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A surge controller, a gas compression system comprising a surge controller, and a method for controlling a gas compression system to prevent the occurrence of surge.

IP.com Disclosure Number: IPCOM000244608D
Publication Date: 2015-Dec-28

Publishing Venue

The IP.com Prior Art Database

Abstract

A surge controller (6) for a gas compression system (4) comprising a compressor (10) and a method for controlling the gas compression system are disclosed. The surge controller is adapted to receive measured values of system parameters (Q,P1,P2,T1,T2,) of the gas compression system and to detect a surge situation 5 based on the measured values of the system parameters and current value of at least one control parameter (CP) for the gas compression system. The surge controller comprises: a simulator unit (22) configured to run simulations of the gas compression system based on a model of the gas compression system, and to repeatedly during operation of the gas compression system predict the state of the 10 gas compression system at a future point in time based on the received measured values of system parameters and the current value of the control parameter, and to provide predicted values of the system parameters at said future point in time; and a control part (20) adapted to detect a surge situation based on said predicted values of the system parameters, and upon detecting a surge situation to determine a new value for the control parameter. 15

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A surge controller, a gas compression system comprising a surge controller, and a method  for controlling a gas compression system to prevent the occurrence of surge. 
 

Field of the invention 

The  present  invention  relates  to  a  surge  controller  for  a  gas  compression  system.  The 

present  invention  also  relates  to  a  gas  compression  system  comprising  such  a  surge  controller, and a method for controlling a gas compression system to prevent the occurrence  of a surge in the compression system. The present invention further relates to the use of a  surge controller for a subsea gas compression system. The present invention is suitable for  use in subsea oil and gas production systems.  

 

Background and prior art 

Compressors  are  widely  used  in  industrial  applications  to  compress  gas.  Centrifugal  compressors, sometimes referred to as radial compressors, are one of the most commonly  used for gas compression. A centrifugal compressor includes a rotating wheel, also called an 

impeller, for increasing the velocity of the gas. The compressor wheel is drivingly connected  via a shaft to a motor. A centrifugal compressor is a sort of dynamic compressor. It is known  that the operation of dynamic gas compressor systems can become unstable due to changes  in various operating conditions, for example flow rate or pressure. A phenomenon known as  compressor surge can occur. Surge is characterized by violent changes in the speed of the 

compressor with highly increased noise and vibration of the compressor. During surge the  flow reverses through the compressor and gives rise to pressure fluctuations of very high  amplitude  that  may  be  50  to  100  %  of  the  pressure  ratio.  The  speed  at  which  the  flow  reverses  and  recovers  is  primarily  a  function  of  the  volume  of  the  compression  system.  Compressor  surge  condition  can  lead  to  vibration  in  the  compressor  shaft  and  serious 

damage to the compressor. The surge phenomenon is inherent in all dynamic compressor  systems. 
 

Operation  of  centrifugal  gas  compressors  can  be  defined  by  speed,  head  and  flow.  Centrifugal compressors have a maximum head that can be achieved at a given speed. At 

that  maximum  head  there  is  a  corresponding  flow.  This  is  a  stability  limit.  The  system  is  stable as long as reductions in head result in increases in flow. Surge occurs when the peak  head capability of the compressor is reached and flow is further reduced. When a centrifugal  compressor  approaches  its  surge ...