NKT starts harsh-environment flexibles review

NKT Flexibles has started a three-year program aimed at developing flexible pipes for super-critical carbon dioxide (CO2) applications.

Offshore staff

BRONDBY, Denmark -- NKT Flexibles has started a three-year program aimed at developing flexible pipes for super-critical carbon dioxide (CO2) applications.

NKT’s three-year program will focus on materials testing and qualification; mid-scale testing; and a review of design rules to ensure that the influence of supercritical CO2 is taken into account in every way.

The company is participating in the TWI-organized joint industry project Material Assessment for Supercritical CO2Transport. Results to date suggest that XLPE liners and non-plasticized PVDF liners offer superior properties for handling supercritical CO2.

There is growing demand for risers capable of handling production from deepwater high pressure reservoirs with a high CO2 content. There also is increasing interest, NKT points out, in re-injecting CO2 into the reservoir, either for enhanced oil recovery, or to cut CO2 emissions for carbon capture and storage.

In all cases, CO2 will likely be present in a supercritical phase, a mixture between liquid and gas. CO2 becomes supercritical above 31°C (88°F) and 73 atm.

NKT says supercritical CO2 exhibits high solubility in certain polymers and a strong extraction power. This could causes swift de-plasticization of otherwise plasticized polymers.

Also, the high CO2 content, combined with water, creates a corrosive environment that could negatively impact the metallic layers.

12/31/2010

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