Application and Control of Variable Speed Centrifugal Compressors in The Oil and Gas Industry

Centrifugal Compressors in the Oil and Gas Industry frequently use electric motors as drivers. Due to the high variability in process conditions users often specify variable speed electric motors, which allow the variation of the compressor speed over a wide range.The paper discusses the interaction between a centrifugal compressor and the process, and as a result, the control requirements for centrifugal compressor packages. The focus is on variable speed, upstream and midstream applications. The impact of the interaction between system characteristics and compressor characteristics, both under steady state and transient conditions, is explained. Also considered are concepts to optimize and control the units. Special attention is given to the specific speed-torque characteristics of variable frequency drive electric motors and variable speed hydrodynamic drives.Additionally, the impact of the process and how the process dynamics interact with the compressor is analyzed, categorized, and explained.