Demonstration of the Rotordynamic Effects of Centrifugal Liquid Separation and Gas Compression in an Oil-free Integrated Motor-compressor

The application of oil-free-integrated motor-compressors has become increasingly popular in recent years. One of the significant features of this class of machinery is compactness, providing space-savings compared to traditional-oil-lubricated compressors with associated gearboxes and lubrication systems. The integration of a turbo separator with such a compressor has resulted in the creation of a new class of turbomachinery promising even greater system compactness. This new machine type provides further size reduction benefits through the elimination of large static separation vessels often required on traditional compressor trains. A compressor manufacturer has successfully developed a centrifugal compressor with integrated turbo separator from design, development, and prototype testing on a demonstration rig through to manufacture, testing, and shipment of a production unit. This paper focuses on the details and results of the testing performed at the manufacturer’s factory that confirmed the soundness and acceptability of the design. Rigorous testing of the demonstration rig has confirmed acceptable rotordynamic performance including stable operation over a wide range of operating pressures and liquid injection rates. The rotordynamic performance of this machinery type has been demonstrated to be virtually insensitive to liquid injection.