Online performance tracking and load sharing optimization for parallel operation of gas compressors

• Performance tracking algorithm for centrifugal gas compressors.
• Parameter estimation using constrained least-squares with moving data windows.
• Load sharing optimization for parallel compressors with varying performance models.
• Significant fuel savings indicated by field data from a compression station.

Compressor stations on natural gas pipelines are typically composed of multiple parallel compressors for operational flexibility. The aim of load sharing optimization is to operate the compressor units of a gas compression station in an energy efficient way while satisfying the varying gas demand. This paper presents a problem formulation for compressor load sharing optimization, as well as a novel method to track the performance characteristics of gas compressors using thermodynamic models and historical operating data. An implementation of the proposed algorithm together with a dedicated case study concerning a station with 10 gas turbine driven compressor units are presented. The optimization results, which are based on simulations with actual operating data spanning over a 1 year duration, indicate an annual fuel saving potential of over 5% potentially leading to improved profitability and to a significant reduction of CO2 emissions from the gas turbine drivers.