Degussa: Polyamide 12 Receives First Certification for Offshore Pipelines

VESTAMID® LX9020 of Degussa AG (www.degussa-hpp.com) is the first polyamide 12 to be granted certification by Lloyd’s Register for use in the manufacture of non-bonded flexible pipes for the transport of offshore production & injection fluids, according to the API 17 J "flexible risers" norm, and EN ISO 13628-2. Wellstream International Limited of Great Britain, which processed the pipeline material developed by Degussa´s High Performance Polymers Business Unit, was the company that received the certificate. The required tests, which lasted two-and-a-half years, were conducted jointly by the two companies.

The non-bonded flexible pipes used for the transport of offshore production & injection fluids may be laid as a single line from the offshore platform to the well head in water depths up to 2,000m. An unbonded flexible pipe is a multi-layered structure of helically wound metallic wires and tapes, and extruded thermoplastics. A plastic shield protects the steel layers from external salt water corrosion and internally is used as a barrier against the often aggressive corrosive fluids transported. Flexible pipes are designed to have a service life in excess of 20 years.

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VESTAMID® LX9020 – Advantages over polymers currently used
Polyethylene (PE), polyvinylidene fluoride (PVDF) and polyamide 11 (PA 11) are the materials currently used for offshore pipelines. Now, with its recent certification, VESTAMID® LX9020 can also be used. The compound is chemically resistant to offshore fluids at high and low temperatures. Many of its long-term properties, e.g., hydrolysis resistance and creep behavior, are superior to those of the current material. The biggest advantage comes at the processing stage: VESTAMID® LX9020 is delivered dry and can be processed directly from its packaging without additional predrying. Because of its high melt stiffness, the material displays consistent processing behavior in the extruder. The absence of fluctuations makes it easier to achieve large pipe diameters given a constant overall diameter.

Development partnership strengthens market launch
VESTAMID® LX9020 was developed and tested in partnership with Wellstream International. Degussa’s technical service engineers also helped out in the processing stage, contributing expertise gained from many years of experience in pipe extrusion. Both partners introduced the advantages of pipes made of VESTAMID® LX9020 to the oil industry. As the customer for the pipes, it is the industry which provides the final acceptance of PA 12.

More thick-walled pipes under development
Offshore pipes are not the only type of thick-walled tubes High Performance Polymers is working on. A test installation of gas pipes made of VESTAMID®, under a constant gas pressure of 24 bar, have been continuously monitored online since the fall of 2005. The manufacture of relining pipes is also a possibility.

Picture: Without any problems 1.5 km of VESTAMID® tubing is produced and coiled on a 28feet diameter reel (about 8.5 m) for further processing.

Degussa AG, Düsseldorf

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