Nuovo Pignone Spa

Nuovo Pignone Srl

Nuovo Pignone Tecnologie Srl

David Rossi

Lorenzo Gallinelli

Daniele Galeotti

Laurence Casali

Alessio Cacitti

The compressor system comprises a compressor having first compressor stage and a second compressor stage in a back-to-back arrangement. A first gas flow is provided at the suction side of the compressor. A seal arrangement is provided between the first compressor stage and the second compressor stage. A side stream line is in fluid communication with the suction side of the second compressor stage. A side stream valve on the side stream line and a side stream controller are provided, for adjusting the flow of the second gas. An antisurge arrangement comprised of a bypass line and an antisurge valve is arranged at the first compressor stage for preventing surge of the first compressor stage. The side stream controller is configured for reducing the flow of the second gas when an alteration of the pressure ratio across the first compress stag is detected.

Method and system for operating a back-to-back compressor with a side stream

A method for detecting rotating stall in a compressor is disclosed herein. The method comprises measuring radial vibration of the rotor relative to the stator and generating a vibration measurement signal, calculating a frequency spectrum of the vibration measurement signal, identifying a plurality of frequency bandwidths of the frequency spectrum, neglecting one first frequency bandwidth of the plurality of frequency bandwidths if the rotation frequency of the rotor falls within the first frequency bandwidth, neglecting at least one second frequency bandwidth of the plurality of frequency bandwidths if the rotation frequency of the rotor falls below the second frequency bandwidth, determining the maximum magnitude of the spectrum in each of the non-neglected frequency bandwidths, and comparing each determined maximum magnitude and a predetermined value. Rotating stall is considered occurring if at least one of the comparisons shows that the corresponding determined maximum magnitude is greater than the predetermined value.

Method and equipment for detecting rotating stall and compressor

A method of decreasing a transition time through a speed range that is unsafe for an integrity of a first expander, by automatically biasing a speed of a second expander that receives a fluid flow output from the first expander is provided, when the current speed of the first expander is within a bias application range. The method includes setting the speed of the second expander to be larger than a current speed of the first expander when the current speed of the first expander increases and is smaller than a first speed value, or decreases and is smaller than a second speed value, and setting the speed of the second expander to be smaller than the current speed of the first expander, when the current speed of the first expander increases and is larger than the first speed value or decreases and is larger than the second speed value.

Methods and devices used for automatically controlling speed of an expander

A method of controlling a transition time through a speed range that is unsafe for an integrity of a second expander that receives a fluid flow from a first expander, by automatically biasing a speed of the second expander is provided. The method includes setting the speed of the second expander to be smaller than a current speed of the first expander. The method also includes setting the speed of the second expander to be larger than the current speed of the first expander, when the current speed of the first expander is within the bias application range, and the current speed of the second expander increases and is larger than the first speed value, or decreases and is larger than the second speed value.

Growing community of inventors

Florence, Italy

David Rossi