24"/900 HIPPS for a pipeline landfall

Mokveld HIPPS skid installed at Cruden Bay to protect the pipeline against over-pressurisation.

The 500km Forties Oil and Gas Pipeline System (FPS), in the UK, forms the main artery for gas and oil transportation in the UK, moving 600,000 barrels of oil a day, about 40% of the UK’s production.

The FPS 36 inch diameter subsea pipeline extends from the Forties Charlie platform via the Forties Unity platform to a landfall at Cruden Bay on the North East Coast of Scotland, a distance of 169 kilometres. From there, the FPS landline, again 36 inch diameter, travels 209 kilometres south to the Kinneil Terminal at the Kerse of Kinneil, Grangemouth via three pumping stations at Cruden Bay, Netherley and Brechin which provide booster compression

To protect the pipeline against over-pressurisation, Mokveld was awarded to supply a High Integrity Pressure Protection Systems-skid (HIPPS). Due to the critical role of the FPS line the operator is committed to reliability and availability. Mokveld’s reputation and proven track record made Mokveld the supplier for this safety system; the Mokveld HIPPS installed base totals close to 5.000 valves and close to 50.000 operational years and is therefore proven-in-use for high reliability safety applications.

As HIPPS integrator Mokveld designed, manufactured, assembled and assessed the HIPPS skid. The skid comprises of two 24” class 900 Mokveld axial on-off valves with integrated actuators as final elements, as well as three separate 2” pressure sensing points to feed in to 3 Astava manifolds. Lastly the HIPPS skid is integrated with a Sella Controls Hima Logic Solver.

The HIPPS skid is placed between the transition of the upstream sea line and the downstream landline to protect the Cruden Bay terminal and downstream pipeline against overpressure events. The FPS changes in pipe specification between the sea line and landline sections, dropping 80barg. This transition in piping specification introduces a high severity potential hazard in which a blocked outlet on the landline section can cause a pressure rise and potentially catastrophic failure of the landline. The HIPPS skid is fully independent, self-contained and provides SIL 3 protection yet its testing regime doesn’t require the existing pipeline shutdown frequency to be increased.

The design of this HIPPS skid required, next to the safety engineering, practical thinking and out of the box solutions. Transportation of this skid is, due to its size, challenging. The skid was transported by road and at site had to be installed next to and between existing equipment. Therefore Mokveld adapted the design within tight dimensional limits to allow easy passage of the carrier.

  • Country: United Kingdom
  • Business area: Transmission
  • Application: 2oo3 HIPPS skid
  • Size and rating: 24" ASME 900

Product support

In order to ensure you continue to benefit from valves that offer high capacity and safety as standard, we offer a range of modernisation services. For more information about our modernisation services, please contact your Mokveld support office or representative.