FROM DESIGN ASPECTS THROUGH TO TESTING OF THE MAN DIESEL TURBO SUBSEA MOTOR-COMPRESSOR FOR THE ASGARD SUBSEA PROJECT

摘要

This paper outlines pioneering work in the field of subsea compressor technology. The guiding design principles for the subsea motor-compressor of the authors' company were operational safety, robustness, reliability, and remote operability. An early demonstrator was realized and tested in collaboration with the end-user upfront and consecutively improved gradually where indicated. This turned out to be beneficial in the phase of project execution since the early knowledge of application specific requirements resulted in an already elaborated overall design basis. The presented design also draws on extensive top side experience from sealed motor-compressors, where a portion of the process gas is taken directly from an intermediate stage of the compressor and fed back to the suction line after passing through, and thus cooling, the motor and the active magnetic bearings. This minimizes the number of interfaces and required sub-systems. Various simulations were performed to account for differences between subsea and topside environments. The focus of the work presented in this paper is on the effect of the high heat transfer resulting in an altered overall temperature situation. At the time of writing, the first units of the discussed subsea motor-compressor have successfully passed Factory Acceptance Testing (FAT) under atmospheric conditions. At the moment, they are being prepared for extended submerged testing with production gas at a test facility of the end-user.