution has several challenges, both when it comes to infrastructure, logistics and delivery capacity.

- We knew what we needed, but such a solution for use offshore was never delivered and used before. All the pieces were not completely in place, Pedersen says.

The project was of such a nature that several the components and equipment had to be approved for use in offshore. This was something completely new, and approval takes time. After working on the solution for a while, Linde came on the field. - They proved to be adaptable and had the ability to understand our challenges and find good solutions, Pedersen explains. 

- It has been a very good collaboration with AF Gruppen, says Bjarte Krossøy, Sales Manager Offshore in Linde.

- Now we have developed a solution together, a tailor-made scheme with all the infrastructure needed to carry out such large assignments. The new solution has provided major savings both in terms of logistics and space requirements. For example, one of our tanks is three full trucks with bottles. Linde has used the entire toolbox with all areas of expertise internally in the development of the new concept. AF Gruppen has very innovative and good people. In Linde, we have strengthened our organization and been creative in finding new, advanced solutions for the AF Group. This is a solution we have such great faith in that Linde has implemented several major investments for future projects, he says.

A sharp reduction in the need for deliveries of gas racks resulted in a direct saving in the form of at least two trips less to the platform with a supply boat, further positive effects were a reduced need for internal transfers of gas in the offshore workplace. These savings also directly reduce emissions from the vessels.

Both companies agree that everyone today has an obligation to find environmental solutions. When the projects become so large, liquefied gas is better both environmentally and logistically. By using large suppliers such as AF Gruppen and Linde, an enormously high recycling rate and marginal need for disposal can be ensured. Steel goes back to society.

The new solution provides a much higher form of flexibility and mobility. In addition, Linde has four factories with geographical spread - at Tjeldbergodden, Leirdal, Mo i Rana and Kårstø - which can supply liquefied gas to their regions and thus cover the entire country without unnecessarily long transport.

- You can almost call it short-distance gas, laughs Krossøy.

- Linde follows the steel absolutely all the way, Krossøy explains. - We supply the gas that welds the platforms together, we supply the gas that dismantles the platforms when they are no longer in use - and we deliver the gases to Celsa in Mo i Rana, which melts the steel for reuse. You can say we are "from cradle to cradle", he concludes.

The latest project where Linde and AF Decom are collaborating offshore is Brae Bravo. Linde also delivers products and support to AF Miljøbase Vats, where further processing for reuse and recycling takes place on both this and other projects.