INSTALLATION OF ROTATING-MACHINERY SKIDS ON OFFSHORE STRUCTURES INTERFACE AND STRUCTURAL ASPECTS

摘要

One of the most important aspects, to be considered, in the offshore installation of turbomachinery and reciprocating compressors is the interface between the machine skid and the main structure. The whole structural design is to be such that under the most severe static and dynamic loads the machine alignment and the vibrations are maintained to acceptable levels either if the rotating machinery is installed in a module or directly on the platform deck. There are two structural solutions to achieve the above conditions and they are: the multipoint skid, typically used when the structure stiffness allows it, and the three point supported skid that is used whenever the main structure displacements are too high for the conventional baseplates. Both multipoint and three point skids have been studied to accommodate different types of driver and driven machines. To assure the suitability of the baseplates against the several operating conditions its design is carried out by applying a finite element analysis either in static or dynamic conditions considering the simulation of the machine effects and the stiffness characteristics of the main structure. The purpose of this paper is to illustrate the Nuovo Pignone criteria and experiences of designing machine skids suitable for the most severe operating conditions, maintaining reliability, availability and operability of the units. Moreover a description of reciprocating compressors named "SHMB" designed for offshore application which minimize the dynamic loads and, consequently, the induced vibrations is included.