Subsea centrifugal compressor with horizontal shaft and with only one axial thrust bearing

Abstract

A centrifugal compressor unit including a motor having a rotor, at least one compressor having a shaft driven by the rotor; and a set of bladed wheels fitted on the driven shaft, the motor and the compressor being mounted in a common watertight casing. It further includes cooling means for cooling the motor, the cooling means having a gas cooler outside the casing. In operation, the motor, the compressor and the casing having the motor and the compressor are arranged horizontally, one axial thrust bearing only being provided on a compressor side.

Description

BACKGROUND OF THE INVENTION[0001]Embodiments of the invention relate to a turbocompressor or a motor compressor, and particularly to an integrated motor compressor unit.[0002]More particularly, embodiments of the present invention relate to a motor compressor unit for subsea applications.[0003]Motor compressor units of the integrated type comprise a motor means, generally an electric drive motor, and a compressor having one or more compression stages, depending on the applications, the motor means and the compressor being mounted in a common casing that is sealed against the gas handled by the compressor unit.[0004]Each compression stage comprises a bladed impeller mounted on a shaft driven by a rotor, which is driven by the motor means.[0005]According to the state of the art, when used under special operating conditions, especially for underwater operations, the motor compressor is usually arranged vertically to facilitate draining of the interior of the casing.[0006]A compressor u...

AI Technical Summary

Benefits of technology

The present invention provides a centrifugal compressor unit for subsea applications that overcomes the problem of axial displacement of the bladed wheels mounted on the compressor shaft. This means that the compressor can operate more efficiently and with less wear and tear.

Problems solved by technology

However, this type of arrangement in which the rotor is axially supported by one thrust bearing has the disadvantage that the coupling between the rotor of the motor and the compressor shaft may be prejudicial to the accuracy of the axial position of the rotating elements of the compressor which may impact the motor compressor efficiency, in particular during transient phases.

This problem may in particular incur at high loads, due to a thermal expansion of the compressor shaft driven by the motor means and may arise for compressor units having a high pressure ratio, namely above 3, and having an increased number of compression stages, equal or higher than 3.

Such an arrangement does not permit, however, to increase the number of the compression stages such that the motor compressor unit cannot be equipped with more than three compression stages.

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