Eupec to manage Nord Stream pipeline coating process

Earlier this year, Dunkerque-based Eupec signed a letter of intent to supply concrete weight coating and logistics services for the Nord Stream pipeline project. This will take gas from Russia across the Baltic Sea to mainland Europe via two lines, each 1,210 km (752 mi) long, with a combined capacity of 55 bcm/yr (1.9 tcf/yr).

Germany’s Europipe and Russia’s OMW will manufacture the pipeline sections from high tensile steel, with wall thickness varying from 27-41 mm (1.06-1.61 in.), in accordance with pressure decline along the proposed route. Internally, the pipes will be coated with an anti-friction coating, while externally, they will be protected with a layer of anti-corrosion coating.

Schematic shows Eupec’s five-layer polypropylene foam coating system.

To provide extra weight and stability on the seabed, the steel pipe joints, each 12 m (39.4 ft) long, will also undergo external concrete coating with a thickness varying from 60-110 mm (2.36-4.33 in.). A comprehensive inspection program will then be applied involving ultrasonic, magnetic particle, radiographic and other non-destructive testing techniques, to ensure the joints can withstand the pipelines’ maximum internal pressure of over 200 bar (20 MPa).

Concrete weight coating will be performed at new coating plants to be constructed on the Baltic coast at Kotka in Finland and Mukran on the island of Ruegen, off northern Germany. The Nord Stream partners have selected Slite on the island of Gotland, off eastern Sweden, as the site of the main interim stock yard, with Hanko in southern Finland and Karlshamm in southern Sweden identified as strategic locations for additional interim stock yards, the aim being to keep transportation distances within 100 mi (161 km).

Eupec, as Nord Stream’s logistics partner, will manage discussions with authorities at these locations about the type of facilities needed to ensure deliveries of weight coating and logistics services. The five proposed sites should employ up to 375 personnel for this project.

The two coating plants will employ the same coating processes applied by Eupec at its factory in Grande Synthe, France. For the first line, 75% of the pipes will be manufactured in Germany, with Mukran coating 770 km (478 mi) of those pipes. The coating plant will occupy an area of 10,220 sq m (110,007 sq ft), with a slightly larger area for the steam-curing facility.

First pipe sections were due to reach Mukran and Kotka in April and June, respectively, with pipe coating scheduled to start at Mukran next January and at Kotka in March 2009.

Coating for the first of the Nord Stream pipelines should be completed by the following December. All completed pipes will then be transported to the interim stick yards and from there to the designated lay barge. The total budget for the coating and logistics contract is €650 million ($1.025 billion), with around €100 million ($157 million) allocated to establishment of coating and logistics infrastructure.

The intake point for the Nord Stream system will be Vyborg in Russia, the delivery point in Germany being a reception terminal in Lubmin, near Greifswald. The first of the pipelines should be operational in spring 2011, with annual throughput capacity of 55 bcm/yr (1.9 tcf/yr) being reached the following year on completion of the second phase.

Wet/dry insulation

Eupec provides thermal insulation coating services for shallow and deepwater steel pipelines, currently at depths up to 3,000 m (9,842 ft). These include polyurethane-based systems for wet insulation (solid, foam, syntactic, or glass syntactic). They are applied either via injection molding, rotational casting, spraying, or in the form of polyurethane half-shells.

The company also supplies multi-layer anti-corrosion coating systems in a wide range of layers and thicknesses. Linepipe coating is applied by side extrusion, with a patented injection moulding technique implemented for field joints, both suited for reel lay, J-lay, and S-lay installations.

One of the company’s more strategic product developments for 2008 is a five-layer foam polypropylene coating system for applications involving transportation of a high temperature well stream, where a minimal temperature drop is stipulated - i.e. to avoid shut down due to hydrates formation, to reduce fluid viscosity, or to increase pipeline flow.

The coating system, applied via a side extrusion process and an electrostatic spraying technique, involves application of five different layers of coating:

•     1st layer (fusion bonded epoxy- FBE) provides the main anti-corrosion properties
•     2nd layer (polypropylene –PP –adhesive) is designed to ensure high strength properties between the PP and the FBE. The adhesive should be sufficiently thick to absorb interfacial stress between the epoxy layer and the solid PP layer
•     3rd layer (solid polypropylene) is an intermediate layer providing a safe anti-corrosion protection, also ensuring that water ingress does not reach the steel pipe
•     4th layer (foam polypropylene), is also the thickest, designed to assure the thermal insulation properties of the five-layer coating
•     5th layer (solid polypropylene), is the system’s outer sheath, which is stabilized against ultra-violet radiation and also thermally stabilized against ageing by thermal and UV degradation. This outer coat also reduces the speed of water ingress through the insulation PP foam, and provides additional mechanical protection of the PP foam layer.

Immediately after each coat has been applied, cooling is applied with fresh water.

In recent years, Eupec has also managed fabrication of Interpipe’s pipe-in-pipe (PIP) systems in Dunkerque, its scope including pipe coating, PIP sleeve installation, welding, and logistics.

05/01/2008

http://www.offshore-mag.com/articles/print/volume-68/issue-5/france/eupec-to-manage-nord-stream-pipeline-coating-process.html