Valves in action -
Pressure reducing valve DM 618
Compressed air reduction for deep-sea oil drilling
One effect of the increasing shortfall of oil resources expected for the future is the upward tendency for expanding offshore oil and gas activities into much deeper waters. Deep-sea oil deposits such as the supergiant fields at the continental margin off the Brazilian coast are very difficult to access since they are located below a water depth of up to 3,000 m and are coated by a several kilometres thick seabed, partly also below salt crusts. The exploration and development of such ultra-deep deposits require technically sophisticated oil drilling and production ships. One such is the deep-sea drilling ship of a big Italian company that can place drillholes up to 3,000 m below the surface of the water by reaching drilling depth of nearly 10,000 m. It can be held in position during such difficult drilling procedures thanks to its satellite controlled dynamic positioning system, a hydro-acoustic reference system and six azimut thrusters. In addition, a computerised system corrects the effects of wind, waves, and currents in realtime.
TASK // Compressed air reduction in highly corrosive maritime atmosphere
The drilling ship can process approx. 20,000 barrels of crude oil per day and bunker up to 140,000 barrels in her tank system in the double hull. The storage, cleaning and transhipment of the produced crude oil as well as various drive units, control and back-up systems on board require compressed air for operation. The compressed air tanks have a service pressure of 8 bar whilst the downstream systems are operated at 5 bar only. Pressure reducing valves ensure pressure reduction to reach the required network pressure.
SOLUTION // Self-acting pressure reducing valve DM 618
The self-acting DM 618 reduces the pressure downstream of the compressed air tank. The diaphragm-operated and spring-loaded proportional valve is balanced and designed for high flow rates. Its compact design is the perfect solution for use in the confined space on the ship. The cast steel body of GS-C 25/A216WCB and the internal parts, diaphragm casing and spring cap, all made from stainless steel (316L), are ideally suited to withstand harsh maritime atmospheres.
