The active heave compensators and deck mating & removal systems developed by Bosch Rexroth are characterized by sophisticated combinations of measuring and control technology and reliable hydraulics and are successfully applied on a worldwide level. The Bosch Rexroth deck mating concept is modular, allowing for systems that can be built quickly and economically in any desired capacity and configuration.
In the case of Nigeria, the topside was produced in Korea by Hyundai Heavy Industry for the Escravos Gas Project EGP-3A, and was brought to position by means of a float-over procedure. The system applied for the EGP-3A consists of 4 stand alone 1,655-ton Deck Mating Modules (DMM's), controlled by the central control system. Each DMM is comprised of an HPU, two 825-ton cylinders with an integrated measuring system and first-rate ceramic rod coating (Ceramax), a local control panel, a fast retract N2-system and interfacing piping. The design criteria were: a SWL of 4,400 tons, a maximum lifting height of 8 feet, a synchronized lifting speed of 0.1 cm/sec, a maximum loaded lowering speed of 4 cm/sec and an unloaded fast retraction speed of 4 cm/sec over 8 feet.
Both in the drive system and the control system much attention is paid to increased safety through over-capacity, redundancy, synchrony of the cylinders, extra sensors and transmitters and advanced control loops with periodic system checks. Even in case of cylinder failure the operation can be completed safely and accurately.
The season during which, in the offshore world, topsides can securely and economically be placed or removed on the open seas can be drastically extended thanks to the modular deck mating systems developed by Bosch Rexroth. Sophisticated hydraulic technology makes it possible to, also in case of heavy seas, place topsides on the piles of offshore platforms with great precision. Where hydraulics are concerned, there are factually no restrictions with regard to the dimensions and weight of the topside while the modular composition implies that deck mating and removal vessels can be deployed in a broader and far more economical manner.
Later in 2007, a larger Bosch Rexroth system will be utilized for the float over of a 13,225-ton topside for the EPC-1B project in the East Area Gas field.
As a system integrator and hydraulics manufacturer Bosch Rexroth has over 50 years of experience in the elimination of the adverse effects of wave movements in offshore applications. Bosch Rexroth's Offshore & Dredging division is particularly engaged in the development of solutions for the oil and natural gas industry (offshore), the dredging industry and the maritime sector.
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